CN108736491B

CN108736491B - Method and system for evaluating optimal energy storage capacity in power system frequency modulation field

Info

Publication number: CN108736491B
Application number: CN201810443825.9A
Authority: CN
Inventors: 杨水丽; 王金浩; 常潇; 雷达; 肖莹; 朱燕芳; 王澍; 王琤; 马会萌; 李相俊
Original assignee: Electric Power Research Institute of State Grid Shanxi Electric Power Co Ltd; China Electric Power Research Institute Co Ltd CEPRI
Current assignee: Electric Power Research Institute of State Grid Shanxi Electric Power Co Ltd; China Electric Power Research Institute Co Ltd CEPRI
Priority date: 2018-05-10
Filing date: 2018-05-10
Publication date: 2021-08-31
Anticipated expiration: 2038-05-10
Also published as: CN108736491A

Abstract

The invention discloses an evaluation method of energy storage optimal capacity in the field of frequency modulation of a power system, which comprises the following steps: establishing an energy storage output power model, and determining the adjustable capacity of energy storage according to the energy storage output power model; establishing an output power model of a conventional unit, and determining the adjustable capacity of the conventional unit according to the output power model of the conventional unit; establishing a frequency modulation scheduling strategy model, and carrying out capacity adjustment on the energy storage or conventional unit according to the required frequency modulation capacity of the power system and the adjustable capacity of the energy storage or the adjustable capacity of the conventional unit; establishing a frequency modulation compensation rule model, and determining the total compensation amount of the energy storage or conventional unit according to the frequency modulation compensation rule model; setting capacity proportion of energy storage; establishing a frequency modulation time sequence simulation model, establishing a simulation algorithm input database, and performing frequency modulation time sequence simulation according to the capacity ratio of the stored energy; and calculating the total frequency modulation compensation cost of all conventional units and stored energy in a typical frequency modulation day according to the data in a certain time period.

Description

Method and system for evaluating optimal energy storage capacity in power system frequency modulation field

Technical Field

The invention relates to the technical field of power system frequency modulation, in particular to a method and a system for evaluating optimal energy storage capacity in the field of power system frequency modulation.

Background

With the gradual expansion of the proportion of intermittent performances such as wind power, solar energy and the like in a power grid, the frequency modulation of a power system faces more and more serious challenges, and a novel electric energy storage technology is gradually entering the power system mainly relying on a thermal power generating unit to provide frequency modulation service. The optimal capacity of the electrical energy storage to provide frequency modulation services in the power system is an important consideration for the power system. Intermittent energy refers to energy generated discontinuously by solar energy, wind energy and the like, and the randomness, uncertainty and other characteristics of wind energy and solar energy can cause the voltage and frequency of electric energy provided by the intermittent energy to fluctuate, so that the large-scale use of the intermittent energy is limited. The electric power auxiliary service is an essential service developed for ensuring safe and stable operation and power supply quality of an electric power system, and international definition of contents included in the auxiliary service is not uniform, but generally includes: primary frequency modulation, secondary frequency modulation (AGC service), standby, reactive compensation, black start and the like. According to the relevant regulations of 'grid-connected power plant auxiliary service management temporary method' published by the electric prisoner in 2006, electric power auxiliary services in China are divided into two main categories, namely basic auxiliary services and paid auxiliary services. The basic auxiliary services comprise primary frequency modulation, basic peak regulation, basic reactive power regulation and the like; paid ancillary services include Automatic Generation Control (AGC), paid peak shaving, standby, paid reactive regulation, black start, and the like. The basic service is provided by the generator set, compensation is not carried out, and the compensation auxiliary service is required. The frequency of the power system, which is one of the main indicators of the quality of electric energy, is defined as the number of repetitions of a fundamental voltage waveform measured at a predetermined time interval, and reflects the balance relationship between the generated active power and the load. Each country will set a reference frequency according to the actual situation of the power grid in the country, for example, the reference frequency of the east power system in china, europe, australia and japan is 50HZ, and the reference frequency of the west and west power systems in north america and japan is 60 HZ.

The frequency modulation of the power system is that the frequency cannot be constantly kept in a reference frequency state in the actual operation of the power system, and when the power of a motor and the load power in the power system are changed, the frequency of the power system is inevitably changed. The deviation of the frequency is not beneficial to the safe and efficient operation of power utilization and power generation equipment, and even damages the equipment under certain conditions, so that the frequency adjustment is necessary after the deviation of the system frequency exceeds the allowable range of the deviation in China, which means the frequency adjustment. Power system frequency modulation is one type of power service and includes primary frequency modulation, secondary frequency modulation (AGC),

the Automatic Generation Control (AGC) changes the load frequency characteristic of the generator set by each regional power grid depending on a centralized computer control system, thereby achieving the purpose of restoring the system frequency to the initial state and realizing the adjustment without difference. The response time of AGC adjustment of a thermal power generating unit generally needs 1-2 minutes. The Chinese unit provides AGC frequency modulation auxiliary service, and income can be obtained according to the auxiliary service implementation rule of each regional power grid.

Energy storage, defined by the International Electrotechnical Commission (IEC), is stored in a device or physical medium and released when needed. The reports mainly discuss the storage of electrical energy in an electrical power system, i.e. electricity in the electrical power system is converted into some form of energy to be stored, converted back into electrical energy when needed, or still directly applied as some form of energy. Energy storage is mainly classified into five categories by IEC, which are: machinery, including pumped storage, compressed air storage, flywheel storage; the electrical class, which includes supercapacitors that store energy in an electric field and superconducting energy storage that stores energy in a magnetic field; electrochemistry, including various secondary chemistries, specifically lithium ion batteries, lead storage batteries, molten salt batteries, and flow batteries; thermal energy storage, including high-temperature molten salt heat storage, ice cold storage, energy storage by adopting phase change materials and thermochemical materials and the like; and chemicals, such as hydrogen energy, synthetic natural gas and the like, are used as secondary energy carriers to store energy in chemical fuels.

And (4) an energy storage output power model. The method refers to a charging and discharging power setting strategy and a charging and discharging duration strategy when the stored energy is charged or discharged after receiving a system frequency modulation instruction.

The signals sent by the power grid to the energy storage are divided into positive and negative signals. If the signal value is positive, the stored energy is discharged, and the system power is increased. If the signal is negative, the energy is stored for charging operation, and the system power is reduced; after receiving the power grid frequency modulation signal, the stored energy judges whether the stored energy is in a frequency modulation invoked state, if the stored energy is in the invoked state, namely the last power grid frequency modulation command is in execution, the stored energy does not respond to the power grid frequency modulation signal; after the stored energy receives the power grid frequency modulation signal, judging that the stored energy is not in a frequency modulation and modulated use state, and responding to the frequency modulation signal; and if the grid frequency modulation signal is positive, determining the energy storage discharge and outputting the power. And comparing the target power of the frequency modulation signal of the power grid with the rated power of the stored energy, taking the smaller value of the target power and the rated power of the stored energy as the output power of the stored energy, and carrying out discharge operation according to the output power of the stored energy within 1 second.

The energy storage discharge power is min (frequency modulation signal target power, energy storage rated power)

And calculating the theoretical longest discharge time of the stored energy in the state, if the duration of the frequency modulation signal exceeds the longest discharge time (namely the stored energy of the energy storage system is exhausted, and the frequency modulation signal is still in duration), stopping discharging the stored energy, and switching the state to charge at 20% rated power until the stored energy is fully charged by 100% or the next regulating instruction comes. And if the duration time of the frequency modulation signal is less than the minimum discharge time, finishing the response of energy storage, stopping discharging, and converting to 20% rated power for charging until the next adjustment instruction comes. As shown in fig. 2 and 3.

And the power grid frequency modulation signal is negative, and the stored energy is used for charging operation. And comparing the absolute value of the target power of the frequency modulation signal of the power grid with the rated power of the stored energy, taking the smaller value of the absolute value and the rated power of the stored energy as the charging power of the stored energy, and charging the stored energy according to the power within 1 second.

The energy storage charging power is min (| target power of frequency modulation signal |, rated power of energy storage)

And calculating the theoretical longest charging time of the stored energy in the state, and if the duration of the frequency modulation signal exceeds the longest discharging time (namely the stored energy system is full of electric quantity, and the frequency modulation signal is still in duration), stopping charging the stored energy, and keeping the output power at 0 in a standby state until the next instruction comes. And if the duration time of the frequency modulation signal is less than the longest discharge time, finishing the response of energy storage, converting the output power to 0, and keeping in a standby state until the next instruction comes. As shown in fig. 4 and 5.

However, in the prior art, the evaluation of the optimal energy stored in the frequency modulation field of the power system cannot be realized.

Therefore, a technology is needed to realize an evaluation technology for the optimal energy storage capacity in the power system frequency modulation field.

Disclosure of Invention

The technical scheme of the invention provides an evaluation method and system for the optimal energy storage capacity in the frequency modulation field of a power system, and aims to solve the problem of how to evaluate the optimal energy storage capacity in the frequency modulation field of the power system.

In order to solve the above problem, the present invention provides a method for evaluating an optimal energy storage capacity in a frequency modulation field of an electric power system, wherein the method comprises:

establishing an energy storage output power model, and determining the adjustable capacity of the stored energy according to the energy storage output power model;

establishing a conventional unit output power model, and determining the adjustable capacity of the conventional unit according to the conventional unit output power model;

establishing a frequency modulation scheduling strategy model, and adjusting the capacity of the energy storage unit or the conventional unit according to the required frequency modulation capacity of the power system and the adjustable capacity of the energy storage unit or the adjustable capacity of the conventional unit;

establishing a frequency modulation compensation rule model, and determining the compensation total of the energy storage unit or the conventional unit according to the frequency modulation compensation rule model;

setting the capacity ratio of the stored energy;

establishing a frequency modulation time sequence simulation model, establishing a simulation algorithm input database, and performing frequency modulation time sequence simulation according to the capacity ratio of the stored energy: adjusting active power of the power system according to the area control deviation ACE of the power system, determining the frequency modulation requirement of the power system, determining the distribution mode of the active power according to the frequency modulation requirement, and sending a frequency modulation instruction to the energy storage or the conventional unit participating in frequency modulation; simulating a response curve of the energy storage unit or the conventional unit to respond to the load frequency; selecting a typical frequency modulation day, and recording power data of all the conventional units and the stored energy in a certain time period in the typical frequency modulation day; and calculating the total frequency modulation compensation cost of all the conventional units and the stored energy in the typical frequency modulation day according to the data in the certain time period.

Preferably, the method further comprises:

and adjusting the capacity ratio of the stored energy, and calculating the total frequency modulation compensation cost of all the conventional units and the stored energy in the typical frequency modulation day according to the adjusted capacity ratio of the stored energy.

Preferably, the method further comprises:

and selecting the capacity ratio of the stored energy corresponding to the minimum total frequency modulation compensation cost in the total frequency modulation compensation costs of all the conventional units and the stored energy in the typical frequency modulation day as the optimal capacity.

Preferably, the establishing a simulation algorithm database includes: and determining the adjustable capacity of the stored energy, the adjustable capacity of the conventional unit, the grid frequency data of the power system and the net load.

Preferably, the payload comprises: load, tie line power, and renewable energy generation capacity.

Preferably, the establishing of the energy storage output power model includes:

after receiving a frequency modulation signal of a power system, the energy storage judges whether the energy storage is in a frequency modulation and utilization state, and if the energy storage is in the frequency modulation and utilization state, the energy storage does not respond to the frequency modulation signal of the power system;

if the stored energy is not in a frequency modulation and use state, receiving a current frequency modulation signal of the power system;

comparing the target power of the power system frequency modulation signal with the rated power of the stored energy, and taking the smaller value of the target power and the rated power as the output power of the stored energy, wherein the output power is as follows:

the output power of the stored energy is min (the target power of the frequency modulation signal and the rated power of the stored energy)

Calculating the energy storage theoretical longest discharge time: when the duration time of the frequency modulation signal exceeds the longest discharge time, the stored energy stops discharging, the state is switched, and the stored energy is charged at 20% of rated power until the stored energy is fully charged by 100% or the next frequency modulation instruction comes;

when the frequency modulation signal of the power system is negative, the stored energy is charged; judging the absolute value of the target power of the frequency modulation signal of the power system and the rated power of the stored energy, taking the smaller value of the absolute value and the rated power of the stored energy as the charging power of the stored energy, and charging the stored energy according to the power within 1 second;

Calculating the theoretical longest charging time of the stored energy in the state, stopping charging the stored energy when the duration of the frequency modulation signal exceeds the longest discharging time, and keeping the output power at 0 in a standby state until the next frequency modulation instruction comes;

preferably, the establishing of the conventional unit output power model includes:

after receiving a frequency modulation signal of the power system, the conventional unit judges whether the conventional unit is in a frequency modulation modulated state, and if the conventional unit is in the frequency modulation modulated state, the conventional unit does not respond to the current frequency modulation signal of the power system;

if the conventional unit is not in a frequency modulation and utilization state, receiving a current frequency modulation signal of the power system;

after the conventional unit receives the decision of the frequency modulation signal, when the target power value of the frequency modulation signal is greater than the current running power of the conventional unit, the load-increasing operation is carried out, and the power output of the conventional unit is increased; if the target power value of the frequency modulation signal is smaller than the current running power of the conventional unit, the load reduction operation is performed, and the power output of the conventional unit is reduced;

when the conventional unit is in load-increasing operation, the target output power of the conventional unit is set to be the smaller value of the target power of the frequency modulation signal and the rated power of the conventional unit;

set load-up target output power min (frequency modulation signal target power, set rated power)

When the conventional unit is in load reduction operation, the target output power of the conventional unit is set to be the maximum value of the target power of the frequency modulation signal and the minimum running power of the conventional unit;

the unit load reduction target output power is max (frequency modulation signal target power, minimum operating power of the unit)

And the load ascending and load descending rates of the conventional unit are respectively set according to different conventional unit types.

Preferably, the establishing a frequency modulation scheduling policy model includes:

determining a required frequency modulation capacity (MW) of the power system;

analyzing the conventional unit in existing operation and the adjustable capacity (MW) of the stored energy;

and calling the running conventional units or the energy storage units in sequence according to the principle that the regulation performance (Kpd) is from high to low until the total calling capacity meets the frequency modulation capacity required by the power system.

Preferably, the establishing a frequency modulation compensation rule model includes:

the frequency modulation compensation rule is calculated according to the following formula:

r_ij＝D_ij×Kpd_ij×P

wherein:

a.r_ijthe compensation sum of the conventional unit or the stored energy i on the j day;

b.D_ijthe total adjustment depth of the conventional unit or the energy storage i on the j day is the absolute value of the difference value between the response end point output P and the response front output P' of the conventional unit or the energy storage i when the conventional unit or the energy storage is subjected to response adjustment once, and the arithmetic sum of the adjustment depths of all adjustment times n in the whole day is D for the adjustment depth of the response_ijThe calculation is as follows:

c.Kpd_ijthe regulation performance of the conventional unit or the energy storage i on the j day is regulated by a regulation rate index K₁And an adjustment accuracy index K₂Response time index K₃The three indexes jointly determine that the adjustment performance of the conventional unit or the stored energy i in the k adjustment on the j day is calculated as follows:

the adjustment performance throughout the day is taken as the calculated average of all adjustment performance, and if the day is not called, the adjustment performance is taken as 1:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

V_Nistandard regulation rate, V, of the conventional unit or the stored energy specified for the system_ijkFor the actual rate of regulation of the conventional unit or of the stored energy, the regulation depth for the kth regulation is Δ MW_ijkThe time taken to reach the target regulation point after receiving the instruction is Δ T_ijkAnd then:

ΔP_ijkafter the target output is reached, in a response period, the actual P of the conventional unit_ijk(t) target force P_ijkThe average value of the difference between the two is recorded as the time T when the target output is reached₀At the end of the regulation period, it is recorded as time T₁Then the adjustment deviation amount for the kth adjustment is calculated as:

the allowable deviation value of the regulation is 1 percent of the rated active power of the conventional unit or the stored energy, delta t_ijkAfter receiving a secondary frequency modulation signal AGC instruction of the power system, the conventional unit or the energy storage unit increases or decreases the time consumed when the load exceeds 1% of the rated power of the conventional unit or the energy storage unit in the correct direction;

d.P is the frequency modulation compensation standard (element/MW), and P is 6-12 element/MW.

Preferably, the capacity ratio of the stored energy is 0% to 100%, and the capacity ratio of the stored energy is adjusted to increase by 1% each time.

According to another aspect of the present invention, there is provided a system for evaluating an optimal energy storage capacity in a frequency modulation domain of a power system, the system comprising:

the first establishing unit is used for establishing an energy storage output power model and determining the adjustable capacity of the stored energy according to the energy storage output power model;

the second establishing unit is used for establishing a conventional unit output power model and determining the adjustable capacity of the conventional unit according to the conventional unit output power model;

a third establishing unit, configured to establish a frequency modulation scheduling policy model, and perform capacity adjustment on the stored energy or the conventional unit according to a required frequency modulation capacity of an electric power system, and the adjustable capacity of the stored energy or the adjustable capacity of the conventional unit;

the fourth establishing unit is used for establishing a frequency modulation compensation rule model and determining the total compensation amount of the energy storage unit or the conventional unit according to the frequency modulation compensation rule model;

the setting unit is used for setting the capacity ratio of the stored energy;

the fifth establishing unit is used for establishing a frequency modulation time sequence simulation model, establishing a simulation algorithm input database, and performing frequency modulation time sequence simulation according to the energy storage capacity ratio: adjusting active power of the power system according to the area control deviation ACE of the power system, determining the frequency modulation requirement of the power system, determining the distribution mode of the active power according to the frequency modulation requirement, and sending a frequency modulation instruction to the energy storage or the conventional unit participating in frequency modulation; simulating a response curve of the energy storage unit or the conventional unit to respond to the load frequency; selecting a typical frequency modulation day, and recording power data of all the conventional units and the stored energy in a certain time period in the typical frequency modulation day; and calculating the total frequency modulation compensation cost of all the conventional units and the stored energy in the typical frequency modulation day according to the data in the certain time period.

Preferably, the setting unit is further configured to:

Preferably, the device further comprises a selection unit for:

Preferably, the fifth establishing unit is further configured to establish a simulation algorithm database, where the simulation algorithm database includes: and determining the adjustable capacity of the stored energy, the adjustable capacity of the conventional unit, the grid frequency data of the power system and the net load.

Preferably, the first establishing unit is configured to establish an energy storage output power model, and includes:

preferably, the second establishing unit is configured to establish a conventional unit output power model, and includes:

Preferably, the third establishing unit is configured to establish a frequency modulation scheduling policy model, and includes:

determining a required frequency modulation capacity (MW) of the power system;

Preferably, the fourth establishing unit is configured to establish a frequency modulation compensation rule model, and includes:

r_ij＝D_ij×Kpd_ij×P

wherein:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

The technical scheme of the invention provides an evaluation method and system for energy storage optimal capacity in the field of frequency modulation of a power system, and belongs to the field of analysis and calculation of the power system. The evaluation method is based on a time sequence simulation model and comprises the following steps: establishing an energy storage output power model; establishing a conventional generator set output power model; establishing a frequency modulation scheduling strategy model; establishing a frequency modulation compensation rule model; establishing a time sequence simulation model; establishing a simulation algorithm input database; aiming at the frequency modulation capacity ratios of different energy storages and conventional generator sets, carrying out frequency modulation time sequence simulation and calculating the total frequency modulation compensation of the system; and analyzing the simulation result to obtain the frequency modulation capacity ratio of the optimal energy storage to the conventional generator. The technical scheme of the invention is used for determining the optimal energy storage capacity of the secondary frequency modulation (AGC) of the system. The technical scheme of the invention adopts a time sequence simulation means and measures and calculates the optimal energy storage capacity allocation in the power system on the principle of minimum compensation amount of typical daily frequency modulation auxiliary service of the power system. The optimal energy storage capacity configuration can guide the power system to carry out power grid planning and guide related parties to deploy energy storage facilities.

Drawings

A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:

fig. 1 is a flowchart of a method for evaluating an optimal energy storage capacity in a frequency modulation field of a power system according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of the energy storage discharge time exceeding the maximum duration;

FIG. 3 is a schematic diagram of an energy storage discharge time less than a maximum duration;

FIG. 4 is a schematic diagram of the energy storage charging time exceeding the maximum duration;

FIG. 5 is a schematic diagram of an energy storage charging time less than a maximum duration;

FIG. 6 is a flow chart of energy storage capacity estimation based on time series simulation according to an embodiment of the present invention;

FIG. 7 is a flow chart of energy storage capacity estimation based on time series simulation according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a frequency modulated resource response to power system commands during a conditioning period in accordance with an embodiment of the present invention; and

fig. 9 is a structural diagram of an evaluation system for energy storage optimal capacity in the frequency modulation field of a power system according to a preferred embodiment of the invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

Fig. 1 is a flowchart of a method for evaluating an optimal energy storage capacity in a frequency modulation field of a power system according to a preferred embodiment of the present invention. As shown in fig. 1, an evaluation method for an optimal energy storage capacity in a frequency modulation field of an electric power system according to an embodiment of the present invention includes:

preferably, in step 101: and establishing an energy storage output power model, and determining the adjustable capacity of the stored energy according to the energy storage output power model.

Preferably, establishing the energy storage output power model comprises:

after receiving the frequency modulation signal of the power system, the energy storage judges whether the energy storage is in a frequency modulation and use state, if so, the energy storage does not respond to the frequency modulation signal of the power system;

if the stored energy is not in a frequency modulation and use state, receiving the current frequency modulation signal of the power system;

Calculating the longest discharge time of the energy storage theory: when the duration time of the frequency modulation signal exceeds the longest discharge time, the stored energy stops discharging, the state is switched, and the stored energy is charged at 20% of rated power until the stored energy is fully charged by 100% or the next frequency modulation instruction comes;

when the frequency modulation signal of the power system is negative, the stored energy is used for charging; judging the absolute value of the target power of the frequency modulation signal of the power system and the rated power of the stored energy, taking the smaller value of the absolute value and the rated power of the stored energy as the charging power of the stored energy, and charging the stored energy according to the power within 1 second;

preferably, at step 102: establishing an output power model of a conventional unit, and determining the adjustable capacity of the conventional unit according to the output power model of the conventional unit;

preferably, the establishing of the conventional unit output power model comprises:

after receiving a frequency modulation signal of the power system, the conventional unit judges whether the conventional unit is in a frequency modulation and utilization state, and if the conventional unit is in the frequency modulation and utilization state, the conventional unit does not respond to the current frequency modulation signal of the power system;

if the conventional unit is not in a frequency modulation and use state, receiving a current frequency modulation signal of the power system;

after the conventional unit receives the decision of the frequency modulation signal, when the target power value of the frequency modulation signal is greater than the current running power of the conventional unit, the load-increasing operation is carried out, and the power output of the conventional unit is increased; if the target power value of the frequency modulation signal is smaller than the current running power of the conventional unit, the conventional unit reduces power output for load reduction operation;

When the load of the conventional unit is reduced, the target output power of the conventional unit is set to be the maximum value of the target power of the frequency modulation signal and the minimum running power of the conventional unit;

The load ascending and load descending rates of the conventional unit are respectively set according to different types of the conventional unit.

Preferably, in step 103: and establishing a frequency modulation scheduling strategy model, and carrying out capacity adjustment on the energy storage or the conventional unit according to the required frequency modulation capacity of the power system, the adjustable capacity of the energy storage or the adjustable capacity of the conventional unit.

Preferably, the establishing of the frequency modulation scheduling policy model includes:

determining a required frequency modulation capacity (MW) of the power system;

analyzing the conventional unit operated currently and the adjustable capacity (MW) of the stored energy;

and calling the running conventional units or stored energy in sequence according to the principle that the regulating performance (Kpd) is from high to low until the total calling capacity meets the frequency modulation capacity required by the power system.

Preferably, at step 104: and establishing a frequency modulation compensation rule model, and determining the total compensation amount of the energy storage or conventional unit according to the frequency modulation compensation rule model.

Preferably, the establishing of the frequency modulation compensation rule model comprises:

r_ij＝D_ij×Kpd_ij×P

wherein:

b.D_ijthe total adjustment depth of the conventional unit or the energy storage i on the j day is defined as the sum of the arithmetic of the adjustment depths of all the adjustment times n on the whole day, namely D, the absolute value of the difference value between the final response output P and the output P' before the response when the conventional unit or the energy storage is subjected to response adjustment once_ijThe calculation is as follows:

c.Kpd_ijthe regulation performance of the conventional unit or the energy storage i on the j day is regulated by a regulation rate index K₁And an adjustment accuracy index K₂Response time index K₃The three indexes jointly determine that the adjustment performance of the conventional unit or the energy storage i in the k adjustment on the j day is calculated as follows:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

V_Nistandard regulation rate, V, of conventional units or stored energy specified for the system_ijkFor the actual regulating rate of the conventional unit or the stored energy, if the regulating depth of the k-th regulation is delta MW_ijkThe time taken to reach the target regulation point after receiving the instruction is Δ T_ijkAnd then:

ΔP_ijkafter the target output is reached, the actual P of the conventional unit is within the response time period_ijk(t) target force P_ijkThe average value of the difference between the two is recorded as the time T when the target output is reached₀At the end of the regulation period, it is recorded as time T₁Then the adjustment deviation amount for the kth adjustment is calculated as:

the allowable deviation value of the regulation is 1 percent of the rated active power of the conventional unit or the stored energy, delta t_ijkThe time consumed when the load is increased or decreased towards the correct direction after the conventional unit or the stored energy receives a secondary frequency modulation signal AGC instruction of the power system and exceeds 1% of the rated power of the conventional unit or the stored energy;

Preferably, at step 105: setting capacity proportion of energy storage;

preferably, the method further comprises the following steps:

and adjusting the capacity ratio of the stored energy, and calculating the total frequency modulation compensation cost of all conventional units and the stored energy in a typical frequency modulation day according to the adjusted capacity ratio of the stored energy.

Preferably, the method further comprises the following steps:

and selecting the capacity ratio of the stored energy corresponding to the minimum total frequency modulation compensation cost in the total frequency modulation compensation costs of all the conventional units and the stored energy in a typical frequency modulation day as the optimal capacity.

Preferably, at step 106: establishing a frequency modulation time sequence simulation model, establishing a simulation algorithm input database, and performing frequency modulation time sequence simulation according to the capacity ratio of the stored energy: adjusting the active power of the power system according to the area control deviation ACE of the power system, determining the frequency modulation requirement of the power system, determining the distribution mode of the active power according to the frequency modulation requirement, and sending a frequency modulation instruction to an energy storage or conventional unit participating in frequency modulation; simulating a response curve of an energy storage or conventional unit to respond to the load frequency; selecting a typical frequency modulation day, and recording power data of all conventional units and stored energy in a certain time period in the typical frequency modulation day; and calculating the total frequency modulation compensation cost of all conventional units and stored energy in a typical frequency modulation day according to the data in a certain time period.

Preferably, a simulation algorithm database is established, the simulation algorithm database comprising: and determining the adjustable capacity of stored energy, the adjustable capacity of a conventional unit, the grid frequency data of the power system and the net load.

In the method, not specifically described, the system frequency modulation signals are all referred to as system secondary frequency modulation (AGC) signals.

The method for measuring and calculating the optimal energy storage capacity configuration in the frequency modulation field of the power system based on the time sequence simulation comprises the following steps:

setting the energy storage configuration capacity, configuring according to 0-100% of the installed capacity of the conventional units in the system, setting the initial configuration as 0%, gradually increasing the value by 100%, and increasing the amplitude by 1% each time.

And establishing an energy storage power response model and a conventional unit power response model.

And establishing a frequency modulation compensation rule model.

And establishing a simulation algorithm input database which comprises generator data, energy storage system data, power grid AGC control parameters, power grid frequency and net load (load, tie line power and renewable energy).

And aiming at the frequency modulation capacity ratios of different energy storage units and the conventional generator set, frequency modulation time sequence simulation is carried out, and the time sequence simulation is carried out in seconds.

Adjusting the active power of the power grid according to the power grid regional control deviation ACE, determining the frequency modulation requirement of the power system, determining the active power distribution mode, and sending a frequency modulation instruction to a frequency modulation unit/an energy storage system.

And simulating a response curve of the unit/energy storage system to perform load frequency response.

And recording power data of all the units/energy storage systems in the system every second in a typical day.

And calculating the adjustment depth, the response performance and the frequency modulation compensation of all the units/energy storage systems within a typical day according to the second-level data, and calculating the total frequency modulation compensation cost of the power system all day.

Adjusting the energy storage ratio, and performing simulation calculation again.

And when the energy storage ratio is 100% of the installed capacity of the conventional unit in the system, finishing the simulation after the calculation is finished.

When the energy storage percentage is from 0% to 100%, the compensation total amount of the frequency modulation auxiliary service of the power system is compared, and the percentage of the energy storage when the compensation total amount is minimum is selected, namely the optimal energy storage capacity in the frequency modulation field of the power system sought by the application.

Fig. 6 is a flow chart of energy storage capacity evaluation based on time series simulation according to an embodiment of the invention.

Fig. 7 is a flow chart of energy storage capacity evaluation based on time series simulation according to an embodiment of the invention.

As shown in fig. 6 or fig. 7, in the embodiment of the present application, on the premise of different energy storage ratios, the energy storage and generator set power output model is set according to the method of the present invention, and the total frequency modulation compensation benefit of the system is calculated multiple times by using the time sequence simulation model, so that the energy storage ratio with the minimum total frequency modulation benefit of the system is selected.

The energy storage capacity evaluation method provided by the application is operated according to the following steps:

(1) establishing an energy storage power output model;

(2) establishing a power output model of a conventional unit;

(3) setting the capacity ratio of stored energy, wherein the initial capacity ratio is 0 percent, namely the installed capacity of stored energy is 0 percent of the installed capacity of the conventional unit of the system, and calculating the stored energy capacity in the system;

(4) the energy storage capacity, the capacity of a conventional unit, the frequency data of a power grid and the data of net loads (load, tie line power and renewable energy power generation capacity) are recorded into a simulation algorithm database;

(5) reading data;

(6) setting the time point to be 0 second, starting the simulation at the time 0 (t is 0):

adjusting active power according to the area control deviation ACE simulated by the system, and sending the active power adjustment requirement of the area control deviation ACE of the power grid to a unit or an energy storage system according to a scheduling strategy;

calling an energy storage power output model and a conventional unit power output model, simulating an output curve, responding and adjusting, and recording energy storage and real-time power data of the unit;

adjusting the area control deviation ACE value after the adjustment is finished

The time point is adjusted to 1 st second (t ═ t +1), and the simulation is performed again by returning to step 7. Taking seconds as a unit, increasing 1 second every time, calculating until 86399 times of calculation are finished all day, finishing the circular calculation, and entering the step (6);

(7) outputting the second-level power data of the whole day;

(8) according to a specified auxiliary service compensation calculation method, calculating frequency modulation auxiliary service compensation cost of each unit and the energy storage system, and calculating total frequency modulation auxiliary service compensation cost of the system;

(9) adjusting the energy storage ratio to 1%, calculating the energy storage capacity, returning to the step (4) for calculation again until the configuration ratio of the energy storage is adjusted to 100%, and finishing the calculation.

(10) And sequencing the total frequency modulation compensation cost of the system under the condition that the energy storage ratio is 0-100%, and removing the ratio of the energy storage when the total compensation is minimum, thereby obtaining the optimal energy storage capacity ratio in the frequency modulation field of the power system.

The method is optimally applied to the power system which has energy storage participating in frequency modulation or is about to have energy storage participating in frequency modulation, and the compensation calculation rule of the frequency modulation is similar to the frequency modulation compensation calculation principle of the method.

The application provides a method for evaluating the optimal capacity of energy storage in the field of frequency modulation of an electric power system, which is characterized by comprising the following steps of: the method is based on a time sequence simulation model, a specific power response model, a frequency modulation scheduling strategy model and a frequency modulation compensation rule model are established, and the optimal energy storage capacity in the frequency modulation field is analyzed, and the method comprises the following steps:

(1) establishing an energy storage output power model;

(2) establishing a conventional generator set output power model;

(3) establishing a frequency modulation scheduling strategy model;

(4) establishing a frequency modulation compensation rule model;

(5) establishing a frequency modulation time sequence simulation model;

(6) establishing a simulation algorithm input database;

(7) aiming at the frequency modulation capacity ratios of different energy storages and conventional generator sets, carrying out frequency modulation time sequence simulation and calculating the total frequency modulation compensation of the system;

(8) and analyzing the simulation result to obtain the frequency modulation capacity ratio of the optimal energy storage to the conventional generator.

And (2) establishing an energy storage output power model in the step (1) according to the following strategy.

a. The signals sent by the power grid to the energy storage are divided into positive and negative signals. If the signal value is positive, the stored energy is discharged, and the system power is increased. If the signal is negative, the energy is stored for charging operation, and the system power is reduced;

b. after receiving the power grid frequency modulation signal, the stored energy judges whether the stored energy is in a frequency modulation invoked state, if the stored energy is in the invoked state, namely the last power grid frequency modulation command is in execution, the stored energy does not respond to the power grid frequency modulation signal;

b. after the stored energy receives the power grid frequency modulation signal, judging that the stored energy is not in a frequency modulation and modulated use state, and responding to the frequency modulation signal;

c. and if the grid frequency modulation signal is positive, determining the energy storage discharge and outputting the power. And comparing the target power of the frequency modulation signal of the power grid with the rated power of the stored energy, taking the smaller value of the target power and the rated power of the stored energy as the output power of the stored energy, and carrying out discharge operation according to the output power of the stored energy within 1 second.

d. And calculating the theoretical longest discharge time of the stored energy in the state, if the duration of the frequency modulation signal exceeds the longest discharge time (namely the stored energy of the energy storage system is exhausted, and the frequency modulation signal is still in duration), stopping discharging the stored energy, and switching the state to charge at 20% rated power until the stored energy is fully charged by 100% or the next regulating instruction comes.

e. And the power grid frequency modulation signal is negative, and the stored energy is used for charging operation. And comparing the absolute value of the target power of the frequency modulation signal of the power grid with the rated power of the stored energy, taking the smaller value of the absolute value and the rated power of the stored energy as the charging power of the stored energy, and charging the stored energy according to the power within 1 second.

f. And calculating the theoretical longest charging time of the stored energy in the state, and if the duration of the frequency modulation signal exceeds the longest discharging time (namely the stored energy system is full of electric quantity, and the frequency modulation signal is still in duration), stopping charging the stored energy, and keeping the output power at 0 in a standby state until the next instruction comes.

Wherein, the conventional generator set in the step (2) is established according to the following strategies according to an output power model:

a. after receiving the power grid frequency modulation signal, the conventional unit judges whether the conventional unit is in a frequency modulation invoked state, and if the conventional unit is in the invoked state, namely the last power grid frequency modulation instruction is in execution, the conventional unit does not respond to the power grid frequency modulation signal;

b. after the conventional unit receives the power grid frequency modulation signal, judging that the conventional unit is not in a frequency modulation and modulated state, and responding to the frequency modulation signal;

c. and after a decision for responding the frequency modulation signal is made, judging the relationship between the frequency modulation signal and the rated capacity of the unit. If the target power value of the frequency modulation signal is larger than the current running power of the unit, the load is increased, and the power output of the unit is increased; and if the target power value of the frequency modulation signal is less than the current running power of the unit, the unit reduces the power output for load reduction operation.

d. And (4) the unit is in load-increasing operation, and the target output power of the unit is set to be the smaller value of the target power of the frequency modulation signal and the rated power of the unit.

e. And (4) carrying out load reduction operation on the unit, and setting the target output power of the unit as the maximum value of the target power of the frequency modulation signal and the minimum operating power of the unit.

f. The load ascending and load descending rates of the conventional unit are respectively set according to different unit types.

The scheduling strategy in the step (3) is carried out according to the following steps:

a. determining the frequency modulation capacity (MW) required by the system;

b. analyzing the adjustable capacity (MW) of the existing running unit and the energy storage equipment;

c. and sequentially calling the running unit/energy storage equipment according to the principle that the regulation performance (Kpd) is from high to low until the total calling capacity meets the frequency modulation capacity required by the system.

The frequency modulation compensation rule in the step (4) is calculated according to the following formula:

r_ij＝D_ij×Kpd_ij×P

wherein:

a.r_ijthe compensation sum of the unit/energy storage equipment i on the j day is obtained;

b.D_ijthe total adjustment depth of the unit/energy storage equipment i on the j day is the absolute value of the difference value between the response end output (P) and the response front output (P') of the unit/energy storage equipment each time the unit/energy storage equipment performs response adjustment, and the arithmetic sum of the adjustment depths of all adjustment times (n times) on the whole day is D for the adjustment depth of the response_ijThe calculation is as follows:

c.Kpa_ijthe adjustment performance of the unit/energy storage equipment i on the j day is determined by three indexes, namely an adjustment rate index K1, an adjustment precision index K2 and a response time index K3, and the adjustment performance of the unit/energy storage equipment i on the K-th adjustment on the j day is calculated as follows:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

V_Niand (3) calculating the standard regulating rate of the unit/energy storage equipment specified for the system according to the regulating rate specified in the step (2). V_ijkFor the actual regulation rate of the unit/energy storage equipment, if the regulation depth of the k regulation is delta MW_ijkThe time taken to reach the target regulation point after receiving the instruction is Δ T_ijkAnd then:

ΔP_ijkin response time interval after target output is reached, the actual P of the unit_ijk(t) target force P_ijk(MW) betweenIf the target output is reached, the average value of the difference values is recorded as time T₀At the end of the regulation period, it is recorded as time T₁Then the adjustment deviation amount for the kth adjustment is calculated as:

the deviation allowed by the regulation is 1% of the rated active power of the unit/energy storage.

Δt_ijkAnd after the unit/energy storage system receives the system AGC instruction, the time spent on increasing/decreasing the load in the correct direction is more than 1% of the rated power of the unit/energy storage system.

The standard response time is specified as follows: the response time of the thermal power generating unit AGC should be less than 1 minute, the response time of the hydroelectric generating unit AGC should be less than 20 seconds, and the energy storage response time is less than 1 second.

d.P is the FM offset standard (M/MW), which is 10M/MW.

And (5) establishing a time sequence simulation model according to the following strategies:

a. and establishing a simulation algorithm input database which comprises generator data, energy storage system data, power grid AGC control parameters, power grid frequency and net load (load, tie line power and renewable energy).

b. And aiming at the specific ratio of the energy storage capacity to the frequency modulation capacity of the conventional generator set, carrying out frequency modulation time sequence simulation, wherein the time sequence simulation is carried out in seconds.

c. Adjusting the active power of the power grid according to the power grid regional control deviation ACE, determining the frequency modulation requirement of the power system, determining the active power distribution mode, and sending a frequency modulation instruction to a frequency modulation unit/an energy storage system.

d. And simulating a response curve of the unit/energy storage system to perform load frequency response.

e. And recording power data of all the units/energy storage systems in the system every second in a selected typical day.

f. And calculating the adjustment depth, the response performance and the frequency modulation compensation of all the units/energy storage systems on the day according to the second-level data, and calculating the total frequency modulation compensation cost on the day.

Wherein, the simulation algorithm input database in the step (6) comprises the following data contents:

generator data, energy storage system data, grid AGC control parameters, grid frequency, net load (load, tie line power, renewable energy)

Wherein, the time sequence simulation of the step (7) is carried out according to the following strategies:

a. taking the total installed capacity of other conventional units in the system as the highest installed capacity (MW) of stored energy;

b. simulating the energy storage configuration proportion according to 0% -100% of the highest configuration capacity respectively, wherein the proportion is increased by 1% each time, and the simulation is carried out for 101 times until the energy storage proportion is 100% of the highest configuration capacity;

c. and performing time sequence simulation by taking the typical day as a simulation period and the second as a calculation time interval every time of adjusting the energy storage configuration capacity, calculating the performance index and the adjustment depth of all the units/energy storage systems in the system under different energy storage configuration capacities on the basis of second-level data, calculating the compensation amount of each typical day, and adding the total frequency modulation compensation amount of the system in the calculation day.

Wherein, the step (8) is carried out according to the following strategies:

and analyzing the daily frequency modulation compensation sum of the system under different energy storage ratio conditions, searching the ratio of the energy storage when the frequency modulation compensation sum is minimum, and determining the ratio of the optimal energy storage to the frequency modulation capacity of the conventional generator.

The output power model of the conventional generator set refers to the output power strategy of the conventional generator set after the AGC command of the power grid is issued. In the method, the following strategies are adopted:

f. The load ascending and load descending rates of the conventional unit are respectively set according to different unit types;

the load rate (MW/min) of the boiler thermal power generating unit of the direct-fired pulverizing system is equal to the rated active power of the unit multiplied by 1.5 percent;

the load rate (MW/min) of the thermal power generating unit with the intermediate storage pulverizing system is equal to the rated active power of the unit multiplied by 2 percent;

the load rate (MW/min) of the thermal power generating unit for circulating fluidized bed units and burning special coal (such as inferior coal, high-moisture low-heat value lignite and the like) is equal to the rated active power of the unit multiplied by 1 percent;

the load rate (MW/min) of the supercritical constant-pressure operation direct-current furnace set is equal to the rated active power of the set multiplied by 1 percent;

the load rate (MW/min) of other types of direct current furnace units is equal to the rated active power of the units multiplied by 1.5 percent;

the load rate (MW/min) of the gas turbine set is equal to the rated active power of the gas turbine set multiplied by 4 percent;

the load rate (MW/min) of the hydroelectric generating set is equal to the rated active power of the hydroelectric generating set multiplied by 10 percent;

the optimal capacity of the stored energy is determined by taking the principle that the typical daily total compensation expense of the frequency modulation auxiliary service of the power system is minimum.

The conventional unit/energy storage system participates in compensation of the frequency modulation auxiliary service. According to the method, a unit and an energy storage system which provide frequency modulation auxiliary service for a power grid calculate frequency modulation compensation according to the following steps according to the adjustment depth (D), the adjustment performance (Kpd) and the adjustment unit price (p).

Compensation cost (unit: yuan) of the j th day (typical day) of the unit/energy storage system i:

r_ij＝D_ij×Kpd_ij×P

and the power system frequency modulation auxiliary service is compensated. And supposing that the system totally has N sets of units/energy storage systems participating in frequency modulation auxiliary service, the frequency modulation auxiliary service of the whole system at the j day is the compensation sum of each set/energy storage system.

Adjustment depth D of conventional unit/energy storage system ith day_ij(unit: MW). After receiving an AGC instruction at a certain moment on the j day of the unit/energy storage system i, carrying out load ascending/descending operation, wherein the absolute value of the load ascending/descending is the adjustment depth of one adjustment, and the sum of the adjustment depths of all the days is the adjustment depth D of all the days_ij. As shown in fig. 8, a frequency modulation resource responds to a power grid command in a regulation period. The red line is the output variation condition of the frequency modulation resource, the green arrow (dMW1-dMW7) is the output variation condition in the adjusting process, namely the adjusting depth, and the lower output variation value is calculated according to the absolute value. The total adjustment depth for this adjustment period is calculated as follows:

the adjustment depth of the unit i on the j day is the sum of the adjustment depths in all adjustment periods of the whole day.

Wherein, n: the total number of adjustments made by the unit/energy storage system per day.

And adjusting the performance index Kpd. The regulation performance is determined by a regulation rate index K₁And an adjustment accuracy index K₂Response time index K₃The three indexes jointly determine, reflect the service level of the unit/energy storage system for providing the frequency modulation auxiliary service, the unit/energy storage system with good performance can provide high-quality service, the total frequency modulation capacity requirement of the system can be reduced to a certain extent, and efficient utilization of system resources is facilitated. The adjustment performance was calculated by the following formula.

K_pd＝K₁×K₂×K₃

Namely, each time the unit/energy storage system is adjusted, the power system calculates an adjustment performance index, and the adjustment performance index calculation formula of the unit/energy storage system i adjusted at the kth time on the jth day is as follows:

assuming that the unit/energy storage system i is adjusted for n times in total on the j th day, the adjustment performance index on the j th day

Taking the average value of the performance indexes of each adjustment, as follows:

adjustment rate index K₁And calculating the regulation rate of the unit/energy storage system.

The adjusting rate of the unit/energy storage system refers to a ratio of adjusting depth to consumed time when the unit/energy storage system reaches a target adjusting value after responding to a power grid AGC instruction, and the adjusting rate of the unit/energy storage system i adjusted at the jth day k is calculated as follows:

wherein, is Δ MW_ijkAdjustment depth for the kth adjustment, Δ T_ijkThe time it takes to reach the target force value after receiving the command.

The adjustment rate index of the unit/energy storage system i at the k adjustment on the j day is calculated as follows:

wherein:

the adjustment rate index of the unit/energy storage system i adjusted at the kth time on the jth day is shown; v_NiThe numerical value is determined according to the standard regulation rate published by each power grid and is generally determined by the type of the unit; v_ijkAnd (4) the actual regulating rate of the k regulation of the j day of the unit/energy storage system i.

Adjustment accuracy index K₂，K₂The deviation degree between the actual output and the target output is measured within a period of time after the unit/energy storage system is adjusted to the target processing point.

Assuming that the k adjustment of the unit/energy storage system i on the j day is carried out, the target output is P_ijk(MW), the actual output of the unit is P_ijk(T) (MW) and time T when the target output is reached₀At the end of the regulation period, it is recorded as time T₁Then the adjustment deviation amount for the kth adjustment is calculated as:

the adjustment accuracy index of the unit/energy storage system i adjusted at the jth day and the kth time is calculated as follows:

the deviation allowed by the regulation is 1% of the rated active power of the unit, and the value is different according to different types of the unit.

Response time index K₃And after the unit/energy storage system receives a system AGC command, when the ascending/descending load exceeds 1% of the rated power of the unit/energy storage system, the unit/energy storage system is considered to have responded to the system command, and the time consumed in the process is response time which is expressed by delta t.

The kth response of the j day of the unit i, with the response time delta t_ijkThen response time indicator

The calculation is as follows:

wherein the standard response time is specified as follows: the response time of the thermal power generating unit AGC should be less than 1 minute, the response time of the hydroelectric generating unit AGC should be less than 20 seconds, and the energy storage response time is less than 1 second.

The unit price P is regulated in units of units/MW, and is characterized by the level of compensation that can be achieved for each 1MW regulation provided by the unit and/or the energy storage system. This value is set in the present method to a fixed value of 10 m/MW.

The time sequence simulation method is adopted in the calculation process of the application. The electric power system time sequence simulation is that according to the time sequence, the operation of the electric power system is simulated according to the states of elements such as a power supply, a power grid, a load and the like in the electric power system at each moment and the operation rule of the system, after the simulation of a certain period is completed, the physical and economic statistical analysis is carried out on various elements, and various performance indexes of the system in different aspects are obtained.

According to the method, second-level data of the power grid are adopted, time sequence simulation, calculation and collection are carried out on power data of each generator set/energy storage device in the power grid every second, and the data are utilized to calculate the adjusting performance and the adjusting depth of all the generator sets/energy storage systems participating in AGC adjustment in the power grid, so that the compensation cost of all the generator sets/energy storage systems in the day is calculated.

Fig. 9 is a structural diagram of an evaluation system for energy storage optimal capacity in the frequency modulation field of a power system according to a preferred embodiment of the invention. As shown in fig. 9, an evaluation system for energy storage optimal capacity in the frequency modulation field of an electric power system includes:

the first establishing unit 901 is configured to establish an energy storage output power model, and determine an adjustable capacity of energy storage according to the energy storage output power model.

The second establishing unit 902 is configured to establish a conventional unit output power model, and determine an adjustable capacity of the conventional unit according to the conventional unit output power model.

A third establishing unit 903, configured to establish a frequency modulation scheduling policy model, and perform capacity adjustment on the energy storage or the conventional unit according to the required frequency modulation capacity of the power system, and the adjustable capacity of the energy storage or the adjustable capacity of the conventional unit.

And a fourth establishing unit 904, configured to establish a frequency modulation compensation rule model, and determine a total compensation amount of the energy storage or the conventional unit according to the frequency modulation compensation rule model.

The setting unit 905 is used for setting the capacity ratio of the stored energy. Preferably, the setting unit 905 is further configured to:

A fifth establishing unit 906, configured to establish a frequency modulation timing simulation model, establish a simulation algorithm input database, and perform frequency modulation timing simulation according to the capacity ratio of the stored energy: adjusting the active power of the power system according to the area control deviation ACE of the power system, determining the frequency modulation requirement of the power system, determining the distribution mode of the active power according to the frequency modulation requirement, and sending a frequency modulation instruction to an energy storage or conventional unit participating in frequency modulation; simulating a response curve of an energy storage or conventional unit to respond to the load frequency; selecting a typical frequency modulation day, and recording power data of all conventional units and stored energy in a certain time period in the typical frequency modulation day; and calculating the total frequency modulation compensation cost of all conventional units and stored energy in a typical frequency modulation day according to the data in a certain time period.

Preferably, the system further comprises a selection unit for:

Preferably, the fifth establishing unit 906 is further configured to establish a simulation algorithm database, where the simulation algorithm database includes: and determining the adjustable capacity of stored energy, the adjustable capacity of a conventional unit, the grid frequency data of the power system and the net load.

Preferably, the first establishing unit 901 is configured to establish an energy storage output power model, and includes:

preferably, the second establishing unit 902 is configured to establish a conventional unit output power model, including:

Preferably, the third establishing unit 903 is configured to establish a frequency modulation scheduling policy model, and includes:

determining a required frequency modulation capacity (MW) of the power system;

Preferably, the fourth establishing unit 904 is configured to establish a frequency modulation compensation rule model, including:

r_ij＝D_ij×Kpd_ij×P

wherein:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

V_Nistandard regulation rate, V, of conventional units or stored energy specified for the system_ijkFor the actual regulating rate of the conventional unit or the stored energy, if the regulating depth of the k-th regulation is delta MW_ijkReceiving an instructionThe time taken to reach the target regulation point after the start is Δ T_ijkAnd then:

The system for evaluating the optimal capacity of energy storage in the frequency modulation field of the power system in the preferred embodiment of the present invention corresponds to the method for evaluating the optimal capacity of energy storage in the frequency modulation field of the power system in another preferred embodiment of the present invention, and details thereof are not repeated herein.

The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Claims

1. A method for evaluating the optimal capacity of energy storage in the field of frequency modulation of an electric power system comprises the following steps:

establishing an energy storage output power model, and determining the adjustable capacity of the stored energy according to the energy storage output power model; the establishing of the energy storage output power model comprises the following steps:

establishing a conventional unit output power model, and determining the adjustable capacity of the conventional unit according to the conventional unit output power model; the establishing of the conventional unit output power model comprises the following steps:

The load ascending and load descending rates of the conventional unit are respectively set according to different types of the conventional unit;

establishing a frequency modulation scheduling strategy model, and adjusting the capacity of the energy storage unit or the conventional unit according to the required frequency modulation capacity of the power system and the adjustable capacity of the energy storage unit or the adjustable capacity of the conventional unit; the establishing of the frequency modulation scheduling strategy model comprises the following steps:

determining the needed frequency modulation capacity MW of the power system;

analyzing the conventional unit which is operated currently and the adjustable capacity MW of the stored energy;

according to the principle that the adjusting performance Kpd is from high to low, the running conventional units or the energy storage units are sequentially called until the total calling capacity meets the frequency modulation capacity required by the power system;

establishing a frequency modulation compensation rule model, and determining the compensation total of the energy storage unit or the conventional unit according to the frequency modulation compensation rule model; the establishing of the frequency modulation compensation rule model comprises the following steps:

r_ij＝D_ij×Kpd_ij×P

wherein:

and taking the average value of the calculated number of all the adjusting performances of the j day all day, and if the j day is not called, taking the adjusting performance as 1:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

d.P is the standard element/MW of frequency modulation compensation, P takes the value of 6-12 elements/MW;

setting the capacity ratio of the stored energy, wherein the capacity ratio of the stored energy is 0-100%, and adjusting the capacity ratio of the stored energy by 1% each time;

2. The method of claim 1, further comprising:

3. The method of claim 2, further comprising:

4. The method of claim 1, said building a simulation algorithm input database, said simulation algorithm input database comprising: and determining the adjustable capacity of the stored energy, the adjustable capacity of the conventional unit, the grid frequency data of the power system and the net load.

5. The method of claim 4, the payload comprising: load, tie line power, and renewable energy generation capacity.

6. An evaluation system for energy storage optimal capacity in the field of frequency modulation of an electric power system, the system comprising:

the first establishing unit is used for establishing an energy storage output power model and determining the adjustable capacity of the stored energy according to the energy storage output power model, and comprises the following steps:

the second establishing unit is used for establishing a conventional unit output power model, and determining the adjustable capacity of the conventional unit according to the conventional unit output power model, and comprises the following steps:

a third establishing unit, configured to establish a frequency modulation scheduling policy model, and adjust the capacity of the energy storage unit or the conventional unit according to a required frequency modulation capacity of an electric power system, and the adjustable capacity of the energy storage unit or the adjustable capacity of the conventional unit, where the third establishing unit is configured to establish a frequency modulation scheduling policy model, and includes:

determining the needed frequency modulation capacity MW of the power system;

the fourth establishing unit is configured to establish a frequency modulation compensation rule model, and determine the total compensation amount of the stored energy or the conventional unit according to the frequency modulation compensation rule model, and includes:

r_ij＝D_ij×Kpd_ij×P

wherein:

wherein the rate index is adjusted

Adjusting rate index

Response time indicator

Is calculated as follows:

wherein,

the setting unit is used for setting the capacity ratio of the stored energy, the capacity ratio of the stored energy is 0-100%, and the capacity ratio of the stored energy is adjusted to increase by 1% each time;

7. The system of claim 6, the setup unit further to:

8. The system of claim 7, further comprising a selection unit to:

9. The system of claim 6, the fifth building unit further configured to build a simulation algorithm input database, the simulation algorithm input database comprising: and determining the adjustable capacity of the stored energy, the adjustable capacity of the conventional unit, the grid frequency data of the power system and the net load.

10. The system of claim 9, the payload comprising: load, tie line power, and renewable energy generation capacity.