CN113988442B

CN113988442B - Optimization method, device, terminal and storage medium of receiving end power grid architecture

Info

Publication number: CN113988442B
Application number: CN202111291940.7A
Authority: CN
Inventors: 张菁; 齐晓光; 王颖; 徐田丰; 张丽洁; 陈宇; 柳璐; 万振东
Original assignee: Shanghai Jiaotong University; State Grid Corp of China SGCC; China Power Engineering Consulting Group East China Electric Power Design Institute Co Ltd; Economic and Technological Research Institute of State Grid Hebei Electric Power Co Ltd
Current assignee: Shanghai Jiaotong University; State Grid Corp of China SGCC; China Power Engineering Consulting Group East China Electric Power Design Institute Co Ltd; Economic and Technological Research Institute of State Grid Hebei Electric Power Co Ltd
Priority date: 2021-11-03
Filing date: 2021-11-03
Publication date: 2024-06-21
Anticipated expiration: 2041-11-03
Also published as: CN113988442A

Abstract

The application provides a preferred method, a device, a terminal and a storage medium of a receiving end power grid architecture, wherein the method comprises the following steps: determining at least one layered grid planning scheme corresponding to the grid to be implemented according to the grid data of the grid to be implemented; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme; respectively carrying out power flow calculation on each layered grid planning scheme, and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result; for any layered grid planning scheme, determining the comprehensive weight of each evaluation index of the layered grid planning scheme by adopting a comprehensive weighting method, and calculating the comprehensive score of the layered grid planning scheme based on the comprehensive weight of each evaluation index; an optimal hierarchical rack planning scheme is determined based on the composite scores of the individual hierarchical rack planning schemes. Through the scheme, the application can ensure the flexibility and reliability requirements while constructing the power grid.

Description

Optimization method, device, terminal and storage medium of receiving end power grid architecture

Technical Field

The present invention relates to the field of receiving end power grid technologies, and in particular, to a method, an apparatus, a terminal, and a storage medium for optimizing a receiving end power grid architecture.

Background

At present, the energy resource distribution and the load distribution in China have the problem of extremely unmatched energy resource distribution and load distribution. The reverse energy endowment characteristics determine the characteristics of large scale, long distance and cross regions of electric energy transmission in China, so that a receiving end power grid characterized by high proportion of external incoming calls and alternating current-direct current series-parallel connection is formed, clean energy consumption is promoted, and green low-carbon development is promoted.

The 220 KV and above receiving end power grid is a power transmission main network for connecting power plants, power substations or power substations, mainly bears the task of conveying electric energy, is a basis for realizing the electrifying of the whole people in China, and is a key ring for guaranteeing the output and the use of renewable energy sources.

The construction of 220 KV and above receiving end power grids involves multiple aspects of grid scheme generation, partitioning, evaluation optimization and the like. In terms of grid plan generation, conventional power system planning methods generally have a few possible plans given by a planner based on his own experience, and then select a recommended plan through a comparison of technical and economic. However, this method only considers the technical economy, and the reliability and flexibility of the operation of the power grid are poor.

Disclosure of Invention

In view of the above, the invention provides a preferred method, a device, a terminal and a storage medium of a receiving-end power grid architecture, which can solve the problem of poor reliability and flexibility of 220kV and above receiving-end power grids in the prior art.

In a first aspect, an embodiment of the present invention provides a preferred method for a receiving-end power grid architecture, including:

acquiring power grid data of a grid to be implemented;

determining at least one layered grid frame planning scheme corresponding to the grid frame to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme;

Respectively carrying out power flow calculation on each layered grid planning scheme, and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result, wherein the evaluation indexes comprise a contribution coefficient of renewable energy sources to an expected value of electric quantity deficiency, risk of electric power system flexibility margin deficiency, N-1 passing rate in an extreme/typical scene operation mode, N-2 passing rate in an extreme/typical scene operation mode and generalized short-circuit ratio of a multi-feed-in system;

For any layered grid planning scheme, determining the comprehensive weight of each evaluation index of the layered grid planning scheme by adopting a comprehensive weighting method, and calculating the comprehensive score of the layered grid planning scheme based on the comprehensive weight of each evaluation index;

An optimal hierarchical rack planning scheme is determined based on the composite scores of the individual hierarchical rack planning schemes.

In a second aspect, an embodiment of the present invention provides a preferred apparatus of a receiving-end power grid architecture, including:

the power grid quantity acquisition module is used for acquiring power grid data of the grid to be implemented;

The layered grid planning scheme acquisition module is used for determining at least one layered grid planning scheme corresponding to the grid to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme;

The evaluation index acquisition module is used for respectively carrying out power flow calculation on each layered grid planning scheme and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result, wherein the evaluation indexes comprise a contribution coefficient of renewable energy sources to expected values of electric quantity deficiency, risks of electric power system flexibility margin deficiency, N-1 passing rate in an extreme/typical scene operation mode, N-2 passing rate in an extreme/typical scene operation mode and generalized short-circuit ratio of the multi-feed-in system;

The comprehensive score calculation module is used for determining the comprehensive weight of each evaluation index of the layered grid planning scheme by adopting a comprehensive weighting method aiming at any layered grid planning scheme, and calculating the comprehensive score of the layered grid planning scheme based on the comprehensive weight of each evaluation index;

and the optimal scheme determining module is used for determining an optimal layered grid planning scheme based on the comprehensive scores of the layered grid planning schemes.

In a third aspect, an embodiment of the present invention provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the method according to any one of the possible implementations of the first aspect above when the computer program is executed.

In a fourth aspect, embodiments of the present invention provide a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the method as described in any one of the possible implementations of the first aspect above.

Compared with the prior art, the embodiment of the invention has the beneficial effects that:

The embodiment of the invention firstly acquires the power grid data of the net rack to be implemented; then, determining at least one layered grid frame planning scheme corresponding to the grid frame to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme; respectively carrying out power flow calculation on each layered grid planning scheme, and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result, wherein the evaluation indexes comprise a contribution coefficient of renewable energy sources to an expected value of electric quantity deficiency, risk of electric power system flexibility margin deficiency, N-1 passing rate in an extreme/typical scene operation mode, N-2 passing rate in an extreme/typical scene operation mode and generalized short-circuit ratio of a multi-feed-in system; finally, aiming at any layered grid planning scheme, determining the comprehensive weight of each evaluation index of the layered grid planning scheme by adopting a comprehensive weighting method, and calculating the comprehensive score of the layered grid planning scheme based on the comprehensive weight of each evaluation index; an optimal hierarchical rack planning scheme is determined based on the composite scores of the individual hierarchical rack planning schemes. Through the scheme, the embodiment can ensure flexibility and reliability requirements while constructing the power grid.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a flowchart of a preferred method for implementing a receiver-side power grid architecture according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a longitudinal split mode according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an inner and outer ring division method according to an embodiment of the present invention;

Fig. 4 is an evaluation index radar chart provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a preferred device of a receiving-end power grid architecture according to an embodiment of the present invention;

fig. 6 is a schematic diagram of a terminal according to an embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the following description will be made by way of specific embodiments with reference to the accompanying drawings.

Referring to fig. 1, a flowchart of an implementation of a preferred method of a receiving-end power grid architecture according to an embodiment of the present invention is shown, and details are as follows:

s101: and acquiring power grid data of the grid to be implemented.

In this embodiment, the grid data includes existing grid data, future grid data, and future demand data. The existing network frame data comprise a network topological structure, an existing transformer substation capacity, an existing power supply capacity, a line model, a capacity, impedance, length, and existing space load distribution and size. Future grid data comprise newly-added power distribution points and capacity, and newly-added transformer substation distribution points and capacity; out-of-zone electrical drop points and capacities, selectable overhead corridors to be selected, line model, capacities, impedances and lengths. Future demand data includes predicted spatial load distribution and size, off-site electricity consumption demand, and renewable energy consumption demand.

S102: determining at least one layered grid frame planning scheme corresponding to the grid frame to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme.

In this embodiment, the grid to be implemented is planned in a layered and partitioned manner according to the grid data. The 500kV grid planning scheme gives out a plurality of to-be-selected schemes according to a typical structure and a construction thought of a 500kV power grid.

Specifically, the 500kV power grid is mainly used as a main grid of a provincial grid and a main grid of a regional grid structurally, and is also used as a power supply of the regional grid. According to the structural type characteristics, the connection mode between 500kV alternating current power grids can be divided into single-channel type, channel interconnection type, network-to-network type, dense type and other structures. From the internal structure of the transmitting and receiving end power grid, there are two main forms of ring-type structure and grid-type structure. The ring structure is characterized in that the mutual supporting capability between transformer stations on the ring network is strong, and the ring structure is convenient to receive power from multiple directions and is adjusted in a ring-releasing or ring-expanding mode. The grid structure has the characteristics of short circuit, stronger mutual supporting capability, firm grid, convenience for receiving power at multiple points, and has the defects that the short circuit current is difficult to control and the accident range is difficult to control by adopting measures for disconnecting the power grid. The ring structure can be divided into a single ring network, a C (U) ring network (semi-ring network) and a double ring network in morphology, and the single ring network and the semi-ring network can be easily transited to the double ring network respectively corresponding to different stages of urban power grid development. The grid structure can be divided into a Chinese character 'ri' shape, a Chinese character 'mu' shape, a Chinese character 'tian' shape and a network shape in morphology and is formed by overlapping 500kV ring networks surrounding a plurality of central areas of cities or a plurality of cities. The Chinese character 'ri', mu 'character' shape, tian 'character' shape and network type are correspondent to different stages of city expansion, and the transition mode is double-ring network-Chinese character 'ri' -mu 'character' shape-Tian 'character' shape-network type.

The core problem to be solved in 500kV power grid planning in the load center of the receiving end power grid with dense extra-high voltage alternating current and direct current falling points is how to ensure safe evacuation of alternating current and direct current received power under the condition of meeting the controllable constraint of short circuit current. The construction idea is that an alternating current and direct current power supply area is reasonably divided in a bus sectional mode that an extra-high voltage alternating current main transformer is connected to an existing power grid, the electric distance between the extra-high voltage main transformers is pulled, the step-down power of each extra-high voltage station is balanced, short circuit current is effectively controlled, and safe evacuation of alternating current and direct current received power is guaranteed.

In one embodiment, the rack to be implemented includes an existing rack and a future rack; the power grid data comprise existing grid data, future grid data and future demand data; the existing network frame data comprise an existing network topological structure, an existing transformer substation capacity, an existing transformer substation distribution point and an existing space load distribution; the future grid data comprise newly-increased substation capacity and newly-increased substation distribution points; the future demand data includes a predicted spatial load distribution; the 500kV grid planning scheme comprises a bus sectioning mode of an extra-high voltage transformer substation connected to the existing grid, 500kV grade power supply subareas and main transformer total capacity required by each 500kV grade power supply subarea; the specific implementation flow of S102 includes:

S201: carrying out load flow calculation on the net rack to be implemented according to the existing net rack data to obtain a load flow calculation result, and determining alternative extra-high voltage alternating current-direct current drop points near the extra-high voltage transformer substation according to the load flow calculation result, the existing transformer substation distribution point and the newly-added transformer substation distribution point;

S202: determining a bus segmentation mode of the extra-high voltage transformer substation connected with the existing grid frame based on alternative extra-high voltage alternating current-direct current drop points, existing space load distribution and predicted space load distribution near the extra-high voltage transformer substation, wherein the bus segmentation mode comprises transverse segmentation, longitudinal segmentation and inner and outer ring segmentation;

S203: dividing the grid to be implemented into a plurality of 500 kV-level power supply subareas based on a bus segmentation mode of the extra-high voltage transformer substation connected with the existing grid;

s204: and determining the total main transformer capacity required by each 500 kV-level power supply partition based on the space load distribution of each 500 kV-level power supply partition.

Illustratively, the grid to be implemented has 2 extra-high voltage transformer stations, and the main transformer capacity is 1200 kilovolts; 23 seats of 500 kilovolt transformer substation and 5000 kilovolt-amperes of main transformer capacity. The extra-high voltage alternating current power grid forms a 'two-station three-channel'; under the large pattern of four transverse and two longitudinal, 500 kv forms a ring network, a C-shaped double ring network and other structures locally. The full-caliber installed capacity is 4088 kilowatts, wherein the thermal power accounts for over 70 percent, the maximum load is 4013.3 kilowatts, the maximum power receiving outside the area is 1447 kilowatts, and the maximum load accounts for 36 percent, and the thermal power is received through a power grid of 500 kilovolts or more.

Firstly, judging that a large-scale new energy source exists in the west and the possibility of drawing and accumulating layout exists according to the conditions of selectable extra-high voltage alternating current and direct current drop points near an extra-high voltage transformer station, the predicted space load distribution and the size of a grid to be implemented, the external electricity absorption requirement of a region, the renewable energy source absorption requirement and the like, and avoiding the networking thought of transverse segmentation (north-south segmentation) as far as possible in order to avoid uneven voltage reduction of a main transformer of the extra-high voltage transformer station.

Secondly, a first network construction mode, namely a network construction thought of longitudinally dividing an extra-high voltage a station and an extra-high voltage b station, is established, 2 main transformers of the extra-high voltage a station (north) are supplied to a north power grid, 4 main transformers of the extra-high voltage a station (south) +the extra-high voltage b station (north) are supplied to a middle power grid, and the extra-high voltage b station (south) is supplied to a south power grid, as shown in fig. 2. Specifically, the load size, the capacity ratio requirement, the reliability standard and the like of the north and south areas calculate that the power required for the downlink of the south and north areas is about 9000 kilowatts, 15000 kilowatts and 5000 kilowatts, so that 2 main transformers can be used for supplying south areas, 4 main transformer power supply areas and 2 main transformer power supply north areas. In order to control the short-circuit current level, the power grids in the north and the south can be segmented through measures such as 500kV bus segmentation or line start under the condition that the power grids are provided with conditions, namely, three segments in the north and the south are combined to form a ring respectively. Besides directly unlocking the 1000/500kV electromagnetic ring network, the connection between the south and north 500kV power grids can be weakened by additionally installing serial reactance, back-to-back and the like, and the system has more sufficient power grid safety margin on the basis of controllable short circuit current.

In one embodiment, the specific implementation procedure of S203 includes:

When the bus sectioning mode is inner and outer ring sectioning, determining load density based on the predicted load space distribution and the existing load space distribution of the grid to be implemented, and defining a region around the extra-high voltage alternating current and direct current drop point, where the load density is higher than a first preset density threshold value, as a 500 kV-level power supply partition to construct an inner ring grid.

Specifically, the embodiment provides a network construction method II, namely, a network construction thought of dividing an inner ring and an outer ring of an extra-high voltage a station and an extra-high voltage b station, the network construction thought is derived on the basis of a longitudinal bus segmentation thought, a western power supply long bus and an expansion outer ring are constructed, a high-load density inner ring taking an extra-high voltage alternating current/direct current landing point as a core is constructed, and weak connection is formed between the inner ring and the outer ring through bus segmentation switches or back to back, as shown in fig. 3. Specifically, the high-load density inner ring power grid is defined by combining administrative region division of the grid to be implemented, prediction of space load distribution and size, existing transformer substation distribution points, newly-added transformer substation distribution points and the like, the required power for down-feeding of the inner ring power grid is calculated to be about 11000 kilowatts, and 3 main transformers can be used for supplying the inner ring by the extra-high voltage station a and the extra-high voltage station b.

In one embodiment, the rack to be implemented includes an existing rack and a future rack; the power grid data comprise existing grid data, future grid data and future demand data; the existing network frame data comprise an existing network topological structure, an existing transformer substation capacity, an existing transformer substation distribution point and an existing space load distribution; the future grid data comprise newly-increased substation capacity and newly-increased substation distribution points; the future demand data includes a predicted spatial load distribution; the 220kV grid planning scheme comprises a power grid operation mode, 220kV power supply areas and the maximum access capacity of each 220kV power supply area;

The specific implementation flow of S102 further includes:

S301: determining the load density of a plurality of 220kV power supply areas according to the existing space load distribution and the predicted space load distribution, determining the power grid operation mode of the corresponding 220kV power supply areas according to the load density of each 220kV power supply area,

S302: and calculating the short-circuit current of each 220kV power supply area according to the power grid data, and determining the maximum access capacity of different 220kV power supply areas under each power grid operation mode by taking the constraint condition that the short-circuit current is not greater than a first preset threshold value.

Specifically, in areas with higher load density, 220kV power grids have been converted to high-voltage power distribution networks; in areas with low load density, the 220kV grid is still the backbone grid. In particular to a single-side double-loop chain type, a single-side radiation type, a single-loop type double mesh, double loop, and double loop chain.

In one embodiment, the specific implementation procedure of S301 includes:

Selecting an independent slice forming mode as a power grid operation mode in a 220kV power supply slice region with the load density higher than a second preset density threshold value, or with the electrical distance of a 500kV transformer substation smaller than a preset electrical distance threshold value, or with the number of 220kV and below power sources smaller than a first preset number threshold value;

and selecting a combined operation mode as a power grid operation mode in the power grid development excessive period, or in the 220kV power supply areas with the number of power supplies of 220kV or below being larger than a first preset number threshold value, or in the 220kV power supply areas with the number of 220kV connecting channels between 500kV transformer stations being larger than a second preset number threshold value.

Specifically, in the process of determining the 220kV grid frame planning scheme, according to the load density condition, an independent sheet mode is selected in a region with the load density higher than a second preset density threshold value, a region with a close electric distance of a 500kV transformer substation and a region with less power supply of 220kV or below, and a joint operation mode is selected in a transition period of power grid development or in a region with more power supply of 220kV or below and a region with more 220kV connecting channels between 500kV transformer stations.

Independent sheet scheme mode with single 500kV transformer substation as core: the independent piece 500kV outgoing line is generally four times or more, the 500kV transformer substation is at least provided with 3 main transformers or more, and if only 3 main transformers are provided, a certain 220kV power supply support is needed. And a standby tie line is arranged between the regional power grids, and important loads in the power supply region are powered in a power grid fault mode (a main power plant or a transformer substation in the power supply region).

The mode of an 'N+N' combined operation scheme formed by combining N main transformers of two 500kV substations is as follows: each 500kV transformer substation combined into a piece is provided with at least 2 main transformers and more, and a connecting line between the two 500kV transformer substations needs to be strongly connected to meet the trend transfer under the fault.

After determining the 220kV power supply area and the power grid operation mode, in order to avoid the overrun of the short circuit current, the embodiment takes the constraint condition that the short circuit current does not exceed the first preset threshold value, and takes typical parameters to analyze the general principles of the configured 500kV main transformer capacity and the maximum accessed 220kV power supply capacity under the two power grid operation modes of the 220kV power supply subarea power grid, as shown in table 1 and table 2, table 1 shows the 220kV power supply capacity part table accessed in the 500kV substation power supply area under the independent operation mode, and table 2 shows the 220kV power supply capacity part table accessed in the 500kV substation power supply area under the combined operation mode.

TABLE 1

TABLE 2

According to the characteristics of the embodiment of power grid economic development, load volume development, region area and the like, each city is divided into three types of regions according to load density. And carrying out short-circuit current measurement and calculation of the power supply sheet area by combining the calculation methods of the table 1 and the table 2.

In the embodiment, the embodiment power grid is divided into 6 large 220kV power supply sheet areas, and 3 to 4 500kV transformer substations in each 220kV power supply sheet area are operated in a combined mode. Two partitioning schemes are given for saturation:

According to the scheme I, 11 220kV power supply sheet areas are originally planned, 12-13 main transformers are expected to be connected into each 220kV power supply sheet area, 220kV power supplies connected into each 220kV power supply sheet area are evenly distributed to reach 1152MW, under the scheme, the control pressure of short-circuit current of a 220kV power grid is large, and short-circuit current limiting measures can be further adopted according to the step of S302.

In the scheme II, assuming that all 500kV main transformers in a saturation year are updated to 18% impedance, the short-circuit current at the system side is calculated according to 60kA, and the interruption capacity of a 220kV switch is 50kA as constraint, the saturation year is divided into 20 220kV power supply sheet areas, 500kV main transformers connected into each 220kV power supply sheet area are not more than 7, and the average power supply connected into each sheet area is 633MW.

S103: and respectively carrying out power flow calculation on each layered grid planning scheme, and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result, wherein the evaluation indexes comprise a contribution coefficient of renewable energy sources to an expected value of electric quantity deficiency, risk of electric power system flexibility margin deficiency, N-1 passing rate in an extreme/typical scene operation mode, N-2 passing rate in an extreme/typical scene operation mode and generalized short-circuit ratio of a multi-feed-in system.

In one embodiment, S103 includes:

By the formula Obtaining a contribution coefficient of the renewable energy source to the expected value of the electric quantity deficiency, wherein B _R-EENS represents the contribution coefficient of the renewable energy source to the expected value of the electric quantity deficiency,/>Representing expected value of insufficient system electric quantity before renewable energy is accessed,/>E _RE represents the grid-connected electric quantity of the renewable energy;

By the formula Obtaining the risk of insufficient flexibility margin of the power system; wherein f (z) represents a probability density function of a system flexibility margin, and R _fle represents a risk of insufficient power system flexibility margin; z represents a power system state variable;

The generalized short-circuit ratio of the multi-feed system is obtained by the formula gscr= (max lambda (J _z))^-1; wherein,

J _z denotes the weighted ac system impedance matrix, Z _nm denotes the impedance between nodes n and m, and P _n denotes the node n weight.

In this embodiment, the contribution coefficient of the renewable energy source to the expected value of the insufficient electric quantity is defined as the ratio of the variation of the expected value of the insufficient electric quantity of the system after the renewable energy source is connected to the electric quantity of the renewable energy source, and the contribution of the renewable energy source to the reliability of the system after the renewable energy source is connected to the electric quantity can be directly reflected. The index reflects the capability of the power grid planning scheme for coping with the uncertainty of the renewable energy, and if the cut-load probability and the expected value of the electric quantity deficiency of the system can be effectively reduced by accessing the renewable energy, the influence of the power grid on the renewable energy access can be better indicated, and the safety and the reliability of the power grid planning scheme are better represented.

The risk of insufficient flexibility margin of the power system is defined as the convolution of the probability of insufficient flexibility margin and the expected insufficient flexibility margin, and the index can describe the random variable of the flexibility margin from the aspects of probability and consequences at the same time. Wherein f (z) is obtained by performing rolling difference calculation by probability distribution functions of uncertain factors such as output probability distribution, load, renewable energy sources and the like of various flexible resources. The risk of insufficient flexibility margin of the power system reflects the difficulty of flexibility balance brought by high-proportion renewable energy source access to the power grid at the receiving end, and the power system has the characteristics of directivity, probability, multi-time-space scale characteristic, state dependence and bidirectional conversion.

The N-1 pass rate in extreme/typical scene operation is defined as the sum of the N-1 pass rates in extreme and typical scenes. The N-1 passing rate index in the evaluation of the traditional planning scheme aims at the normal running state or the typical running scene, and under the background of the diversification of the running scene of the power system, meeting the typical running scene does not mean meeting the extreme running scene. The extreme scene of the receiving end power grid is defined as a scene of the system running close to a safety boundary, and the extreme scene needs to be determined according to the characteristics of the system, for example, a representative extreme scene, namely, an inverse peak regulation scene, is that the daily output increasing trend of renewable energy sources is opposite to a system load curve, and the peak-valley difference of a system net load curve is increased instead after the renewable energy sources are connected.

The N-2 pass rate in extreme/typical scene operation is defined as the sum of the N-2 pass rates in extreme and typical scenes.

The short-circuit ratio is a common measurement index of the power system, which represents the short-circuit capacity of the system divided by the equipment capacity, and the multi-feed system generalized short-circuit ratio index can not only represent the strength of the multi-feed direct-current system like the multi-feed short-circuit ratio, but also can directly distinguish strong and weak alternating-current systems from numerical values like the short-circuit ratio, namely, when the multi-feed system generalized short-circuit ratio is more than 3, the strong power grid is a weak power grid, and when the multi-feed system generalized short-circuit ratio is less than 2, the weak power grid is a weak power grid.

In one embodiment, the evaluation index further includes a safety reliability index, an economical index, a flexibility index, and an environmental protection index;

the safety reliability indexes comprise power shortage probability, power shortage expectation and severity indexes;

the economic indicators comprise investment cost, operation cost, renewable energy consumption cost, internal yield and investment recovery period;

The flexibility indexes comprise a maximum load rate, an average load rate, a load unbalance degree, a load increase margin and a power grid expansion margin;

the environmental protection indicators include carbon emissions and pollutant emissions.

In this embodiment, the low power probability (LOLP), also referred to as the no-load probability, is conventionally defined as the probability that the available capacity of the power generation system cannot meet the annual maximum load demand of the system.

The expected value of the shortage of electric power (ENS: expected energy not served) refers to the amount of electric power that is consumed by the load due to the shutdown of the power generation equipment in the study period, and the average number of times of the load due to the shortage of electric power in a certain period (LOLF and average duration of each power outage (LOLD).

The severity index indicates the duration of loss of full load in the event of peak load.

In this embodiment, the cost of renewable energy consumption can be defined as the power generation investment cost and the grid investment cost.

The internal yield is the discount rate of 0 of the sum of economic or financial net present values in the calculation period of the power grid planning project, and is calculated by the formulaCalculating an internal yield, wherein F _IRR represents the internal yield and F _ic.t represents the cash inflow at the t-th stage; f _co.t represents the cash flow amount at the t-th stage, and Y represents the item calculator.

The investment recovery period is also referred to as "investment recovery period". The total amount of revenue obtained after investment of an investment project reaches the time (years) required for the total amount of investment of the investment project. There are various methods for calculating the investment recovery period. According to different starting time of investment recovery, two kinds of calculation are carried out from the date of project production and from the date of investment use; according to the difference of the main body of the recovery investment, there are a social investment recovery period and an enterprise investment recovery period; the method is different according to the income composition of the recovery investment, and is beneficial to the profitable recovery investment period and the earning investment recovery period.

In this embodiment, the maximum load factor is the maximum value of all line load factors.

The degree of load imbalance is an equation of the load rate of all lines, namelyWhere n represents the total number of lines, l _i represents the load factor of the ith line, and l represents the average value of the load factors of all lines.

The power grid expansion margin refers to the ratio of the sum of the maximum allowable newly increased outlet numbers of all nodes in the power grid to the maximum allowable outlet numbers, and can be calculated by the formulaWherein M represents the maximum allowable outgoing line number of the node, L _j represents the existing outgoing line number of the node j, and M represents the node number of the power grid.

In this embodiment, the safety and reliability index further includes a capacity-to-load ratio and a short-circuit current adequacy. The economic indicators also comprise the total length, load and electricity consumption of the 500kV line. The environmental protection index also comprises a renewable energy power ratio and a renewable energy power ratio.

S104: for any layered grid planning scheme, a comprehensive weighting method is adopted to determine the comprehensive weight of each evaluation index of the layered grid planning scheme, and the comprehensive score of the layered grid planning scheme is calculated based on the comprehensive weight of each evaluation index.

In this embodiment, the comprehensive weighting method includes a subjective weighting method and an objective weighting method, and the indexes are weighted by using the Delphi subjective weighting method and the entropy value objective weighting method respectively, and then the index weights of the two methods corresponding to the same index are weighted and summed to obtain the comprehensive weight corresponding to the index.

In this embodiment, the severity index, investment cost, line load factor average value, and carbon emission are selected as representatives, and the Z-score normalization method is adopted to normalize each index based on the average value and standard deviation of all the indexes. The processed data conforms to the standard normal distribution, namely the mean value is 0, and the standard deviation is 1. Because the four indexes are all cost type (smaller and better type) indexes, the visual requirements are considered, the visual requirements are converted into benefit type (larger and better type) indexes, subjective weighting is carried out on each index, and the comprehensive score is larger and better.

In this embodiment, after the weight of each index is obtained by calculation, the score of each index may be calculated according to the comprehensive weight and the numerical value of each index, and then the classification score of the class to which the index belongs may be calculated according to the score of each index, where the class to which the index belongs includes safety reliability, environmental protection, economy and flexibility. An index radar map is generated from the classification scores of the four major classes, as shown in fig. 4.

S105: an optimal hierarchical rack planning scheme is determined based on the composite scores of the individual hierarchical rack planning schemes.

In this embodiment, the hierarchical rack planning scheme with the highest comprehensive score is selected as the optimal hierarchical rack planning scheme.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.

The following are device embodiments of the invention, for details not described in detail therein, reference may be made to the corresponding method embodiments described above.

Fig. 5 shows a schematic structural diagram of a preferred device of a receiving-end power grid architecture according to an embodiment of the present invention, and for convenience of explanation, only the portions relevant to the embodiment of the present invention are shown, which are described in detail below:

as shown in fig. 5, a preferred apparatus 100 of the receiving-end grid architecture comprises: .

A power grid quantity acquisition module 110, configured to acquire power grid data of a grid to be implemented;

The layered grid planning scheme obtaining module 120 is configured to determine at least one layered grid planning scheme corresponding to the grid to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme;

The evaluation index obtaining module 130 is configured to perform load flow calculation on each layered grid planning scheme, and determine an evaluation index corresponding to each layered grid planning scheme according to a load flow calculation result, where the evaluation index includes a contribution coefficient of renewable energy sources to an expected value of insufficient electric quantity, risk of insufficient flexibility margin of the power system, N-1 passing rate in an extreme/typical scenario operation mode, N-2 passing rate in an extreme/typical scenario operation mode, and generalized short-circuit ratio of the multi-feed-in system;

A comprehensive score calculating module 140, configured to determine, for any hierarchical rack planning scheme, a comprehensive weight of each evaluation index of the hierarchical rack planning scheme by using a comprehensive weighting method, and calculate a comprehensive score of the hierarchical rack planning scheme based on the comprehensive weight of each evaluation index;

the optimal solution determining module 150 is configured to determine an optimal layered grid planning solution based on the composite score of each layered grid planning solution.

In one embodiment, the rack to be implemented includes an existing rack and a future rack; the power grid data comprise existing grid data, future grid data and future demand data; the existing network frame data comprise an existing network topological structure, an existing transformer substation capacity, an existing transformer substation distribution point and an existing space load distribution; the future grid data comprise newly-increased substation capacity and newly-increased substation distribution points; the future demand data includes a predicted spatial load distribution; the 500kV grid planning scheme comprises a bus sectioning mode of an extra-high voltage transformer substation connected to the existing grid, 500kV grade power supply subareas and main transformer total capacity required by each 500kV grade power supply subarea;

the hierarchical rack planning scheme acquisition module 120 specifically includes:

The alternating current-direct current falling point determining unit is used for carrying out load flow calculation on the net rack to be implemented according to the existing net rack data to obtain a load flow calculation result, and determining an extra-high voltage alternating current-direct current falling point which can be selected near the extra-high voltage transformer substation according to the load flow calculation result, the existing transformer substation distribution point and the newly-added transformer substation distribution point;

the bus segmentation method determining unit is used for determining a bus segmentation method of the extra-high voltage transformer substation connected with the existing grid frame based on alternative extra-high voltage alternating current-direct current drop points, the existing space load distribution and the predicted space load distribution near the extra-high voltage transformer substation, wherein the bus segmentation method comprises transverse segmentation, longitudinal segmentation and inner and outer ring segmentation;

The 500 kV-level power supply partition dividing unit is used for dividing the grid to be implemented into a plurality of 500 kV-level power supply partitions based on a bus segmentation mode of the extra-high voltage transformer substation connected to the existing grid;

And the main transformer total capacity calculation unit is used for determining the main transformer total capacity required by each 500 kV-level power supply partition based on the space load distribution of each 500 kV-level power supply partition.

In one embodiment, the 500 kV-level power supply partition dividing unit includes:

A power grid operation mode determining unit for determining the load density of a plurality of 220kV power supply areas according to the existing space load distribution and the predicted space load distribution, determining the power grid operation mode corresponding to the 220kV power supply areas according to the load density of each 220kV power supply area,

And the maximum access capacity calculation unit is used for calculating the short-circuit current of each 220kV power supply area according to the power grid data, and determining the maximum access capacity of different 220kV power supply areas under each power grid operation mode by taking the constraint condition that the short-circuit current is not greater than a first preset threshold value.

In one embodiment, the grid operation mode determination unit includes:

In one embodiment, the evaluation index acquisition module 130 includes:

The embodiment of the invention firstly acquires the power grid data of the net rack to be implemented; then, determining at least one layered grid frame planning scheme corresponding to the grid frame to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme; respectively carrying out power flow calculation on each layered grid planning scheme, and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result, wherein the evaluation indexes comprise a contribution coefficient of renewable energy sources to an expected value of electric quantity deficiency, risk of electric power system flexibility margin deficiency, N-1 passing rate in an extreme/typical scene operation mode, N-2 passing rate in an extreme/typical scene operation mode and generalized short-circuit ratio of a multi-feed-in system; finally, aiming at any layered grid planning scheme, determining the comprehensive weight of each evaluation index of the layered grid planning scheme by adopting a comprehensive weighting method, and calculating the comprehensive score of the layered grid planning scheme based on the comprehensive weight of each evaluation index; an optimal hierarchical rack planning scheme is determined based on the composite scores of the individual hierarchical rack planning schemes. Through the scheme, the embodiment is beneficial to guaranteeing flexibility and reliability requirements while constructing the power grid.

Fig. 6 is a schematic diagram of a terminal according to an embodiment of the present invention. As shown in fig. 6, the terminal 6 of this embodiment includes: a processor 60, a memory 61 and a computer program 62 stored in said memory 61 and executable on said processor 60. The processor 60, when executing the computer program 62, implements the steps of the preferred method embodiments of the respective receiving grid architecture described above, such as steps 101 through 105 shown in fig. 1. Or the processor 60, when executing the computer program 62, performs the functions of the modules/units of the apparatus embodiments described above, such as the functions of the units 110 to 150 shown in fig. 5.

Illustratively, the computer program 62 may be partitioned into one or more modules/units that are stored in the memory 61 and executed by the processor 60 to complete the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing the specified functions, which instruction segments are used for describing the execution of the computer program 62 in the terminal 6.

The terminal 6 may be a computing device such as a desktop computer, a notebook computer, a palm computer, a cloud server, etc. The terminal 6 may include, but is not limited to, a processor 60, a memory 61. It will be appreciated by those skilled in the art that fig. 6 is merely an example of terminal 6 and is not intended to limit terminal 6, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the terminal may further include an input-output device, a network access device, a bus, etc.

The Processor 60 may be a central processing unit (Central Processing Unit, CPU), other general purpose Processor, digital signal Processor (DIGITAL SIGNAL Processor, DSP), application SPECIFIC INTEGRATED Circuit (ASIC), field-Programmable gate array (Field-Programmable GATE ARRAY, FPGA) or other Programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 61 may be an internal storage unit of the terminal 6, such as a hard disk or a memory of the terminal 6. The memory 61 may also be an external storage device of the terminal 6, such as a plug-in hard disk, a smart memory card (SMART MEDIA CARD, SMC), a Secure Digital (SD) card, a flash memory card (FLASH CARD) or the like, which are provided on the terminal 6. Further, the memory 61 may also include both an internal storage unit and an external storage device of the terminal 6. The memory 61 is used for storing the computer program and other programs and data required by the terminal. The memory 61 may also be used for temporarily storing data that has been output or is to be output.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, the specific names of the functional units and modules are only for distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal and method may be implemented in other manners. For example, the apparatus/terminal embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present invention may also be implemented by implementing all or part of the procedures in the methods of the above embodiments, or by instructing the relevant hardware by a computer program, where the computer program may be stored in a computer readable storage medium, and the computer program may be executed by a processor to implement the steps of the preferred method embodiments of each of the above receiver grid architectures. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the computer readable medium may include content that is subject to appropriate increases and decreases as required by jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is not included as electrical carrier signals and telecommunication signals.

The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.

Claims

1. A preferred method of a receiver-side power grid architecture, comprising: acquiring power grid data of a grid to be implemented; determining at least one layered grid frame planning scheme corresponding to the grid frame to be implemented according to the grid data; the layered grid planning scheme comprises a 500kV grid planning scheme and a 220kV grid planning scheme; respectively carrying out power flow calculation on each layered grid planning scheme, and determining evaluation indexes corresponding to each layered grid planning scheme according to a power flow calculation result, wherein the evaluation indexes comprise a contribution coefficient of renewable energy sources to an expected value of electric quantity deficiency, risk of electric power system flexibility margin deficiency, N-1 passing rate in an extreme/typical scene operation mode, N-2 passing rate in an extreme/typical scene operation mode and generalized short-circuit ratio of a multi-feed-in system; for any layered grid planning scheme, determining the comprehensive weight of each evaluation index of the layered grid planning scheme by adopting a comprehensive weighting method, and calculating the comprehensive score of the layered grid planning scheme based on the comprehensive weight of each evaluation index; determining an optimal layered grid planning scheme based on the composite scores of the layered grid planning schemes;

The determining the evaluation index corresponding to each layered grid planning scheme according to the tide calculation result comprises the following steps:

J _z denotes the weighted ac system impedance matrix, Z _nm denotes the impedance between nodes n and m, and P _n denotes the weight of node n.

2. The preferred method of the grid framework of claim 1, wherein the grid to be implemented comprises an existing grid and a future grid; the power grid data comprise existing grid data, future grid data and future demand data; the existing network frame data comprise an existing network topological structure, an existing transformer substation capacity, an existing transformer substation distribution point and an existing space load distribution; the future grid data comprise newly-increased substation capacity and newly-increased substation distribution points; the future demand data includes a predicted spatial load distribution; the 500kV grid planning scheme comprises a bus sectioning mode of an extra-high voltage transformer substation connected to the existing grid, 500kV grade power supply subareas and main transformer total capacity required by each 500kV grade power supply subarea;

The determining at least one layered grid frame planning scheme corresponding to the grid frame to be implemented according to the grid data comprises the following steps:

Carrying out load flow calculation on the net rack to be implemented according to the existing net rack data to obtain a load flow calculation result, and determining alternative extra-high voltage alternating current-direct current drop points near the extra-high voltage transformer substation according to the load flow calculation result, the existing transformer substation distribution point and the newly-added transformer substation distribution point;

Determining a bus segmentation mode of the extra-high voltage transformer substation connected with the existing grid frame based on alternative extra-high voltage alternating current-direct current drop points, existing space load distribution and predicted space load distribution near the extra-high voltage transformer substation, wherein the bus segmentation mode comprises transverse segmentation, longitudinal segmentation and inner and outer ring segmentation;

dividing the grid to be implemented into a plurality of 500 kV-level power supply subareas based on a bus segmentation mode of the extra-high voltage transformer substation connected with the existing grid;

And determining the total main transformer capacity required by each 500 kV-level power supply partition based on the space load distribution of each 500 kV-level power supply partition.

3. The method for optimizing the power grid architecture of the receiving end according to claim 2, wherein the bus sectioning mode based on the access of the extra-high voltage transformer substation to the existing network frame divides the network frame to be implemented into a plurality of 500kV class power supply sections, and the method comprises the following steps:

4. The preferred method of the grid framework of claim 1, wherein the grid to be implemented comprises an existing grid and a future grid; the power grid data comprise existing grid data, future grid data and future demand data; the existing network frame data comprise an existing network topological structure, an existing transformer substation capacity, an existing transformer substation distribution point and an existing space load distribution; the future grid data comprise newly-increased substation capacity and newly-increased substation distribution points; the future demand data includes a predicted spatial load distribution; the 220kV grid planning scheme comprises a power grid operation mode, 220kV power supply areas and the maximum access capacity of each 220kV power supply area;

Determining the load density of a plurality of 220kV power supply areas according to the existing space load distribution and the predicted space load distribution, determining the power grid operation mode of the corresponding 220kV power supply areas according to the load density of each 220kV power supply area,

And calculating the short-circuit current of each 220kV power supply area according to the power grid data, and determining the maximum access capacity of different 220kV power supply areas under each power grid operation mode by taking the constraint condition that the short-circuit current is not greater than a first preset threshold value.

5. The method according to claim 4, wherein determining the power grid operation mode of the corresponding 220kV power supply panel according to the load density of each 220kV power supply panel comprises:

6. The preferred method of the receiver grid architecture according to claim 1, wherein the evaluation metrics further comprise a safety reliability metric, an economic metric, a flexibility metric, and an environmental performance metric;

7. A preferred apparatus for a receiver-side power grid architecture, comprising:

the optimal scheme determining module is used for determining an optimal layered grid planning scheme based on the comprehensive scores of the layered grid planning schemes;

The evaluation index acquisition module includes:

8. A terminal comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any of the preceding claims 1 to 6 when the computer program is executed.

9. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the method according to any of the preceding claims 1 to 6.