CN112202208B - Ad hoc network control method and system for small hydropower micro-grid cutting machine - Google Patents
Ad hoc network control method and system for small hydropower micro-grid cutting machine Download PDFInfo
- Publication number
- CN112202208B CN112202208B CN202011017394.3A CN202011017394A CN112202208B CN 112202208 B CN112202208 B CN 112202208B CN 202011017394 A CN202011017394 A CN 202011017394A CN 112202208 B CN112202208 B CN 112202208B
- Authority
- CN
- China
- Prior art keywords
- frequency
- cutting machine
- grid
- micro
- small hydropower
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
The embodiment of the invention discloses a small hydropower micro-grid cutting machine ad hoc network control method and a small hydropower micro-grid cutting machine ad hoc network control system, wherein the method comprises the following steps: collecting the power grid frequency of a small hydropower micro-grid, and taking the collected power grid frequency as a first frequency; determining whether high-cycle cutting machine protection is performed according to the first frequency; if the high-frequency cutting machine protection is performed, determining cutting operation of the high-frequency cutting machine according to the change rate of the first frequency; collecting the power grid frequency of the small hydropower micro-grid after high-frequency cutting and taking the power grid frequency as a second frequency; and carrying out layered frequency modulation control on the second frequency according to the output power and the reference frequency of the small hydropower micro-grid after the high-frequency cutting. According to the technical scheme provided by the embodiment of the invention, the action of the high-frequency cutting machine is determined according to the change rate of the first frequency, the overdriving or undercutting of the cutting machine capacity can be avoided, the frequency modulation control is carried out on the second frequency after cutting, the second frequency of the output of the small hydropower micro-grid in the island operation state can be quickly stabilized, and the second frequency is in a normal range.
Description
Technical Field
The embodiment of the invention relates to the technical field of micro-grid control, in particular to a small hydropower micro-grid cutting machine ad hoc network control method and system.
Background
The small hydropower micro-grid can solve the problems that the large power grid is too concentrated in power distribution and long-distance transmission is slow to recover after being affected by accidents, faults and the like, and meets the power supply requirements of people.
The small hydropower micro-grid accords with the new sustainable development concept of economy and environmental protection, can also supply power for a large power grid on the basis of the excellent zero-pollution power supply, and has higher benefit and economy. However, the small hydropower micro-grid is not provided with an automatic frequency modulation device, when the small hydropower micro-grid is in an island state due to the interruption of the contact with the large power grid, the frequency of the small hydropower micro-grid is suddenly increased to damage the power grid and user equipment, and meanwhile, the small hydropower micro-grid networking and frequency modulation control are difficult due to the lack of communication means meeting the scheduling requirement.
Disclosure of Invention
The embodiment of the invention provides a small hydropower micro-grid cutting machine ad hoc network control method and system, which are used for solving the problems of small hydropower micro-grid networking and frequency modulation control.
In a first aspect, an embodiment of the present invention provides a small hydropower micro-grid cutting machine ad hoc network control method, including:
collecting the power grid frequency of a small hydropower micro-grid, and taking the collected power grid frequency as a first frequency;
determining whether high-cycle cutting machine protection is performed according to the first frequency;
if the high-frequency cutting machine protection is carried out, determining the cutting machine action of the high-frequency cutting machine according to the change rate of the first frequency;
collecting the power grid frequency of the small hydropower micro-grid after high-frequency cutting and taking the power grid frequency as a second frequency;
and carrying out layered frequency modulation control on the second frequency according to the output power and the reference frequency of the small hydropower micro-grid after the high-frequency cutting.
Optionally, the determining whether to perform high-frequency cutter protection according to the first frequency includes:
if the first frequency is greater than or equal to a preset frequency and the duration is greater than or equal to a preset time, high Zhou Qieji protection is performed; wherein the preset frequency is the first round of cutter frequency of the Gao Zhouqie machine.
Optionally, if the high-cycle cutting machine protection is performed, determining the cutting machine operation of the high-cycle cutting machine according to the change rate of the first frequency includes:
if the change rate of the first frequency is larger than the first change rate, starting a third cutting machine;
if the change rate of the first frequency is larger than the second change rate and smaller than the first change rate, starting a second rotary cutter;
otherwise, the first round of cutting machine is started.
Optionally, after the third wheel cutting machine acts, the second wheel cutting machine and the first wheel cutting machine are sequentially performed.
Optionally, the cutting capacity of the Gao Zhouqie machine is sequentially from large to small: the cutting machine comprises a second round of cutting machine, a third round of cutting machine and a first round of cutting machine, wherein the cutting capacity of the third round of cutting machine is equal to that of the first round of cutting machine.
Optionally, the hierarchical frequency modulation control includes a primary frequency modulation control and a secondary frequency modulation control.
Optionally, the primary frequency modulation control includes:
and adjusting the second frequency in a sagging control mode according to the output power of the small hydropower micro-grid after the high-frequency cutting machine.
Optionally, the secondary frequency modulation control includes:
and adjusting the second frequency in a closed-loop PI control mode according to the reference frequency.
Optionally, if the high-cycle cutting machine protection is determined to be performed according to the first frequency, the method includes, before performing the high Zhou Qieji protection:
and calculating the change rate of the first frequency according to the power shortage of the small hydropower micro-grid.
In a second aspect, the embodiment of the invention also provides a small hydropower micro-grid cutting machine ad hoc network control system, which comprises the small hydropower micro-grid cutting machine ad hoc network control method provided by any embodiment of the invention.
According to the technical scheme provided by the embodiment of the invention, whether the high Zhou Qieji protection is needed or not is determined according to the collected first frequency of the small hydropower micro-grid, when the high-perimeter cutting machine protection is determined, the action of the high-perimeter cutting machine is determined according to the change rate of the first frequency, the excessive cutting of the capacity of the small hydropower micro-grid or the excessive cutting of the capacity of the small hydropower micro-grid can be avoided, the action of the high-perimeter cutting machine is reasonably configured, the frequency modulation control is carried out in combination with the second frequency output by the small hydropower micro-grid after cutting, the second frequency of the output of the small hydropower micro-grid in the island operation state can be quickly stabilized, and the second frequency is in the normal range.
Drawings
Fig. 1 is a flowchart of a small hydropower micro-grid cutting machine ad hoc network control method according to a first embodiment of the invention;
fig. 2 is a schematic structural diagram of an equivalent circuit for grid connection of a hydroelectric generating set according to a first embodiment of the present invention;
FIG. 3 is a flowchart of another method for controlling the ad hoc network of a small hydropower micro-grid cutting machine according to a second embodiment of the invention;
FIG. 4 is a flowchart of another method for controlling the ad hoc network of a small hydropower micro-grid cutting machine according to a second embodiment of the invention;
fig. 5 is a schematic structural diagram of a hierarchical fm control according to a third embodiment of the present invention;
fig. 6 is a waveform diagram of a small hydropower micro-grid cutting machine ad hoc network according to a third embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all structures related to the present invention are shown in the drawings.
Example 1
Fig. 1 is a flowchart of a small hydropower micro-grid cutting machine ad hoc network control method according to an embodiment of the invention, and referring to fig. 1, the small hydropower micro-grid cutting machine ad hoc network control method according to the embodiment of the invention includes:
s110, collecting the power grid frequency of the small hydropower micro-grid, and taking the collected power grid frequency as a first frequency.
Specifically, the small hydropower station can form a small power grid to independently operate or output electric energy to a large power grid, and when the frequency of the power grid where the small hydropower micro-grid is positioned is synchronous with the frequency of the large power grid, grid connection can be performed to operate in a combined mode with the large power grid. When the small hydropower micro-grid breaks away from the large power grid and supplies power to other electric equipment independently, the small hydropower micro-grid is in an island operation state, if the small hydropower micro-grid operates in an island, the power supply efficiency can be greatly affected, the service life of the equipment is easy to reduce, and various electronic instruments can cause certain damage. The small hydropower stations are distributed in remote mountain areas, are connected to the 10kV feeder terminal of the power distribution network in a multiple mode, have the characteristics of small capacity, scattered positions and poor regulation performance, and compared with a networked power system, the island is poor in static stability and dynamic stability due to limitation of various frequency modulation means and insufficient reactive compensation control means, and the phenomenon of frequency collapse and voltage collapse can be recovered after long-time power generation adjustment when active imbalance occurs. Because the running state of the small hydropower micro-grid is related to the frequency of the power grid where the small hydropower micro-grid is located, the frequency of the power grid where the small hydropower micro-grid is located can be detected through a hardware or software method, and the detected frequency of the power grid is used as the first frequency. The method comprises the steps that an electric network frequency where a small hydropower micro-grid is located can be detected by adopting a phase-locked loop or a counter and other hardware technology methods, frequency tracking locking is realized by adopting a closed loop formed by a phase comparator and an oscillator, the period of a signal is measured firstly, and the signal is converted into frequency to improve the accuracy of frequency detection; and a software method for carrying out Fourier transformation on the voltage and the current output by the small hydropower micro-grid can be adopted to obtain the frequency of the power grid where the small hydropower micro-grid is positioned.
S120, determining whether high-cycle cutting machine protection is performed according to the first frequency.
Specifically, after a plurality of small hydropower stations form a micro-grid, the frequency of the small hydropower stations is controlled in a V-F mode in a grid-connected mode; the frequency of the small hydropower micro-grid is controlled in an island mode in a P-Q mode, and the problem of frequency deviation caused by a large amount of unbalanced power generated by disconnection of a connecting line between the micro-grid and a large power grid is solved through an active power control strategy. The high-frequency cutting machine protection can ensure that the small hydropower micro-grid stably operates, when the active power of the power system is remained, and the collected first frequency rises, the small hydropower micro-grid formed by the remaining generators can be quickly restored to rated power to continue to operate by timely cutting off the generators with proper capacity.
And S130, if the high-frequency cutting machine protection is performed, determining the cutting machine operation of the high-frequency cutting machine according to the change rate of the first frequency.
In particular, in order to reduce the influence of the first frequency sudden rise on a user or a hydroelectric generating set caused by the blockage of an outgoing channel of the small hydropower micro-grid, a high-frequency cutting machine is adopted to protect a generator with a surplus part cut off rapidly, so that the small hydropower micro-grid in an island operation mode is ensured to be capable of maintaining the stability of frequency. However, the Gao Zhouqie machine protection often causes insufficient cutting machine or excessive cutting machine due to system capacity, so that the frequency of the small hydropower micro-grid after cutting machine is difficult to maintain at rated power. Therefore, the technical scheme provided by the embodiment of the invention determines the action of the high-frequency cutting machine according to the change rate of the first frequency, wherein the action of the high-frequency cutting machine can comprise a multi-wheel cutting machine. For example, if the change rate of the first frequency is smaller, the first round of cutting machine can be directly performed, and less capacity of the generator set is cut off; if the change rate of the first frequency is large, the generator set is cut off in a plurality of rounds so as to prevent the occurrence of the phenomenon of over-cutting or under-cutting.
Fig. 2 is a schematic structural diagram of an equivalent circuit for grid connection of a hydroelectric generating set according to the first embodiment of the present invention, and referring to fig. 2, the difference between the output power of the synchronous generator SG and the consumption power of the load L may be balanced by a large power grid, so as to ensure that the frequency of the whole system remains unchanged, i.e. the small hydropower micro-grid formed by the synchronous generator SG and the load L is in a grid connection operation mode. When the power system breaks down to block the transmission channel of the small hydropower micro-grid, the circuit breaker CB is opened to disconnect the connection between the small hydropower micro-grid and the large power grid, so that the small hydropower micro-grid is in an island operation mode, and the active power of the small hydropower micro-grid is in an unbalanced state. Because the small hydropower micro-grid is sent out in high power, the frequency of the small hydropower micro-grid in an island state is suddenly increased due to the surplus of active power, namely the collected first frequency is increased, and the first frequency is dynamically changed. The relay rocf can detect the speed of the first frequency change and determine the operation of the high cycle cutting machine based on the rate of change of the first frequency. Wherein the relay ROCOF is capable of sampling the frequency signal of the terminal voltage of the synchronous generator SG and calculating the frequency change rate.
And S140, collecting the power grid frequency of the small hydropower micro-grid after the Gao Zhouqie machine and taking the power grid frequency as a second frequency.
And S150, performing layered frequency modulation control on the second frequency according to the output power and the reference frequency of the small hydropower micro-grid after the high-frequency cutting.
In particular, in order to keep the output frequency of the small hydropower microgrid stable after high-frequency cutting machine protection, the small hydropower microgrid in the island operation mode needs to be subjected to frequency modulation. And collecting the power grid frequency of the small hydropower micro-grid after cutting as a second frequency, and performing layered frequency modulation control on the second frequency according to the power output by the small hydropower micro-grid after cutting and the reference frequency, wherein the reference frequency is used for performing feedback regulation on the second frequency, and the layered control can comprise primary frequency modulation control and secondary frequency modulation control. The small hydropower micro-grid after being cut in the island operation mode is subjected to frequency modulation control, so that the output frequency of the small hydropower micro-grid is kept stable, and the small hydropower micro-grid is quickly restored to rated power to continue operation.
According to the small hydropower micro-grid cutting machine ad hoc network control method provided by the embodiment of the invention, whether the small hydropower micro-grid needs to be subjected to high Zhou Qieji protection is determined according to the collected first frequency, when the high-frequency cutting machine protection is determined, the action of the high-frequency cutting machine is determined according to the change rate of the first frequency, the excessive cutting of the small hydropower micro-grid capacity or the insufficient cutting of the small hydropower micro-grid capacity can be avoided, the action of the high-frequency cutting machine is reasonably configured, the frequency modulation control is performed in combination with the second frequency outputted by the small hydropower micro-grid after cutting, and the second frequency outputted by the small hydropower micro-grid in the island operation state can be quickly stabilized and is in a normal range.
Example two
Fig. 3 is a flowchart of another method for controlling an ad hoc network of a small hydropower micro-grid cutting machine according to the second embodiment of the invention, and fig. 4 is a flowchart of another method for controlling an ad hoc network of a small hydropower micro-grid cutting machine according to the second embodiment of the invention, and on the basis of the above embodiments, referring to fig. 3 and fig. 4, the method for controlling an ad hoc network of a small hydropower micro-grid cutting machine according to the embodiment of the invention includes:
s210, collecting the power grid frequency of the small hydropower micro-grid, and taking the collected power grid frequency as a first frequency.
S220, if the first frequency is greater than or equal to the preset frequency and the duration is greater than or equal to the preset time, performing high-frequency cutting machine protection.
And S230, if the change rate of the first frequency is larger than the first change rate, starting the third cutting machine.
S240, if the change rate of the first frequency is larger than the second change rate and smaller than the first change rate, starting the second rotary cutter.
S250, if not, starting the first round of cutting machine.
Specifically, the preset frequency fop is the first round of cutter frequency of high Zhou Qieji, when the first frequency f1 that gathers exceeds preset frequency fop, and the duration exceeds preset time, indicate that the delivery channel of little water and electricity micro-grid is obstructed, little water and electricity micro-grid is in island operation mode, in order to avoid causing the frequency to rise suddenly because of the delivery channel is obstructed, cause the influence to user equipment and hydroelectric generating set, can adopt high week cutter protection to cut off partial surplus generator fast to ensure that generating set and user equipment can safe and stable operation. At the moment, the small hydropower micro-grid is sent out in high power, and the frequency of the small hydropower micro-grid in an island state is suddenly increased due to surplus active power, namely the collected first frequency f1 is increased, and the first frequency f1 is dynamically changed. The cutting action is determined from a rate of change df/dt of the first frequency, wherein the rate of change df/dt of the first frequency can be calculated by a relay. Illustratively, if the rate of change df/dt of the first frequency is less than the second rate of change dop2, the first rotary cutter is directly started and a portion of the generator is cut off; if the change rate df/dt of the first frequency is larger than the second change rate dop2 and smaller than the first change rate dop1, starting a second round of cutting machine, and after finishing the second round of cutting machine, carrying out the first round of cutting machine; if the change rate df/dt of the first frequency is larger than the first change rate dop1, the change amplitude of the frequency of the small hydropower micro-grid is larger, and the third rotary cutting machine is started. After the third round of cutting machine is performed, the second round of cutting machine and the first round of cutting machine are sequentially performed.
Optionally, the cutting capacity of the high-cycle cutting machine is sequentially from large to small: the cutting machine comprises a second round of cutting machine, a third round of cutting machine and a first round of cutting machine, wherein the cutting capacity of the third round of cutting machine is equal to that of the first round of cutting machine.
Specifically, the cut-out capacity refers to the percentage of the total amount of load that each of the rotary cutter can cut out. When unbalanced power appears in the small hydropower micro-grid, the unbalanced power is firstly converted into kinetic energy through a generator rotor to influence the rotating speed and frequency of the generator, and the frequency change of the generator can cause the frequency adjustment effect of the prime motor, the speed regulator and the load to form power opposite to the input unbalanced power, and the power is fed back to the input unbalanced power. Therefore, the frequency adjusting capability of the system mainly depends on the rotating inertia of the generator set rotor, the adjusting effect of the prime motor and the speed regulator, the adjusting effect of the load and the like, and when a part of capacity of the generator is cut off, the rotating inertia of the generator set rotor, the adjusting effect of the prime motor and the speed regulator and the adjusting effect of the load are reduced in proportion, so that the frequency adjusting capability of the system is greatly reduced, and frequency oscillation is easy to cause. It follows that the cut-off capacity of the high-cycle cutter cannot be excessive at a time, and in order to maintain the frequency adjustment capability of the system, the total cut-off capacity should be divided into a plurality of rounds of batch cutting, for example, the cut-off capacity of each round may be determined according to the cut-off total capacity and the setting value of Gao Zhouqie machine, the cut-off capacity of the first round of cutter is 30% of the total capacity, the cut-off capacity of the second round of cutter is 40% of the total capacity, and the cut-off capacity of the third round of cutter is 30% of the total capacity.
And S260, collecting the power grid frequency of the small hydropower micro-grid after the Gao Zhouqie machine and taking the power grid frequency as a second frequency.
S270, performing layered frequency modulation control on the second frequency according to the output power and the reference frequency of the small hydropower micro-grid after the high-frequency cutting.
Optionally, if the high-cycle cutting machine protection is determined to be performed according to the first frequency f1, the high-cycle cutting machine protection method includes, before performing the high-cycle cutting machine protection: the rate of change df/dt of the first frequency is calculated from the power deficit of the small hydropower microgrid. Referring to fig. 2 and 4, in order for the relay rocf to be able to operate reliably, the relay rocf needs to be integratedAnd (3) determining so as to maintain the second frequency f2 of the small hydropower station micro-grid in the island operation mode at a frequency expected value, and setting the frequency expected value to be 55Hz in order to avoid the small hydropower station micro-grid from being re-connected. Rate of change of first frequency
Wherein f N The rated frequency of the small hydropower micro-grid is set; t is any time after the power shortage of the small hydropower micro-grid occurs; ΔP t The power shortage of the small hydropower micro-grid at the time t can be obtained by an empirical value; h is the constant number of inertia time after a plurality of generators of the small hydropower micro-grid are combined into one equivalent generator, < +.>
i is an integer greater than 1. According to the method, the change rate df/dt of the first frequency can be calculated, the action of the high-frequency cutting machine is determined according to the change rate df/dt of the first frequency, and the layered frequency modulation control is carried out on the second frequency f2 according to the output power of the small hydropower microgrid after the high-frequency cutting machine and the reference frequency, so that the second frequency output by the small hydropower microgrid in the island operation mode can be maintained at a frequency expected value, and the safe and stable operation of the small hydropower microgrid is further ensured.
Example III
Fig. 5 is a schematic structural diagram of a hierarchical fm control according to a third embodiment of the present invention, and on the basis of the foregoing embodiments, referring to fig. 4 and fig. 5, the hierarchical control according to the embodiment of the present invention includes primary fm control and secondary fm control. Because the hydropower enrichment area is mostly located in mountain areas, effective communication conditions are lacking, the condition of centralized control by the micro-grid dispatching center is not mature, and then the method is simple, flexible and cost-effective in peer-to-peer control mode. The existing small hydroelectric generating sets do not all have frequency modulation capability, the regional positions of the hydroelectric generating sets are concentrated, the stock capacity of the small hydroelectric generating sets has no economical difference, and the advantage of ensuring economical tertiary frequency modulation control in classical frequency modulation control is not obvious, so that the embodiment of the invention only considers primary frequency modulation control and secondary frequency modulation control. The primary frequency modulation control includes: according to high frequency of cuttingThe output power of the small hydropower micro-grid after the machine is controlled by adopting a sagging control mode to adjust the second frequency f2. The secondary frequency modulation control comprises the following steps: and adjusting the second frequency f2 by adopting a closed-loop PI control mode according to the reference frequency. Referring to fig. 5, the primary frequency modulation control adopts a linear droop control strategy, and since the slope of a droop curve is constant, the load of the small hydropower micro-grid can be distributed according to rated power, so that the small hydropower micro-grid is ensured to have good dynamic characteristics. The secondary frequency modulation control is carried out by directly adding a feedback link to maintain the second frequency f2 at a frequency expected value by means of the second frequency f2 output by the small hydropower micro-grid, so that the frequency deviation during steady operation of the small hydropower micro-grid can be controlled to be small enough. As can be seen from fig. 5, the second frequency f2 output by the small hydropower micro-grid is equal to the sum of the primary frequency modulation and the secondary frequency modulation, that is,
wherein the primary frequency is->
f min And f max T is the minimum and maximum of dynamic frequency 1 And α are respectively important parameters affecting the control effect, such as proportional integral parameters. When the small hydropower microgrid is in steady-state operation, the larger the value of alpha is, the smaller the frequency deviation is when the small hydropower microgrid is in steady-state operation, namely the closer the second frequency f2 is to the frequency expected value.
The embodiment of the invention specifically describes a 35kV hong ling small hydropower station in a Shaoguan tumbler source region and a downstream circuit thereof. The small red-mountain hydropower station is connected with a large power grid through a 35kV bus, and four 10kV lines are arranged in the station. The small hydropower stations in 10kV plum diagonal lines have sufficient storage capacity, and the units can be used as 1000kW frequency modulation units and can be responsible for frequency modulation tasks of island micro-grids; the generators of other circuits are 250kW and have limited adjusting capability (a small hydropower station 1, a small hydropower station 2 and a small hydropower station 3), and fixed power control is adopted; all loads subordinate to the red-ridge station are equivalent to concentrated loads. The generator and the load are connected into the power grid through a serial structure. In order to avoid misoperation of the grid-connected circuit breaker, the island operation frequency of the small hydropower micro-grid is set to be 55Hz. The frequency of the first round of cutting machine with the height of Zhou Qieji is 57Hz, and as the frequency of the small hydropower micro-grid in grid-connected operation is 50Hz, the island operation frequency of the small hydropower micro-grid is set to be 55Hz, so that the frequency of the small hydropower micro-grid in the island operation state can be fluctuated, and the frequency setting values of the second round of cutting machine and the third round of cutting machine are set to be more than 55Hz, so that the over-cutting of the generator set is prevented. The protocol of the high cycle cutting machine employed in the examples of the present invention is shown in table 1.
TABLE 1
| Cutting machine motor | Action signal | Cutting machine set | Delay/ms |
| First round cutting machine | f>57Hz | Small hydroelectric generating set 1 | 200 |
| Second round cutting machine | f>57Hz，df/dt>3Hz/s | Small hydroelectric generating set 2 | 200 |
| Third wheel cutting machine | f>57Hz，df/dt>5Hz/s | Small hydroelectric generating set 3 | 200 |
Fig. 6 is a waveform diagram of a small hydropower station cutting machine ad hoc network according to the third embodiment of the present invention, specifically, fig. 6 is a waveform diagram of a second frequency f2 of the cutting machine ad hoc network when the power supply side of the small hydropower station in red mountain breaks down and the island microgrid load is 1000 kW. Referring to table 1 and fig. 6, in the case that the outgoing channel of the small hydropower station is blocked, the technical scheme provided by the embodiment of the invention can rapidly output the cutting signal according to the change rate of the first frequency, and can rapidly recover to the island operation frequency and stably operate after cutting off a proper amount of generators. Referring to fig. 6, after the island is formed by the small hydropower micro-grid, the island load is 1700kW, 300kW load is cut off at the moment of 4s, 100kW load is input at the moment of 9s, and 200kW load is input at the moment of 15s, as can be seen from fig. 6, the maximum value of the frequency fluctuation of each generator set occurs at the moment of load switching, and then the generator sets tend to be stable within 3 seconds; the difference value between the dynamic process frequency and the island operation frequency set value of 55Hz is not more than 0.2Hz, so that the characteristic of primary frequency modulation control of a frequency modulation strategy is reflected; the frequency hardly fluctuates in a steady state, so that the requirement of the power grid on the frequency stabilization under the normal working condition is met, and the characteristic of secondary frequency modulation control of a frequency modulation strategy is reflected. Compared with the prior art, the technical scheme provided by the embodiment of the invention can keep the stability of the frequency of the small hydropower micro-grid after high-cycle cutting machine protection, and the frequency of each generator set can be quickly restored to a stable state when the load fluctuates, thereby being beneficial to improving the reliability of the small hydropower micro-grid.
Optionally, the embodiment of the invention also provides a small hydropower micro-grid cutting machine ad hoc network control system, which is controlled by adopting the small hydropower micro-grid cutting machine ad hoc network control method provided by any embodiment of the invention, so that the small hydropower micro-grid cutting machine ad hoc network control system provided by the embodiment of the invention also has the beneficial effects described in any embodiment.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of numerous obvious changes, rearrangements and substitutions without departing from the scope of the present invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (8)
1. The utility model provides a little water and electricity micro-grid cutting machine ad hoc network control method which is characterized in that the method comprises the following steps:
collecting the power grid frequency of a small hydropower micro-grid, and taking the collected power grid frequency as a first frequency;
determining whether high-cycle cutting machine protection is performed according to the first frequency;
if the high-frequency cutting machine protection is carried out, determining the cutting machine action of the high-frequency cutting machine according to the change rate of the first frequency;
collecting the power grid frequency of the small hydropower micro-grid after high-frequency cutting and taking the power grid frequency as a second frequency;
performing layered frequency modulation control on the second frequency according to the output power and the reference frequency of the small hydropower micro-grid after high-frequency cutting;
wherein the layered frequency modulation control comprises primary frequency modulation control and secondary frequency modulation control;
if the high-cycle cutting machine protection is performed, determining the cutting machine operation of the high-cycle cutting machine according to the change rate of the first frequency comprises:
if the change rate of the first frequency is larger than the first change rate, starting a third cutting machine;
if the change rate of the first frequency is larger than the second change rate and smaller than the first change rate, starting a second rotary cutter;
otherwise, the first round of cutting machine is started.
2. The method of claim 1, wherein determining whether to perform high-frequency cutter protection according to the first frequency comprises:
if the first frequency is greater than or equal to a preset frequency and the duration is greater than or equal to a preset time, high Zhou Qieji protection is performed; wherein the preset frequency is the first round of cutter frequency of the Gao Zhouqie machine.
3. The method for controlling the ad hoc network of small hydropower micro-grid cutting machine according to claim 1, wherein the second wheel cutting machine and the first wheel cutting machine are sequentially performed after the third wheel cutting machine acts.
4. The small hydropower micro-grid cutting machine ad hoc network control method according to claim 1, wherein the cutting capacity of the Gao Zhouqie machine is as follows in order from large to small: the cutting machine comprises a second round of cutting machine, a third round of cutting machine and a first round of cutting machine, wherein the cutting capacity of the third round of cutting machine is equal to that of the first round of cutting machine.
5. The small hydropower micro-grid cutting machine ad hoc network control method according to claim 1, wherein the primary frequency modulation control comprises:
and adjusting the second frequency in a sagging control mode according to the output power of the small hydropower micro-grid after the high-frequency cutting machine.
6. The small hydropower micro-grid cutting machine ad hoc network control method according to claim 4, wherein the secondary frequency modulation control comprises:
and adjusting the second frequency in a closed-loop PI control mode according to the reference frequency.
7. The small hydropower micro-grid cutter ad hoc network control method according to claim 1, wherein if the high-cycle cutter protection is determined to be performed according to the first frequency, comprising, before performing the high-cycle cutter protection:
and calculating the change rate of the first frequency according to the power shortage of the small hydropower micro-grid.
8. A small hydropower micro-grid cutting machine ad hoc network control system, characterized in that the small hydropower micro-grid cutting machine ad hoc network control method is adopted for control according to any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011017394.3A CN112202208B (en) | 2020-09-24 | 2020-09-24 | Ad hoc network control method and system for small hydropower micro-grid cutting machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011017394.3A CN112202208B (en) | 2020-09-24 | 2020-09-24 | Ad hoc network control method and system for small hydropower micro-grid cutting machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112202208A CN112202208A (en) | 2021-01-08 |
| CN112202208B true CN112202208B (en) | 2023-05-05 |
Family
ID=74006595
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011017394.3A Active CN112202208B (en) | 2020-09-24 | 2020-09-24 | Ad hoc network control method and system for small hydropower micro-grid cutting machine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112202208B (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103078326B (en) * | 2012-12-28 | 2014-09-10 | 中国电力科学研究院 | Optimization method for improving safety and stability of grid frequency |
| CN109842148A (en) * | 2018-02-01 | 2019-06-04 | 大全集团有限公司 | A kind of micro-grid connection turns the stable control method of isolated operation mode |
-
2020
- 2020-09-24 CN CN202011017394.3A patent/CN112202208B/en active Active
Non-Patent Citations (2)
| Title |
|---|
| 孤岛运行模式下微网的稳定控制仿真分析;付超等;《南方电网技术》;20131031;第66-68页 * |
| 提高农村小水电网并大网重合闸成功率的研究;王晓慧;《中国优秀硕士学位论文全文数据库工程科技II辑》;20120815;第33-34页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112202208A (en) | 2021-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103475023B (en) | On/off-grid control method for microgrid with a plurality of distributed power supplies | |
| CN111987723B (en) | Micro-grid operation control method | |
| CN108199420A (en) | Photovoltaic power plant and secondary frequency modulation control method thereof | |
| CN104538939B (en) | Adapt to the trip isolated power grid containing wind-powered electricity generation to be formed of three-phase and send out the coincidence method of line | |
| CN105552962A (en) | Micro-grid system and control method therefor | |
| CN109038664B (en) | High-frequency turn setting method considering fan grid-involvement protection | |
| CN111555310B (en) | Method for participating in frequency modulation of asynchronous power grid at transmitting end by new energy | |
| Ilyushin | Emergency and post-emergency control in the formation of micro-grids | |
| CN104935073A (en) | Method for improving power system stability by using large wind farm STATCOM centralized hierarchical decentralized coordination control | |
| CN103595052A (en) | Method for stably controlling switchover from micro-grid connection into island state | |
| CN115764929B (en) | Backup voltage frequency supporting method for 100% new energy source power grid | |
| CN111555309A (en) | Method for new energy to participate in frequency modulation of asynchronous transmission-end power grid | |
| CN112087003B (en) | New energy centralized frequency correction control system and control method | |
| CN112202208B (en) | Ad hoc network control method and system for small hydropower micro-grid cutting machine | |
| CN110518617B (en) | MMC-MTDC droop control method considering operation state of alternating current side | |
| US11898540B2 (en) | Method for feeding electrical power into an electrical supply network | |
| CN103296699B (en) | A kind of fast control method of the plan island with power conversion power-balance based on Wide-area Measurement Information | |
| Chen et al. | Analysis of power flow in wind farm with matpower | |
| CN109687525B (en) | Method and device for automatic off-grid control of hydropower microgrid | |
| CN111864783A (en) | Direct-current short-circuit fault ride-through control method and related device | |
| CN111276984A (en) | Method and system for cooperative control of primary frequency modulation subareas of direct-current floor point near-district power grid | |
| CN111555306A (en) | System and method for wind turbine generator set to participate in rapid frequency modulation of regional power grid | |
| Dhir et al. | A review of microgrid control strategies | |
| CN112165116B (en) | Handling method and device for small hydropower system with unplanned island effect | |
| CN113937806B (en) | Method for inhibiting overvoltage of wind-solar water passing through sending end of direct-current sending system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |