Multi-source cooperative AGC frequency control method based on multi-level control

Abstract

The application provides a multi-source cooperative AGC frequency modulation control method based on multi-level control, belongs to the technical field of power systems, and is an AGC hierarchical control method according to unit performance. The method classifies units into fast area units, medium speed area units and slow speed area units according to performance, distributes the control signals of the AGC to the units in each area through filtering processing, and fully considers the battery charging and discharging states of energy storage power stations. Through multi-level cooperative control, the frequency modulation resources are fully utilized, the comprehensive frequency modulation effect is improved, and the economic benefit is improved. The application can solve the problems of unclear function positioning of various frequency modulation resources, insufficient resource utilization, and series problems such as squeezing of frequency modulation resources, unreasonable calling, and inability to fully play a role in the current frequency modulation auxiliary service, can effectively improve the comprehensive frequency modulation effect, and thus improve the economic benefit.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a multi-source collaborative AGC frequency regulation control method based on multi-level control. Background Technology

[0002] In recent years, the construction of my country's new power system has been continuously deepened, and the importance of ancillary services cannot be ignored. The active power of the system is highly correlated with the frequency. With the increasing installed capacity and proportion of new energy sources year by year, the difficulty of balancing supply and demand has increased, and the Automatic Generation Control (AGC) system also faces important challenges in ensuring the stable operation of the system.

[0003] Different types of frequency regulation resources have different response characteristics to AGC control. Current common AGC control methods do not differentiate based on power source characteristics, easily leading to unclear functional positioning and insufficient resource utilization for each type of frequency regulation resource. This results in a series of problems such as resource overcrowding, unreasonable allocation, and failure to fully utilize frequency regulation resources. For example, independent new energy storage, as a rapid regulation resource, participates in the frequency regulation service market with its rapid response and high regulation accuracy, but its regulation capacity is small, it cannot execute large-step frequency regulation commands, and it needs to consider the problem of overcharging and discharging. Pumped storage and traditional hydropower units have relatively fast speeds and medium regulation capacities; thermal power units have slow response times to AGC commands but large regulation capacities.

[0004] How to comprehensively consider the characteristics of various power supplies, give full play to the advantages of each type of power supply, and avoid wasting frequency regulation resources is an urgent problem to be solved. Summary of the Invention

[0005] This invention proposes a multi-source collaborative AGC frequency modulation control method based on multi-level control, which can solve a series of problems in the current frequency modulation auxiliary service, such as unclear functional positioning of various frequency modulation resources, insufficient resource utilization, resulting in frequency modulation resource squeeze, unreasonable allocation, and failure to fully play its role. It can effectively improve the overall frequency modulation effect, thereby improving economic benefits.

[0006] The present invention adopts the following technical solution.

[0007] A multi-source collaborative AGC frequency regulation control method based on multi-level control is proposed for electrochemical energy storage power stations. This method employs an interconnected power grid AGC control model using frequency and tie-line deviation control. First, the generating units are classified into fast-speed, medium-speed, and slow-speed zones based on their performance. When an imbalance in active power between the generation and consumption sides causes frequency fluctuations in the power grid, resulting in a deviation of the power system frequency from the target frequency, the AGC control signal from the power grid dispatch center is filtered and distributed to the corresponding generating units in each zone, taking into account the battery charging and discharging status of the energy storage power station. Through multi-level collaborative control, the generating units operating in the power grid adjust their active power output to reduce frequency deviation via speed regulation systems and automatic power control, thereby achieving full utilization of frequency regulation resources and improving the overall frequency regulation effect.

[0008] The AGC control signal acquisition method is as follows: the power grid dispatch center calculates the ACE value, which reflects the active power deviation between total generation and total load in the entire control area, through the frequency deviation and tie-line power deviation in the system. The signal corresponding to the ACE value is passed through the frequency regulation controller to obtain the total frequency regulation command, and the frequency regulation command is decomposed into commands to increase or decrease output and sent to each unit participating in frequency regulation. Each unit adjusts its output in real time according to the command to keep the ACE value within the allowable range. At the same time, the dispatch center generates charging or discharging commands and sends them to the energy storage power station. The energy storage power station performs charging or discharging according to the dispatch command of the power grid.

[0009] The control method includes the following steps;

[0010] Step S1: Read the historical comprehensive performance indicators of each unit in the system, and divide them into high-speed zone units, medium-speed zone units and slow-speed zone units according to the level of comprehensive performance indicators. Then proceed to step S2.

[0011] Step S2: Perform high-pass, band-pass, and low-pass filtering on the ACE signal used for frequency modulation control to divide the signal into dead zone signal, fast zone signal, medium-speed zone signal, and slow zone signal, and then execute step S3.

[0012] Step S3: Read the current state of charge (SOC) of the electrochemical energy storage battery in the system. Based on whether the SOC of the electrochemical energy storage power station has reached the limit value, adjust some fast zone signals to medium zone and execute step S4.

[0013] Step S4: Distribute the signals from different partitions to the corresponding units in the partitions, and then proceed to step S5;

[0014] Step S5: Based on the actual response of each unit within the preset time period, recalculate the comprehensive performance index of the unit, correct the calculation results in real time, and update them to step S1.

[0015] In step S1, the various units in the system are classified according to their actual performance, including the following steps:

[0016] Step S11: Define the unit's regulation speed K1, regulation accuracy K2, and response time K3, and then execute step S12;

[0017]

[0018]

[0019]

[0020] Step S12: Calculate the comprehensive performance index K based on the weighted average, and then proceed to step S13;

[0021] K = 0.25 × (2 × K1 + K + 2K3)

[0022] Step S13, the comprehensive performance index K value is greater than K f The unit is defined as a high-speed unit, and the comprehensive performance index K value is within K. f and K s The range is defined as medium-speed units, where the comprehensive performance index K value is less than K. s The definition is a slow-speed unit.

[0023] In step S2, the ACE signal in the system is processed by filtering, including the following steps:

[0024] Step S21: Process the signal using Fast Fourier Transform to obtain the frequency domain information of the ACE signal, and then proceed to step S22.

[0025] Step S22: Define signals with frequencies above fd as dead zones, and signals with frequencies below fd as dead zones. d and f f The range between these two points is defined as the fast zone signal, with a frequency between f. f and f s The range between these two is defined as the medium-speed signal, with frequencies between f and f. s The following definition is for slow-speed signals.

[0026] In step S3, the fast zone signal is reallocated according to the SOC of the energy stored in the system, including the following steps:

[0027] Step S31: Read the SOC of the energy stored in the system and determine whether it is overcharged / discharged. If it is overcharged / discharged, proceed to step S32. If it is in a normal state, no adjustment is made.

[0028] Step S32: Determine whether the signal helps the energy storage battery get out of the overcharge / discharge state. If not, proceed to step S33. If yes, no adjustment is made.

[0029] Step S33: Adjust the corresponding fast zone signal to the medium zone.

[0030] In step S4, the signals from different partitions are distributed to the units in different partitions, including the following steps:

[0031] Step S41: Divide the bid prices of the units in different zones by the comprehensive performance index, sort them from low to high, and proceed to step S42.

[0032] Step S42: The response principle of each unit in the system is as follows: dead zone signals are not responded to, fast zone signals are assigned to fast zone units for response, medium speed zone signals are assigned to medium speed zone units for response, and slow speed zone signals are assigned to slow zone units for response. Then proceed to step S43.

[0033] Step S43: Prioritize allocating ACE adjustment requirements to the highest-ranked units in each zone, and prioritize calling units with high performance and low price, until the requirements are met.

[0034] The preset duration for step S5 is 15 minutes.

[0035] This invention relates to a multi-source collaborative AGC frequency regulation control method based on multi-level control, belonging to the field of power system technology. It proposes a hierarchical AGC control method based on unit performance, which solves a series of problems in the current frequency regulation ancillary services, such as unclear functional positioning of various frequency regulation resources, insufficient resource utilization, and resulting in frequency regulation resource squeeze, unreasonable allocation, and failure to fully play its role. It can effectively improve the overall frequency regulation effect, thereby improving economic benefits.

[0036] This invention proposes a multi-source collaborative AGC frequency regulation control method based on multi-level control. The method classifies generating units into high-speed, medium-speed, and low-speed zones according to their performance. The AGC control signals are then filtered and distributed to the corresponding units in each zone, taking into full account the charging and discharging states of the energy storage station's batteries. Through multi-level collaborative control, frequency regulation resources are fully utilized, improving the overall frequency regulation effect and thus increasing economic efficiency.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] One of the beneficial effects of this solution is that, in the context of unclear functional positioning and insufficient utilization of various frequency regulation resources in the pre-frequency regulation ancillary services, which leads to a series of problems such as the squeezing of frequency regulation resources, unreasonable allocation, and failure to fully utilize their functions, the ACE value is decomposed through filtering based on the characteristics of different performance units. This allows units with different performance to play their maximum role, while also considering the charging and discharging limits of energy storage batteries. This achieves the optimal unit combination in the frequency regulation ancillary services market, which can effectively improve the overall frequency regulation effect and increase economic benefits. Attached Figure Description

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0040] Appendix Figure 1 This is a flowchart of a multi-source collaborative AGC frequency modulation control based on multi-level control according to the present invention;

[0041] Appendix Figure 2 This is a schematic diagram of the second-level ACE signal in the embodiment;

[0042] Appendix Figure 3 This is a schematic diagram of the signal corresponding partition decomposition in the embodiment;

[0043] Appendix Figure 4 This is a schematic diagram of the fast and medium speed zones of the energy storage battery under low power conditions in the embodiment.

[0044] Appendix Figure 5 This is a schematic diagram of the frequency modulation process of AGC. Detailed Implementation

[0045] The following description, in conjunction with the appendix of the present invention, Figure 1 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] like Figure 1 As shown, a multi-source collaborative AGC frequency regulation control method based on multi-level control is used in electrochemical energy storage power stations. The method employs an interconnected power grid AGC control model using frequency and tie-line deviation control. First, the generating units are classified into fast-speed, medium-speed, and slow-speed zones based on their performance. When an imbalance in active power between the generation and consumption sides causes frequency fluctuations in the power grid, resulting in a deviation of the power system frequency from the target frequency, the AGC control signal from the power grid dispatch center is filtered and distributed to the generating units in each zone accordingly. Furthermore, based on the battery charging and discharging status of the energy storage power station, multi-level collaborative control is used to adjust the active power output of the generating units operating in the power grid through speed regulation systems and automatic power control to reduce frequency deviation. This achieves full utilization of frequency regulation resources and improves the overall frequency regulation effect.

[0047] The AGC control signal acquisition method is as follows: the power grid dispatch center calculates the ACE value, reflecting the active power deviation between total generation and total load in the entire control area, based on the frequency deviation and tie-line power deviation in the system. The signal corresponding to the ACE value is processed by the frequency controller to obtain the overall frequency regulation command, which is then decomposed into commands to increase or decrease output and issued to each unit participating in the frequency regulation. Each unit adjusts its output in real time according to the command to keep the ACE value within the allowable range. Simultaneously, the dispatch center generates charging or discharging commands and issues them to the energy storage power station, which performs charging or discharging according to the power grid's dispatch command. The ACE consists of two parts: the actual power flow deviation from the planned flow in the tie-line and the deviation between the system frequency and the target frequency. The calculation process considers the current generation, load, and frequency factors of the control area system. The ACE calculation formula is:

[0048] ACE = ΔP t -10BΔf.

[0049] In the formula, ΔP is the real-time tie-line power deviation, B is the regional frequency deviation coefficient, and Δf is the frequency deviation.

[0050] The control method includes the following steps;

[0051] Step S1: Read the historical comprehensive performance indicators of each unit in the system, and divide them into high-speed zone units, medium-speed zone units and slow-speed zone units according to the level of comprehensive performance indicators. Then proceed to step S2.

[0052] Step S2: Perform high-pass, band-pass, and low-pass filtering on the ACE signal used for frequency modulation control to divide the signal into dead zone signal, fast zone signal, medium-speed zone signal, and slow zone signal, and then execute step S3.

[0053] Step S3: Read the state of charge (SOC) of the electrochemical energy storage battery in the current system. Based on whether the SOC of the electrochemical energy storage power station has reached the limit value, adjust some fast zone signals to medium zone and execute step S4.

[0054] Step S4: Distribute the signals from different partitions to the corresponding units in the partitions, and then proceed to step S5;

[0055] Step S5: Based on the actual response of each unit within the preset time period, recalculate the comprehensive performance index of the unit, correct the calculation results in real time, and update them to step S1.

[0056] In step S1, the various units in the system are classified according to their actual performance, including the following steps:

[0057] Step S11: Define the unit's regulation speed K1, regulation accuracy K2, and response time K3, and then execute step S12;

[0058]

[0059]

[0060]

[0061] Step S12: Calculate the comprehensive performance index K based on the weighted average, and then proceed to step S13;

[0062] K = 0.25 × (2 × K1 + K + 2K3)

[0063] Step S13, the comprehensive performance index K value is greater than K f The unit is defined as a high-speed unit, and the comprehensive performance index K value is within K. f and K s The range is defined as medium-speed units, where the comprehensive performance index K value is less than K. s The definition is a slow-speed unit.

[0064] In step S2, the ACE signal in the system is processed by filtering, including the following steps:

[0065] Step S21: Process the signal using Fast Fourier Transform to obtain the frequency domain information of the ACE signal, and then proceed to step S22.

[0066] Step S22: Define signals with frequencies above fd as dead zones, and signals with frequencies below fd as dead zones. d and f f The range between these two points is defined as the fast zone signal, with a frequency between f. f and f s The range between these two is defined as the medium-speed signal, with frequencies between f and f. s The following definition is for slow-speed signals.

[0067] In step S3, the fast zone signal is reallocated according to the SOC of the energy stored in the system, including the following steps:

[0068] Step S31: Read the SOC of the energy stored in the system and determine whether it is overcharged / discharged. If it is overcharged / discharged, proceed to step S32. If it is in a normal state, no adjustment is made.

[0069] Step S32: Determine whether the signal helps the energy storage battery get out of the overcharge / discharge state. If not, proceed to step S33. If yes, no adjustment is made.

[0070] Step S33: Adjust the corresponding fast zone signal to the medium zone.

[0071] In step S4, the signals from different partitions are distributed to the units in different partitions, including the following steps:

[0072] Step S41: Divide the bid prices of the units in different zones by the comprehensive performance index, sort them from low to high, and proceed to step S42.

[0073] Step S42: The response principle of each unit in the system is as follows: dead zone signals are not responded to, fast zone signals are assigned to fast zone units for response, medium speed zone signals are assigned to medium speed zone units for response, and slow speed zone signals are assigned to slow zone units for response. Then proceed to step S43.

[0074] Step S42: Prioritize allocating ACE adjustment requirements to the highest-ranked units in each zone, and prioritize calling units with high performance and low price, until the requirements are met.

[0075] The preset duration for step S5 is 15 minutes.

[0076] Example:

[0077] Assuming that during a certain time period, the system includes 1 energy storage unit, 3 hydropower units, and 2 coal-fired power units participating in frequency regulation, their performance parameters are shown in the table below:

[0078]

[0079] Step 1: Analyze the overall performance indicators of the computer groups and classify them according to these indicators. Groups with an overall performance indicator greater than 6 are defined as high-speed groups, those between 3 and 6 are defined as medium-speed groups, and those below 3 are defined as low-speed groups. The classification is as follows:

[0080]

[0081] Step 2: ACE demand within 3 minutes at a certain time period, such as... Figure 2 As shown, the signal is processed using Fast Fourier Transform (FFT). Signals with frequencies above fd are defined as dead zones, frequencies between fd and ff are defined as fast zones, frequencies between ff and fs are defined as medium-speed zones, and frequencies below fs are defined as slow zones. The signal partitioning is as follows: Figure 3 As shown

[0082] Step 3: Read the SOC of the stored energy in the system to determine if it is overcharged / discharged. Assuming the current SOC of the stored energy battery is low, in this state, adjust the signal from the fast-speed zone to the medium-speed zone. The adjusted signal is as follows: Figure 4 As shown.

[0083] Step 4: Filter the dead zone signal, allocate the fast zone signal to the fast zone unit response, allocate the medium zone signal to the medium zone unit response, and allocate the slow zone signal to the slow zone unit response.

[0084] Step 5: Based on the actual response of each unit within 15 minutes, recalculate the comprehensive performance index of the computer group, and correct and update the calculation results in real time.

[0085] In summary, to address the series of problems in pre-modulation auxiliary services, such as unclear functional positioning of various FM resources, insufficient resource utilization, resulting in FM resource shortages, unreasonable allocation, and failure to fully utilize their functions, the comprehensive FM effect can be effectively improved, thereby increasing economic benefits.

[0086] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A multi-source collaborative AGC frequency control method based on multi-level control for an electrochemical energy storage power station, characterized in that: The method is an interconnected power grid AGC control method using a frequency and tie-line deviation control mode, first classifying each unit into a fast zone unit, a medium speed zone unit and a slow speed zone unit according to performance, when active power imbalance at the power generation side and the power consumption side causes frequency fluctuation of the power grid and the frequency of the power system deviates from the target frequency, filtering the AGC control signal of the power grid dispatching center and distributing it to the units in each zone, and according to the battery charging and discharging state of the energy storage power station, adjusting the active output of the units in operation in the power grid through the speed regulation system and automatic power control to reduce the frequency deviation, achieving full utilization of frequency modulation resources and improving the comprehensive frequency modulation effect; The AGC control signal acquisition method is that the dispatching center of the power grid calculates the ACE value reflecting the active deviation of the total power generation and total load in the entire control zone through the frequency deviation and tie-line power deviation in the system, the ACE value corresponding signal passes through the frequency modulation controller to obtain the total frequency modulation instruction, and the frequency modulation instruction is decomposed into an increase or decrease output instruction and is issued to each unit participating in frequency modulation, each unit adjusts the output in real time according to the instruction to keep the ACE value within the allowed range; meanwhile, the dispatching center generates a charging or discharging instruction and issues it to the energy storage power station, and the energy storage power station executes the charging or discharging according to the dispatching instruction of the power grid; The control method comprises the following steps: Step S1, read the historical comprehensive performance index of each unit in the system, and divide the units into fast zone units, medium speed zone units and slow speed zone units according to the high and low of the comprehensive performance index, and execute step S2; Step S2, high-pass, band-pass and low-pass filter processing is performed on the ACE signal used for frequency modulation control, the signal is divided into dead zone signal, fast zone signal, medium speed zone signal and slow speed zone signal, and step S3 is executed; Step S3, read the current state of charge SOC of the electrochemical energy storage battery, and adjust part of the fast zone signal to the medium speed zone according to whether the SOC of the electrochemical energy storage power station reaches the limit value, and execute step S4; Step S4, distribute the signals of different partitions to the units in the corresponding partitions, and execute step S5; Step S5, according to the actual response of each unit within a predetermined time, recalculate the comprehensive performance index of each unit, and update the calculation result to step S1 in real time; In step S1, each unit in the system is classified according to actual performance, comprising the following steps: Step S11, define the regulation speed K1, regulation accuracy K2 and response time K3 of the unit, and execute step S12; Step S12, calculate the comprehensive performance index K according to the weighted calculation, and execute step S13; Step S13, the comprehensive performance index K value is greater than K f The unit is defined as fast unit, the comprehensive performance index K value is between K f and K s The unit is defined as medium speed unit, the comprehensive performance index K value is less than K s The unit is defined as slow unit.

2. The multi-source coordinated AGC frequency control method based on multi-level control according to claim 1, characterized in that: In step S2, the ACE signal in the system is processed by filtering, comprising the following steps: Step S21, use fast Fourier transform to process the signal to obtain the frequency domain information of the ACE signal, and execute step S22; Step S22, the frequency in f d The above signal is defined as dead zone, the frequency in f d and f f is defined as fast zone signal, the frequency in f f and f s is defined as medium speed zone signal, the frequency in f s The following is defined as slow zone signal.

3. The multi-source coordinated AGC frequency control method based on multi-level control according to claim 2, characterized in that: In step S3, the fast zone signal is redistributed according to the SOC of the system energy storage, comprising the following steps: Step S31: Read the SOC of the energy stored in the system and determine whether it is overcharged / discharged. If it is overcharged / discharged, proceed to step S32. If it is in a normal state, no adjustment is made. Step S32: Determine whether the signal helps the energy storage battery get out of the overcharge / discharge state. If not, proceed to step S33. If yes, no adjustment is made. Step S33: Adjust the corresponding fast zone signal to the medium zone.

4. The multi-source coordinated AGC frequency control method based on multi-level control according to claim 3, characterized in that: In step S4, the signals from different partitions are distributed to the units in different partitions, including the following steps: Step S41: Divide the bid prices of the units in different zones by the comprehensive performance index, sort them from low to high, and proceed to step S42. Step S42: The response principle of each unit in the system is as follows: dead zone signals are not responded to, fast zone signals are assigned to fast zone units for response, medium speed zone signals are assigned to medium speed zone units for response, and slow speed zone signals are assigned to slow zone units for response. Then proceed to step S43. Step S43: Prioritize allocating ACE adjustment requirements to the highest-ranked units in each zone, and prioritize calling units with high performance and low price, until the requirements are met.

5. The multi-source coordinated AGC frequency control method based on multi-level control according to claim 4, characterized in that: The preset duration for step S5 is 15 minutes.

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