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

Abstract

The invention provides a multi-source cooperative AGC frequency modulation control method based on multi-level control, belongs to the technical field of power systems, and relates to an AGC hierarchical control method based on unit performance, which comprises the following steps of: classifying units into a fast-speed area unit, a medium-speed area unit and a slow-speed area unit according to the performance, and filtering an AGC control signal to obtain an AGC frequency modulation signal; and the battery charging and discharging states of the energy storage power station are fully considered. Through multi-level cooperative control, full utilization of frequency modulation resources is achieved, the comprehensive frequency modulation effect is improved, and therefore economic benefits are improved. According to the method, a series of problems of squeezing, unreasonable calling, incapability of fully playing roles and the like of frequency modulation resources caused by unclear function positioning and insufficient resource utilization of various frequency modulation resources in the current frequency modulation auxiliary service can be solved, the comprehensive frequency modulation effect can be effectively improved, and thus the economic benefit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a multi-source coordinated AGC frequency modulation control method based on multi-level control. Background Art

[0002] In recent years, the construction of my country's new power system has continued to deepen, and the importance of auxiliary services cannot be ignored. The active power and frequency of the system are highly correlated. As the installed capacity and proportion of new energy sources increase year by year and the difficulty of balancing supply and demand increases, the Automatic Generation Control (AGC) system also faces important challenges in ensuring the stable operation of the system.

[0003] The response characteristics of various types of frequency regulation resources to AGC control are different. The current common AGC control methods do not distinguish according to the characteristics of the power supply, which easily leads to unclear functional positioning of various types of frequency regulation resources and insufficient resource utilization, which in turn leads to a series of problems such as frequency regulation resource runs, unreasonable calls, and inability to fully play their roles. For example, independent new energy storage, as a fast regulation resource, participates in the frequency regulation service market with the characteristics of rapid response and high regulation accuracy, but its regulation capacity is small, and it cannot execute large-step frequency regulation instructions, and it needs to consider the problem of overcharging and discharging; pumped storage and traditional hydropower units are fast and have medium regulation capacity; thermal power units respond slowly to AGC instructions, but have large regulation capacity.

[0004] How to comprehensively consider the characteristics of various power sources, give full play to the advantages of various power sources, and avoid wasting frequency modulation resources is a problem that needs to be solved urgently. Summary of the invention

[0005] The present 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 services, such as unclear functional positioning of various frequency modulation resources and insufficient resource utilization, which further leads to a run on frequency modulation resources, unreasonable calling, and inability to fully play their roles. It can effectively improve the comprehensive frequency modulation effect, thereby improving economic benefits.

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

[0007] A multi-source coordinated AGC frequency modulation control method based on multi-level control is used for electrochemical energy storage power stations. The method is an interconnected power grid AGC control model method using a frequency and tie line deviation control mode. Each unit is first classified into a fast-speed zone unit, a medium-speed zone unit and a slow-speed zone unit according to performance. When the active power imbalance on the power generation side and the power consumption side causes the frequency fluctuation of the power grid and causes the power system frequency to deviate from the target frequency, the AGC control signal of the power grid dispatching center is processed by filtering and distributed to the units in each zone accordingly, and according to the battery charging and discharging status of the energy storage power station; through multi-level coordinated control, the units running in the power grid are adjusted through the speed regulation system and automatic power control to reduce the frequency deviation; the full utilization of frequency modulation resources is achieved, and the comprehensive frequency modulation effect is improved.

[0008] The AGC control signal acquisition method is as follows: the dispatching center of the power grid calculates the ACE value reflecting the active power deviation between the total power generation and the total load in the entire control area through the frequency deviation in the system and the tie line power deviation; the signal corresponding to the ACE value is passed through the frequency modulation controller to obtain the total frequency modulation instruction, and the frequency modulation instruction is decomposed into instructions to increase or reduce the output and sent to each unit involved in the frequency modulation; each unit adjusts the output in real time according to the instruction to keep the ACE value within the allowable range; at the same time, the dispatching center generates a charging or discharging instruction and sends it to the energy storage power station, and the energy storage power station performs charging or discharging according to the dispatching instruction of the power grid.

[0009] The control method comprises the following steps:

[0010] Step S1, read the historical comprehensive performance indicators of each unit in the system, and divide them into fast-speed zone units, medium-speed zone units and slow-speed zone units according to the comprehensive performance indicators, and execute step S2;

[0011] Step S2, performing high-pass, band-pass and low-pass filtering on the ACE signal used for frequency modulation control, dividing the signal into a dead zone signal, a fast zone signal, a medium-speed zone signal and a slow zone signal, and executing step S3;

[0012] Step S3, reading the state of charge (SOC) of the battery of the electrochemical energy storage in the current system, and adjusting part of the fast zone signal to the medium speed zone based on whether the SOC of the electrochemical energy storage power station reaches the limit value, and executing step S4;

[0013] Step S4, distribute the signals of different partitions to the units in the corresponding partitions, and execute step S5;

[0014] Step S5: recalculate the comprehensive performance index of the computer group according to the actual response of each unit within the preset time, and correct and update the calculation result in real time to step S1.

[0015] In step S1, each unit in the system is classified according to actual performance, including the following steps:

[0016] Step S11, define the regulating speed K1, regulating accuracy K2 and response time K3 of the unit, and execute step S12;

[0017]

[0018]

[0019]

[0020] Step S12, executing step S13 according to the weighted calculation comprehensive performance index K;

[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 fast unit, and the comprehensive performance index K value is K f and K s The medium speed unit is defined as the unit with a comprehensive performance index K value less than K s is defined as a slow unit.

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

[0024] Step S21, using fast Fourier transform to process the signal to obtain frequency domain information of the ACE signal, and then executing step S22;

[0025] Step S22, define the signal with frequency above fd as dead zone, and the signal with frequency below fd as dead zone. d and f f The fast zone signal is defined as the frequency between f f and f s The signal between is defined as the medium speed zone, with a frequency of f s The following are defined as slow zone signals.

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

[0027] Step S31, reading the SOC of the energy storage in the system to determine whether it is in overcharge / discharge, if it is in overcharge / discharge, executing step S32, if it is in normal state, no adjustment is performed;

[0028] Step S32, determining whether the signal helps the energy storage battery to escape from an overcharge / discharge state, if not, executing step S33, if yes, no adjustment is performed;

[0029] Step S33, adjusting the corresponding fast-speed zone signal to the medium-speed zone.

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

[0031] Step S41, dividing the quotations of the units in different partitions by the comprehensive performance index, sorting them from low to high, and executing step S42;

[0032] Step S42, the response principle of each unit in the system is: no response to the dead zone signal, the fast zone signal is allocated to the fast zone unit for response, the medium speed zone signal is allocated to the medium speed zone unit for response, and the slow zone signal is allocated to the slow zone unit for response, and then execute step S43;

[0033] Step S43, preferentially allocating ACE adjustment requirements to the units with the highest ranking in each partition, and preferentially calling the units with high performance and low quotations until the requirements are met.

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

[0035] The present invention relates to a multi-source coordinated AGC frequency regulation control method based on multi-level control, belonging to the technical field of power system, and proposes an AGC hierarchical control method according to unit performance, which solves a series of problems in the current frequency regulation auxiliary service, such as unclear functional positioning of various frequency regulation resources and insufficient resource utilization, which leads to a run on frequency regulation resources, unreasonable call, and inability to give full play to the resources, and can effectively improve the comprehensive frequency regulation effect, thereby improving the economic benefits.

[0036] The present invention proposes a multi-source coordinated AGC frequency modulation control method based on multi-level control, which classifies the units into fast-speed zone units, medium-speed zone units and slow-speed zone units according to their performance, and then distributes the AGC control signal to the units in each zone through filtering, and fully considers the battery charging and discharging status of the energy storage power station. Through multi-level coordinated control, full utilization of frequency modulation resources is achieved, and the comprehensive frequency modulation effect is improved, thereby improving economic benefits.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] One of the beneficial effects of this scheme is that, in order to address a series of problems in the previous frequency regulation auxiliary service, such as unclear functional positioning of various frequency regulation resources and insufficient resource utilization, which in turn lead to frequency regulation resource runs, unreasonable calls, and inability to fully play their roles, the ACE value is decomposed through filtering according to the characteristics of units with different performances, so that units with different performances can each play their maximum role. At the same time, the charging and discharging limits of the energy storage battery are taken into consideration to achieve the optimal unit combination in the frequency regulation auxiliary service market, which can effectively improve the comprehensive frequency regulation effect and improve economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0040] Attached Figure 1 It is a multi-source cooperative AGC frequency modulation control flow chart based on multi-level control of the present invention;

[0041] Attached Figure 2 is a schematic diagram of a second-level ACE signal in an embodiment;

[0042] Attached Figure 3 Schematic diagram of signal corresponding partition decomposition in the embodiment;

[0043] Attached Figure 4 It is a schematic diagram of fast zone and medium speed zone signals when the energy storage battery is low in power in the embodiment;

[0044] Attached Figure 5 This is a schematic diagram of the AGC frequency modulation process. DETAILED DESCRIPTION

[0045] Below in conjunction with the appended Figure 1 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] like Figure 1 As shown, a multi-source collaborative AGC frequency modulation control method based on multi-level control is used for electrochemical energy storage power stations. The method is an interconnected power grid AGC control model method using a frequency and tie line deviation control mode. First, each unit is classified into a fast zone unit, a medium speed zone unit and a slow zone unit according to performance. When the active power imbalance on the power generation side and the power consumption side causes the frequency fluctuation of the power grid and the power system frequency deviates from the target frequency, the AGC control signal of the power grid dispatching center is processed by filtering and distributed to the units in each zone accordingly, and according to the battery charging and discharging status of the energy storage power station; through multi-level collaborative control, the units running in the power grid adjust the active output to reduce the frequency deviation through the speed regulation system and automatic power control; the full utilization of frequency modulation resources is achieved and the comprehensive frequency modulation effect is improved.

[0047] The AGC control signal acquisition method is as follows: the dispatching center of the power grid calculates the ACE value reflecting the active power deviation between the total power generation and the total load in the entire control area through the frequency deviation in the system and the power deviation of the tie line. The signal corresponding to the ACE value is passed through the frequency modulation controller to obtain the total frequency modulation instruction, and the frequency modulation instruction is decomposed into an instruction to increase or reduce the output and sent to each unit participating in the frequency modulation. Each unit adjusts the output in real time according to the instruction to keep the ACE value within the allowable range; at the same time, the dispatching center generates a charging or discharging instruction and sends it to the energy storage power station, and the energy storage power station performs charging or discharging according to the dispatching instruction of the power grid; ACE consists of two parts: the actual flow of the tie line and the planned deviation, and the system frequency and the target frequency deviation. The calculation process takes into account the factors of the current power generation, load and frequency of the control area system; the ACE calculation formula is:

[0048] ACE=ΔP t -10BΔf.

[0049] Where 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 comprises the following steps:

[0051] Step S1, read the historical comprehensive performance indicators of each unit in the system, and divide them into fast-speed zone units, medium-speed zone units and slow-speed zone units according to the comprehensive performance indicators, and execute step S2;

[0052] Step S2, performing high-pass, band-pass and low-pass filtering on the ACE signal used for frequency modulation control, dividing the signal into a dead zone signal, a fast zone signal, a medium-speed zone signal and a slow zone signal, and executing step S3;

[0053] Step S3, reading the state of charge (SOC) of the battery of the electrochemical energy storage in the current system, and adjusting part of the fast zone signal to the medium speed zone based on whether the SOC of the electrochemical energy storage power station reaches the limit value, and executing step S4;

[0054] Step S4, distribute the signals of different partitions to the units in the corresponding partitions, and execute step S5;

[0055] Step S5: recalculate the comprehensive performance index of the computer group according to the actual response of each unit within the preset time, and correct and update the calculation result in real time to step S1.

[0056] In step S1, each unit in the system is classified according to actual performance, including the following steps:

[0057] Step S11, define the regulating speed K1, regulating accuracy K2 and response time K3 of the unit, and execute step S12;

[0058]

[0059]

[0060]

[0061] Step S12, executing step S13 according to the weighted calculation comprehensive performance index K;

[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 fast unit, and the comprehensive performance index K value is K f and K s The medium speed unit is defined as the unit with a comprehensive performance index K value less than K s is defined as a slow unit.

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

[0065] Step S21, using fast Fourier transform to process the signal to obtain frequency domain information of the ACE signal, and then executing step S22;

[0066] Step S22, define the signal with frequency above fd as dead zone, and the signal with frequency below fd as dead zone. d and f f The fast zone signal is defined as the frequency between f f and f s The signal between is defined as the medium speed zone, with a frequency of f s The following are defined as slow zone signals.

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

[0068] Step S31, reading the SOC of the energy storage in the system to determine whether it is in overcharge / discharge, if it is in overcharge / discharge, executing step S32, if it is in normal state, no adjustment is performed;

[0069] Step S32, determining whether the signal helps the energy storage battery to escape from an overcharge / discharge state, if not, executing step S33, if yes, no adjustment is performed;

[0070] Step S33, adjusting the corresponding fast-speed zone signal to the medium-speed zone.

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

[0072] Step S41, dividing the quotations of the units in different partitions by the comprehensive performance index, sorting them from low to high, and executing step S42;

[0073] Step S42, the response principle of each unit in the system is: no response to the dead zone signal, the fast zone signal is allocated to the fast zone unit for response, the medium speed zone signal is allocated to the medium speed zone unit for response, and the slow zone signal is allocated to the slow zone unit for response, and then execute step S43;

[0074] Step S42, preferentially allocating ACE adjustment requirements to the units with the highest ranking in each partition, and preferentially calling the units with high performance and low quotations until the requirements are met.

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

[0076] Example:

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

[0078]

[0079] Step 1: Calculate the comprehensive performance index of the unit and classify the units according to the comprehensive performance index. The units with comprehensive performance index greater than 6 are defined as fast units, the units with comprehensive performance between 3 and 6 are defined as medium-speed units, and the units with comprehensive performance below 3 are defined as slow units. The divisions are as follows:

[0080]

[0081] Step 2: The ACE demand in seconds within 3 minutes in a certain period is as follows: Figure 2 As shown in the figure, the fast Fourier transform is used to process the signal, and the signal with frequency above fd is defined as the dead zone, the signal with frequency between fd and ff is defined as the fast zone signal, the signal with frequency between ff and fs is defined as the medium zone signal, and the signal with frequency below fs is defined as the slow zone signal. Figure 3 Shown

[0082] Step 3: Read the SOC of the energy storage in the system to determine whether it is in overcharge / discharge. Assuming that the SOC of the energy storage battery is at low power at the current moment, the signal of increasing output in the original fast zone is adjusted to the medium speed zone. The adjusted signal is as follows: Figure 4 shown.

[0083] Step 4: Filter the dead zone signal, assign the fast zone signal to the fast zone unit response, the medium speed zone signal to the medium speed zone unit response, and 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 indicators of the computer group and correct and update the calculation results in real time.

[0085] To sum up, in order to address a series of problems in the front-end frequency regulation auxiliary service, such as unclear functional positioning of various frequency regulation resources and insufficient resource utilization, which lead to frequency regulation resource runs, unreasonable calls, and inability to fully play their roles, the comprehensive frequency regulation effect can be effectively improved, thereby improving economic benefits.

[0086] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A multi-source coordinated AGC frequency modulation control method based on multi-level control for electrochemical energy storage power stations. Features: The method is an interconnected power grid AGC control model method using a frequency and tie line deviation control mode. Each unit is first classified into a fast-speed zone unit, a medium-speed zone unit and a slow-speed zone unit according to performance. When the active power imbalance on the power generation side and the power consumption side causes the frequency fluctuation of the power grid and causes the power system frequency to deviate from the target frequency, the AGC control signal of the power grid dispatching center is processed by filtering and distributed to the units in each zone accordingly, and according to the battery charging and discharging status of the energy storage power station; through multi-level coordinated control, the units running in the power grid adjust the active output to reduce the frequency deviation through the speed regulation system and automatic power control; the full utilization of frequency regulation resources is achieved, and the comprehensive frequency regulation effect is improved.

2. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 1, Features: The AGC control signal acquisition method is as follows: the dispatching center of the power grid calculates the ACE value reflecting the active power deviation between the total power generation and the total load in the entire control area through the frequency deviation in the system and the tie line power deviation; the signal corresponding to the ACE value is passed through the frequency modulation controller to obtain the total frequency modulation instruction, and the frequency modulation instruction is decomposed into instructions to increase or reduce the output and sent to each unit involved in the frequency modulation; each unit adjusts the output in real time according to the instruction to keep the ACE value within the allowable range; at the same time, the dispatching center generates a charging or discharging instruction and sends it to the energy storage power station, and the energy storage power station performs charging or discharging according to the dispatching instruction of the power grid.

3. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 2, Features: The control method comprises the following steps: Step S1, read the historical comprehensive performance indicators of each unit in the system, and divide them into fast-speed zone units, medium-speed zone units and slow-speed zone units according to the comprehensive performance indicators, and execute step S2; Step S2, performing high-pass, band-pass and low-pass filtering on the ACE signal used for frequency modulation control, dividing the signal into a dead zone signal, a fast zone signal, a medium-speed zone signal and a slow zone signal, and executing step S3; Step S3, reading the battery state of charge SOC of the electrochemical energy storage in the current system, and adjusting part of the fast zone signal to the medium speed zone based on whether the SOC of the electrochemical energy storage power station reaches the limit value, and executing step S4; Step S4, distribute the signals of different partitions to the units in the corresponding partitions, and execute step S5; Step S5: recalculate the comprehensive performance index of the computer group according to the actual response of each unit within the preset time, and correct and update the calculation result in real time to step S1.

4. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 3, Features: In step S1, each unit in the system is classified according to actual performance, including the following steps: Step S11, define the regulating speed K of the unit 1 , Adjustment accuracy K 2 and response time K 3 , execute step S12; Step S12, executing step S13 according to the weighted calculation comprehensive performance index K; K=0.25×(2×K 1 +K+ 2 K 3 ) Step S13: the comprehensive performance index K value is greater than K f The unit is defined as a fast unit, and the comprehensive performance index K value is K f and K s The medium speed unit is defined as the unit with a comprehensive performance index K value less than K s is defined as a slow unit.

5. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 4, Features: In step S2, the ACE signal in the system is processed by filtering, including the following steps: Step S21, using fast Fourier transform to process the signal to obtain frequency domain information of the ACE signal, and then executing step S22; Step S22, define the signal with frequency above fd as dead zone, and the signal with frequency below fd as dead zone. d and f f The fast zone signal is defined as the frequency between f f and f s The signal between is defined as the medium speed zone, with a frequency of f s The following are defined as slow zone signals.

6. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 5, Features: In step S3, the fast zone signal is reallocated according to the SOC of the energy storage in the system, including the following steps: Step S31, reading the SOC of the energy storage in the system to determine whether it is in overcharge / discharge, if it is in overcharge / discharge, executing step S32, if it is in normal state, no adjustment is performed; Step S32, determining whether the signal helps the energy storage battery to escape from an overcharge / discharge state, if not, executing step S33, if yes, no adjustment is performed; Step S33, adjusting the corresponding fast-speed zone signal to the medium-speed zone.

7. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 6, Features: In step S4, the signals of different partitions are respectively distributed to the units of different partitions, including the following steps: Step S41, dividing the quotations of the units in different partitions by the comprehensive performance index, sorting them from low to high, and executing step S42; Step S42, the response principle of each unit in the system is: no response to the dead zone signal, the fast zone signal is allocated to the fast zone unit for response, the medium speed zone signal is allocated to the medium speed zone unit for response, and the slow zone signal is allocated to the slow zone unit for response, and then execute step S43; Step S43, preferentially allocating ACE adjustment requirements to the units with the highest ranking in each partition, and preferentially calling the units with high performance and low quotations until the requirements are met.

8. A multi-source coordinated AGC frequency modulation control method based on multi-level control according to claim 7, Features: The preset duration of step S5 is 15 minutes.

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