Control method of thermal power energy storage combined frequency modulation and capacity self-recovery system

Abstract

The invention provides a control method of a thermal power and energy storage combined frequency modulation and capacity self-recovery system, original control logic irrelevant to energy storage system parameters of a thermal power generating unit control system is changed, an AGC instruction prediction mechanism is established, a real-time two-way communication mechanism is established between the thermal power generating unit control system and an energy storage control system, and coordinated control is achieved. The complementary effect is fully exerted; a stable regulation mode and an overshoot mode of the thermal power generating unit and a frequency modulation mode and a self-recovery mode of the energy storage system are established, output of the thermal power generating unit is maximized, regulation of different powers and capacity self-recovery of the energy storage system in different charge states are realized, climbing limitation of the thermal power generating unit and frequency modulation limitation of the energy storage system are broken through, and the energy storage system is enabled to be more stable and reliable. The service life of the energy storage system is prolonged, the bidirectional frequency modulation capability of the energy storage system is improved, and the combined frequency modulation capability of the thermal power generating unit and the energy storage system is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage, and in particular relates to a control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system. Background Art

[0002] The proportion of renewable energy generation in my country's power system is gradually increasing, but renewable energy generation is random, volatile and intermittent, which limits the power grid's ability to absorb renewable energy generation. The frequency regulation task of my country's power system is mainly undertaken by coal-fired units. Compared with hydropower and gas units, thermal power has the worst frequency regulation capability. When participating in frequency regulation, the thermal power units have low ramp rate and slow response speed, and they have difficulty in tracking frequency regulation instructions, thus failing to ensure the accuracy requirements of frequency control. In addition, traditional thermal power units will also have some adverse effects on the economy and stability of the units when performing frequency regulation tasks. Energy storage systems have the characteristics of short response time, fast ramp rate and precise power control. The joint participation of energy storage systems and thermal power units in the automatic generation control (AGC) of the power grid can significantly improve the performance of the thermal power plant's response AGC, but the biggest limitation is its own capacity and state of charge (SOC).

[0003] At present, the control strategy for the combined frequency regulation of thermal power and energy storage is generally one-way compensation, that is, the DCS system of the thermal power unit adjusts the unit output according to the AGC command in accordance with the conventional control strategy, which is not affected by the energy storage system and does not consider the energy state and power changes of the energy storage system at all; for the AGC command, there is no decomposition of the frequency regulation demand based on the change size of the AGC command and the change prediction of the AGC command. Most of the situations that require fast rate response are completely borne by the battery. In particular, when the unit experiences continuous load changes in one direction, its battery energy state will most likely remain in a fully charged or empty state for a long time, basically losing the auxiliary response capability to a certain direction command, which will greatly affect the frequency regulation of the entire system. energy; the energy storage system can only passively use the difference between the AGC command and the actual output of the unit as its output. If the energy storage system recovers energy, it can only give up responding to some grid commands; the output of the energy storage system generally adopts full power compensation, which causes the energy storage system to discharge or charge at full power for a long time, resulting in long-term overuse of the energy storage system, thus affecting the service life of the energy storage system; the control and monitoring of the thermal power unit and the energy storage system are still relatively independent, failing to give full play to the complementary role of the thermal power unit and the energy storage system and further improve the frequency regulation performance, which may cause the thermal power unit or the energy storage system to perform unnecessary adjustment processes, and also fail to fully consider the stable demand of the energy storage system's charge state in an excellent two-way adjustment range. Summary of the invention

[0004] The purpose of the present invention is to propose a control method for a thermal power energy storage combined frequency regulation and capacity self-recovery system, which changes the original control logic of the thermal power unit control system that is independent of the energy storage system parameters, and establishes a prediction mechanism for AGC instructions. The thermal power unit control system and the energy storage control system establish a real-time two-way communication mechanism, coordinate control, give full play to the complementary role, maximize the output of the thermal power unit, and realize the regulation of different powers and capacity self-recovery of the energy storage system under different charge states.

[0005] In order to achieve the above-mentioned object, the present invention proposes a control method for a thermal power energy storage combined frequency regulation and capacity self-recovery system, which is characterized by comprising the following steps: Step 1: The thermal power unit control system and the energy storage control system respectively receive the frequency regulation demand command (AGC command) issued by the power grid dispatching center through the power plant remote terminal unit, as well as the operating data of the thermal power unit and the energy storage system, and analyze and judge the received data; calculate and predict the AGC command based on the received AGC command, and calculate the AGC command based on the formula ∆P A =P AGC -P AGC-1 Calculate the update amplitude of the AGC instruction; establish the prediction mechanism of the AGC instruction based on the historical database of the AGC instruction, and use the formula ∆P A预 =P AGC预 -P AGC Calculate and predict the update amplitude of AGC command; set the secondary frequency modulation dead zone P d , P d The value of is less than or equal to 0.3% of the rated power of the thermal power unit; if the absolute value of the update amplitude is less than P d , then it is a microinstruction, if P d ≤ absolute value of update amplitude ≤ P max , then it is a medium instruction. If the absolute value of the update amplitude is greater than P max , then it is a large instruction; according to the formula ∆P=P AGC -P G , calculate the frequency modulation demand deviation of the current AGC instruction; determine the SOC of the energy storage system; Step 2: The control system of the thermal power unit changes the original control logic that is unrelated to the parameters of the energy storage system, and A ,∆P A预 , ΔP, SOC of energy storage system, P of thermal power unit G Calculate the parameters and send the main frequency regulation demand instruction P to the thermal power unit 主 , in order to realize the main frequency regulation; the thermal power unit control system and the energy storage control system establish a real-time two-way communication mechanism, the thermal power unit control system obtains the SOC of the energy storage system in real time, and the energy storage control system obtains the output power of the thermal power unit in real time; the energy storage control system obtains the output power of the thermal power unit according to ∆P A ,∆PA预 , ΔP, SOC of energy storage system, P of thermal power unit G Calculate the parameters and send the secondary frequency regulation demand instruction P to the energy storage system 次 , to achieve sub-frequency modulation; Step 3, after receiving the main frequency regulation demand instruction, the thermal power unit adjusts the boiler or steam turbine parameters so that the output power of the thermal power unit responds to the main frequency regulation demand instruction, and sends the generator power to the energy storage control system in real time, and receives the SOC and energy storage output power sent by the energy storage control system in real time. The frequency regulation of the thermal power unit is divided into a stable regulation mode and an overshoot mode. In the stable regulation mode, the thermal power unit and the energy storage system jointly output to meet the requirements of the AGC instruction. In the overshoot mode, the output of the thermal power unit is maximized while the capacity of the energy storage system is restored. After receiving the secondary frequency regulation demand instruction from the energy storage control system, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into a frequency regulation mode and a self-recovery mode. Among them, the frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit. Step 4: During the joint frequency regulation of the thermal power unit and the energy storage system, the joint frequency regulation of the thermal power unit and the energy storage system always meets the frequency regulation requirements of the AGC instruction, and at the same time, ensures that the energy storage system has appropriate two-way frequency regulation capabilities; after executing an AGC instruction, the frequency regulation performance is calculated. In order to quantitatively describe the effect of the joint frequency regulation of the thermal power unit and the energy storage system, the frequency regulation performance index M is defined. , and set the frequency regulation limit M0 of M. The smaller M is, the smaller the deviation of the thermal power unit and the energy storage system in coordinating the response to the AGC command is, and the better the frequency regulation effect is; when M>M0, repeat steps 1 to 4, and when M<M0, the frequency regulation ends.

[0006] Furthermore, in step 3, the steady regulation mode of the thermal power unit determines the joint frequency regulation mode of the energy storage system and the thermal power unit according to the update amplitude and SOC of the AGC instruction. When the AGC instruction is a microinstruction, the joint frequency regulation is preferentially responded by the energy storage system, the thermal power unit does not work, the power of the thermal power unit remains unchanged, and the output power of the energy storage system is specifically determined according to the SOC until the combined power of the thermal power unit and the energy storage system is equal to the AGC instruction. However, when the output power corresponding to the SOC before the energy storage system responds is 0 or the SOC enters the range of output power 0 during the response process, the thermal power unit responds instead of the energy storage system; when the AGC instruction is a medium instruction, the thermal power unit and the energy storage system jointly respond, and the thermal power unit responds at a reference regulation rate. The value of the reference regulation rate is determined according to the frequency regulation demand deviation of the AGC instruction, and the reference regulation rate is positively correlated with the frequency regulation demand deviation of the AGC instruction. The power of the energy storage system is specifically determined according to different SOCs until the combined power of the thermal power unit and the energy storage system is equal to the AGC instruction; when the AGC instruction is a large instruction, the thermal power unit and the energy storage system jointly respond, and the thermal power unit responds at a high regulation rate. The value of the high regulation rate is determined according to the frequency regulation demand deviation of the AGC instruction, and the high regulation rate is positively correlated with the frequency regulation demand deviation of the AGC instruction. The power of the energy storage system is specifically determined according to different SOCs until the combined power of the thermal power unit and the energy storage system is equal to the AGC instruction.

[0007] Furthermore, in step 3, the output power of the energy storage system at different states of charge SOC is different, and the capacity is limited. When the SOC is extremely large, the charging power is small, and when the SOC is extremely small, the discharging power is small, which makes the energy storage system under-powered at the extreme SOC value, and limits the system capacity recovery. Therefore, the maximum value SOCmax and minimum value SOCmin of the state of charge of the energy storage system, as well as the upper limit SOC1 and lower limit SOC2 of the recovery target are set, SOCmax≥96%, SOCmin≤4%, 47%≤SOC1≤50%≤SOC2≤53%, and when SOC1≤SOC≤SOC2, the energy storage system has a bidirectional adjustment capability.

[0008] Furthermore, in step 3, the frequency modulation mode of the energy storage system, the SOC of the energy storage system prioritizes the output of the energy storage system, and the dead zone is immediately activated in the current operating state and the output power is output at the output power of the SOC corresponding area. The output power is positive, the energy storage system is discharged, and the output power is negative, the energy storage system is charged; when charging, when SOC≤SOC2, the output power of the energy storage system is -P RBWhen SOC2≤SOC≤SOCmax, the output power of the energy storage system is a linear function of SOC, and the output power decreases as SOC increases. When SOC≥SOCmax, the output power of the energy storage system is 0; during discharge, when SOC≤SOCmin, the output power of the energy storage system is 0. min When SOC≤SOC1, the output power of the energy storage system is a linear function of SOC, and the output power increases with the increase of SOC. When SOC≥SOC1, the output power of the energy storage system is P RB .

[0009] Furthermore, in step 3, when the stable regulation mode of the thermal power unit is completed, it enters the overregulation mode. If ∆P A预 With ∆P A If both are greater than zero or both are less than zero, then P AGC预 With P AGC Positive correlation; on the contrary, P AGC预 With P AGC Negative correlation; regardless of ∆P A is greater than zero or less than zero, if ∆P A预 is equal to 0, then P AGC预 With P AGC Zero correlation; when P AGC预 With P AGC When the correlation is positive or negative, the overshoot coefficient f ranges from 0.1 to 0.3. AGC预 With P AGC When the correlation is zero, the overshoot coefficient f ranges from 0 to 0.2. The specific overshoot coefficient is determined according to P AGC预 With P AGC The correlation and SOC determination of the energy storage system.

[0010] Furthermore, in step 3, in the overshoot mode, P AGC预 With P AGC Positive or negative correlation, when the thermal power unit just enters the overshoot mode, the energy storage system SOC≤SOCmin or SOC≥SOCmax, 0.25<f<0.3, when the thermal power unit just enters the overshoot mode, the energy storage system SOCmin≤SOC≤SOC1 or SOC2≤SOC≤SOCmax, 0.15<f<0.25, when the thermal power unit just enters the overshoot mode, the energy storage system SOC1≤SOC≤SOC2, 0.1<f<0.15; P AGC预 With P AGCWhen the correlation is zero, when the energy storage system SOC≤SOCmin or SOC≥SOCmax when the thermal power unit just enters the overshoot mode, 0.15<f<0.2, when the energy storage system SOCmin≤SOC≤SOC1 or SOC2≤SOC≤SOCmax when the thermal power unit just enters the overshoot mode, 0.05<f<0.15, when the energy storage system SOC1≤SOC≤SOC2 when the thermal power unit just enters the overshoot mode, f=0.

[0011] Furthermore, in step 3, when the thermal power unit enters the overshoot mode, the thermal power unit continues to increase or decrease at the standard rate, the energy storage system enters the self-recovery mode, and the output power of the energy storage system gradually decreases or increases. During the gradual exit of the energy storage system, the joint frequency regulation of the thermal power unit and the energy storage system always meets the frequency regulation demand instruction P AGC When the output power of the thermal power unit independently meets the frequency regulation demand instruction P AGC After the demand is met, the output power of the energy storage system is zero, the thermal power unit continues to operate in overshoot mode, and the energy storage system begins to self-recover its capacity.

[0012] Furthermore, in step 3, if P AGC预 With P AGC If the actual correlation is different from the predicted correlation, the energy storage system immediately exits the self-recovery mode and enters the regulation mode.

[0013] Furthermore, in step 3, the time for the thermal power unit to complete the steady-state mode and the overshoot mode depends on the regulation rate of the thermal power unit. The baseline regulation rate is set to 1%-1.5% MW / min of the rated power of the thermal power unit, and the high regulation rate is set to 1.5%-2% MW / min of the rated power of the thermal power unit.

[0014] Furthermore, in step 3, the self-recovery mode is established on the basis of the overshoot mode of the thermal power unit and is determined according to the SOC of the energy storage system. The self-recovery mode is divided into four modes: strong charging, strong discharging, unidirectional adaptive, and bidirectional adaptive. When SOC≤SOCmin, the energy storage system is in the strong charging mode; when SOC≥SOCmax, the energy storage system is in the strong discharging mode; when SOCmin≤SOC≤SOC1 or SOC2≤SOC≤SOCmax, the energy storage system is in the unidirectional adaptive mode; when SOC1≤SOC≤SOC2, the energy storage system is in the bidirectional adaptive mode.

[0015] Furthermore, in step 3, in the strong charge or strong discharge mode in the self-recovery mode, while the thermal power unit satisfies the AGC instruction, the overshoot of the thermal power unit gives priority to compensating the capacity of the energy storage system, so that the SOC of the energy storage system is restored to the SOC corresponding to the unidirectional adaptive mode as soon as possible. The SOC of the energy storage system changes, and the self-recovery mode of the energy storage system is switched accordingly; in the unidirectional adaptive mode in the self-recovery mode, while the thermal power unit satisfies the AGC instruction, the capacity of the energy storage system is restored at a ratio of not less than 40%; in the bidirectional adaptive mode in the self-recovery mode, the thermal power unit gives priority to satisfying the AGC instruction, and the capacity of the energy storage system is not restored.

[0016] Furthermore, in step 3, the thermal power unit completes the overshoot capacity corresponding to the overshoot coefficient or the SOC of the energy storage system is in the bidirectional suitable zone. If either of the two conditions is met, the overshoot mode ends.

[0017] Through the above technical scheme, the present invention has the following beneficial effects: the present invention changes the original control logic of the thermal power unit control system that is independent of the parameters of the energy storage system, and establishes a prediction mechanism for AGC instructions. The thermal power unit control system and the energy storage control system establish a real-time two-way communication mechanism for coordinated control and full complementarity; the stable regulation mode and overregulation mode of the thermal power unit, the frequency regulation mode and self-recovery mode of the energy storage system are established, and while maximizing the output of the thermal power unit, the regulation of different powers under different charge states of the energy storage system and the capacity self-recovery are realized, breaking through the climbing limit of the thermal power unit, breaking through the frequency regulation limit of the energy storage system, improving the life of the energy storage system, and improving the two-way frequency regulation capability of the energy storage system, thereby improving the joint frequency regulation capability of the thermal power unit and the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will be explained in more detail below with the aid of the accompanying drawings, wherein the same reference numerals denote the same elements.

[0019] Figure 1 It is a control flow chart showing a control method of a thermal power energy storage combined frequency regulation and capacity self-recovery system.

[0020] Figure 2 It is a detailed diagram showing a control method of a thermal power energy storage combined frequency regulation and capacity self-recovery system. DETAILED DESCRIPTION

[0021] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. It should be noted that for other technical personnel in the technical field, the present invention can be modified or changed without departing from the principle of the present invention, but these modifications or changes also fall within the scope of protection of the claims of the present invention.

[0022] like Figure 1 As shown, the present invention proposes a control method for a thermal power energy storage combined frequency regulation and capacity self-recovery system, which is characterized by comprising the following steps: Step 1: The thermal power unit control system and the energy storage control system respectively receive the frequency regulation demand command (AGC command) issued by the power grid dispatching center through the power plant remote terminal unit, as well as the operating data of the thermal power unit and the energy storage system, and analyze and judge the received data; calculate and predict the AGC command based on the received AGC command, and calculate the AGC command based on the formula ∆P A =P AGC -P AGC-1 Calculate the update amplitude of the AGC instruction; establish the prediction mechanism of the AGC instruction based on the historical database of the AGC instruction, and use the formula ∆P A预 =P AGC预 -P AGC Calculate and predict the update amplitude of AGC command; set the secondary frequency modulation dead zone P d , P d The value of is less than or equal to 0.3% of the rated power of the thermal power unit; if the absolute value of the update amplitude is less than P d , then it is a microinstruction, if P d ≤ absolute value of update amplitude ≤ P max , then it is a medium instruction. If the absolute value of the update amplitude is greater than P max , then it is a large instruction; according to the formula ∆P=P AGC -P G , calculate the frequency modulation demand deviation of the current AGC instruction; determine the SOC of the energy storage system; Step 2: The control system of the thermal power unit changes the original control logic that is unrelated to the parameters of the energy storage system, and A ,∆P A预 , ΔP, SOC of energy storage system, P of thermal power unit G Calculate the parameters and send the main frequency regulation demand instruction P to the thermal power unit 主 , in order to realize the main frequency regulation; the thermal power unit control system and the energy storage control system establish a real-time two-way communication mechanism, the thermal power unit control system obtains the SOC of the energy storage system in real time, and the energy storage control system obtains the output power of the thermal power unit in real time; the energy storage control system obtains the output power of the thermal power unit according to ∆P A ,∆P A预 , ΔP SOC of energy storage system, P of thermal power unit G Calculate the parameters and send the secondary frequency regulation demand instruction P to the energy storage system 次 , to achieve sub-frequency modulation; Step 3, after receiving the main frequency regulation demand instruction, the thermal power unit adjusts the boiler or steam turbine parameters so that the output power of the thermal power unit responds to the main frequency regulation demand instruction, and sends the generator power to the energy storage control system in real time, and receives the SOC and energy storage output power sent by the energy storage control system in real time. The frequency regulation of the thermal power unit is divided into a stable regulation mode and an overshoot mode. In the stable regulation mode, the thermal power unit and the energy storage system jointly output to meet the requirements of the AGC instruction. In the overshoot mode, the output of the thermal power unit is maximized while the capacity of the energy storage system is restored. After receiving the secondary frequency regulation demand instruction from the energy storage control system, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into a frequency regulation mode and a self-recovery mode. Among them, the frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit. Step 4: In the process of joint frequency regulation of thermal power generation units and energy storage systems, the joint frequency regulation of thermal power generation units and energy storage systems always meets the frequency regulation requirements of AGC instructions, and at the same time, ensures that the energy storage system has appropriate two-way frequency regulation capabilities; after executing an AGC instruction, the frequency regulation performance is calculated. In order to quantitatively describe the effect of joint frequency regulation of thermal power generation units and energy storage systems, the frequency regulation performance index M is defined, M=, and the frequency regulation limit M0 of M is set. The smaller M is, the smaller the deviation of the coordinated response of thermal power generation units and energy storage systems to AGC instructions is, and the better the frequency regulation effect is. When M>M0, repeat steps 1-4. When M<M0, the frequency regulation ends.

[0023] like Figure 2 As shown in the frequency modulation mode of the energy storage system, the SOC of the energy storage system first determines the output of the energy storage system. In the current operating state, the dead zone is immediately activated and the output power is output at the output power corresponding to the SOC area. The output power is positive, the energy storage system is discharged, and the output power is negative, the energy storage system is charged; when charging, when SOC≤SOC2, the output power of the energy storage system is -P RB When SOC2≤SOC≤SOCmax, the output power of the energy storage system is a linear function of SOC, and the output power decreases as SOC increases. When SOC≥SOCmax, the output power of the energy storage system is 0; during discharge, when SOC≤SOCmin, the output power of the energy storage system is 0. min When SOC≤SOC1, the output power of the energy storage system is a linear function of SOC, and the output power increases with the increase of SOC. When SOC≥SOC1, the output power of the energy storage system is P RB .

[0024] Example 1: The rated output power of the thermal power unit is 600MW, the rated output power of the energy storage system is 18MW, the last AGC instruction is 575MW, the current AGC instruction is 590MW, the predicted AGC instruction is 600MW, and the actual output power of the current thermal power unit is 575MW. At this time, the update amplitude of the AGC instruction ∆P A The predicted AGC command update amplitude ∆P is 15MW. A预 is 10MW, the frequency regulation demand deviation ∆P of the AGC instruction is 15MW, and the SOC of the energy storage system is 3%. According to ∆P A ,∆P A预 , ΔP SOC of energy storage system, P of thermal power unit G Calculate the frequency modulation demand instruction P using the following parameters 主 and sub-frequency modulation demand command P 次 After receiving the main frequency regulation demand instruction, the thermal power unit responds to the main frequency regulation demand instruction by adjusting the boiler or steam turbine parameters. The frequency regulation of the thermal power unit is divided into stable regulation mode and overshoot mode; after receiving the secondary frequency regulation demand instruction, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into frequency regulation mode and self-recovery mode. The frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit; the thermal power unit and the energy storage system jointly respond to the AGC instruction. When the stable regulation mode of the thermal power unit ends, the output power of the thermal power unit It is 583MW, and the output power of the energy storage system is 7MW; then, the thermal power unit enters the overshoot mode, the thermal power unit continues to increase at the standard rate, the energy storage system enters the self-recovery mode, and the power of the energy storage system gradually decreases. In the process of gradually decreasing the power of the energy storage system, the total output power of the thermal power unit and the energy storage system is always 590MW. When the output power of the thermal power unit reaches 590MW, the output power of the energy storage system is zero, and then the output power of the thermal power unit increases at the standard rate. At the end of the overshoot mode, the output power of the thermal power unit is 593MW, of which 3MW is used for self-recovery of the energy storage system capacity.

[0025] Example 2: The rated output power of the thermal power unit is 600MW, the rated output power of the energy storage system is 18MW, the last AGC instruction is 575MW, the current AGC instruction is 560MW, the predicted AGC instruction is 550MW, and the actual output power of the current thermal power unit is 575MW. At this time, the update amplitude of the AGC instruction is ∆P A =-15MW, predicting the update amplitude of AGC command ∆P A预 is -10MW, the frequency regulation demand deviation ∆P of the AGC instruction is -15MW, and the SOC of the energy storage system is 3%. According to ∆P A ,∆P A预 , ΔP SOC of energy storage system, P of thermal power unit GCalculate the frequency modulation demand instruction P using the following parameters 主 and sub-frequency modulation demand command P 次 After receiving the main frequency regulation demand instruction, the thermal power unit responds to the main frequency regulation demand instruction by adjusting the boiler or steam turbine parameters. The frequency regulation of the thermal power unit is divided into stable regulation mode and overshoot mode; after receiving the secondary frequency regulation demand instruction, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into frequency regulation mode and self-recovery mode. The frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit; the thermal power unit and the energy storage system jointly respond to the AGC instruction. When the stable regulation mode of the thermal power unit ends, the output power of the thermal power unit is 568MW, the output power of the energy storage system is -8MW; then, the thermal power unit enters the overshoot mode, the thermal power unit continues to reduce at the standard rate, the energy storage system enters the self-recovery mode, and the power of the energy storage system gradually increases. In the process of the energy storage system power gradually increasing, the total output power of the thermal power unit and the energy storage system is always 560MW. When the output power of the thermal power unit reaches 560MW, the output power of the energy storage system is zero, and then the output power of the thermal power unit is reduced at the standard rate. At the end of the overshoot mode, the output power of the thermal power unit is 557MW, of which 3MW is used for self-recovery of the energy storage system capacity.

[0026] Example 3: The rated output power of the thermal power unit is 600MW, the rated output power of the energy storage system is 18MW, the last AGC instruction is 575MW, the current AGC instruction is 580MW, the predicted AGC instruction is 580MW, and the actual output power of the current thermal power unit is 575MW. At this time, the update amplitude of the AGC instruction is ∆P A The predicted AGC command update amplitude ∆P is 5MW. A预 is 0MW, the frequency regulation demand deviation ∆P of the AGC instruction is 5MW, and the SOC of the energy storage system is 50%. According to ∆P A ,∆P A预 , ΔP SOC of energy storage system, P of thermal power unit G Calculate the frequency modulation demand instruction P using the following parameters 主 and sub-frequency modulation demand command P 次After receiving the main frequency regulation demand instruction, the thermal power unit responds to the main frequency regulation demand instruction by adjusting the boiler or steam turbine parameters. The frequency regulation of the thermal power unit is divided into stable regulation mode and overshoot mode; after receiving the secondary frequency regulation demand instruction, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into frequency regulation mode and self-recovery mode. The frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit; the thermal power unit and the energy storage system jointly respond to the AGC instruction. When the stable regulation mode of the thermal power unit ends, the thermal power unit The output power is 577MW, and the output power of the energy storage system is 3MW; then, the thermal power unit enters the overshoot mode, the thermal power unit continues to increase at the standard rate, the energy storage system enters the self-recovery mode, and the power of the energy storage system gradually decreases. In the process of the energy storage system power gradually decreasing, the total output power of the thermal power unit and the energy storage system is always 580MW. When the output power of the thermal power unit reaches 580MW, the output power of the energy storage system is zero, and then the output power of the thermal power unit remains unchanged. At the end of the overshoot mode, the output power of the thermal power unit is still 580MW, and the energy storage system does not need capacity self-recovery.

[0027] Example 4: The rated output power of the thermal power unit is 600MW, the rated output power of the energy storage system is 18MW, the last AGC instruction is 575MW, the current AGC instruction is 576MW, the predicted AGC instruction is 585MW, and the actual output power of the current thermal power unit is 575MW. At this time, the update amplitude of the AGC instruction is ∆P A The update amplitude of the AGC command is ∆P, which is 1MW. A预 is 9MW, the frequency regulation demand deviation ∆P of the AGC instruction is 1MW, and the SOC of the energy storage system is 30%. According to ∆P A ,∆P A预 , ΔP SOC of energy storage system, P of thermal power unit G Calculate the frequency modulation demand instruction P using the following parameters 主 and sub-frequency modulation demand command P 次After receiving the main frequency regulation demand instruction, the thermal power unit responds to the main frequency regulation demand instruction by adjusting the boiler or steam turbine parameters. The frequency regulation of the thermal power unit is divided into stable regulation mode and overshoot mode; after receiving the secondary frequency regulation demand instruction, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into frequency regulation mode and self-recovery mode. The frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit; the thermal power unit and the energy storage system jointly respond to the AGC instruction. When the stable regulation mode of the thermal power unit ends, the output power of the thermal power unit The output power of the energy storage system is 1MW; then, the thermal power unit enters the overshoot mode, the thermal power unit continues to increase at the standard rate, the energy storage system enters the self-recovery mode, and the power of the energy storage system gradually decreases. In the process of the energy storage system power gradually decreasing, the total output power of the thermal power unit and the energy storage system is always 576MW. When the output power of the thermal power unit reaches 576MW, the output power of the energy storage system is zero, and then the output power of the thermal power unit increases at the standard rate. At the end of the overshoot mode, the output power of the thermal power unit is 578MW, of which 2MW is used for self-recovery of the energy storage system capacity.

[0028] Example 5: The rated output power of the thermal power unit is 600MW, the rated output power of the energy storage system is 18MW, the last AGC instruction is 575MW, the current AGC instruction is 595MW, the predicted AGC instruction is 587MW, and the actual output power of the current thermal power unit is 575MW. At this time, the update amplitude of the AGC instruction is ∆P A The predicted AGC command update amplitude ∆P is 20MW. A预 is -8MW, the frequency regulation demand deviation ∆P of the AGC instruction is 20MW, and the SOC of the energy storage system is 80%. According to ∆P A ,∆P A预 , ΔP SOC of energy storage system, P of thermal power unit G Calculate the frequency modulation demand instruction P using the following parameters 主 and sub-frequency modulation demand command P 次After receiving the main frequency regulation demand instruction, the thermal power unit responds to the main frequency regulation demand instruction by adjusting the boiler or steam turbine parameters. The frequency regulation of the thermal power unit is divided into stable regulation mode and overshoot mode; after receiving the secondary frequency regulation demand instruction, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into frequency regulation mode and self-recovery mode. The frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit; the thermal power unit and the energy storage system jointly respond to the AGC instruction. When the stable regulation mode of the thermal power unit ends, the output power of the thermal power unit is 583MW, the output power of the energy storage system is 12MW; then, the thermal power unit enters the overshoot mode, the thermal power unit continues to increase at the standard rate, the energy storage system enters the self-recovery mode, and the power of the energy storage system gradually decreases. In the process of the energy storage system power gradually decreasing, the total output power of the thermal power unit and the energy storage system is always 595MW. When the output power of the thermal power unit reaches 595MW, the output power of the energy storage system is zero, and then the output power of the thermal power unit decreases at the standard rate. At the end of the overshoot mode, the output power of the thermal power unit is 593MW, of which 2MW is used for self-recovery of the energy storage system capacity.

[0029] As mentioned above, although the typical embodiment designed by this invention was demonstrated, this invention is not limited to the said embodiment, Various corrections and changes can be implemented within the scope of a claim.

Claims

1. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system, characterized in that: The following steps are involved: Step 1: The thermal power unit control system and the energy storage control system respectively receive the frequency regulation demand command (AGC command) issued by the power grid dispatching center through the power plant remote terminal unit, as well as the operating data of the thermal power unit and the energy storage system, and analyze and judge the received data; calculate and predict the AGC command based on the received AGC command, and calculate the AGC command based on the formula ∆P A =P AGC -P AGC-1 Calculate the update amplitude of the AGC instruction; establish the prediction mechanism of the AGC instruction based on the historical database of the AGC instruction, and use the formula ∆P A预 =P AGC预 -P AGC Calculate the update amplitude of the predicted AGC instruction; Set the secondary frequency modulation dead zone P d , P d The value of is less than or equal to 0.3% of the rated power of the thermal power unit; if the absolute value of the update amplitude is less than P d , then it is a microinstruction, if P d ≤ absolute value of update amplitude ≤ P max , then it is a medium instruction. If the absolute value of the update amplitude is greater than P max , then it is a large instruction; according to the formula ∆P=P AGC -P G , calculate the frequency modulation demand deviation of the current AGC instruction; determine the SOC of the energy storage system; Step 2: The control system of the thermal power unit changes the original control logic that is unrelated to the parameters of the energy storage system, and A ,∆P A预 , ΔP, SOC of energy storage system, P of thermal power unit G Calculate the parameters and send the main frequency regulation demand instruction P to the thermal power unit 主 , in order to realize the main frequency regulation; the thermal power unit control system and the energy storage control system establish a real-time two-way communication mechanism, the thermal power unit control system obtains the SOC of the energy storage system in real time, and the energy storage control system obtains the output power of the thermal power unit in real time; the energy storage control system obtains the output power of the thermal power unit according to ∆P A ,∆P A预 , ΔP, SOC of energy storage system, P of thermal power unit G Calculate the parameters and send the secondary frequency regulation demand instruction P to the energy storage system 次 , to achieve sub-frequency modulation; Step 3, after receiving the main frequency regulation demand instruction, the thermal power unit adjusts the boiler or steam turbine parameters so that the output power of the thermal power unit responds to the main frequency regulation demand instruction, and sends the generator power to the energy storage control system in real time, and receives the SOC and energy storage output power sent by the energy storage control system in real time. The frequency regulation of the thermal power unit is divided into a stable regulation mode and an overshoot mode. In the stable regulation mode, the thermal power unit and the energy storage system jointly output to meet the requirements of the AGC instruction. In the overshoot mode, the output of the thermal power unit is maximized while the capacity of the energy storage system is restored. After receiving the secondary frequency regulation demand instruction from the energy storage control system, the energy storage system responds to the secondary frequency regulation demand instruction by controlling the converter parameters. The frequency regulation of the energy storage system is divided into a frequency regulation mode and a self-recovery mode. Among them, the frequency regulation mode of the energy storage system is synchronized with the stable regulation mode of the thermal power unit, and the self-recovery mode of the energy storage system is synchronized with the overshoot mode of the thermal power unit. Step 4: During the joint frequency regulation of the thermal power unit and the energy storage system, the joint frequency regulation of the thermal power unit and the energy storage system always meets the frequency regulation requirements of the AGC instruction, and at the same time, ensures that the energy storage system has appropriate two-way frequency regulation capabilities; after executing an AGC instruction, the frequency regulation performance is calculated. In order to quantitatively describe the effect of the joint frequency regulation of the thermal power unit and the energy storage system, the frequency regulation performance index M is defined. , and set the frequency regulation limit M0 of M. The smaller M is, the smaller the deviation of the thermal power unit and the energy storage system in coordinating the response to the AGC command is, and the better the frequency regulation effect is; when M>M0, repeat steps 1 to 4, and when M<M0, the frequency regulation ends.

2. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, the stable regulation mode of the thermal power unit determines the joint frequency regulation mode of the energy storage system and the thermal power unit according to the update amplitude and SOC of the AGC instruction. When the AGC instruction is a microinstruction, the joint frequency regulation is responded to by the energy storage system first, the thermal power unit does not work, the power of the thermal power unit remains unchanged, and the output power of the energy storage system is specifically determined according to the SOC until the combined power of the thermal power unit and the energy storage system is equal to the AGC instruction. However, when the output power corresponding to the SOC before the energy storage system responds is 0 or the SOC enters the range of output power 0 during the response process, the thermal power unit responds instead of the energy storage system; when the AGC instruction is a medium instruction, the thermal power unit and the energy storage system jointly respond, and the thermal power unit responds at a reference regulation rate. The value of the reference regulation rate is determined according to the frequency regulation demand deviation of the AGC instruction, and the reference regulation rate is positively correlated with the frequency regulation demand deviation of the AGC instruction. The power of the energy storage system is specifically determined according to different SOCs until the combined power of the thermal power unit and the energy storage system is equal to the AGC instruction; when the AGC instruction is a large instruction, the thermal power unit and the energy storage system jointly respond, and the thermal power unit responds at a high regulation rate. The value of the high regulation rate is determined according to the frequency regulation demand deviation of the AGC instruction, and the high regulation rate is positively correlated with the frequency regulation demand deviation of the AGC instruction. The power of the energy storage system is specifically determined according to different SOCs until the combined power of the thermal power unit and the energy storage system is equal to the AGC instruction.

3. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, the output power of the energy storage system at different states of charge SOC is different, and the capacity is limited. When the SOC is extremely large, the charging power is small, and when the SOC is extremely small, the discharging power is small, which makes the energy storage system under-powered at the extreme SOC value, and limits the system capacity recovery. Therefore, the maximum value SOCmax and minimum value SOCmin of the state of charge of the energy storage system, as well as the upper limit SOC1 and lower limit SOC2 of the recovery target are set, SOCmax≥96%, SOCmin≤4%, 47%≤SOC1≤50%≤SOC2≤53%, when SOC1≤SOC≤SOC2, the energy storage system has a bidirectional adjustment capability.

4. The control method of a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, the frequency modulation mode of the energy storage system, the SOC of the energy storage system prioritizes the output of the energy storage system, and the dead zone is immediately activated in the current operating state and the output power is output at the output power of the SOC corresponding area. The output power is positive, the energy storage system is discharged, and the output power is negative, the energy storage system is charged; when charging, when SOC≤SOC2, the output power of the energy storage system is -P RB When SOC2≤SOC≤SOCmax, the output power of the energy storage system is a linear function of SOC, and the output power decreases as SOC increases. When SOC≥SOCmax, the output power of the energy storage system is 0; during discharge, when SOC≤SOCmin, the output power of the energy storage system is 0. min When SOC≤SOC1, the output power of the energy storage system is a linear function of SOC, and the output power increases with the increase of SOC. When SOC≥SOC1, the output power of the energy storage system is P RB .

5. The control method of a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, when the stable regulation mode of the thermal power unit is completed, it enters the overregulation mode. If ∆P A预 With ∆P A If both are greater than zero or both are less than zero, then P AGC预 With P AGC Positive correlation; on the contrary, P AGC预 With P AGC Negative correlation; regardless of ∆P A is greater than zero or less than zero, if ∆P A预 is equal to 0, then P AGC预 With P AGC Zero correlation; when P AGC预 With P AGC When the correlation is positive or negative, the overshoot coefficient f ranges from 0.1 to 0.

3. AGC预 With P AGC When the correlation is zero, the overshoot coefficient f ranges from 0 to 0.

2. The specific overshoot coefficient is determined according to P AGC预 With P AGC The correlation and SOC determination of the energy storage system.

6. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, in overshoot mode, P AGC预 With P AGC Positive or negative correlation, when the thermal power unit just enters the overshoot mode, the energy storage system SOC≤SOCmin or SOC≥SOCmax, 0.25<f<0.3, when the thermal power unit just enters the overshoot mode, the energy storage system SOCmin≤SOC≤SOC1 or SOC2≤SOC≤SOCmax, 0.15<f<0.25, when the thermal power unit just enters the overshoot mode, the energy storage system SOC1≤SOC≤SOC2, 0.1<f<0.15; P AGC预 With P AGC When the correlation is zero, when the energy storage system SOC≤SOCmin or SOC≥SOCmax when the thermal power unit just enters the overshoot mode, 0.15<f<0.2, when the energy storage system SOCmin≤SOC≤SOC1 or SOC2≤SOC≤SOCmax when the thermal power unit just enters the overshoot mode, 0.05<f<0.15, when the energy storage system SOC1≤SOC≤SOC2 when the thermal power unit just enters the overshoot mode, f=0.

7. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, after the thermal power unit enters the overshoot mode, the thermal power unit continues to increase or decrease at the standard rate, the energy storage system enters the self-recovery mode, and the output power of the energy storage system gradually decreases or increases. During the gradual withdrawal of the energy storage system, the joint frequency regulation of the thermal power unit and the energy storage system always meets the frequency regulation demand instruction P AGC When the output power of the thermal power unit independently meets the frequency regulation demand instruction P AGC After the demand is met, the output power of the energy storage system is zero, the thermal power unit continues to operate in overshoot mode, and the energy storage system begins to self-recover its capacity.

8. The control method of a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: Furthermore, in step 3, if P AGC预 With P AGC If the actual correlation is different from the predicted correlation, the energy storage system immediately exits the self-recovery mode and enters the regulation mode.

9. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, the time for the thermal power unit to complete the steady regulation mode and the overregulation mode depends on the regulation rate of the thermal power unit. The reference regulation rate is set to 1%-1.5% MW / min of the rated power of the thermal power unit, and the high regulation rate is set to 1.5%-2% MW / min of the rated power of the thermal power unit.

10. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, the self-recovery mode is established on the basis of the overshoot mode of the thermal power unit and is determined according to the SOC of the energy storage system. The self-recovery mode is divided into four modes: strong charging, strong discharging, unidirectional adaptive, and bidirectional adaptive. When SOC≤SOCmin, the energy storage system is in the strong charging mode; when SOC≥SOCmax, the energy storage system is in the strong discharging mode; when SOCmin≤SOC≤SOC1 or SOC2≤SOC≤SOCmax, the energy storage system is in the unidirectional adaptive mode; when SOC1≤SOC≤SOC2, the energy storage system is in the bidirectional adaptive mode.

11. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, in the strong charge or strong discharge mode in the self-recovery mode, while the thermal power unit meets the AGC instruction, the overshoot of the thermal power unit gives priority to compensating the capacity of the energy storage system, so that the SOC of the energy storage system is restored to the SOC corresponding to the unidirectional adaptive mode as soon as possible. The SOC of the energy storage system changes, and the self-recovery mode of the energy storage system is switched accordingly; in the unidirectional adaptive mode in the self-recovery mode, while the thermal power unit meets the AGC instruction, the capacity of the energy storage system is restored at a ratio of not less than 40%; in the bidirectional adaptive mode in the self-recovery mode, the thermal power unit gives priority to meeting the AGC instruction, and the capacity of the energy storage system is not restored.

12. A control method for a thermal power energy storage combined frequency modulation and capacity self-recovery system according to claim 1, characterized in that: In step 3, the thermal power unit completes the overshoot capacity corresponding to the overshoot coefficient or the SOC of the energy storage system is in the bidirectional suitable zone. If either of the two conditions is met, the overshoot mode ends.

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