Energy storage cluster cooperates with shagehuang new energy base to optimize frequency modulation power of thermal power

Abstract

The present application relates to the field of energy storage frequency modulation system, and particularly relates to a method for optimizing the frequency modulation power of a thermal power plant in a sanduo desert new energy base in cooperation with an energy storage cluster, aiming at the problem that the frequency modulation capacity of an energy storage cluster power station in a high-proportion new energy power system is limited due to power-capacity constraints, and then the frequency modulation enthusiasm is reduced, the output compensation of a thermal power unit is designed to reserve the frequency modulation capacity of the energy storage cluster power station, and an adequacy coefficient related to the residual frequency modulation capacity of the thermal power unit is introduced, and a frequency modulation power distribution model of the thermal power unit is designed, so as to reduce the operation cost of the thermal power unit and reduce the equipment loss of the unit. Considering the overall balance of the SOC of each energy storage power station, the cycle life and the economy, the preference decision of the SOC balance target of the energy storage power station is ensured to guarantee the adequacy of the frequency modulation capacity of the energy storage power station, so as to reduce the frequency modulation cost of the energy storage cluster and fully utilize the frequency modulation capacity of each energy storage power station.

Description

Technical Field

[0001] This invention relates to the field of energy storage frequency regulation systems, specifically to a method for optimizing the frequency regulation power of thermal power plants in the Shagohuang New Energy Base in collaboration with energy storage clusters. Background Technology

[0002] In response to the call for low-carbon development, my country's installed capacity of renewable energy sources such as wind power and distributed photovoltaics is continuously increasing, especially in desert and Gobi regions where the transmission of renewable energy has become a key way to solve energy and power supply problems. However, as the proportion of renewable energy gradually increases, the power grid faces frequency regulation pressure due to issues such as declining inertia and insufficient frequency regulation capacity. Energy storage, with its rapid response and bidirectional regulation capabilities, is highly effective in quickly responding to frequency regulation commands and maintaining system frequency stability. Furthermore, with national policies supporting and developing energy storage construction, the installed capacity of energy storage in the power grid has exploded in the past two years, showing a clustered development trend. Therefore, how to coordinate the frequency regulation of thermal power units and energy storage, maintain large-scale cluster control of energy storage, and simultaneously meet the requirements of sufficient system frequency regulation capacity and frequency stability is an important research topic.

[0003] Therefore, there is an urgent need for a new technical solution to address this problem. Summary of the Invention

[0004] The purpose of this invention is to address the problem that the frequency regulation capability of energy storage cluster power stations in high-proportion new energy power systems is limited due to power-capacity constraints, thereby reducing their frequency regulation incentives. This invention provides an optimized control strategy for the frequency regulation power of energy storage clusters in conjunction with thermal power in the Shagohuang new energy base, taking into account both frequency regulation capacity and target cost. The strategy designs a method for coordinating the compensated output of thermal power units with the frequency regulation of the energy storage cluster, reasonably reserving frequency regulation capacity for the energy storage cluster, and balancing the energy storage power station's state-of-charge equilibrium, cycle life, and economic objectives. A multi-objective algorithm based on decision preferences is used to complete the allocation of energy storage frequency regulation power.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang New Energy Base in collaboration with energy storage clusters includes the following steps:

[0007] S1: Design the compensation output of the thermal power unit, specifically:

[0008] S11, Regional power grid frequency fluctuation analysis;

[0009] S12, Thermal power-energy storage frequency regulation power control strategy;

[0010] S2: Establish a margin factor related to the remaining frequency regulation capacity of thermal power units, specifically:

[0011] S21. Construction of frequency regulation power allocation model for thermal power units;

[0012] S22. System operating constraints;

[0013] S3: Construct a frequency regulation power allocation model for energy storage cluster power stations, specifically:

[0014] S31. Construction of frequency regulation power allocation model for energy storage clusters;

[0015] S32, System operation constraints.

[0016] As a further aspect of the present invention: In S11, the regional power grid frequency fluctuation analysis takes a power system including new energy power plants, thermal power units, and multiple energy storage power stations as the research object. Due to real-time fluctuations between sources and loads within the power system area, corresponding frequency fluctuations will occur, and their real-time frequency expression is as follows:

[0017]

[0018] In the formula, Δf is the system frequency deviation, D and M are the damping coefficient and equivalent inertial constant within the system region, respectively, and ΔP G ΔP W ΔP L , respectively, represent the changes in output of thermal power units, the changes in output of wind power units, and the changes in load.

[0019] As a further aspect of the present invention: In S12, the operating state m1: P AGC,t >0, P b,rate <P AGC,t ,|P G,t -P G,t-1 | <P climb When the frequency regulation demand is greater than 0, the rated power of the energy storage cannot meet the frequency regulation power demand, and the thermal power unit has sufficient ramp-up capability. In this case, the remaining frequency regulation demand is made up by the thermal power unit; P AGC,t For the AGC frequency regulation command at time t within the power system area, P b,rate P is the rated power of the energy storage power station. climb P is the ramp rate of the thermal power unit. G,t Let P be the unit output power at time t. G,t-1 The unit output power at time t-1;

[0020] Running status m2: P AGC,t >0, P b,rate <P AGC,t ,|P G,t -P G,t-1 |>P climb When the frequency regulation demand is greater than 0, the rated power of the energy storage does not meet the frequency regulation power demand, and the thermal power unit's ramping ability is insufficient. In this case, the thermal power unit participates in frequency regulation according to the maximum output capacity of the thermal power-storage unit.

[0021] Running status m3: P AGC,t >0, P b,rate >P AGC,t When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation power demand, and the energy storage participates in the grid frequency regulation at this time.

[0022] Running status m4: P AGC,t >0, P b,rate >P AGC,t ,|P G,t -P G,t-1 | <P climb E AGC >E B When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation demand, the thermal power unit has sufficient ramping capability, and the frequency regulation capacity demand of the energy storage is greater than the rated capacity, then the additional power output of the thermal power unit is considered to be charged to make up for the capacity demand during the energy storage charging time.

[0023] Running status m5: P AGC,t >0, P b,rate >P AGC,t ,|P G,t -P G,t-1 |>P climb E AGC >E B When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is insufficient, and the frequency regulation capacity demand of the energy storage is greater than the rated capacity. At this time, the power output is increased to compensate for the maximum frequency regulation output of the thermal power unit.

[0024] Running status m6: P AGC,t <0, P b,rate <P AGC,t ,|P G,t -P G,t-1 | <P climb When the frequency regulation demand is less than 0, the rated power of the energy storage cannot meet the frequency regulation demand, and the thermal power unit has sufficient ramping capability. At this time, the remaining frequency regulation demand is made up by the thermal power unit.

[0025] Running status m7: P AGC,t <0, P b,rate <P AGC,t ,|P G,t -P G,t-1 |>P climb When the frequency regulation demand is less than 0, the rated power of the energy storage does not meet the frequency regulation demand, and the thermal power unit's ramping ability is insufficient, then the unit participates in frequency regulation according to the maximum output capacity of the thermal power-storage system.

[0026] Running status m8: P AGC,t <0, P b,rate>P AGC,t When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation power demand, and the energy storage participates in the grid frequency regulation at this time.

[0027] Running status m9: P AGC,t <0, P b,rate >P AGC,t ,|P G,t -P G,t-1 | <P climb E AGC >E B When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is sufficient, and the frequency regulation capacity demand of the energy storage is less than the rated capacity, then the power of the energy storage is increased to make up for the capacity demand when the thermal power unit reduces the load to compensate for the discharge state of the energy storage.

[0028] Running status m 10 :P AGC,t <0, P b,rate >P AGC,t ,|P G,t -P G,t-1 |>P climb E AGC >E B When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is insufficient, and the frequency regulation capacity demand of the energy storage is less than the rated capacity. At this time, the output is reduced to compensate for the maximum frequency regulation output of the thermal power unit.

[0029] As a further aspect of the present invention: in S21, the method for determining the adequacy coefficient is as follows:

[0030]

[0031] In the formula, A j,t Let be the margin factor of thermal power unit j at time t. Let j be the rated capacity of the thermal power unit.

[0032] As a further aspect of the present invention: In S21, the system operation constraints are specifically as follows:

[0033] Thermal power unit output balance constraints:

[0034]

[0035] In the formula: P g,j,t Let be the frequency-modulated power output of thermal power unit j in each region at time t;

[0036] The output constraints of thermal power units are:

[0037]

[0038] In the formula: and These are the minimum and maximum output limits of unit j, respectively;

[0039] The ramping constraint for thermal power units is:

[0040] P climb,j ≤P g,j,t -P g,j,t-1 ≤P climb (15)

[0041] In the formula: P g,j,t-1 Let P be the actual output power of thermal power unit j at time t-1. climb,j is the maximum ramp rate of thermal power unit j;

[0042] Network operation constraints are:

[0043]

[0044] In the formula: P represents the upper limit of active power transmitted by line mn within the region. mn,t Let be the active power flowing from node m to node n on line mn at time t, expressed as follows:

[0045]

[0046] In the formula, X mr X nr x is an element of the network node impedance matrix. kn P is the reactance value of line mn. r,t Let P be the active power output of power node r at time t. q,t Let q be the set of active power of load nodes at time t.

[0047] As a further aspect of this invention: In S31, the frequency regulation power allocation model of the energy storage cluster is analyzed, mainly including the initial investment cost, power loss cost, and lifespan loss cost of the energy storage power station.

[0048]

[0049] In the formula, C inv,j,t C loss,j,t C life,j,t These represent the initial investment cost, power loss cost, and lifetime loss cost of power station j within the regional energy storage cluster; c a,j c p,j These represent the unit capacity cost and unit power cost of energy storage power station j, respectively. Let n be the rated capacity of energy storage power station j. a T represents the total number of scheduling operations for the energy storage cluster, q represents the energy storage discount rate, and T represents the total number of scheduling operations for the cluster.fl,j The float charging life of energy storage power station j; and Let t represent the charging and discharging power of the energy storage power station j under economic operating conditions. The rated power of energy storage power station j and These represent the charging efficiency and discharging efficiency of energy storage power station j, respectively; N c,j Δt represents the equivalent number of cycles for an energy storage power station under full charge and discharge conditions, and Δt represents the scheduling cycle of the energy storage cluster.

[0050] As a further aspect of the present invention: In S32, the frequency modulation power balance constraint is:

[0051]

[0052] As a further aspect of the present invention: in S32, the energy storage power constraint is:

[0053]

[0054] As a further aspect of the present invention: in S32, the energy storage SOC capacity constraint is:

[0055] SOC j,min ≤SOC j,t ≤SOC j,max (29)

[0056] In the formula, SOC j,min With SOC j,max These are the minimum and maximum values ​​of energy storage power station j, respectively.

[0057] The beneficial effects of this invention are:

[0058] This invention presents an optimized control strategy for the frequency regulation power of thermal power plants in the Shagohuang New Energy Base, taking into account both frequency regulation capacity and target cost. Addressing the issue of limited frequency regulation capability due to power-capacity constraints in high-proportion new energy power systems, which reduces the frequency regulation incentive of energy storage cluster power plants, the invention designs a strategy to reserve frequency regulation capacity for thermal power units by compensating for the energy storage cluster power plants. Simultaneously, it introduces a sufficiency coefficient related to the remaining frequency regulation capacity of thermal power units and designs a frequency regulation power allocation model for thermal power units, reducing both the operating costs and equipment losses of the thermal power units. Considering the overall SOC balance target, cycle life, and economic targets of each energy storage power plant, a preference decision is made for the SOC balance target of the energy storage power plants to ensure sufficient frequency regulation capacity, thereby reducing the frequency regulation cost of the energy storage cluster while fully utilizing the frequency regulation capacity of each energy storage power plant. Simulation analysis and comparison of dynamic control effects based on the above methods demonstrate the systematic and scientific nature of this approach. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 A schematic diagram of a thermal power-energy storage frequency regulation system for the present invention, which provides a method for optimizing the frequency regulation power of thermal power plants in the Shagohuang New Energy Base in collaboration with energy storage clusters;

[0061] Figure 2 A schematic diagram illustrating the coordinated operation of thermal power and energy storage in the Shagohuang New Energy Base thermal power frequency regulation power optimization method provided by this invention;

[0062] Figure 3 This invention provides a two-layer optimization control strategy framework diagram for the energy storage cluster collaborative thermal power frequency regulation power optimization method of the Shagohuang New Energy Base;

[0063] Figure 4 A schematic diagram of the thermal-storage frequency regulation power control strategy for the energy storage cluster collaborative method for optimizing the frequency regulation power of thermal power in the Shagohuang new energy base is provided for this invention.

[0064] Figure 5 This invention provides a modified frequency regulation power curve for an energy storage cluster power station, which optimizes the frequency regulation power of thermal power plants in the Shagohuang New Energy Base in collaboration with energy storage clusters.

[0065] Figure 6 This invention provides frequency regulation power allocation curves of thermal power units under different strategies for the energy storage cluster collaborative optimization method of thermal power frequency regulation power in the Shagohuang new energy base;

[0066] Figure 7 This invention provides curves showing the frequency regulation power and SOC changes of each energy storage power station under different strategies for optimizing the frequency regulation power of thermal power plants in the Shagohuang New Energy Base in collaboration with energy storage clusters.

[0067] Figure 8 This invention provides the equivalent number of cycles for each energy storage power station under Strategy 3 and Strategy 4 of the method for optimizing the frequency regulation power of thermal power plants in the Shagohuang New Energy Base in collaboration with energy storage clusters. Detailed Implementation

[0068] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0069] like Figures 1-8 As shown in the embodiment of the present invention, the method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters includes: firstly, designing the compensation output of thermal power units to reserve frequency regulation capacity for the energy storage cluster power station; then, introducing a sufficiency coefficient related to the remaining frequency regulation capacity of the thermal power units, and designing a frequency regulation power allocation model for the thermal power units. Considering the overall SOC balance target, cycle life, and economic targets of each energy storage power station, a preference decision is made for the SOC balance target of the energy storage power station to ensure sufficient frequency regulation capacity of the energy storage power station; and a power system frequency regulation model is built using the MATLAB simulation platform for simulation. The specific steps are as follows:

[0070] Step 1, design the compensation output of thermal power units; specifically including: regional power grid frequency fluctuation analysis and thermal power-energy storage frequency regulation power control strategy;

[0071] In step 1, the process of analyzing the frequency fluctuations of the regional power grid is as follows:

[0072] This paper analyzes the frequency fluctuations of a regional power grid, taking a power system that includes new energy power plants, thermal power units, and multiple energy storage power stations as the research object. Within the power system region, real-time fluctuations between sources and loads will cause corresponding frequency fluctuations, which are expressed in the following formula:

[0073]

[0074] In the formula, Δf is the system frequency deviation, D and M are the damping coefficient and equivalent inertial constant within the system region, respectively, and ΔP G ΔP W ΔP L , , respectively represent the changes in output of thermal power units, the changes in output of wind power units, and the changes in load in the system, where n is the total number of thermal power units.

[0075] In step 1, a thermal power-storage frequency regulation power control strategy is designed, specifically as follows:

[0076] Running status m1: P AGC,t >0, P b,rate <P AGC,t ,|P G,t -P G,t-1 | <P climbWhen the frequency regulation demand is greater than 0, the rated power of the energy storage cannot meet the frequency regulation power demand, and the thermal power unit has sufficient ramping capability. In this case, the remaining frequency regulation demand is made up by the thermal power unit.

[0077]

[0078] In the formula, P AGC,t For the AGC frequency regulation command at time t within the power system area, P b,rate P is the rated power of the energy storage power station. climb P is the ramp rate of the thermal power unit. G,t Let P be the unit output power at time t. G,t-1 The unit output power at time t-1;

[0079] Running status m2: P AGC,t >0, P b,rate <P AGC,t ,|P G,t -P G,t-1 |>P climb When the frequency regulation demand is greater than 0, the rated power of the energy storage cannot meet the frequency regulation power demand, and the thermal power unit's ramp-up capability is insufficient. In this case, the thermal power-storage unit participates in frequency regulation according to its maximum output capacity.

[0080]

[0081] In the formula, P B,t This is the output power of the energy storage power station;

[0082] Running status m3: P AGC,t >0, P b,rate >P AGC,t When the frequency regulation demand is greater than 0, and the rated power of the energy storage meets the frequency regulation power demand, the energy storage participates in grid frequency regulation.

[0083] P B,t =P AGC,t (4)

[0084] Running status m4: P AGC,t >0, P b,rate >P AGC,t ,|P G,t -P G,t-1 | <P climb E AGC >E B When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation demand, the thermal power unit has sufficient ramping capability, and the frequency regulation capacity demand of the energy storage exceeds the rated capacity, then it is considered that the additional output of the thermal power unit will be used to charge the energy storage to make up for the capacity demand during the charging time:

[0085]

[0086] In the formula, T represents the total cycle of frequency regulation participated in by the energy storage power station.

[0087] Running status m5: P AGC,t >0, P b,rate >P AGC,t ,|P G,t -P G,t-1 |>P climb E AGC >E B When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation demand, the ramp-up capability of the thermal power unit is insufficient, and the frequency regulation capacity demand of the energy storage exceeds the rated capacity, then the additional output is compensated based on the maximum frequency regulation output of the thermal power unit:

[0088]

[0089] Running status m6: P AGC,t <0, P b,rate <P AGC,t ,|P G,t -P G,t-1 | <P climb When the frequency regulation demand is less than 0, the rated power of the energy storage cannot meet the frequency regulation demand, and the thermal power unit has sufficient ramping capability, the remaining frequency regulation demand is made up by the thermal power unit:

[0090]

[0091] Running status m7: P AGC,t <0, P b,rate <P AGC,t ,|P G,t -P G,t-1 |>P climb When the frequency regulation demand is less than 0, the rated power of the energy storage does not meet the frequency regulation demand, and the thermal power unit's ramping ability is insufficient. At this time, the frequency regulation is carried out according to the maximum output capacity of the thermal power-storage unit, and the operating state is the same as that in equation (3).

[0092] Running status m8: P AGC,t <0, P b,rate >P AGC,t When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation power demand. At this time, the energy storage participates in the grid frequency regulation, and the operating state is the same as in equation (4).

[0093] Running status m9: P AGC,t <0, P b,rate >P AGC,t ,|P G,t -P G,t-1 | <P climb E AGC >E BWhen the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is sufficient, and the frequency regulation capacity demand of the energy storage is less than the rated capacity, then the power of the energy storage is increased to make up for the capacity demand due to the load reduction compensation output of the thermal power unit.

[0094]

[0095] Running status m 10 :P AGC,t <0, P b,rate >P AGC,t ,|P G,t -P G,t-1 |>P climb E AGC >E B When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is insufficient, and the frequency regulation capacity of the energy storage is less than the rated capacity. In this case, the output is reduced to compensate for the maximum frequency regulation output of the thermal power unit:

[0096]

[0097] Step 2: Establish the margin coefficient related to the remaining frequency regulation capacity of thermal power units, including the construction of the frequency regulation power allocation model of thermal power units and the system operation constraints;

[0098] In step 2, the process of constructing the frequency regulation power allocation model for thermal power units is as follows:

[0099] Construct a frequency regulation power allocation model for thermal power units, consisting of the operating costs of the thermal power units:

[0100]

[0101] In the formula, C G,t For the operating cost of thermal power units, a j b j c j These are the energy consumption coefficients of thermal power unit j, λ and λ. j Let N be the loss cost coefficient of thermal power unit j. G P represents the number of thermal power units. g,j,t Let J be the output power of thermal power unit j at time t.

[0102] The design margin factor for thermal power units increases their willingness to regulate frequency. Units with greater remaining frequency regulation capacity have a larger margin factor, meaning they are prioritized for frequency regulation power tasks. The margin factor is determined as follows:

[0103]

[0104] In the formula, A j,tLet be the margin factor of thermal power unit j at time t. The rated capacity of thermal power unit j is... P is the maximum output power of thermal power unit j. g,j,t Let J be the output power of thermal power unit j at time t. The maximum output power of thermal power unit j is... P is the rated output power of thermal power unit j. AGC,t This is the general command for frequency regulation AGC in the power system.

[0105] The objective function of the frequency regulation power allocation model for thermal power units considering the adequacy factor is as follows:

[0106]

[0107] In step 2, the process of proposing system operation constraints is as follows:

[0108] The above-mentioned model is subject to constraints, the first being the power output balance constraint of thermal power units:

[0109]

[0110] In the formula: P g,j,t Let be the frequency-modulated power output of thermal power unit j in each region at time t.

[0111] Secondly, the output constraints of thermal power units are:

[0112]

[0113] In the formula: and These represent the minimum and maximum output limits of unit j, respectively.

[0114] The ramping constraint for thermal power units is:

[0115]

[0116] In the formula: P g,j,t-1 Let P be the actual output power of thermal power unit j at time t-1. climb,j The maximum ramp rate of thermal power unit j is expressed in MW / min.

[0117] Finally, the network operation constraints are:

[0118]

[0119] In the formula: P represents the upper limit of active power transmitted by line mn within the region. mn,t Let be the active power flowing from node m to node n on line mn at time t, expressed as follows:

[0120]

[0121] In the formula, X mr X nr x is an element of the network node impedance matrix. kn P represents the reactance value of line mn. r,t Let P be the active power output of power node r at time t. q,t Let q be the set of active power of load nodes at time t.

[0122] Step 3: Construct a frequency regulation power allocation model for the energy storage cluster power station, which includes: construction of the energy storage cluster frequency regulation power allocation model and system operation constraints;

[0123] In step 3, the process of constructing the frequency regulation power allocation model for the energy storage cluster is as follows:

[0124] The construction of a frequency regulation power allocation model for energy storage clusters mainly includes initial investment costs, power loss costs, and lifespan loss costs of energy storage power stations.

[0125]

[0126] In the formula, C inv,j,t C loss,j,t C life,j,t These represent the initial investment cost, power loss cost, and lifetime loss cost of power station j within the regional energy storage cluster; c a,j c p,j These represent the unit capacity cost and unit power cost of energy storage power station j, respectively. Let n be the rated capacity of energy storage power station j. a T represents the total number of scheduling operations for the energy storage cluster, q represents the energy storage discount rate (taken as 8%), and T represents the total number of scheduling operations for the energy storage cluster. fl,j The float charging life of energy storage power station j; and Let t represent the charging and discharging power of the energy storage power station j under economic operating conditions. The rated power of energy storage power station j and These represent the charging efficiency and discharging efficiency of energy storage power station j, respectively; N c,j Δt represents the equivalent number of cycles for an energy storage power station under full charge and discharge conditions, and Δt represents the scheduling cycle of the energy storage cluster.

[0127] The economic objective expression for energy storage power stations participating in frequency regulation is as follows:

[0128]

[0129] In the formula, C B,j,tLet F1 be the frequency regulation cost of energy storage power station j participating in frequency regulation, and F1 be the total frequency regulation cost of energy storage cluster power stations participating in frequency regulation.

[0130] During the allocation of frequency regulation power among energy storage power stations in an energy storage cluster, relying solely on the frequency regulation cost of each power station for power allocation may lead to the more economical station continuously bearing the frequency regulation commands, causing the energy storage station to prematurely lose its frequency regulation capability. Specifically, this manifests as the energy storage station's real-time SOC being at its lowest / highest boundary state, making it unable to track charge and discharge commands, and a significant difference between the SOC states of the energy storage station and those of other energy storage stations. Considering only economic operation, the SOC state expression of energy storage station j is as follows:

[0131]

[0132] To address this issue, a SOC (State of Charge) balance target for energy storage clusters is established for frequency regulation power allocation. The expression for the SOC balance target of the energy storage cluster is as follows:

[0133]

[0134] In the formula, This represents the State of Charge (SOC) of the energy storage power station j at time t, operating with an economic objective. This represents the State of Charge (SOC) of energy storage power station j at time t-1 under economic operating conditions. j,t This represents the SOC state of energy storage power station j at time t. j,t-1 This represents the SOC state of energy storage power station j at time t-1. and Let SOC represent the charging and discharging power of the energy storage power station j at time t under economic operating conditions. bala,t This represents the overall SOC balance of the energy storage cluster;

[0135] The expression for the SOC equilibrium target of an energy storage power station is as follows:

[0136]

[0137] In the formula, F2 represents the SOC equalization degree of the energy storage cluster power station participating in frequency regulation.

[0138] Furthermore, considering the cycle life target of the energy storage power station, which is affected by many factors, this chapter describes the cycle life of the energy storage power station by the number of energy storage operations and the equivalent number of cycles under full charge and discharge corresponding to the energy storage charge and discharge depth ΔDOD. The formula for calculating the energy storage charge and discharge depth is as follows:

[0139]

[0140] In the formula, DOD(t1) represents the initial charging / discharging time of energy storage, at which time the energy storage state of charge begins to rise / fall, and DOD(t0) represents the initial charging / discharging time of energy storage, at which time the energy storage state of charge begins to fall / rise. The difference in SOC between the two is denoted as the charging / discharging depth of energy storage station j.

[0141] Based on the depth of charge and discharge of energy storage, its corresponding equivalent cycle number can be further fitted, as shown in the following expression:

[0142]

[0143] In the formula, N c,j Let N be the equivalent number of cycles for energy storage power station j. r The rated number of cycles for an energy storage power station, DOD c Let t be the depth of charge / discharge, DOD j Let α and β be the rated depth of charge and discharge of energy storage power station j, and α and β be the fitting coefficients, which are related to the type of energy storage power station.

[0144] The expression for the cycle life target of the energy storage power station is as follows:

[0145]

[0146] In the formula, F3 represents the sum of the equivalent attenuation lifetimes of the energy storage cluster power stations participating in frequency regulation.

[0147] In step 3, the system operation constraints are proposed, specifically:

[0148] Frequency modulation power balance constraints:

[0149]

[0150] In the formula, P B,t N represents the total frequency regulation power involved in the energy storage cluster power station. B P represents the number of energy storage power stations. b,j,t Let j be the frequency regulation power output of the energy storage power station at time t.

[0151] Energy storage power constraints:

[0152]

[0153] In the formula, Let P be the discharge power of energy storage power station j at time t. b c,j,t represents the charging power of energy storage station j at time t. The rated power of energy storage power station j

[0154] Energy storage SOC capacity constraints:

[0155] SOC j,min≤SOC j,t ≤SOC j,max (29)

[0156] In the formula, SOC j,min With SOC j,max These are the minimum and maximum values ​​of energy storage power station j, respectively.

[0157] In summary, the analysis method of this invention is used to perform corresponding simulation analysis on specific examples.

[0158] In MATLAB Figure 1 The thermal power-energy storage frequency regulation system shown was constructed, and the frequency regulation power of the energy storage cluster and the thermal power unit was adjusted according to the strategy designed by the optimization analysis method of this invention. The effect was then analyzed.

[0159] Firstly, an improved IEEE-57 node pair was adopted. Figure 1 The regional power grid shown is used for a simulation example. The region includes thermal power units and energy storage cluster power stations. The energy storage cluster contains 5 energy storage power stations used for frequency regulation. Figure 5 To correct the frequency regulation power curve of energy storage cluster power stations Figure 6 The graph shows the frequency regulation power allocation curves of thermal power units under different strategies. Figure 7 The graphs show the frequency regulation power and SOC changes of various energy storage power stations under different strategies. Figure 8 This represents the equivalent number of cycles for each energy storage power station under strategies 3 and 4.

[0160] Comparative analysis reveals that this strategy comprehensively considers the three objectives of SOC capacity balance, cycle life, and frequency regulation cost of energy storage power stations for power allocation. While ensuring sufficient frequency regulation capacity and extending cycle life of energy storage power stations, it reduces the unit frequency regulation cost of the system. Under this strategy, the cost is 5.42% and 2.4% lower than that of strategies 1 and 2, respectively, which significantly improves the frequency regulation willingness of energy storage power stations and ensures the stable operation of the power system.

[0161] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters, characterized in that: Includes the following steps: S1: Design the compensation output of the thermal power unit, specifically: S11, Regional power grid frequency fluctuation analysis; S12, Thermal power-energy storage frequency regulation power control strategy; S2: Establish a margin factor related to the remaining frequency regulation capacity of thermal power units, specifically: S21. Construction of frequency regulation power allocation model for thermal power units; S22. System operating constraints; In S21, the sufficiency coefficient is determined as follows: In the formula, For thermal power units at time t The sufficiency coefficient, P is the maximum output power of thermal power unit j. g,j,t Let J be the output power of thermal power unit j at time t. The maximum output power of thermal power unit j is... The rated output power of thermal power unit j is... This is the general AGC command for frequency regulation in the power system, where T represents the total cycle of frequency regulation participation by the energy storage power station. S3: Construct a frequency regulation power allocation model for energy storage cluster power stations, specifically: S31. Construction of frequency regulation power allocation model for energy storage clusters; S32. System operating constraints; In S12, the running state m1: P AGC,t >0, P b,rate <P AGC,t ,|P G,t -P G,t-1 | <P climb When the frequency regulation demand is greater than 0, the rated power of the energy storage cannot meet the frequency regulation power demand, and the thermal power unit has sufficient ramping capability. At this time, the remaining frequency regulation demand is made up by the thermal power unit. This refers to the AGC frequency regulation command at time t within the power system area. This refers to the rated power of the energy storage power station. P is the ramp rate of the thermal power unit. G,t Let t be the unit's output power. The unit output power at time t-1; Running status m2: P AGC,t >0, P b,rate <P AGC,t ,|P G,t -P G,t-1 |>P climb When the frequency regulation demand is greater than 0, the rated power of the energy storage does not meet the frequency regulation power demand, and the thermal power unit's ramping ability is insufficient. In this case, the thermal power unit participates in frequency regulation according to the maximum output capacity of the thermal power-storage unit. Running status m3: P AGC,t >0, P b,rate >P AGC,t When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation power demand, and the energy storage participates in the grid frequency regulation at this time. Running status m4: P AGC,t >0, P b,rate >P AGC,t ,|P G,t -P G,t-1 | <P climb E AGC >E B When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation demand, the thermal power unit has sufficient ramping capability, and the frequency regulation capacity demand of the energy storage is greater than the rated capacity, then the additional power output of the thermal power unit is considered to be charged to make up for the capacity demand during the energy storage charging time. Running status m5: P AGC,t >0, P b,rate >P AGC,t ,|P G,t -P G,t-1 |>P climb E AGC >E B When the frequency regulation demand is greater than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is insufficient, and the frequency regulation capacity demand of the energy storage is greater than the rated capacity. At this time, the power output is increased to compensate for the maximum frequency regulation output of the thermal power unit. Running status m6: P AGC,t <0, P b,rate <P AGC,t ,|P G,t -P G,t-1 | <P climb When the frequency regulation demand is less than 0, the rated power of the energy storage cannot meet the frequency regulation demand, and the thermal power unit has sufficient ramping capability. At this time, the remaining frequency regulation demand is made up by the thermal power unit. Running status m7: P AGC,t <0, P b,rate <P AGC,t ,|P G,t -P G,t-1 |>P climb When the frequency regulation demand is less than 0, the rated power of the energy storage does not meet the frequency regulation demand, and the thermal power unit's ramping ability is insufficient, then the unit participates in frequency regulation according to the maximum output capacity of the thermal power-storage system. Running status m8: P AGC,t <0, P b,rate >P AGC,t When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation power demand, and the energy storage participates in the grid frequency regulation at this time. Running status m9: P AGC,t <0, P b,rate >P AGC,t ,|P G,t -P G,t-1 | <P climb E AGC >E B When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is sufficient, and the frequency regulation capacity demand of the energy storage is less than the rated capacity, then the power of the energy storage is increased to make up for the capacity demand when the thermal power unit reduces the load to compensate for the discharge state of the energy storage. Running status m 10 :P AGC,t <0, P b,rate >P AGC,t ,|P G,t -P G,t-1 |>P climb E AGC >E B When the frequency regulation demand is less than 0, the rated power of the energy storage meets the frequency regulation demand, the climbing ability of the thermal power unit is insufficient, and the frequency regulation capacity demand of the energy storage is less than the rated capacity. At this time, the output is reduced to compensate for the maximum frequency regulation output of the thermal power unit.

2. The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters according to claim 1, characterized in that, In S11, the regional power grid frequency fluctuation analysis takes the power system, which includes new energy power plants, thermal power units, and multiple energy storage power stations, as the research object. Due to real-time fluctuations between sources and loads within the power system area, corresponding frequency fluctuations will occur. The real-time frequency is expressed as follows: In the formula, For system frequency deviation, , These represent the damping coefficient and equivalent inertial constant within the system region, respectively. , , , , respectively represent the changes in output of thermal power units, changes in output of wind power units, and changes in load of the system, and n is the total number of thermal power units.

3. The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters according to claim 1, characterized in that, In S21, the system operation constraints are as follows: Thermal power unit output balance constraints: In the formula: For thermal power units in various regions exist Frequency modulation power output at any given time; N G This represents the number of thermal power units. The output constraints of thermal power units are: In the formula: and The units The minimum and maximum output values; The ramping constraint for thermal power units is: In the formula: For thermal power units exist Actual output power at any given time For thermal power units Maximum climbing rate; Network operation constraints are: In the formula: This represents the upper limit of active power transmitted by line mn within the region. for Timetable By node Flow to Node The active power is expressed as follows: In the formula, , These are the elements of the network node impedance matrix. For the line Reactance value, for Power Node Output active power for Time-based load nodes Active power set.

4. The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters according to claim 1, characterized in that, In S31, the frequency regulation power allocation model for energy storage clusters is analyzed, mainly including initial investment cost, power loss cost, and lifespan loss cost of energy storage power stations: In the formula, , , These are power stations within the regional energy storage cluster. Initial investment cost, power loss cost, and lifetime loss cost; , Energy storage power stations Unit capacity cost and unit power cost; For energy storage power stations Rated capacity, For the total number of times the energy storage cluster is scheduled, The energy storage discount rate, For energy storage power stations float charge lifetime; and for Real-time energy storage power station Charging and discharging power under economic operating conditions For energy storage power stations Rated power, and Energy storage power stations The charging efficiency and discharging efficiency; This represents the equivalent number of cycles for an energy storage power station under full charge and discharge conditions. This refers to the scheduling cycle of the energy storage cluster.

5. The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters according to claim 1, characterized in that, In S32, frequency modulation power balance constraints: In the formula, The total frequency regulation power involved by the energy storage cluster power station. The number of energy storage power stations Let be the frequency regulation power output of energy storage power station j at time t.

6. The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters according to claim 5, is characterized in that... In S32, energy storage power constraints: In the formula, Let j be the discharge power of the energy storage power station at time t. Let be the charging power of energy storage station j at time t. Let j be the rated power of the energy storage power station.

7. The method for optimizing the frequency regulation power of thermal power plants in the Shagohuang new energy base in collaboration with energy storage clusters according to claim 6, characterized in that, In S32, the energy storage SOC capacity constraint is: In the formula, and Energy storage power stations The minimum and maximum values, Representative energy storage power station The SOC state at time t.

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