Sagomean new energy base energy storage cluster auxiliary thermal power peak regulation and frequency modulation control method

Abstract

The invention relates to the field of energy storage frequency modulation systems, in particular to an auxiliary thermal power peak regulation and frequency modulation control method for an energy storage cluster of a Sagomegai new energy base, and aims to solve the problem that the frequency modulation enthusiasm of an energy storage cluster power station in a high-proportion new energy power system is reduced due to the fact that the frequency modulation capability is limited due to power-capacity constraint. Thermal power generating unit compensation output is designed to reserve frequency modulation capacity for an energy storage cluster power station, meanwhile, sufficient coefficients related to the residual frequency modulation capacity of the thermal power generating unit are introduced, a thermal power generating unit frequency modulation power distribution model is designed, and the equipment loss condition of the unit is reduced while the operation cost of the thermal power generating unit is reduced. The SOC overall balance target, the cycle life and the economical efficiency target of each energy storage power station are considered, preference decision making is carried out on the SOC balance target of the energy storage power station to ensure that the frequency modulation capacity of the energy storage power station is sufficient, and the frequency modulation capacity of each energy storage power station is fully utilized while the frequency modulation cost of the energy storage cluster is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy storage frequency modulation system, in particular to a Shagehuang new energy base energy storage cluster auxiliary thermal power peak regulation and frequency modulation control method. BACKGROUND

[0002] In response to the call for low-carbon development, the installed capacity of renewable new energy such as wind power and distributed photovoltaic in China is increasing, especially in Shagehuang area, the delivery of new energy has become a key way to solve energy and power supply. However, with the increasing proportion of renewable energy, the grid will face the problem of frequency modulation pressure caused by the decrease of inertia and the lack of frequency modulation capacity. Since energy storage has the ability of fast response and bidirectional regulation, it has obvious effect in fast response to frequency modulation instruction and maintaining system frequency stability. At the same time, with the support and development of national policy on energy storage construction, the installed capacity of energy storage in the grid has increased explosively in the past two years, and the development of energy storage has shown a cluster trend. Therefore, how to coordinate the frequency modulation of thermal power units and energy storage, maintain the control of large-scale energy storage cluster, and meet the requirements of sufficient system frequency modulation capacity and frequency stability is an important research topic.

[0003] Therefore, there is an urgent need in the prior art for a new technical solution to solve this problem. SUMMARY

[0004] The purpose of the present application is to solve the problem of limited frequency modulation capacity of energy storage cluster power station in high proportion of new energy power system due to power-capacity constraint, and to provide a Shagehuang new energy base energy storage cluster auxiliary thermal power peak regulation and frequency modulation control method considering frequency modulation capacity and target cost. The design of thermal power unit compensation output cooperates with energy storage cluster frequency modulation, reasonably reserves frequency modulation capacity for energy storage cluster, considers the state of charge balance target, cycle life and economic target of energy storage power station, and completes energy storage frequency modulation power distribution by using decision preference multi-objective algorithm.

[0005] The purpose of the present application can be realized by the following technical solutions:

[0006] The Shagehuang new energy base energy storage cluster auxiliary thermal power peak regulation and frequency modulation control method comprises the following steps:

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

[0008] S11, regional grid frequency fluctuation analysis;

[0009] S12, thermal power- energy storage frequency modulation power control strategy;

[0010] S2: establish the adequacy coefficient related to the remaining frequency modulation capacity of thermal power unit, specifically:

[0011] S21, thermal power unit frequency modulation power distribution model construction;

[0012] S22, system operation constraint condition;

[0013] S3: build a frequency modulation power distribution model of the energy storage cluster power station, specifically:

[0014] S31, build a frequency modulation power distribution model of the energy storage cluster;

[0015] S32, system operation constraint condition.

[0016] As a further scheme of the application: in S11, the power system containing new energy field station, thermal power unit and multiple energy storage power stations is taken as the research object in the regional power grid frequency fluctuation analysis. The real-time fluctuation between the source and load in the power system region will bring corresponding frequency fluctuation. The 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 inertia constant in the system region respectively, ΔP G , ΔP W , ΔP L , are the output change amount of the thermal power unit, the output change amount of the wind power unit and the load change amount respectively.

[0019] As a further scheme of the application: in S12, the operation state m1: P AGC,t >0, P b,rate <P AGC,t , |P G,t -P G,t-1 |<P climb , when the frequency modulation demand is greater than 0, the rated power of the energy storage does not meet the frequency modulation power demand, the climbing ability of the thermal power unit is sufficient, at this time the remaining frequency modulation demand is compensated by the thermal power unit; P AGC,t is the AGC frequency modulation instruction of the power system region at t time, P b,rate is the rated power of the energy storage power station, P climb is the climbing rate of the thermal power unit, P G,t is the unit output power at t time, P G,t-1 is the unit output power at t-1 time.

[0020] The operation state m2: P AGC,t >0, P b,rate <P AGC,t , |P G,t -P G,t-1 |>P climb , when the frequency modulation demand is greater than 0, the rated power of the energy storage does not meet the frequency modulation power demand, the climbing ability of the thermal power unit is insufficient, at this time the thermal- energy storage maximum output capacity participates in frequency modulation.

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

[0022] Running state 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 modulation demand is greater than 0, the energy storage rated power meets the frequency modulation demand, the thermal power unit climbing ability is sufficient, and the energy storage participates in the frequency modulation capacity demand is greater than the rated capacity, the compensation output of the thermal power unit is considered at the charging time of the energy storage to charge and make up the capacity demand;

[0023] Running state 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 modulation demand is greater than 0, the energy storage rated power meets the frequency modulation demand, the thermal power unit climbing ability is insufficient, and the energy storage participates in the frequency modulation capacity demand is greater than the rated capacity, the compensation output of the thermal power unit is considered at the charging time of the energy storage to charge and make up the capacity demand;

[0024] Running state m6: P AGC,t <0, P b,rate <P AGC,t , |P G,t -P G,t-1 |<P climb When the frequency modulation demand is less than 0, the energy storage rated power does not meet the frequency modulation demand, and the thermal power unit climbing ability is sufficient, the remaining frequency modulation demand is compensated by the thermal power unit at this time;

[0025] Running state m7: P AGC,t <0, P b,rate <P AGC,t , |P G,t -P G,t-1 |> P climb When the frequency modulation demand is less than 0, the energy storage rated power does not meet the frequency modulation demand, and the thermal power unit climbing ability is insufficient, the thermal- energy storage maximum output capacity participates in the frequency modulation at this time;

[0026] Running state m8: P AGC,t <0, P b,rateP AGC,t When the frequency modulation demand is less than 0, the energy storage rated power meets the frequency modulation power demand, at this time, the energy storage participates in the grid frequency modulation;

[0027] Running state 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 modulation demand is less than 0, the energy storage rated power meets the frequency modulation demand, the climbing ability of the thermal power generating unit is sufficient, the energy storage participates in the frequency modulation capacity demand is less than the rated capacity, at this time, the discharge state of the energy storage is considered to increase the power to compensate the capacity demand of the power compensation output of the thermal power generating unit;

[0028] Running state 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 modulation demand is less than 0, the energy storage rated power meets the frequency modulation demand, the climbing ability of the thermal power generating unit is insufficient, the energy storage participates in the frequency modulation capacity demand is less than the rated capacity, at this time, the maximum frequency modulation output of the thermal power generating unit is compensated according to the load compensation output.

[0029] As a further scheme of the present application: in S21, the determination method of the sufficiency coefficient is as follows:

[0030]

[0031] In the formula, A j,t is the sufficiency coefficient of the thermal power generating unit j at t moment, is the rated capacity of the thermal power generating unit j.

[0032] As a further scheme of the present application: in S21, the system operation constraint condition is as follows:

[0033] The thermal power generating unit compensation output balance constraint is:

[0034]

[0035] In the formula, P g,j,t is the frequency modulation power output by the thermal power generating unit j in each region at t moment;

[0036] The thermal power generating unit output constraint is:

[0037]

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

[0039] The climbing constraint of the thermal power unit 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 The actual output power of the thermal power unit j at t-1, P climb,j The maximum climbing rate of the thermal power unit j;

[0042] The network operation constraint is:

[0043]

[0044] In the formula: The upper limit of the active power transmission of the line mn in the region, P mn,t The active power of the line mn flowing from the node m to the node n at t, and the expression is as follows:

[0045]

[0046] In the formula, X mr , X nr The impedance matrix elements of the network node, x kn The reactance value of the line mn, P r,t The active power output by the power supply node r at t, P q,t The active power set of the load node q at t.

[0047] As a further scheme of the application: in S31, the energy storage cluster frequency regulation power distribution model is analyzed, mainly including the initial investment cost, power loss cost and life 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 The initial investment cost, power loss cost and life loss cost of the internal power station j of the regional energy storage cluster, respectively; c a,j , c p,j The unit capacity cost and unit power cost of the energy storage power station j; The rated capacity of the energy storage power station j, n a The total scheduling times of the energy storage cluster, q is the energy storage discount rate, and Tfl,j is the float life of the energy storage power station j; is the charging power of the energy storage power station j at time t, and is the charging power of the energy storage power station j at time t, and is the rated power of the energy storage power station j, is the charging power of the energy storage power station j at time t, and is the charging power of the energy storage power station j at time t, and c,j is the equivalent cycle number of the energy storage power station under full charging and discharging conditions, and Δt is the scheduling period of the energy storage cluster.

[0050] As a further scheme of the present application: in S32, the frequency modulation power balance constraint is:

[0051]

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

[0053]

[0054] As a further scheme of the present application: 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 and SOC j,max are the minimum and maximum values of the energy storage power station j, respectively.

[0057] The present application has the following beneficial effects:

[0058] The present application is a kind of energy storage cluster collaborative shaguo barren new energy base thermal power frequency modulation power optimization control strategy considering frequency modulation capacity and target cost, for the problem that energy storage cluster power station in high proportion new energy power system is limited due to power-capacity constraint The frequency modulation ability is reduced, and then the frequency modulation enthusiasm is reduced, the thermal power unit compensation output is designed to reserve the frequency modulation capacity of energy storage cluster power station, and the abundance coefficient related to the remaining frequency modulation capacity of thermal power unit is introduced, and the thermal power unit frequency modulation power distribution model is designed, which reduces the operation cost of thermal power unit and reduces the equipment loss of unit. Considering the overall balance of each energy storage station SOC, cycle life and economy target, the preference decision of energy storage station SOC balance target ensures the adequacy of energy storage station frequency modulation capacity, reduces the frequency modulation cost of energy storage cluster, and fully utilizes the frequency modulation capacity of each energy storage station. On the basis of the above method, simulation analysis and comparison of dynamic regulation effect are carried out, which shows the orderliness and scientificity of the method. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0060] Figure 1 A fire-ES system schematic diagram for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0061] Figure 2 A fire-ES collaborative operation schematic diagram for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0062] Figure 3 A double-layer optimization control strategy framework diagram for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0063] Figure 4 A fire-ES frequency modulation power control strategy schematic diagram for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0064] Figure 5 An energy storage cluster power station corrected frequency modulation power curve for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0065] Figure 6 A fire unit frequency modulation power distribution curve diagram under different strategies for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0066] Figure 7 A frequency modulation power and SOC change curve diagram of each energy storage power station under different strategies for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application is provided.

[0067] Figure 8 Equivalent cycle times of each energy storage power station under strategy 3 and strategy 4 for providing the fire-ES frequency modulation system of the Shagehuang new energy base energy storage cluster auxiliary fire power peak regulation and frequency modulation control method of the present application are provided. DETAILED DESCRIPTION

[0068] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0069] As Figures 1-8 shown, the method for assisting thermal power peak regulation and frequency modulation of the Shaoguo Huang new energy base energy storage cluster provided by the embodiments of the present application comprises the following steps: first, designing a thermal power unit compensation output to reserve a frequency modulation capacity for the energy storage cluster power station, then introducing an adequacy coefficient related to the residual frequency modulation capacity of the thermal power unit, and designing a thermal power unit frequency modulation power distribution model. Considering the overall balance of the SOC of each energy storage power station, the cycle life and economic targets, the SOC balance target of the energy storage power station is preferentially decided to ensure the adequacy of the frequency modulation capacity of the energy storage power station, and a MATLAB simulation platform is used to build a power system frequency modulation model for simulation and simulation. The specific steps are as follows:

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

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

[0072] The regional power grid frequency fluctuation is analyzed, taking the power system containing new energy field stations, thermal power units and multiple energy storage power stations as the research object. The real-time frequency fluctuation of the power system region due to the real-time fluctuation between the source and load will bring about the corresponding frequency fluctuation, and the real-time frequency expression is as follows:

[0073]

[0074] In the formula, Δf is the system frequency deviation, D and M are the damping coefficient and equivalent inertia constant inside the system region respectively, ΔP G , ΔP W , ΔP L , are the system thermal power unit output change, wind turbine output change and load change respectively, n is the total number of thermal power units,

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

[0076] Operating state m1: P AGC,t > 0, P b,rate < P AGC,t , |P G,t -P G,t-1 | < P climbWhen the frequency modulation demand is greater than 0, the energy storage rated power does not meet the frequency modulation power demand, and the climbing ability of the thermal power unit is sufficient, at this time, the remaining frequency modulation demand is made up by the thermal power unit:

[0077]

[0078] In the formula, P AGC,t is the AGC frequency modulation instruction of the power system area at time t, P b,rate is the rated power of the energy storage power station, P climb is the climbing rate of the thermal power unit, P G,t is the unit output power at time t, P G,t-1 is the unit output power at time t-1.

[0079] Running state m2: P AGC,t > 0, P b,rate < P AGC,t , |P G,t -P G,t-1 |> P climb When the frequency modulation demand is greater than 0, the energy storage rated power does not meet the frequency modulation power demand, and the climbing ability of the thermal power unit is insufficient, at this time, the maximum output capacity of the thermal- energy storage is used to participate in frequency modulation:

[0080]

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

[0082] Running state m3: P AGC,t > 0, P b,rate >P AGC,t When the frequency modulation demand is greater than 0, the energy storage rated power meets the frequency modulation power demand, at this time, the energy storage participates in the grid frequency modulation:

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

[0084] Running state 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 modulation demand is greater than 0, the energy storage rated power meets the frequency modulation demand, the climbing ability of the thermal power unit is sufficient, and the energy storage participates in the frequency modulation capacity demand is greater than the rated capacity, at this time, the compensation output of the thermal power unit is considered to charge at the charging time of the energy storage to make up the capacity demand:

[0085]

[0086] In the formula, T represents the total period of frequency modulation participated by the energy storage power station,

[0087] Operating state 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 modulation demand is greater than 0, the energy storage rated power meets the frequency modulation demand, the climbing ability of the thermal power unit is insufficient, and the capacity demand of the frequency modulation participated by the energy storage is greater than the rated capacity, at this time, the compensation output power is increased according to the maximum frequency modulation output of the thermal power unit:

[0088]

[0089] Operating state m6: P AGC,t < 0, P b,rate < P AGC,t , |P G,t - P G,t-1 | < P climb When the frequency modulation demand is less than 0, the energy storage rated power does not meet the frequency modulation demand, and the climbing ability of the thermal power unit is sufficient, at this time, the remaining frequency modulation demand is compensated by the thermal power unit:

[0090]

[0091] Operating state m7: P AGC,t < 0, P b,rate < P AGC,t , |P G,t - P G,t-1 | > P climb When the frequency modulation demand is less than 0, the energy storage rated power does not meet the frequency modulation demand, and the climbing ability of the thermal power unit is insufficient, at this time, the frequency modulation is participated according to the maximum output capacity of the thermal- energy storage, and the operating state is the same as formula (3),

[0092] Operating state m8: P AGC,t < 0, P b,rate > P AGC,t When the frequency modulation demand is less than 0, the energy storage rated power meets the frequency modulation power demand, at this time, the energy storage participates in the grid frequency modulation, and the operating state is the same as formula (4),

[0093] Operating state 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 modulation demand is less than 0, the energy storage rated power meets the frequency modulation demand, the climbing ability of the thermal power unit is sufficient, and the energy storage participating frequency modulation capacity demand is less than the rated capacity, at this time, the discharge state of the energy storage is increased power to compensate the capacity demand considering the load shedding compensation output of the thermal power unit:

[0094]

[0095] Running state 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 modulation demand is less than 0, the energy storage rated power meets the frequency modulation demand, the climbing ability of the thermal power unit is insufficient, and the energy storage participating frequency modulation capacity demand is less than the rated capacity, at this time, the maximum frequency modulation output of the thermal power unit is load shedding compensation output:

[0096]

[0097] Step 2: Establish the adequacy coefficient related to the remaining frequency modulation capacity of the thermal power unit, including the construction of the thermal power unit frequency modulation power distribution model and the system operation constraint condition;

[0098] In step 2, the process of constructing the thermal power unit frequency modulation power distribution model is as follows:

[0099] The thermal power unit frequency modulation power distribution model is constructed, which is composed of the operation cost of the thermal power unit:

[0100]

[0101] In the formula, C G,t is the operation cost of the thermal power unit, a j , b j , c j are the energy consumption coefficients of the thermal power unit j respectively, λ j is the loss cost coefficient of the thermal power unit j, N G is the number of thermal power units, P g,j,t is the output power of the thermal power unit j at time t,

[0102] The adequacy coefficient of the thermal power unit is designed to increase the frequency modulation willingness of the thermal power unit, and the greater the remaining frequency modulation capacity, the greater the adequacy coefficient, that is, the thermal power unit is preferentially called to undertake the work of thermal power unit frequency modulation power, and the determination method of the adequacy coefficient is as follows:

[0103]

[0104] In the formula, A j,tThe adequacy coefficient of thermal power unit j at time t, The rated capacity of thermal power unit j, The maximum output power of thermal power unit j, g,j,t The output power of thermal power unit j at time t, The maximum output power of thermal power unit j, The rated output power of thermal power unit j, AGC,t The total AGC command of the power system,

[0105] The objective function of the thermal power unit frequency modulation power allocation model considering the adequacy coefficient is as follows:

[0106] C fill =A j,t ·C G,t (12)

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

[0108] For the above-mentioned model, the first constraint is the balance constraint of the compensation output of thermal power units:

[0109]

[0110] In the formula: P g,j,t is the frequency modulation power output by the thermal power unit j in each region at time t,

[0111] The second constraint is the output constraint of the thermal power unit:

[0112]

[0113] In the formula: and are the minimum and maximum limits of the output of unit j,

[0114] The thermal power unit climbing constraint is:

[0115] P climb,j ≤P g,j,t -P g,j,t-1 ≤P climb,j (15)

[0116] In the formula: P g,j,t-1 is the actual output power of thermal power unit j at time t-1, P climb,j is the maximum climbing rate of thermal power unit j, unit: MW / min,

[0117] Finally, the network operation constraint is:

[0118]

[0119] In the formula: Pmaxmnis the upper limit of the active power transmission for the line mn in the region mn,t Pmn(t) is the active power flowing from node m to node n for line mn at time t, and the expression is as follows:

[0120]

[0121] where Xmn(t) is the active power flowing from node m to node n for line mn at time t mr Xmn(t) is the active power flowing from node m to node n for line mn at time t nr Xmn(t) is the active power flowing from node m to node n for line mn at time t kn Xmn(t) is the active power flowing from node m to node n for line mn at time t r,t Pm(t) is the active power output of the power supply node r at time t q,t Pq(t) is the active power set of the load node q at time t

[0122] Step 3, build the frequency modulation power distribution model of the energy storage cluster power station, which includes: energy storage cluster frequency modulation power distribution model construction and system operation constraint conditions;

[0123] In step 3, the process of building the energy storage cluster frequency modulation power distribution model is as follows:

[0124] Building the energy storage cluster frequency modulation power distribution model mainly includes the initial investment cost, power loss cost and life loss cost of the energy storage power station:

[0125]

[0126] where Cj is the initial investment cost, power loss cost and life loss cost of the energy storage power station j in the region, respectively inv,j,t Cj is the initial investment cost, power loss cost and life loss cost of the energy storage power station j in the region, respectively loss,j,t Cj is the initial investment cost, power loss cost and life loss cost of the energy storage power station j in the region, respectively life,j,t c is the unit capacity cost and unit power cost of the energy storage power station j, respectively a,j c is the unit capacity cost and unit power cost of the energy storage power station j, respectively p,j c is the unit capacity cost and unit power cost of the energy storage power station j, respectively n is the rated capacity of the energy storage power station j a q is the energy storage discount rate, which is 8%, and T is the energy storage cluster scheduling frequency fl,j T is the float life of the energy storage power station j and Pj(t) is the charging power and discharging power of the energy storage power station j at time t under the economic target operation Pj is the rated power of the energy storage power station j and ηj is the charging efficiency and discharging efficiency of the energy storage power station j, respectively c,j N is the equivalent cycle number of the energy storage power station under full charging and discharging conditions, and Δt is the scheduling period of the energy storage cluster

[0127] The economic target expression of the energy storage power station participating in frequency modulation is as follows:

[0128]

[0129] In the formula, C B,j,t is the frequency modulation cost of the energy storage power station j participating in frequency modulation, F1 is the total frequency modulation cost of the energy storage cluster power station participating in frequency modulation,

[0130] In the process of distributing the frequency modulation power among the energy storage power stations in the energy storage cluster, only relying on the frequency modulation cost of the energy storage power station for power distribution may cause the economic optimization to continuously bear the frequency modulation instruction, resulting in the energy storage power station losing the frequency modulation capability in advance. Specifically, the real-time SOC of the energy storage power station is at the lowest / highest boundary state and cannot track the charging / discharging instruction, and there is a large gap in the SOC state among the energy storage power stations. The SOC state expression of the energy storage power station j under the economic operation condition is as follows:

[0131]

[0132] To solve this problem, an energy storage cluster SOC balancing objective is established for frequency modulation power distribution. The SOC balancing degree expression of the energy storage cluster is as follows:

[0133]

[0134] In the formula, represents the SOC state of the energy storage power station j under the economic objective operation at time t, represents the SOC state of the energy storage power station j under the economic objective operation at time t-1, SOC j,t represents the SOC state of the energy storage power station j at time t, SOC j,t-1 represents the SOC state of the energy storage power station j at time t-1, and are the charging power and discharging power of the energy storage power station j under the economic objective operation at time t, SOC bala,t represents the overall SOC balancing degree of the energy storage cluster;

[0135] The expression of the SOC balancing objective of the energy storage power station is as follows:

[0136]

[0137] In the formula, F2 is the SOC balancing degree of the energy storage cluster power station participating in frequency modulation,

[0138] At the same time, the cycle life objective of the energy storage power station is further considered. The cycle life is affected by many factors. In this chapter, the equivalent cycle number corresponding to the complete charging and discharging of the energy storage charging and discharging depth ΔDOD is used to describe the cycle life of the energy storage power station. The calculation formula of the energy storage charging and discharging depth is as follows:

[0139]

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

[0141] According to the energy storage charging / discharging depth, the corresponding equivalent cycle number can be further fitted, and the expression is as follows:

[0142]

[0143] In the formula, N c,j is the equivalent cycle number of the energy storage station j, N r is the rated cycle number of the energy storage station, DOD c is the tth charging / discharging depth, DOD j is the rated charging / discharging depth of the energy storage station j, and α and β are fitting coefficients related to the type of the energy storage station.

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

[0145]

[0146] In the formula, F3 is the total sum of the equivalent attenuation life of the energy storage cluster station participating in frequency modulation,

[0147] In step 3, the system operation constraint condition is proposed, which is specifically:

[0148] Frequency modulation power balance constraint:

[0149]

[0150] In the formula, P B,t is the total frequency modulation power participated by the energy storage cluster station, N B is the number of energy storage stations, P b,j,t is the frequency modulation power output by the energy storage station j at t time,

[0151] Energy storage power constraint:

[0152]

[0153] In the formula, is the discharging power of the energy storage station j at t time, is the charging power of the energy storage station j at t time, is the rated power of the energy storage station j,

[0154] Energy storage SOC capacity constraint:

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

[0157] Where, SOC j,min With SOC j,max are the minimum and maximum values ​​of energy storage station j respectively.

[0158] In summary, the analysis method of the present invention is used to perform corresponding simulation analysis on specific examples.

[0159] In MATLAB Figure 1 The thermal power-energy storage frequency regulation system shown in the figure is constructed, and the frequency regulation power of the energy storage cluster and the thermal power unit is regulated according to the strategy designed by the optimization analysis method of the present invention, and the effect is analyzed.

[0160] Firstly, the improved IEEE-57 node pair Figure 1 The regional power grid shown in the figure is simulated. The region contains thermal power units and energy storage cluster power stations. The energy storage cluster contains 5 energy storage power stations for frequency regulation. Figure 5 Correct the frequency regulation power curve for energy storage cluster power stations, Figure 6 This is the frequency regulation power allocation curve of thermal power units under different strategies. Figure 7 The frequency regulation power and SOC change curves of each energy storage power station under different strategies are as follows: Figure 8 is the equivalent cycle number of each energy storage power station under strategy 3 and strategy 4,

[0161] Through comparison, it was found that this strategy comprehensively considers the three goals of SOC capacity balance, cycle life, and frequency regulation cost of energy storage power stations to allocate power. On the basis of ensuring sufficient frequency regulation capacity of energy storage power stations and extending cycle life, it reduces the system unit frequency regulation cost. This strategy is 5.42% and 2.4% lower than strategies 1 and 2 respectively, fully improving the frequency regulation willingness of energy storage power stations and ensuring the stable operation of the power system.

[0162] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. The energy storage cluster-assisted thermal power peak and frequency regulation control method of the Shagohuang New Energy Base is characterized by: The following steps are involved: S1: Design the compensation output of thermal power units, specifically: S11. Analysis of regional power grid frequency fluctuations; S12, thermal power-storage frequency modulation 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 distribution model for thermal power units; S22, system operation constraints; S3: Construct a frequency regulation power distribution model for energy storage cluster power stations. Specifically: S31. Construction of frequency regulation power distribution model for energy storage cluster; S32. System operation constraints.

2. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 1 is characterized in that: In S11, the regional power grid frequency fluctuation analysis takes the power system including renewable energy stations, thermal power units, and multiple energy storage power stations as the research object. The real-time fluctuations between sources and loads in the power system region will bring about corresponding frequency fluctuations. The real-time frequency is expressed as follows: Where Δf is the system frequency deviation, D and M are the damping coefficient and equivalent inertia constant within the system area, respectively, and ΔP G , ΔP W , ΔP L , are the output change of the system's thermal power units, wind turbine unit output change and load change respectively.

3. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 1 is characterized in that: In S12, 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 energy storage rated power 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 compensated by the thermal power unit; P AGC,t is the AGC frequency regulation instruction at time t in the power system area, P b,rate is the rated power of the energy storage station, P climb is the thermal power unit ramp rate, P G,t is the unit output power at time t, P G,t-1 is the unit output power at time t-1; Running state 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 energy storage rated power does not meet the frequency regulation power demand, and the thermal power unit has insufficient ramping capability, the frequency regulation is carried out according to the maximum output capability of the thermal-storage combination. Running state m3: P AGC,t >0,P b,rate >P AGC,t When the frequency regulation demand is greater than 0 and the energy storage rated power meets the frequency regulation power demand, the energy storage will participate in the grid frequency regulation. 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 capacity demand for the energy storage participating in the frequency regulation is greater than the rated capacity, the thermal power unit will be considered to increase the compensation output to charge the energy storage at the energy storage charging time to make up for the capacity demand; Running state 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 thermal power unit's climbing capacity is insufficient, and the frequency regulation capacity demand of the energy storage is greater than the rated capacity. At this time, the compensation output is increased according to 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 energy storage rated power 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 state 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 energy storage rated power cannot meet the frequency regulation demand, and the thermal power unit has insufficient ramping capability, the frequency regulation is carried out according to the maximum output capacity of the thermal-storage combination. Running status m8: P AGC,t <0, P b,rate >P AGC,t When the frequency regulation demand is less than 0, the energy storage rated power meets the frequency regulation power demand, and the energy storage participates in the grid frequency regulation. 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 thermal power unit has sufficient ramping capability, and the frequency regulation capacity demand of the energy storage is less than the rated capacity, the load shedding of the thermal power unit is considered to compensate for the discharge state of the energy storage and increase the power to compensate for the capacity demand; 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 load reduction compensation output is based on the maximum frequency regulation output of the thermal power unit.

4. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 1 is characterized in that: In S21, the method for determining the sufficiency factor is as follows: Where A j,t is the abundance factor of thermal power unit j at time t, is the rated capacity of thermal power unit j.

5. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 1 is characterized in that: In S21, the system operation constraints are as follows: Compensation output balance constraints of thermal power units: Where: P g,j,t is the frequency modulation power output by thermal power unit j in each region at time t; The output constraints of thermal power units are: Where: and are the minimum and maximum output limits of unit j respectively; The climbing constraint of thermal power unit is: P climb,j ≤P g,j,t -P g,j,t-1 ≤P climb (15) Where: P g,j,t-1 is the actual output power of thermal power unit j at time t-1, P climb,j is the maximum ramp rate of thermal power unit j; The network operation constraints are: Where: is the upper limit of active power transmitted by line mn in the region, P mn,t is the active power flowing from node m to node n on line mn at time t, and is expressed as follows: Where, X mr 、X nr is the network node impedance matrix element, x kn is the line mn reactance value, P r,t is the active power output of power node r at time t, P q,t is the active power set of load node q at time t.

6. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 1 is characterized in that: In S31, the energy storage cluster frequency regulation power allocation model is analyzed, mainly including the initial investment cost, power loss cost and the life loss cost of the energy storage power station: Where C inv,j,t 、C loss,j,t 、C life,j,t are the initial investment cost, power loss cost and life loss cost of power station j within the regional energy storage cluster; c a,j 、c p,j are the unit capacity cost and unit power cost of energy storage station j respectively; is the rated capacity of energy storage station j, n a is the overall dispatching times of the energy storage cluster, q is the energy storage discount rate, T fl,j is the floating charge life of energy storage station j; and is the charging power and discharging power of energy storage station j at time t when operating with economic goals, is the rated power of energy storage station j, and are the charging efficiency and discharging efficiency of energy storage station j respectively; N c,j is the equivalent number of cycles of the energy storage power station under full charge and discharge conditions, and Δt is the scheduling period of the energy storage cluster.

7. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 1 is characterized in that: In S32, the frequency modulation power balance constraint is:

8. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 7 is characterized in that: In S32, energy storage power constraints:

9. The method for controlling peak and frequency regulation of thermal power assisted by energy storage cluster in the Shagohuang New Energy Base according to claim 8 is characterized in that: In S32, the energy storage SOC capacity constraint is: SOC j,min ≤SOC j,t ≤SOC j,max (29) Where, SOC j,min With SOC j,max are the minimum and maximum values ​​of energy storage station j respectively.

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