CN117117899A - Wind-storage cooperative frequency modulation device considering primary frequency modulation dead zone of power grid - Google Patents
Wind-storage cooperative frequency modulation device considering primary frequency modulation dead zone of power grid Download PDFInfo
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Abstract
The invention provides a wind-storage cooperative frequency modulation device considering a primary frequency modulation dead zone of a power grid, which has the characteristics that: the data storage module is used for storing parameters of wind turbine generator and battery energy storage as wind storage parameters; wind-storage cooperative frequency modulation dead zoneThe parameter calculation module is used for storing data of a preset wind-storage combined primary frequency modulation constraint and an effect-economy objective function and calculating wind-storage parameters, the wind-storage combined primary frequency modulation constraint and the effect-economy objective function through a search algorithm to obtain a dead zone threshold d of battery energy storage 1 And dead zone threshold d of wind turbine generator set 2 The method comprises the steps of carrying out a first treatment on the surface of the The power grid frequency detection module is used for collecting the system frequency of the power system; and the wind-storage cooperative frequency modulation control module is used for carrying out three-stage dynamic frequency modulation on the power system with high-power loss. In a word, the method can ensure that the effect and the economical efficiency of the primary frequency modulation of the wind turbine generator and the battery energy storage are optimally balanced.
Description
Technical Field
The invention belongs to the field of operation analysis of power systems, and particularly relates to a wind-storage cooperative frequency modulation device considering a primary frequency modulation dead zone of a power grid.
Background
With the proposal of the strategic targets of carbon peak, carbon neutralization, the installed proportion of new energy sources of the electric power system in China is increasing. However, with the grid connection of renewable energy sources such as highly uncertain wind energy, the inertia of the system is greatly reduced, and the frequency modulation capability of the traditional unit cannot meet the frequency modulation requirement of a high-proportion new energy power system.
The battery energy storage has the characteristics of high response speed, adjustable parameters and the like, and can provide a large amount of active power for a low inertia power system in a short time so as to provide frequency support. Therefore, how to coordinate the wind turbine generator and the battery energy storage to participate in the primary frequency modulation of the system is a popular research content.
In the primary frequency modulation process, the frequency modulation capability mainly depends on adjustable parameters such as a difference modulation coefficient of a speed regulator, various inherent time constants, dead zones, limiting limits and the like. In the specification of grid-connected power supply primary frequency modulation technology and test guidelines, clear requirements are provided for the setting of primary frequency modulation parameters and dynamic performance indexes of various power supplies. However, the dead zone parameter setting problem is still an open problem for new power systems at high proportions of new energy. Because of the nonlinear influence of the dead zone link, the influence cognition of the dead zone link on the primary frequency modulation effect is not clear. At present, the requirements of China on the dead zone range setting of the wind turbine generator and the energy storage are respectively 0.03-0.10 Hz and 0.03-0.05 Hz, a learner points out the influence of the setting of different frequency modulation dead zone parameters on the frequency modulation effect, but the influence caused by dead zone nonlinearity is not analyzed mechanically only through simple qualitative analysis or a large number of simulations for verification. Therefore, the reasonable setting of the primary frequency modulation dead zone parameter is considered to have important significance for frequency stabilization.
In the prior art, most of the problems of frequency modulation dead zone parameter setting of single frequency modulation resources are researched, few documents are researched on the problem of dead zone coordination, and most of the prior art adopts descriptive function analysis based on a frequency domain analysis method, and the method can only be used for researching the frequency domain characteristics of a system.
In a word, the prior art can not enable the wind reservoir to cooperate with primary frequency modulation to achieve the frequency modulation effect and economical efficiency.
Disclosure of Invention
The invention aims to solve the problems, and aims to provide a wind-storage cooperative frequency modulation device considering a primary frequency modulation dead zone of a power grid.
The invention provides a wind-storage cooperative frequency modulation device considering a primary frequency modulation dead zone of a power grid, which is used for controlling a plurality of wind turbine units and battery energy storage to carry out primary frequency modulation on a power system, and has the characteristics that: the data storage module is used for storing parameters of wind turbine generator and battery energy storage as wind storage parameters; the wind-storage cooperative frequency modulation dead zone parameter calculation module is used for storing data of preset wind-storage cooperative primary frequency modulation constraint and effect-economy objective function and calculating wind-storage parameters, wind-storage cooperative primary frequency modulation constraint and effect-economy objective function through a search algorithm to obtain dead zone threshold d of battery energy storage 1 And dead zone threshold d of wind turbine generator set 2 The method comprises the steps of carrying out a first treatment on the surface of the The power grid frequency detection module is used for collecting the system frequency of the power system; the wind-storage cooperative frequency modulation control module is used for carrying out three-stage dynamic frequency modulation on a power system with high-power loss, wherein the specific process of dynamic frequency modulation is as follows: the system frequency is less than or equal to the dead zone threshold d 1 In the first stage, the wind storage cooperative frequency modulation control module controls all wind turbine units and battery energy storage to be inactive, and the system frequency is greater than the dead zone threshold d 1 And less than or equal to the dead zone threshold d 2 In the second stage, the wind-storage cooperative frequency modulation control module controls all the batteries to store energyThe power output and the system frequency are greater than the dead zone threshold d 2 In the third stage, the wind storage cooperative frequency modulation control module controls all wind turbine units and battery energy storage to perform active power output, and the expression of the effect-economical objective function is as follows: min Δf in max (d 1 ，d 2 ) To make Δf max Minimum, Δf max Maximum frequency deviation when primary frequency modulation is sequentially put into wind reservoir, minJ (d 1 ，d 2 ) To make J 1 And J 2 And minimum, J 1 For primary frequency modulation cost of wind turbine generator system, J 2 Primary frequency modulation cost for battery energy storage, n w N is the number of wind turbines b For the number of stored energy of the battery, a 1 Cost adjustment coefficient for power offset of wind turbine generator system, a 2 、a 3 Respectively taking into account cost adjustment coefficients delta P of battery energy storage charge and discharge and SoC deviation w，i (t) is the active output variation quantity, delta P, of the ith wind turbine generator set at the moment t b，i (t) is the active output variation of the energy storage of the ith battery at the moment t, soC i SoC for storing energy for ith battery, soC 0 The battery is charged with the initial SoC state.
The wind-storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid provided by the invention can also have the following characteristics: wherein the maximum frequency deviation Δf max Frequency deviation time domain solution delta f constructed according to dynamic frequency modulation 1 (t) calculating to obtain a frequency deviation time domain solution delta f 1 The expression of (t) is: wherein R is static adjustment difference coefficient of thermal power unit, delta P L Is step power disturbance, D is damping coefficient, alpha is wind turbine generator setCapacity ratio, beta is the capacity ratio of battery energy storage, K b Primary frequency modulation coefficient K set for battery energy storage frequency modulation w Primary frequency modulation coefficient C set for wind turbine generator set frequency modulation 1 、C 2 、C 3 、C 4 、C 5 、C 6 Respectively are undetermined constants lambda 1 、λ 2 、λ 3 、λ 4 、λ 5 、λ 6 Respectively the root of the characteristic equation, the maximum frequency deviation delta f max The expression of (2) is: Δf max ＝max{Δf 1，max ，Δf 2，max }，/> In Deltaf 1，max Is the maximum frequency deviation in the second stage, t 1，max At the time when the system frequency reaches the lowest point in the second stage, deltaf 2，max Is the maximum frequency deviation at the third stage, t 2，max The third stage is the time when the system frequency reaches the lowest point.
The wind-storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid provided by the invention can also have the following characteristics: the wind-storage combined primary frequency modulation constraint comprises a power balance constraint, a generator set constraint, a battery energy storage constraint, a wind turbine set constraint, a dead zone range constraint and a primary frequency modulation effect constraint, wherein the power balance constraint has the following expression: p in the formula G Generating set with t time (t)Output, P w，i (t) is the active output of the ith wind turbine generator system at the moment t, P b，i (t) is the i-th battery energy storage active force at t moment, P L (t) is load disturbance, and the expression of the generator set constraint is: /> In->For the lower output limit of the generator set, < > for>For the upper limit of the output of the generator set, the expression of the energy storage constraint of the battery is as follows: />In->Energy storage active force lower limit for ith battery,/->For the upper limit of the energy storage active force of the ith battery, soC (t) is the value of the energy storage SoC of the battery at the moment t, and SoC min Minimum value of SoC for battery energy storage, soC max For the maximum value of the battery energy storage SoC, the constraint expression of the wind turbine generator is as follows: />In->The lower limit of the active output of the ith wind turbine generator system is +.>Upper limit of active output of ith typhoon electric machine set and dead zone rangeThe surrounding constraint expression is: />The expression of primary frequency modulation effect constraint is: /> In->A lower frequency limit allowed for primary frequency modulation, < >>The upper limit of the allowable frequency for primary frequency modulation is Δf, which is the frequency deviation.
The wind-storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid provided by the invention can also have the following characteristics: the expression of the value SoC (t) of the battery energy storage SoC at the moment t is as follows:in DeltaP b (t) is the change quantity of active output of the battery energy storage at the moment t, E rated Rated capacity for storing energy of the battery.
The wind-storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid provided by the invention can also have the following characteristics: wherein the search algorithm is an improved multi-target particle swarm algorithm, and a dead zone threshold d is obtained 1 And dead zone threshold d 2 The specific steps of (a) are as follows: step S1, initializing the speed and the position of particles according to wind storage parameters; step S2, calculating a particle adaptation value of the particles according to the wind-storage combined primary frequency modulation constraint and the effect-economy objective function, obtaining an individual optimal value of the particles, and obtaining a group global optimal value of the iteration according to the individual optimal value; step S3, judging whether the maximum iteration times are met, if yes, entering a step S5, and if not, entering a step S4; step S4, optimizing the particles according to the learning factorsThe position, optimize the speed of the particle according to the inertia weight, and enter step S2 again; s5, selecting a population global optimum of the front edge from all population global optimum, and obtaining a dead zone threshold d according to an optimal compatible solution optimization method 1 And dead zone threshold d 2 。
The wind-storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid provided by the invention can also have the following characteristics: wherein the parameter settings of the improved multi-objective particle swarm algorithm comprise a particle number of 50, c max Has a value of 2, c min A value of 0.2, w max A value of 0.9, w min The value was 0.4 and the maximum number of iterations was 100.
Effects and effects of the invention
According to the wind storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid, because a plurality of dead zone thresholds d are obtained based on wind storage parameters by an IMOPSP algorithm and combining effect-economical objective function and wind storage combined primary frequency modulation constraint 1 And d 2 Further obtaining dead zone threshold d which is compatible with frequency modulation effect and economy from all the preferred combination pairs by an optimal compatible solution optimization method 1 And d 2 And according to the dead zone threshold d 1 And d 2 And controlling the wind turbine generator and the energy storage battery to act for dynamic frequency modulation. Therefore, the wind storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid can optimally balance the effect and the economical efficiency of the wind turbine generator and the primary frequency modulation of the battery energy storage.
Drawings
FIG. 1 is a schematic diagram of a wind-driven and stored energy co-frequency modulation device in accordance with an embodiment of the present invention;
FIG. 2 is a dead zone threshold d obtained according to IMOPSP algorithm in an embodiment of the invention 1 And dead zone threshold d 2 Is a flow diagram of (1);
FIG. 3 is a schematic diagram of a wind reservoir frequency response model with primary frequency modulation dead zone in an embodiment of the invention;
FIG. 4 is a schematic diagram of the lowest frequency point in dynamic frequency modulation in an embodiment of the present invention;
FIG. 5 is a schematic diagram of an IEEE four-machine two-zone system in an embodiment of the invention;
fig. 6 is a schematic diagram of a Pareto front in an embodiment of the invention.
Detailed Description
In order to make the technical means, creation characteristics, achievement purposes and effects of the invention easy to understand, the following embodiments are used for specifically describing the wind-storage cooperative frequency modulation device taking the primary frequency modulation dead zone of the power grid into consideration with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of a wind-driven and stored energy co-frequency modulation device according to an embodiment of the present invention.
As shown in fig. 1, the wind-storage cooperative frequency modulation device 100 taking into consideration the primary frequency modulation dead zone of the power grid in the present embodiment is used for controlling a plurality of wind turbines and battery energy storage to perform primary frequency modulation on a power system, and includes a data storage module 10, a wind-storage cooperative frequency modulation dead zone parameter calculation module 20, a power grid frequency detection module 30 and a wind-storage cooperative frequency modulation control module 40.
The data storage module 10 is used for storing parameters of wind turbine generator and battery energy storage as wind storage parameters.
The wind-storage cooperative frequency modulation dead zone parameter calculation module 20 stores data of preset wind-storage cooperative primary frequency modulation constraint and effect-economy objective function, and is used for calculating wind-storage parameters, wind-storage cooperative primary frequency modulation constraint and effect-economy objective function through a search algorithm to obtain a dead zone threshold d of battery energy storage 1 And dead zone threshold d of wind turbine generator set 2 。
Wherein the search algorithm is an improved multi-target particle swarm algorithm, i.e. IMOPSP algorithm, and the parameter setting of the improved multi-target particle swarm algorithm comprises a particle number of 50, c max Has a value of 2, c min A value of 0.2, w max A value of 0.9, w min The value was 0.4.
FIG. 2 is a dead zone threshold d obtained according to IMOPSP algorithm in an embodiment of the invention 1 And dead zone threshold d 2 Is a flow diagram of (a).
As shown in fig. 2, the dead zone threshold d is obtained according to the imosp algorithm 1 And dead zone threshold d 2 The method comprises the following steps:
step S1, initializing the speed and the position of the particles according to wind storage parameters.
And S2, calculating a particle adaptation value of the particles according to the wind-storage combined primary frequency modulation constraint and the effect-economy objective function, obtaining an individual optimal value of the particles, and obtaining a group global optimal value of the iteration according to the individual optimal value.
And step S3, judging whether the maximum iteration times are met, if yes, entering a step S5, and if not, entering a step S4.
Wherein the maximum number of iterations is 100.
And S4, optimizing the position of the particles according to the learning factors, optimizing the speed of the particles according to the inertia weight, and entering step S2.
S5, selecting a population global optimum of the front edge from all population global optimum, and obtaining a dead zone threshold d according to an optimal compatible solution optimization method 1 And dead zone threshold d 2 。
The grid frequency detection module 30 is configured to collect a system frequency of the power system.
The wind-storage cooperative frequency modulation control module 40 is used for performing three-stage dynamic frequency modulation on the power system with high power loss.
In the embodiment, during dynamic frequency modulation, the battery energy storage and the wind turbine generator are put into batches, so that the advantages of high response speed and strong climbing capacity of the battery energy storage are fully exerted, and powerful frequency support is provided for the system in the initial disturbance stage, therefore, the three stages of dynamic frequency modulation are realized by using the dead zone threshold d 1 And dead zone threshold d 2 The method comprises the following steps of dividing, namely, the specific process of dynamic frequency modulation in three stages:
the system frequency is less than or equal to the dead zone threshold d 1 I.e. first stage 0-t 0 When the wind power generation and battery energy storage combined frequency modulation control module 40 controls all wind power generation sets and the battery energy storage to be inactive;
the system frequency is greater than the dead zone threshold d 1 And less than or equal to the dead zone threshold d 2 I.e. second stage t 0 ～t 1 When the wind-storage cooperative frequency modulation control module 40 controls all the battery energy storage to perform active output;
the system frequency is greater than the dead zone threshold d 2 I.e. third stage t 1 At a later time, the wind-storage cooperative frequency modulation control module 40 controls all wind turbines and battery energy storage to perform active output.
The derivation process of the effect-economy objective function applicable to the dynamic frequency modulation in this embodiment is as follows:
1. effect objective function
In the dynamic frequency modulation process, as the frequency modulation speed is required to be higher in the initial disturbance stage, and the battery energy storage can accurately control the output power, the characteristic of a step dead zone model is met, so that the battery energy storage adopts a step dead zone, and the expressions of the input and the output of the battery energy storage frequency modulation dead zone are as follows:
in which x is b And (t) is the energy storage and frequency modulation dead zone output of the battery at the moment t, and delta f (t) is the energy storage and frequency modulation dead zone input of the battery at the moment t.
Considering the influence of wind speed uncertainty on the frequency modulation of the fan, the wear of the fan can be effectively reduced by adopting a common dead zone, and the frequency modulation economy is improved, so that the expression of the input and output of the frequency modulation dead zone of the wind turbine generator set is as follows:
in which x is w And (t) is the frequency modulation dead zone output of the wind turbine at the moment t, and Δf (t) is the frequency modulation dead zone input of the wind turbine at the moment t.
FIG. 3 is a schematic diagram of a wind reservoir frequency response model with primary frequency modulation dead zone in an embodiment of the invention.
As shown in fig. 3, a wind storage frequency response model is constructed for the battery energy storage, the wind turbine generator and the aggregated thermal power generation unit, and the input Δp (t) is subtracted by the output power of the battery energy storage, the wind turbine generator and the thermal power generation unit, and then the output Δf is obtained through coefficients, wherein M is an inertia time constant, and D is a damping coefficient.
Converted primary frequency modulation output power delta P of wind turbine generator w The expression of (t) is:
ΔP w (t)＝-αK w x w (t)，
wherein alpha is the capacity ratio of the wind turbine generator, K w Primary frequency modulation coefficient, x, set during frequency modulation of wind turbine generator w (t) i.e. a step dead zone.
Converted battery energy storage primary frequency modulation output power delta P b The expression of (t) is:
ΔP b (t) =βk b x b (t)，
Wherein beta is the capacity ratio of battery energy storage, K b Primary frequency modulation coefficient, x set for battery energy storage frequency modulation b (t) is a normal dead zone.
Converted thermal power unit output power delta P G The expression of (t) is:
f in the formula H T is the percentage of the output power of the high-pressure cylinder to the total output of the steam turbine R The thermal power unit intermediate reheat steam volume time constant is obtained, and R is the thermal power unit static adjustment difference coefficient.
The nonlinear wind-storage frequency response model can be converted into a plurality of linear models according to different stages of dynamic frequency modulation, and continuous analysis and solution before and after a demarcation point are ensured, so that the simultaneous state variable x is built w (t)、x b The time-domain differential equations for (t) and Δf (t) are as follows:
in DeltaP L (t) is a step power disturbance,is an impulse function.
The piecewise linearization solution is conveniently carried out by utilizing the dead zone according to the time domain differential equation, so that a frequency deviation time domain solution delta f of three stages of dynamic frequency modulation can be obtained 1 The expression of (t) is:
c in the formula 1 、C 2 、C 3 、C 4 、C 5 、C 6 Respectively are undetermined constants lambda 1 、λ 2 、λ 3 、λ 4 、λ 5 、λ 6 The roots of the characteristic equation respectively.
Fig. 4 is a schematic diagram of the lowest frequency point in dynamic frequency modulation in an embodiment of the present invention.
As shown in fig. 4, the first case and the second case respectively represent the frequency-time curves of the lowest frequency point in the dynamic frequency modulation in the second stage and the third stage, the abscissa of the first case and the second case are both time t and the ordinate of the second case are both frequency Hz, three primary frequency modulation index points are respectively present in the first case and the second case and respectively represent rocif, namely, 0 time, the lowest frequency point and quasi-steady state frequency in turn, and two primary frequency modulation input time points are respectively present in the first case and the second case and respectively represent t in turn 0 And t 1 It can be seen that, according to the difference of frequency modulation resource investment, the lowest frequency point during dynamic frequency modulation may appear in the second stage or the third stage, and the expression of the corresponding maximum frequency deviation is as follows:
when the lowest frequency point is in the second stage, letThe expression for obtaining the lowest point of the frequency arrival frequency can be simplified as follows:
maximum frequency deviation Δf in the second phase 1，max The expression of (2) is:
when the lowest frequency point is in the second stage, letThe expression for obtaining the lowest point of the frequency arrival frequency can be simplified as follows:
maximum frequency deviation Δf at third stage 2，max The expression of (2) is:
the two conditions are combined, and the maximum frequency deviation delta f when the wind reservoir is sequentially put into primary frequency modulation is obtained max The expression of (2) is: Δf max ＝max{Δf 1，max ，Δf 2，max }, the maximum frequency deviation deltaf max I.e. the effect objective function of the effect-economy objective function.
2. Economic objective function
For the wind turbine, increasing or decreasing power changes the pitch angle in the dynamic frequency modulation process, and the adjustment of the pitch angle causes mechanical abrasion of different degrees, so that the frequency modulation cost is designed according to the quadratic function of the power deviation of the wind turbine, and the primary frequency modulation cost J of the wind turbine is obtained 1 The expression of (2) is:
in which a is 1 For the cost adjustment coefficient of the power offset of the wind turbine generator, delta P w，i (t) is the active output variable quantity of the ith wind turbine generator set at the moment t, n w The number of the wind turbine generators is the number of the wind turbine generators.
For battery energy storage, in the process of participating in dynamic frequency modulation, the cost comes from cycle service life attenuation and battery aging caused by high power and large SoC offset, and the expression of the value SoC (t) of the battery energy storage SoC at the moment t is as follows:
in DeltaP b (t) is the change quantity of active output of the battery energy storage at the moment t, E rated SoC for storing rated capacity of battery 0 The battery is charged with the initial SoC state.
The frequency modulation cost of the battery energy storage consists of two parts of a quadratic function of the power deviation and the SoC deviation degree, and the primary frequency modulation cost J of the battery energy storage 2 The expression of (2) is:
in n b For the number of stored energy of the battery, a 2 、a 3 Respectively taking into account cost adjustment coefficients delta P of battery energy storage charge and discharge and SoC deviation b，i (t) is the active output variation of the energy storage of the ith battery at the moment t, soC i SoC for storing energy for the ith battery.
Primary frequency modulation cost J stored by battery 2 And primary frequency modulation cost J of wind turbine generator 1 The expression for the economic objective function can be constructed as:
minJ(d 1 ，d 2 )＝J 1 +J 2 。
in summary, the expression of the effect-economy objective function is:
furthermore, in order to be able to calculate the dead zone threshold d from the effect-economy objective function 1 And dead zone threshold d 2 It is also necessary to construct a wind-reservoir joint primary frequency modulation constraint, specifically including:
a power balance constraint, expressed as:
p in the formula G (t) is the output of the generator set at the moment t, P w，i (t) is the active output of the ith wind turbine generator system at the moment t, P b，i (t) is the i-th battery energy storage active force at t moment, P L And (t) is a load disturbance.
The generator set constraint is expressed as follows:
in the middle ofFor the lower output limit of the generator set, < > for>The upper limit of the output of the generator set is set.
The energy storage constraint of the battery is expressed as follows:
in the middle ofEnergy storage active force lower limit for ith battery,/->For the upper limit of the energy storage active force of the ith battery, soC (t) is the value of the energy storage SoC of the battery at the moment t, and SoC min Minimum value of SoC for battery energy storage, soC max The maximum value of SoC is stored for the battery.
The wind turbine generator system constraint is as follows:
in the middle ofThe lower limit of the active output of the ith wind turbine generator system is +.>The upper limit of the active output of the ith wind turbine generator system.
Dead zone range constraint, expressed as:
the primary frequency modulation effect constraint has the expression:
in the middle ofA lower frequency limit allowed for primary frequency modulation, < >>The upper limit of the allowable frequency for primary frequency modulation is Δf, which is the frequency deviation.
To evaluate the dead zone threshold d calculated by the stored-air cooperative frequency modulation dead zone parameter calculation module 20 in this embodiment 1 And dead zone threshold d 2 The effectiveness of (2) was tested by the following simulation:
and building an IEEE four-machine two-area system serving as an electric power system on the MATLAB/Simulink simulation platform.
Fig. 5 is a schematic diagram of an IEEE four-machine two-zone system in an embodiment of the present invention.
As shown in fig. 5, the IEEE four-machine two-zone system includes a zone 1 and a zone 2, the zone 1 includes a synchronous generator group G1 with a rated capacity of 150MW, a synchronous generator group G2 with a rated capacity of 200MW, and a wind farm with a rated capacity of 150MW, i.e., a wind turbine, which is composed of 100 DFIG groups with a rated capacity of 1.5MW, the steady-state load of the zone 1, i.e., load 1, is 175WM, and the zone 2 includes a synchronous generator group G3 with a rated capacity of 100MW and a battery energy storage with a rated capacity of 12MW/3mw·h.
The disturbance load of 60MW is suddenly increased to the region 2, namely the load 3, so that the power system is subjected to high-power deficiency, then the numerical value of the parameters in the following table is used as the value of the corresponding parameters of the wind power storage combined primary frequency modulation constraint and effect-economy objective function, and the IMOPSO method is combined to obtain a plurality of group global optimal values, namely the dead zone threshold d 1 And d 2 Is a combination of the pairs.
The first column and the third column in the table are parameters, the second column is the value of the parameter corresponding to the first column, and the fourth column is the value of the parameter corresponding to the third column.
Fig. 6 is a schematic diagram of a Pareto front in an embodiment of the invention.
As shown in FIG. 6, the abscissa indicates the wind-stored primary effect objective function, i.e., the effect objective function, at the dead zone threshold d 1 And d 2 The result of the calculation is that the ordinate is the wind-stored primary economic objective function, namely the economic objective function, is at the dead zone threshold d 1 And d 2 The Pareto front is the front of all combined pairs calculated by the IMOPSO methodAnd combining pairs, wherein each front edge combination pair is the optimal effect of the economic objective function calculation result and the effect objective function calculation result when the dead zone threshold value is obtained, three different dead zone threshold value schemes are selected A, B, C from the front edges, and the corresponding objective functions are calculated, and the results are shown in the following table:
| scheme for the production of a semiconductor device | d 1 | d 2 | Δf max | J |
| A | 0.0302 | 0.0303 | 0.2739 | 0.8737 |
| B | 0.0386 | 0.0579 | 0.2816 | 0.8257 |
| C | 0.0497 | 0.9983 | 0.2979 | 0.8025 |
The first column in the table is the number of the scheme, the second column is the dead zone threshold d1 of the corresponding scheme, and the third column is the dead zone threshold d of the corresponding scheme 2 The fourth column is the result of calculating the effect objective function of the corresponding scheme, the fifth column is the result of calculating the economic objective function of the corresponding scheme, for example, the cells in the second column of the third row represent that the dead zone threshold corresponding to the B scheme in the schematic diagram of the Pareto front is 0.0386.
From the above table, the scheme a only considers the single-objective optimization of the primary frequency modulation effect of the wind reservoir, i.e. has the best effect objective function calculation result, the primary frequency modulation dead zone of the wind reservoir is set close to the lower limit value given in the national standard, the maximum frequency deviation is 0.2739Hz, but the frequency modulation economy is the worst, and compared with the scheme B and the scheme C, the frequency modulation cost is improved by 5.85% and 8.87%, respectively.
The scheme C only considers the single-objective optimization of the wind-storage primary frequency modulation economy, namely the best economic objective function calculation result, and the wind-storage primary frequency modulation dead zone is close to the upper limit value given in the national standard, but the frequency modulation effect is worst at the moment, and the maximum frequency deviation reaches 0.2979Hz.
Scheme B is the dead zone threshold d of battery energy storage obtained from all the leading edge values according to the best compatible solution optimization method in the embodiment 1 And dead zone threshold d of wind turbine generator set 2 In order to comprehensively consider the multi-objective optimization of the primary frequency modulation effect and the frequency modulation economy, the maximum frequency deviation is 0.2816Hz, and the frequency modulation cost is reduced and improved by 5.53% and 2.85% compared with that of the scheme A and the scheme C respectively, so that the contradiction between the primary frequency modulation effect and the economy of the wind reservoir can be fully coordinated, and the method has more advantages.
In summary, by constructing a power system on a simulation platform and performing dead zone threshold d according to wind storage parameters of the power system 1 And dead zone threshold d 2 As can be seen from the calculation of the dead zone threshold d1 and the dead zone threshold d calculated by the wind-stored-energy cooperative frequency modulation dead zone parameter calculation module 20 of the present embodiment 2 Can better coordinate the contradiction between effect and economy compared with other dead zone threshold values, hasBetter balance.
Effects and effects of the examples
According to the wind-storage cooperative frequency modulation device considering the primary frequency modulation dead zone of the power grid, based on wind-storage parameters, a plurality of dead zone thresholds d are obtained through an IMOPSP algorithm and combining an effect-economical objective function and wind-storage combined primary frequency modulation constraint 1 And d 2 Further obtaining dead zone threshold d which is compatible with frequency modulation effect and economy from all the preferred combination pairs by an optimal compatible solution optimization method 1 And d 2 And according to the dead zone threshold d 1 And d 2 And controlling the wind turbine generator and the energy storage battery to act for dynamic frequency modulation. In a word, the method can ensure that the effect and the economical efficiency of the primary frequency modulation of the wind turbine generator and the battery energy storage are optimally balanced.
The above embodiments are preferred examples of the present invention, and are not intended to limit the scope of the present invention.
Claims (6)
1. Wind-storage cooperative frequency modulation device considering primary frequency modulation dead zone of power grid, which is used for controlling a plurality of wind turbine units and battery energy storage to carry out primary frequency modulation on a power system, and is characterized by comprising:
the data storage module is used for storing the parameters of the wind turbine generator and the battery energy storage as wind storage parameters;
the wind storage cooperative frequency modulation dead zone parameter calculation module is used for storing data of preset wind storage cooperative primary frequency modulation constraint and effect-economy objective function and calculating the wind storage parameter, the wind storage cooperative primary frequency modulation constraint and the effect-economy objective function through a search algorithm to obtain a dead zone threshold d of the battery energy storage 1 And a dead zone threshold d of the wind turbine generator set 2 ；
The power grid frequency detection module is used for collecting the system frequency of the power system;
the wind-storage cooperative frequency modulation control module is used for carrying out three-stage dynamic frequency modulation on the power system with high-power loss,
the specific process of the dynamic frequency modulation is as follows:
the system frequency is less than or equal to the dead zone threshold d 1 In the first stage, the wind power generation set and the battery energy storage are controlled by the wind power storage cooperative frequency modulation control module to be not operated,
the system frequency is greater than the dead zone threshold d 1 And less than or equal to the dead zone threshold d 2 In the second stage, the wind-storage cooperative frequency modulation control module controls all the battery energy storage to perform active output,
the system frequency is greater than the dead zone threshold d 2 In the third stage, the wind power storage cooperative frequency modulation control module controls all the wind power generation sets and the battery energy storage to perform active output,
the expression of the effect-economy objective function is:
min Δf in max (d 1 ,d 2 ) To make Δf max Minimum, Δf max Maximum frequency deviation when primary frequency modulation is sequentially put into wind reservoir, minJ (d 1 ,d 2 ) To make J 1 And J 2 And minimum, J 1 For primary frequency modulation cost of wind turbine generator system, J 2 Primary frequency modulation cost for battery energy storage, b w N is the number of wind turbines b For the number of stored energy of the battery, a 1 Cost adjustment coefficient for power offset of wind turbine generator system, a 2 、a 3 Respectively taking into account cost adjustment coefficients delta P of battery energy storage charge and discharge and SoC deviation w,i (t) isActive output variable quantity, delta P, of ith wind turbine generator set at moment t b,i (t) is the active output variation of the energy storage of the ith battery at the moment t, soC i SoC for storing energy for ith battery, soC 0 The battery is charged with the initial SoC state.
2. The wind-storage cooperative frequency modulation dead zone parameter optimization device considering the primary frequency modulation dead zone of the power grid according to claim 1, wherein the wind-storage cooperative frequency modulation dead zone parameter optimization device is characterized in that:
wherein the maximum frequency deviation Δf max A frequency deviation time domain solution delta f constructed according to the dynamic frequency modulation 1 (t) the calculation is carried out to obtain,
frequency deviation time domain solution Δf 1 The expression of (t) is:
wherein R is static adjustment difference coefficient of thermal power unit, delta P L For step power disturbance, D is a damping coefficient, alpha is the capacity duty ratio of the wind turbine generator, beta is the capacity duty ratio of battery energy storage, K b Primary frequency modulation coefficient K set for battery energy storage frequency modulation w Primary frequency modulation coefficient C set for wind turbine generator set frequency modulation 1 、C 2 、C 3 、C 4 、C 5 、C 6 Respectively are undetermined constants lambda 1 、λ 2 、λ 3 、λ 4 、λ 5 、λ 6 The roots of the characteristic equation respectively.
The maximum frequency deviation Δf max The expression of (2) is:
Δf max ＝max{Δf 1,max ,Δf 2,max }，
in Deltaf 1,max Is the maximum frequency deviation in the second stage, t 1,max Δf is the time when the system frequency reaches the lowest point in the second stage 2,max Is the maximum frequency deviation at the third stage, t 2,max And the third stage is the moment when the system frequency reaches the lowest point.
3. The wind-storage cooperative frequency modulation dead zone parameter optimization device considering the primary frequency modulation dead zone of the power grid according to claim 1, wherein the wind-storage cooperative frequency modulation dead zone parameter optimization device is characterized in that:
wherein the wind-storage combined primary frequency modulation constraint comprises a power balance constraint, a generator set constraint, a battery energy storage constraint, a wind generator set constraint, a dead zone range constraint and a primary frequency modulation effect constraint,
the expression of the power balance constraint is:
p in the formula G (t) is the output of the generator set at the moment t, P w,i (t) is the active output of the ith wind turbine generator system at the moment t, P b,i (t) is the i-th battery energy storage active force at t moment, P L (t) is the load disturbance and,
the generator set constraint expression is:
in the middle ofFor the lower output limit of the generator set, < > for>For the upper output limit of the generator set,
the expression of the battery energy storage constraint is as follows:
in the middle ofEnergy storage active force lower limit for ith battery,/->For the upper limit of the energy storage active force of the ith battery, soC (t) is the value of the energy storage SoC of the battery at the moment t, and SoC min Minimum value of SoC for battery energy storage, soC max For the maximum value of the battery energy storage SoC,
the expression of the constraint of the wind turbine generator is as follows:
in the middle ofThe lower limit of the active output of the ith wind turbine generator system is +.>Is the upper limit of the active output of the ith typhoon electric machine group,
the expression of the dead zone range constraint is:
the expression of the primary frequency modulation effect constraint is as follows:
in the middle ofA lower frequency limit allowed for primary frequency modulation, < >>The upper limit of the allowable frequency for primary frequency modulation is Δf, which is the frequency deviation.
4. The wind-storage cooperative frequency modulation dead zone parameter optimization device considering the primary frequency modulation dead zone of the power grid according to claim 3, wherein the wind-storage cooperative frequency modulation dead zone parameter optimization device is characterized in that:
the expression of the value SoC (t) of the battery energy storage SoC at the moment t is as follows:
in DeltaP b (t) is the change quantity of active output of the battery energy storage at the moment t, E rated Rated capacity for storing energy of the battery.
5. The wind-storage cooperative frequency modulation dead zone parameter optimization device considering the primary frequency modulation dead zone of the power grid according to claim 1, wherein the wind-storage cooperative frequency modulation dead zone parameter optimization device is characterized in that:
wherein the search algorithm is an improved multi-target particle swarm algorithm,
obtaining the dead zone threshold d 1 And the dead zone threshold d 2 The specific steps of (a) are as follows:
step S1, initializing the speed and the position of particles according to the wind storage parameters;
step S2, calculating a particle adaptation value of the particle according to the wind-storage combined primary frequency modulation constraint and the effect-economy objective function, obtaining an individual optimal value of the particle, and obtaining a group global optimal value of the iteration according to the individual optimal value;
step S3, judging whether the maximum iteration times are met, if yes, entering a step S5, and if not, entering a step S4;
step S4, optimizing the position of the particles according to the learning factors, optimizing the speed of the particles according to the inertia weight, and entering the step S2;
s5, selecting the global optimum of the leading edge from all the global optimum of the groups, and obtaining the dead zone threshold d according to an optimal compatible solution optimization method 1 And the dead zone threshold d 2 。
6. The wind-storage cooperative frequency modulation dead zone parameter optimization device considering the primary frequency modulation dead zone of the power grid according to claim 5, wherein the wind-storage cooperative frequency modulation dead zone parameter optimization device is characterized in that:
wherein the parameter settings of the improved multi-objective particle swarm algorithm comprise a particle number of 50, c max Has a value of 2, c min A value of 0.2, w max A value of 0.9, w min The value is 0.4, and the maximum iteration number is 100.
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