CN112039088B - Multi-domain multi-source power system load frequency disturbance observer control method - Google Patents

Multi-domain multi-source power system load frequency disturbance observer control method Download PDF

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CN112039088B
CN112039088B CN202010887195.1A CN202010887195A CN112039088B CN 112039088 B CN112039088 B CN 112039088B CN 202010887195 A CN202010887195 A CN 202010887195A CN 112039088 B CN112039088 B CN 112039088B
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CN112039088A (en
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张卫东
阮士涛
黄宇波
张惠炘
张各各
孙敏
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Shanghai Jiaotong University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract

The invention relates to a multi-domain multi-source power system load frequency disturbance observer control method, which comprises the following steps: 1) obtaining a load disturbance model of each subarea in a multi-domain multi-source power system; 2) acquiring a low-order nominal model of the load disturbance model of each sub-area, and solving a low-order nominal model parameter; 3) designing a filter of the disturbance observer system based on the low-order nominal model; 4) designing a feedback controller of a disturbance observer system; 5) and applying the filter and the feedback controller to a load frequency control system to complete the control of the multi-domain multi-source power system load frequency disturbance observer. Compared with the prior art, the method has the advantages of no need of additional observation information, integration of load disturbance estimation and compensation, consideration of multi-domain multi-source structure and wind energy infiltration influence and the like.

Description

Multi-domain multi-source power system load frequency disturbance observer control method
Technical Field
The invention relates to the field of power system safety, in particular to a control method of a multi-domain multi-source power system load frequency disturbance observer.
Background
The frequency is one of the key indexes for the safe and stable operation of the power system, and the frequency fluctuation can affect the power supply quality and the service life of electrical components, thereby causing the stability of the power system to deteriorate and even causing the breakdown of the whole power system. In order to ensure that an electric power system stably and reliably operates, load frequency control is needed to be adopted, the frequency is kept within an acceptable range, in recent years, the scale of the electric power system is gradually enlarged, the interconnection degree between areas is continuously improved, the structure of the electric power system is more complicated, the risk of safe and stable operation of a power grid is increased, in addition, in order to solve the problems of energy crisis, environmental pollution, global warming and the like, the grid-connected scale of new energy power generation represented by wind energy is gradually increased, the fluctuation of the load frequency of the electric power system and the imbalance of active power are aggravated, and higher requirements are provided for the load frequency control.
The actual power system is formed by interconnecting a plurality of areas through a connecting line, and each area generally jointly participates in frequency modulation by a plurality of resources, such as access of new energy power generation including thermal power, water conservancy power generation, wind energy and the like, so that the load frequency control of the multi-domain and multi-source power system becomes a research hotspot in recent years. Jay Singh et al, in Two degree of free internal model control-PID design for LFC of power system via high performance optimization (ISA Trans, 2008, 72, pp.185-196), designed a proportional-integral-derivative load frequency controller for multi-domain multi-source power system, however, this method only considers single-area and Two-area power systems and does not consider the influence of penetration of new energy such as wind energy. Bheem Sonker et al, in Dual loop IMC structure for load frequency control system of multi-area multi-source power systems (Int.J.electric.Power Energy Syst., 2019, 112, pp.476-494), designed a Dual-loop load frequency controller for multi-domain multi-source power systems; the method considers the influence of wind energy permeation, but the control system has a complex structure, and the order of the controller is very high, so that the method is inconvenient for engineering implementation.
Frequency and tie line power fluctuation is aggravated due to power supply and generation unbalance, perturbation of power system parameters and change of an operation working point, and the traditional proportional-integral-derivative control method is difficult to give consideration to control precision, power supply quality and stability of load frequency. Control system performance would be significantly improved if the load disturbances and power system parameter perturbations could be estimated and compensated for. Yang Mi et al, in The sliding mode load frequency control for hybrid power system based on distributed observer (int.J.electric.Power Energy Syst., 2016, 74, pp.446-452), uses a disturbance observer to estimate The load disturbance and uses The estimated disturbance to construct The control rate of The sliding mode controller, however, this method only considers single-domain power systems. A disturbance Observer-based sliding mode controller is designed for a multi-domain multi-source power system in the document of Observer based sliding mode frequency control for multi-machine power systems with high-speed reusable Energy (J.Mod.Power Syst.Clean Energy, 2018, pp.473-481), the disturbance Observer designed by the methods needs to acquire state information of the power system, observation cost is increased, the control system implementation difficulty is increased due to the fact that the disturbance Observer and the sliding mode controller are nonlinear, in addition, the disturbance Observer can only be used for estimating disturbance, and the compensation function of the disturbance is realized by the sliding mode controller.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a control method of a multi-domain multi-source power system load frequency disturbance observer.
The purpose of the invention can be realized by the following technical scheme:
a multi-domain multi-source power system load frequency disturbance observer control method comprises the following steps:
1) obtaining a load disturbance model of each subarea in a multi-domain multi-source power system;
2) acquiring a low-order nominal model of the load disturbance model of each sub-area, and solving a low-order nominal model parameter;
3) designing a filter of the disturbance observer system based on the low-order nominal model;
4) designing a feedback controller of a disturbance observer system;
5) and applying the filter and the feedback controller to a load frequency control system to complete the control of the multi-domain multi-source power system load frequency disturbance observer.
In the step 1), the multi-domain multi-source power system comprises three sub-domains, each sub-domain is formed by connecting a thermal power generation electronic system and a hydraulic power generation subsystem in parallel, and then the load disturbance model transfer function G of the ith sub-domainiThe expression of(s) is:
Figure GDA0003305631630000021
wherein G ispi(s) is the generator and load transfer function, Ggi(s) and Gti(s) regulating the thermal power generation subsystem respectivelyTransfer function of steam turbine of governor and reheat type, GHgi(s)、GHri(s) and GHwi(s) transfer functions of the governor, transient droop compensator, and turbine of the hydro-power generation subsystem, respectively, where s is the Laplace operator, RiIs a permanent state droop characteristic coefficient.
In the load disturbance model transfer function GiIn the step(s), the step (c),
generator and load transfer function GpiThe expression of(s) is:
Figure GDA0003305631630000031
transfer function G of speed regulator of thermal power generation subsystemgiThe expression of(s) is:
Figure GDA0003305631630000032
transfer function G of reheat steam turbine of thermal power generation subsystemtiThe expression of(s) is:
Figure GDA0003305631630000033
transfer function G of speed regulator of hydroelectric power generation subsystemHgiThe expression of(s) is:
Figure GDA0003305631630000034
transfer function G of transient droop compensator for hydroelectric subsystemHriThe expression of(s) is:
Figure GDA0003305631630000035
transfer function G of water turbine of hydroelectric power generation subsystemHwiThe expression of(s) is:
Figure GDA0003305631630000036
wherein, KpiAnd TpiRespectively, power system gain and time constant, TgiAdjusting the time constant, K, for the fireri、TriAnd TtiReheater gain, reheat time constant and turbine time constant, T, respectivelyHgiIs the time constant of the governor of the water turbine, THriAnd THiAs compensator parameters for water turbines, TwiIs the inertia time constant of the water flow of the water turbine.
In the step 2), a load disturbance model G of the area i is obtained by adopting a model order reduction methodi(s) a low-order nominal model, the specific structure of said low-order nominal model being:
Figure GDA0003305631630000037
wherein, aijJ is 1,2,3 and bijJ is 0,1,2 are denominator and numerator polynomial coefficients of the low-order nominal model, respectively, and satisfy the condition aij> 0(j ═ 1,2,3), the low order nominal model was stabilized.
In the step 2), the step of calculating the low-order nominal model parameters specifically includes the following steps:
21) will be provided with
Figure GDA0003305631630000041
Substituting into the low order nominal model GmiIn the expression of(s), there are:
Figure GDA0003305631630000042
wherein the content of the first and second substances,
Figure GDA0003305631630000043
is an imaginary unit, omegaikFor the kth modeled frequency Point, NiThe total number of the frequency points is;
22) model reduced order error function defining sub-region i
Figure GDA0003305631630000044
The model reduced order error function
Figure GDA0003305631630000045
The expression of (a) is:
Figure GDA0003305631630000046
solving the optimal reduced order model problem is equivalent to solving a partial differential equation set, and the following steps are carried out:
Figure GDA0003305631630000047
Figure GDA0003305631630000048
wherein the content of the first and second substances,
Figure GDA0003305631630000049
is composed of
Figure GDA00033056316300000410
The conjugate transpose of (1);
23) solving the partial differential equations in step 22) yields:
Figure GDA00033056316300000411
Figure GDA00033056316300000412
Ωik＝[Im(Gik),b0-Re(Gik),-b0Im(Gik),b0Re(Gik)-|Gik|2,b0Im(Gik)]T,k＝1,2,...,Ni
wherein the superscripts + and T represent the pseudo-inverse and transpose of the matrix, respectively,
Figure GDA00033056316300000413
is the NthiA sub-matrix is modeled, and,
Figure GDA00033056316300000414
is the NthiThe number of sub-vectors to be modeled,
Figure GDA00033056316300000415
Re(Gik) And Im (G)ik) Respectively represent
Figure GDA00033056316300000416
Real and imaginary parts, | Gik|2Is composed of
Figure GDA00033056316300000417
The square of the magnitude of the amplitude is,
Figure GDA00033056316300000418
is the upper bound of the frequency point, and is taken as Gi(s) bandwidth.
In the step 3), the filter structure of the disturbance observer is
Figure GDA00033056316300000419
Wherein n isiOf order of the filter, λiS is the laplacian operator for the filter time constant.
The step 4) specifically comprises the following steps:
41) defining a desired load frequency response transfer function T for a subregion iΔfi(s) then:
Figure GDA0003305631630000051
wherein, tauαi、τβiParameters of the desired load frequency response transfer function, τ, respectivelyαiFor increasing the load disturbance response speed, tauβiTo adjust the robustness of the closed loop system;
42) feedback controller C for selecting PID controller as sub-region ii(s) then:
Figure GDA0003305631630000052
wherein, KPi、TIiAnd TDiProportional gain, integral time constant and differential time constant;
43) defining the feedback controller Ci(s) parameter optimization Performance index JiAnd find the minimum performance index JiOf (2) an optimal solution
Figure GDA00033056316300000513
I.e. the parameters of the feedback controller are obtained.
In the step 43), the performance index JiThe method specifically comprises the following steps:
Figure GDA0003305631630000053
Figure GDA0003305631630000054
θi＝{KPi,TIi,TDi}
wherein, thetaiIs a feedback controller parameter vector.
Said step 43), said optimal solution
Figure GDA0003305631630000055
The expression of (a) is:
Figure GDA0003305631630000056
Figure GDA0003305631630000057
Figure GDA0003305631630000058
wherein the vector
Figure GDA0003305631630000059
Figure GDA00033056316300000510
(Vector)
Figure GDA00033056316300000511
(Vector)
Figure GDA00033056316300000512
Re and Im represent the real and imaginary parts, respectively.
In the step 5), when the area of the load frequency control system contains the influence of wind energy penetration, the wind energy penetration is used as a disturbance item to participate in load frequency adjustment, and a disturbance observer is used for compensating the influence of the wind energy penetration on the load frequency and the exchange power of the connecting line.
Compared with the prior art, the invention has the following advantages:
firstly, no additional observation information is needed: the existing control method of the load frequency disturbance observer needs to acquire the state information of the electric power system, which increases the observation cost and the engineering implementation difficulty.
Secondly, integrating load disturbance estimation and compensation: the control method of the existing load frequency disturbance observer only utilizes the disturbance observer to estimate the load disturbance, and the compensation function of the load disturbance is realized by a sliding mode controller. Because the disturbance observer control method integrates load disturbance estimation and compensation, and the control system structure of the method is simpler, the method is more convenient for engineering implementation, popularization and application.
Considering multi-domain multi-source structure and wind energy infiltration influence: the method considers the influence of the multi-domain multi-source power system structure and the wind energy permeability, and the filter and the controller of the method are flexible in parameter setting, so that the stability of the load frequency and the robustness of the control system are convenient to realize.
Drawings
Fig. 1 is a schematic structural diagram of an electric power system according to the embodiment.
Fig. 2 is a transfer function model of the power system region according to the embodiment.
Fig. 3 is a simulation model of a wind power generation subsystem in a certain region of the power system in this embodiment.
Fig. 4 shows the system frequency deviation response of the power system region 1 according to the present embodiment.
Fig. 5 shows the system frequency deviation response of the power system area 2 according to this embodiment.
Fig. 6 shows the system frequency deviation response of the power system area 3 according to this embodiment.
Fig. 7 shows the tie-line power deviation response between the area 1 and the area 2 of the power system of the present embodiment.
Fig. 8 shows the tie-line power deviation response between the areas 2 and 3 of the power system of the present embodiment.
FIG. 9 is a wind speed variation diagram of the wind power generation subsystem according to the embodiment.
FIG. 10 is a wind power output of the wind power generation subsystem of the present embodiment.
FIG. 11 is a system frequency deviation response of the region 1 including the wind energy penetration power system of the present embodiment.
FIG. 12 is a system frequency deviation response of the region 2 of the wind energy penetration-containing power system of the present embodiment.
FIG. 13 is a system frequency deviation response of the region 3 of the wind energy penetration power system of the present embodiment.
FIG. 14 is a cross-tie power deviation response between region 1 and region 2 of the present embodiment of the wind energy infiltration-containing power system.
FIG. 15 is a cross-tie power deviation response between region 2 and region 3 of the present embodiment of the wind energy infiltration-containing power system.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
Examples
For a multi-domain multi-source power system with wind energy penetration shown in fig. 1, in order to reduce the influence of wind energy fluctuation on the system load frequency and the tie line exchange power, a disturbance observer control method is adopted to optimize load frequency control. The invention provides a multi-domain multi-source power system load frequency disturbance observer control method, which comprises the following steps:
1) obtaining a load disturbance model of each subarea in a multi-domain multi-source power system;
2) acquiring a low-order nominal model of the load disturbance model of each sub-area, and solving a low-order nominal model parameter;
3) designing a filter of the disturbance observer system based on the low-order nominal model;
4) designing a feedback controller of a disturbance observer system;
5) and applying the filter and the feedback controller to a load frequency control system to complete the control of the multi-domain multi-source power system load frequency disturbance observer.
The specific method of each step is as follows:
in the step 1), the constructed multi-domain multi-source power system comprises three sub-regions, and each sub-region is formed by connecting a thermal power generation electronic system and a hydraulic power generation subsystem in parallel. The transfer function expression of the load disturbance model of each subarea is as follows:
Figure GDA0003305631630000071
wherein G ispi(s) is the generator and load transfer function, Ggi(s) and Gti(s) transfer functions of the governor of the thermal power generation subsystem and the reheat turbine, G, respectivelyHgi(s)、GHri(s) and GHwi(s) transfer functions of the governor, transient droop compensator, and turbine of the hydro-power generation subsystem, respectively, where s is the Laplace operator, RiIs a permanent state droop characteristic coefficient.
Transfer function G of load disturbance model of each sub-regioniThe concrete structure of each power system module in(s) is
Figure GDA0003305631630000072
Figure GDA0003305631630000073
Wherein, KpiAnd TpiFor power system gain and time constant, TgiAdjusting the time constant, K, for the fireri、TriAnd TtiReheater gain, reheat time constant and turbine time constant, T, respectivelyHgiIs the time constant of the governor of the water turbine, THriAnd THiAs compensator parameters for water turbines, TwiIs the inertia time constant of the water flow of the water turbine.
For the present example, the transfer function model of the area i is shown in fig. 2, and values of each parameter of the power system are: kp1＝Kp2＝Kp3＝120，Tp1＝Tp2＝Tp3＝20，Tg1＝Tg2＝Tg3＝0.08，Kr1＝Kr2＝Kr3＝0.5，Tr1＝Tr2＝Tr3＝10，Tt1＝Tt2＝Tt3＝0.3，THg1＝THg2＝THg3＝41.6，THr1＝THr2＝THr3＝5，TH1＝TH2＝TH3＝0.513，Tw1＝Tw2＝Tw3＝1，R1＝R2＝R3＝2.4，B1＝B2＝B30.425 (area frequency offset coefficient), T12＝T23The specific transfer function expression of the load disturbance model of the region i (i is 1,2,3) obtained by the method is 0.545 (region tie line constant)
Figure GDA0003305631630000081
The order of the transfer function of the load disturbance model is up to 9, which is not beneficial to the design of a controller and the performance analysis of a control system, so that a model order reduction method is needed to obtain a low-order nominal model of the load disturbance model.
In step 2), obtaining a load disturbance model G of the area i by adopting a model order reduction methodiLow-order nominal models of(s). The specific structure of the low-order nominal model is
Figure GDA0003305631630000082
Wherein, aij(j ═ 1,2,3) and bij(j is 0,1,2) are the denominator and numerator polynomial coefficients of the low-order nominal model, respectively, and satisfy the condition aij> 0(j ═ 1,2,3) to stabilize the low order nominal model.
The specific steps of solving the low-order nominal model parameters are as follows:
21) will be provided with
Figure GDA0003305631630000083
Substituting into the low order nominal model Gmi(s) expression wherein
Figure GDA0003305631630000084
Figure GDA0003305631630000085
Wherein the content of the first and second substances,
Figure GDA0003305631630000086
is an imaginary unit, omegaikRepresenting modeled frequency points, NiRepresenting the total number of frequency points;
22) model reduced order error function defining region iIs composed of
Figure GDA0003305631630000087
Figure GDA0003305631630000088
Solving an optimal reduced order model, which is equivalent to solving partial differential equations
Figure GDA0003305631630000089
And
Figure GDA00033056316300000810
wherein the content of the first and second substances,
Figure GDA00033056316300000811
represents a plurality of numbers
Figure GDA00033056316300000812
The conjugate transpose of (1);
23) let superscript + and T denote the pseudo-inverse and transpose of the matrix, respectively, and can be solved according to the partial differential equation set in 22)
Figure GDA00033056316300000813
Wherein the content of the first and second substances,
Figure GDA0003305631630000091
Ωik＝[Im(Gik),b0-Re(Gik),-b0Im(Gik),b0Re(Gik)-|Gik|2,b0Im(Gik)]T,k＝1,2,...,Ni
wherein the content of the first and second substances,
Figure GDA0003305631630000092
Re(Gik) And Im (G)ik) Respectively represent
Figure GDA0003305631630000093
Real and imaginary parts, | Gik|2Is composed of
Figure GDA0003305631630000094
The square of the amplitude value and the total number of frequency points are defaulted to Ni30(i ═ 1,2,3), upper bound of frequency points
Figure GDA0003305631630000095
Is taken as Gi(s) bandwidth.
Binding of Gi(s) according to step 2) solving for GmiThe process of step(s) can be solved as follows:
Figure GDA0003305631630000096
in step 3), the structure of the designed filter of the disturbance observer is selected as
Figure GDA0003305631630000097
Wherein n isiRepresenting the order of the filter, λiRepresenting the filter time constant, n is chosen for this embodiment i1 and λi＝0.02。
In the step 4), the specific step of solving the feedback controller of the disturbance observer system is as follows:
41) desired load frequency response transfer function for specified region i
Figure GDA0003305631630000098
Wherein tau isαiFor increasing the speed of response to load disturbances, τβiFor adjusting the robustness of the closed loop system;
42) selecting a PID controller as the feedback controller C for zone ii(s) that is
Figure GDA0003305631630000099
Wherein, the parameter KPi、TIiAnd TDiRespectively proportional gain and integral time constantAnd a differential time constant;
43) order to
Figure GDA00033056316300000910
Figure GDA00033056316300000911
And thetai＝{KPi,TIi,TDiDefine the feedback controller Ci(s) parameter optimization of Performance indicators
Figure GDA00033056316300000912
Order to
Figure GDA00033056316300000913
Figure GDA00033056316300000914
And
Figure GDA00033056316300000915
and defining a vector
Figure GDA00033056316300000916
And Γi＝[Γi1,Γi2,…,ΓiN]T. Minimum performance index JiFind the optimal solution as
Figure GDA00033056316300000917
Wherein the content of the first and second substances,
Figure GDA00033056316300000918
44) according to 43) determining a parameter of the feedback controller as
Figure GDA00033056316300000919
And
Figure GDA0003305631630000101
for this embodiment, τ is chosenαi0.2 and τβi0.82, according to step 4)Can be solved to obtain KPi＝0.4368，TIi＝0.6351，TDi0.9565, this is the feedback controller parameter value obtained without considering the effect of interconnect coupling between regions, since B1＝B2＝B30.425, the value of the parameter for the feedback controller for each zone after the interconnection coupling is considered to be KPi＝1.0278，TIi＝0.6351，TDi＝0.9565。
In step 5), a certain area of the load frequency control system contains the influence of wind energy penetration. Wind energy penetration is used as a disturbance term to participate in load frequency regulation. And compensating the adverse effect of wind energy penetration on load frequency and the exchange power of the tie line by using the disturbance observer. For the present embodiment, wind energy infiltration is applied to region 3, and a simulation model of the wind power generation subsystem is shown in FIG. 3.
The method and the classical proportional-integral-derivative control method
Figure GDA0003305631630000102
And (6) comparing. The present embodiment considers two cases: (1) no influence of wind-electricity penetration; (2) the influence of the wind electro-osmosis. For case (1), the regional frequency deviation responses are shown in fig. 4 to 6, respectively, and the tie line power variations are shown in fig. 7 and 8, respectively; obviously, the control effect of the disturbance observer method is obviously superior to that of the traditional proportional-integral-derivative control method. For case 2, a wind power generation subsystem is added in region 3, and the actual wind speed is formed by overlapping a random wind speed and a fixed wind speed. The input of the random wind speed is simulated by a white noise signal with the mean value of 0 and the variance of 0.5, the fixed wind speed is selected to be 15m/s, the wind speed change and the power output of a wind power generation system are respectively shown in figures 9 and 10, the regional frequency deviation response is respectively shown in figures 11 to 13, and the tie line power change is respectively shown in figures 14 and 15.

Claims (6)

1. A multi-domain multi-source power system load frequency disturbance observer control method is characterized by comprising the following steps:
1) obtaining a load disturbance model of each sub-region in a multi-domain multi-source power system, wherein the multi-domain multi-source power system comprises three sub-regions, each sub-region is formed by connecting a thermal power generation electronic system and a hydraulic power generation subsystem in parallel, and then the load disturbance model transfer function G of the ith sub-regioniThe expression of(s) is:
Figure FDA0003305631620000011
wherein G ispi(s) is the generator and load transfer function, Ggi(s) and Gti(s) transfer functions of the governor of the thermal power generation subsystem and the reheat turbine, G, respectivelyHgi(s)、GHri(s) and GHwi(s) transfer functions of the governor, transient droop compensator, and turbine of the hydro-power generation subsystem, respectively, where s is the Laplace operator, RiIs a permanent state droop characteristic coefficient;
in the load disturbance model transfer function GiIn the step(s), the step (c),
generator and load transfer function GpiThe expression of(s) is:
Figure FDA0003305631620000012
transfer function G of speed regulator of thermal power generation subsystemgiThe expression of(s) is:
Figure FDA0003305631620000013
transfer function G of reheat steam turbine of thermal power generation subsystemtiThe expression of(s) is:
Figure FDA0003305631620000014
transfer function G of speed regulator of hydroelectric power generation subsystemHgiThe expression of(s) is:
Figure FDA0003305631620000015
transfer function G of transient droop compensator for hydroelectric subsystemHriThe expression of(s) is:
Figure FDA0003305631620000016
transfer function G of water turbine of hydroelectric power generation subsystemHwiThe expression of(s) is:
Figure FDA0003305631620000021
wherein, KpiAnd TpiRespectively, power system gain and time constant, TgiAdjusting the time constant, K, for the fireri、TriAnd TtiReheater gain, reheat time constant and turbine time constant, T, respectivelyHgiIs the time constant of the governor of the water turbine, THriAnd THiAs compensator parameters for water turbines, TwiIs the water flow inertia time constant of the water turbine;
2) obtaining a low-order nominal model of the load disturbance model of each sub-area, obtaining parameters of the low-order nominal model, and obtaining a load disturbance model G of the area i by adopting a model order reduction methodi(s) a low-order nominal model, the specific structure of said low-order nominal model being:
Figure FDA0003305631620000022
wherein, aijJ is 1,2,3 and bijJ is 0,1,2 are denominator and numerator polynomial coefficients of the low-order nominal model, respectively, and satisfy the condition aijThe j is 1,2 and 3, so that the low-order nominal model is stable;
the step of calculating the low-order nominal model parameters specifically comprises the following steps:
21) will be provided with
Figure FDA0003305631620000023
Substituting into the low order nominal model GmiIn the expression of(s), there are:
Figure FDA0003305631620000024
wherein the content of the first and second substances,
Figure FDA0003305631620000025
is an imaginary unit, omegaikFor the kth modeled frequency Point, NiThe total number of the frequency points is;
22) model reduced order error function defining sub-region i
Figure FDA0003305631620000026
The model reduced order error function
Figure FDA0003305631620000027
The expression of (a) is:
Figure FDA0003305631620000028
solving the optimal reduced order model problem is equivalent to solving a partial differential equation set, and the following steps are carried out:
Figure FDA0003305631620000029
Figure FDA00033056316200000210
wherein the content of the first and second substances,
Figure FDA00033056316200000211
is composed of
Figure FDA00033056316200000212
The conjugate transpose of (1);
23) solving the partial differential equations in step 22) yields:
Figure FDA00033056316200000213
Figure FDA0003305631620000031
Ωik＝[Im(Gik),b0-Re(Gik),-b0Im(Gik),b0Re(Gik)-|Gik|2,b0Im(Gik)]T,k＝1,2,...,Ni
wherein the superscripts + and T represent the pseudo-inverse and transpose of the matrix, respectively,
Figure FDA0003305631620000032
is the NthiA sub-matrix is modeled, and,
Figure FDA0003305631620000033
is the NthiThe number of sub-vectors to be modeled,
Figure FDA0003305631620000034
Re(Gik) And Im (G)ik) Respectively represent
Figure FDA0003305631620000035
Real and imaginary parts, | Gik|2Is composed of
Figure FDA0003305631620000036
The square of the magnitude of the amplitude is,
Figure FDA0003305631620000037
is the upper bound of the frequency point, and is taken as Gi(s) a bandwidth;
3) designing a filter of the disturbance observer system based on the low-order nominal model;
4) designing a feedback controller of a disturbance observer system;
5) and applying the filter and the feedback controller to a load frequency control system to complete the control of the multi-domain multi-source power system load frequency disturbance observer.
2. The method for controlling the multi-domain multi-source power system load frequency disturbance observer according to claim 1, wherein in the step 3), the filter structure of the disturbance observer is
Figure FDA00033056316200000311
Wherein n isiOf order of the filter, λiS is the laplacian operator for the filter time constant.
3. The multi-domain multi-source power system load frequency disturbance observer control method according to claim 1, wherein the step 4) specifically comprises the following steps:
41) defining a desired load frequency response transfer function T for a subregion iΔfi(s) then:
Figure FDA0003305631620000038
wherein, tauαi、τβiParameters of the desired load frequency response transfer function, τ, respectivelyαiFor increasing the load disturbance response speed, tauβiTo adjust the robustness of the closed loop system;
42) feedback controller C for selecting PID controller as sub-region ii(s) then:
Figure FDA0003305631620000039
wherein, KPi、TIiAnd TDiProportional gain, integral time constant and differential time constant;
43) defining the feedback controller Ci(s) parameter optimization Performance index JiAnd find the minimum performance index JiOf (2) an optimal solution
Figure FDA00033056316200000310
I.e. the parameters of the feedback controller are obtained.
4. The method according to claim 3, wherein in step 43), the performance index J is set asiThe method specifically comprises the following steps:
Figure FDA0003305631620000041
Figure FDA0003305631620000042
θi＝{KPi,TIi,TDi}
wherein, thetaiIs a feedback controller parameter vector.
5. The method according to claim 3, wherein the method for controlling the multi-domain multi-source power system load frequency disturbance observer is characterized in thatIn step 43), the optimal solution
Figure FDA0003305631620000043
The expression of (a) is:
Figure FDA0003305631620000044
Figure FDA0003305631620000045
Figure FDA0003305631620000046
wherein the vector
Figure FDA0003305631620000047
Figure FDA0003305631620000048
(Vector)
Figure FDA0003305631620000049
(Vector)
Figure FDA00033056316200000410
Re and Im represent the real and imaginary parts, respectively.
6. The multi-domain multi-source power system load frequency disturbance observer control method according to claim 1, wherein in the step 5), when a region of the load frequency control system contains an influence of wind energy penetration, the wind energy penetration is used as a disturbance term to participate in load frequency regulation, and the disturbance observer is used for compensating the influence of the wind energy penetration on the load frequency and the exchange power of the tie line.
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