Online damping control system and method for main power supply type wind-solar field station

Abstract

The application provides an online damping control system and method for a main power source type wind-solar power station, which comprises the following steps: S1, adjusting parameters of control algorithm software; S2, enabling a multi-machine stability analysis module to calculate characteristic modes of the wind-solar power station; S3, calculating mode traction of each control parameter according to the characteristic modes to obtain corresponding damping parameter adjustment amounts; S4, updating damping parameters of each unit, and calling the multi-machine stability analysis module of the power station again to complete online damping control; and S5, if damping parameter adjustment fails and the system oscillates, sensing an oscillation frequency through a static synchronous machine to inject concentrated damping to suppress oscillation. The application can improve damping of the overall power station and reduce oscillation risk under the condition that operating states of each unit in the main power source type wind-solar power station change at any moment, and can realize rapid suppression of oscillation and reduce the duration of oscillation through concentrated damping injection of the static synchronous machine after the system oscillates.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of voltage source control, stability control and oscillation suppression of wind-solar power stations, in particular to an online damping control system and method for a main power source type wind-solar power station. BACKGROUND

[0002] Currently, wind-solar power stations mainly work in grid-connected power generation mode, have few adaptable operating conditions, and lack flexible operation capability in multiple scenarios. Early wind-solar power grid-connected control methods are mainly based on passive tracking of the grid-connected point voltage, and the main goal is to respond quickly to power, which is difficult to meet the power grid support demand under a large increase in wind-solar ratio. Self-synchronous voltage source control has become a key technology for expanding the multi-scenario operation capability of wind-solar power stations and making them operate as main power sources due to its inherent active power grid support, weak power grid stability, and black start capability.

[0003] However, while self-synchronous voltage source control improves the network construction capability of the station, it also strengthens the power connection between each unit. Under the influence of time-varying parameters such as source input fluctuations (such as wind speed, light intensity fluctuations, etc.), changes in grid strength, etc., there is a risk of power oscillation, and damping control and stability improvement methods for multiple machine interaction characteristics need to be considered. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide an online damping control system and method for a main power source type wind-solar power station.

[0005] According to the online damping control system for a main power source type wind-solar power station provided by the present application, it comprises:

[0006] a control algorithm software and a controller hardware;

[0007] The control algorithm software comprises:

[0008] a damping cooperative control module of the wind-solar power station for multi-machine stability analysis and damping parameter distribution;

[0009] an active damping control module of the static synchronous machine for impedance measurement, oscillation detection and virtual resistance control;

[0010] The controller hardware comprises:

[0011] a wind-solar power generation unit controller carrying a self-synchronous voltage source grid-connected control algorithm, receiving damping parameter regulation instructions, and sending the grid-connected active / reactive power, voltage effective value and damping parameter of the current wind-solar power generation unit;

[0012] A static synchronous compensator controller is deployed in a high-voltage direct-connection energy storage, carries a self-synchronous voltage source grid-connected control algorithm, receives an oscillation frequency detection value and a damping injection instruction, and sends current static synchronous compensator grid-connected active / reactive power, voltage effective value and damping parameters;

[0013] A field station algorithm server carries an online damping control algorithm, receives grid-connected active / reactive power, voltage effective value, damping parameters of each wind and light power generation unit and static synchronous compensator, three-phase voltage and current instantaneous value of the high-voltage side of the field station booster transformer, and the number of operating platforms of the entire wind and light power generation unit; sends damping parameter control instructions of each wind and light power generation unit, oscillation frequency detection value and damping injection instruction of static synchronous compensator, and grid short-circuit ratio identification value and disturbance signal injection information;

[0014] An energy management system server is used for a data transfer station, receives and sends control instructions of the field station algorithm server, working point information of wind and light power generation units and static synchronous compensators, and three-phase voltage and current measurement values of the high-voltage side of the field station booster transformer;

[0015] An upper computer sets configuration parameters of wind and light field stations and static synchronous damping control, displays control instruction values and system instantaneous electrical quantities;

[0016] Real-time data transmission between control algorithm software and controller hardware is completed based on an Ethernet switch and an optical fiber.

[0017] Preferably, the damping cooperative control module of the wind and light field station includes a multi-machine stability analysis module and a damping parameter distribution module;

[0018] The multi-machine stability analysis module includes calculating a characteristic mode of the wind and light field station, constructing a multi-machine dynamic aggregation model, substituting real-time working points of each power generation unit and grid short-circuit ratio into the dynamic aggregation model, calculating characteristic polynomials and characteristic modes of the dynamic aggregation model, and realizing quantitative evaluation of system stability;

[0019] The damping parameter distribution module includes setting damping parameters of each unit, determining key damping parameters in wind and light power generation units according to the obtained characteristic mode, further calculating the traction of the aggregated damping parameters to the real part of the characteristic mode, and calculating the damping parameter adjustment amount according to the real part promotion amount:

[0020]

[0021] In the formula, k PF (λ, ρ D ) represents the control traction of the aggregated damping parameter ρ D to the characteristic mode, Δσ ref represents the set real part promotion amount, and ζ 聚合 is the aggregated damping parameter adjustment amount.

[0022] According to the output level of each unit, the damping parameter adjustment amount corresponding to each unit is calculated:

[0023]

[0024] In the formula, ζ 机,j represents the damping parameter adjustment amount of the jth unit, P 机,j represents the output level.

[0025] Preferably, the active damping control module of the static synchronous machine comprises an oscillation frequency online detection module, a virtual resistance control module and a power grid short-circuit ratio measurement module.

[0026] The oscillation frequency online detection module comprises providing oscillation information and its main oscillation frequency; based on the measurement value of the three-phase voltage and current instantaneous value of the high-voltage side of the substation step-up transformer, the frequency spectrum distribution of the system is obtained through fast Fourier transform; whether the system is oscillating is determined according to the set threshold value, and if it is oscillating, the dominant frequency is extracted;

[0027] The virtual resistance control module comprises improving the system damping at the oscillation frequency; based on the obtained oscillation information, a virtual resistance loop is added to the original control loop of the static synchronous machine, and the resonance frequency of the virtual resistance loop is dynamically adjusted based on the main oscillation frequency;

[0028] The power grid short-circuit ratio measurement module comprises monitoring the strength of the power grid; according to the set measurement frequency band, a disturbance signal is generated and superimposed on the control reference of the internal control loop of the static synchronous machine, based on the three-phase voltage and current measurement value of the high-voltage side of the step-up transformer, the disturbance injection component and its feedback component are extracted through signal analysis, and further through curve fitting, the equivalent resistance R and inductance parameter L of the power grid are obtained:

[0029]

[0030] In the formula, ω p is the disturbance frequency, V and I are the voltage and current disturbance components respectively.

[0031] Preferably, the construction of the multi-machine dynamic aggregation model comprises:

[0032] Based on the capacity equivalent aggregation principle, the aggregation parameters of the main circuit parameters of each unit are obtained according to the number and capacity of each generating unit of the substation; the control parameters of each controller are normalized, and the aggregation parameters of each control parameter are obtained by de-normalizing according to the aggregated capacity;

[0033] For a wind-solar generating unit, an impedance modeling method is used to establish an AC side impedance model, and the substation single-machine aggregation frequency domain model is obtained by substituting the aggregation parameters:

[0034]

[0035] wherein N ∑ represents the number of operating platforms in the wind-solar field unit, P ∑ represents the aggregated capacity, represents the parameter of the power generation unit;

[0036] Based on the principle of energy conservation, the equivalent total impedance Z Line (s) of the power collection network of the wind-solar field is calculated, thereby obtaining the aggregated frequency domain model Z F (s) of the wind-solar field:

[0037]

[0038] Preferably, the feature polynomial of the dynamic aggregated model and the feature mode thereof include:

[0039] Neglecting the real part, substituting s = jω into the multi-machine frequency domain aggregated model Z F (s) converts the symbolic matrix into a numerical matrix:

[0040] Z F (jω), ω ∈ [2πf1, 2πf2];

[0041] wherein f1 and f2 respectively represent the starting range of the considered frequency band.

[0042] Performing eigen-decomposition on Z F (jω) to obtain the trajectory of the modal impedance with respect to ω, determine the resonance peak of the modal impedance, and determine the potential oscillation frequency of the system;

[0043] Calculating the zero point of the reciprocal of the determinant to obtain the feature mode:

[0044]

[0045] wherein σ represents the real part of the feature mode, and ω represents the imaginary part of the feature mode.

[0046] Preferably, the calculation of the traction of the aggregated damping parameter on the real part of the feature mode includes:

[0047] Based on the obtained feature mode, the corresponding mode real part is extracted:

[0048]

[0049] Substituting the above mode into the dynamic aggregated model Z F (s), the left and right eigenvector information of the numerical matrix is obtained through frequency domain modal decomposition, the feature sensitivity matrix is formed based on the left and right eigenvectors, and the sensitivity of the damping parameter to the mode real part is calculated based on the partial derivative of the impedance matrix element to the damping parameter, which is used as the quantitative characterization basis of the mode traction of the damping parameter.

[0050] According to the application, an online damping control method for a main power supply type wind-solar station is provided, comprising:

[0051] Step S1: adjusting parameters of control algorithm software;

[0052] Step S2: based on the control algorithm software, instructing a multi-machine stability analysis module to calculate characteristic modes of the wind-solar station;

[0053] Step S3: according to the characteristic modes, calculating mode traction of each control parameter, calculating a unit adjustment amount of the damping parameter based on the mode traction, and based on the unit adjustment amount of the damping parameter, inversely adjusting the unit according to the output level of each unit to obtain an actual damping parameter adjustment amount corresponding to each unit;

[0054] Step S4: based on the obtained damping parameter adjustment amount, updating the damping parameter of each unit, and calling the multi-machine stability analysis module of the station again to complete online damping control;

[0055] Step S5: if the damping parameter adjustment fails and the system oscillates, sensing the oscillation frequency through a static synchronous machine and injecting concentrated damping to suppress the oscillation.

[0056] Preferably, the step S2 comprises constructing a multi-machine dynamic aggregation model, substituting real-time working points of each power generation unit and a short-circuit ratio of the power grid to calculate characteristic polynomials and characteristic modes of the dynamic aggregation model, and realizing quantitative evaluation of system stability.

[0057] Preferably, the step S3 comprises determining key damping parameters in the wind-solar power generation unit according to the obtained characteristic modes, further calculating traction of the aggregated damping parameter to a real part of the characteristic modes, and calculating the damping parameter adjustment amount according to the real part promotion amount:

[0058]

[0059] In the formula, k PF (λ, ρ D ) represents the aggregated damping parameter ρ D control traction to the characteristic modes, Δσ ref represents a set real part promotion amount, ζ 聚合 is the aggregated damping parameter adjustment amount;

[0060] According to the output level of each unit, the damping parameter adjustment amount corresponding to each unit is calculated:

[0061]

[0062] In the formula, ζ 机,j represents the damping parameter adjustment amount of the jth unit, P 机,j represents the output level thereof.

[0063] Preferably, the construction of the multi-machine dynamic aggregation model comprises:

[0064] For a wind and light power generation unit, an impedance modeling method is used to establish an AC side impedance model, and an aggregation parameter is substituted to obtain a field station single-machine aggregation frequency domain model:

[0065]

[0066] Wherein, N ∑ represents the number of operating wind and light units in the field station, P ∑ represents the aggregation capacity, represents the power generation unit parameter;

[0067] Based on the principle of energy conservation, the equivalent total impedance Z Line (s) of the field station power collection network is calculated, so that the aggregation frequency domain model Z F (s) of the wind and light field station is obtained:

[0068]

[0069] Compared with the prior art, the present application has the following beneficial effects:

[0070] 1. The present application can improve the overall damping of the field station and reduce the risk of oscillation under the condition that the operating state of each unit in the main power type wind and light field station changes in time; and can realize rapid suppression of oscillation and reduce the duration of oscillation through centralized damping injection of the static synchronous machine after the system oscillates.

[0071] 2. The present application can realize stable control of the field station by online setting of the key damping parameters of each unit according to the real-time operating state of each unit, and can realize oscillation suppression through active damping injection of the static synchronous machine after the field station oscillates, which helps to improve the overall damping of the main power type wind and light field station and reduce the harm of oscillation.

[0072] Other beneficial effects of the present application will be described in the specific implementation manner through the introduction of specific technical features and technical solutions, and those skilled in the art should be able to understand the beneficial technical effects brought by the technical features and technical solutions through the introduction of the technical features and technical solutions. BRIEF DESCRIPTION OF DRAWINGS

[0073] Other features, objects and advantages of the present application will become more apparent through reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0074] Figure 1 It is a schematic diagram of the system of the present application.

[0075] Figure 2 It is a diagram of the actual wind farm topology and electrical parameters in the embodiment of the present application.

[0076] Figure 3 The effect schematic diagram of the damping parameter distribution module in the embodiment of the application.

[0077] Figure 4 The effect schematic diagram of the damping parameter distribution module in the embodiment of the application.

[0078] Figure 5 The effect verification diagram of the damping cooperative control in the embodiment of the application.

[0079] Figure 6 The effect verification diagram of the active damping control in the embodiment of the application. DETAILED DESCRIPTION

[0080] The application will be described in detail below with specific embodiments. The following embodiments will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the application. These are within the scope of protection of the application.

[0081] Referring to Figure 1 The online damping control system of a main power type wind-solar station shown in the figure, comprising:

[0082] The control algorithm software includes the damping cooperative control of the wind-solar station and the active damping control of the static synchronous machine, wherein the damping cooperative control of the wind-solar station includes multi-machine stability analysis and damping parameter distribution, and the active damping control of the static synchronous machine is composed of online detection of oscillation frequency, virtual resistance control and measurement of short-circuit ratio of power grid;

[0083] The controller hardware includes the wind-solar power generation unit controller, the static synchronous machine controller, the station algorithm server, the energy management system server, the upper computer, the Ethernet switch and the optical fiber.

[0084] The wind-solar power generation unit controller carries a self-synchronous voltage source grid-connected control algorithm, receives damping parameter regulation instructions, and sends current grid-connected active / reactive power, voltage effective value and damping parameters;

[0085] The static synchronous machine controller is deployed in high-voltage direct-hanging energy storage, carries a self-synchronous voltage source grid-connected control algorithm, receives oscillation frequency detection value and damping injection instructions (i.e. oscillation information), and sends current grid-connected active / reactive power, voltage effective value and damping parameters;

[0086] The field station algorithm server carries an online damping control algorithm, receives the grid-connected active / reactive power, voltage effective value and damping parameters of each wind and light power generation unit and static synchronous machine, three-phase voltage and current instantaneous values of the high-voltage side of the field station booster transformer, and the number of operating units of the entire field wind and light power generation unit; sends the damping parameter control instructions, oscillation frequency detection values, short-circuit ratio identification values, damping injection instructions and disturbance signal injection information of each wind and light power generation unit;

[0087] The energy management system server acts as a data transfer station, receives and sends control instructions of the field station algorithm server, working point information of wind and light power generation units and static synchronous machines, and three-phase voltage and current measurement values of the high-voltage side of the field station booster transformer;

[0088] The upper computer is responsible for setting configuration parameters of wind and light field stations and static synchronous damping control, such as damping enhancement, disturbance injection frequency band, short-circuit ratio detection rate, etc., and displaying control instruction values and system instantaneous electrical quantities;

[0089] The Ethernet switch and optical fiber are responsible for real-time data transmission between controller software and hardware, mainly including field station algorithm server, energy management system server, wind and light power generation unit controller, static synchronous machine controller and upper computer, etc.

[0090] The damping cooperative control module of the wind and light field station in the control algorithm software has the following basic functions and principles:

[0091] The multi-machine stability analysis module is used to calculate the characteristic mode of the wind and light field station. Based on the offline constructed multi-machine dynamic aggregation model, the real-time working point of each power generation unit and the grid short-circuit ratio are substituted to calculate the characteristic polynomial and characteristic mode λ of the dynamic aggregation model, realizing the quantitative evaluation of system stability;

[0092] The modeling steps of the wind and light field station dynamic aggregation model mainly include:

[0093] Firstly, based on the capacity equivalent aggregation principle, the aggregation parameters of the main circuit parameters (AC filter parameters, capacitor parameters, etc.) of each unit are obtained according to the number and capacity of each power generation unit in the field station; the control parameters of each controller are normalized, and then the aggregation parameters of each control parameter are obtained by inverse normalization according to the aggregated capacity;

[0094] Considering a detailed wind and light power generation unit, an impedance modeling method is used to establish an AC side impedance model, and the above aggregation parameters are substituted to obtain the single-machine aggregation frequency domain model of the field station Where N ∑ represents the number of operating units of the field station wind and light unit, P ∑ represents the aggregated capacity, represents the power generation unit parameters.

[0095] Based on the principle of energy conservation, the equivalent total impedance Z of the field station collection network is calculatedLine (s), thereby obtaining the aggregated frequency domain model Z of the wind-solar power station F (s), as follows:

[0096]

[0097] The feature mode calculation is divided into two steps:

[0098] First, ignoring the real part, substituting s = jω into the above multi-machine frequency domain aggregated model, the symbolic matrix Z F (s) is converted into a numerical matrix Z F (jω), ω ∈ [2πf1, 2πf2], where f1 and f2 represent the starting range of the considered frequency band, respectively;

[0099] The characteristic decomposition is performed on Z F (jω) to obtain the trajectory of the modal impedance with respect to ω, determine the resonance peak of the modal impedance, and determine the potential oscillation frequency of the system;

[0100] Near the oscillation frequency obtained above, the zero point of the reciprocal of the determinant is calculated to obtain the feature mode:

[0101]

[0102] The damping parameter assignment module is used to set the damping parameters of each unit. Based on the feature mode obtained above, the key damping parameters in the wind-solar power generation unit are determined, and the traction of the aggregated damping parameters on the real part of the feature mode is further calculated, and the damping parameter adjustment amount is calculated according to the real part improvement amount:

[0103]

[0104] In the formula, k PF (λ, ρ D ) represents the control traction of the aggregated damping parameter ρ D on the feature mode, Δσ ref represents the set real part improvement amount, and ζ 聚合 is the aggregated damping parameter adjustment amount. Further, according to the output level of each unit, the damping parameter adjustment amount corresponding to each unit is calculated (taking the jth unit as an example):

[0105]

[0106] In the formula, ζ 机,j represents the damping parameter adjustment amount of the jth unit, and P 机,j represents the output level thereof.

[0107] The control traction of the damping parameter on the feature mode can be calculated and obtained based on the following steps:

[0108] Based on the characteristic mode obtained by the above calculation, the corresponding mode real part is extracted:

[0109]

[0110] The above mode is substituted into the dynamic aggregation model Z F (s) The left and right eigenvector information of the numerical matrix is obtained by frequency domain modal decomposition, the characteristic sensitivity matrix is formed based on the left and right eigenvectors, and the sensitivity of the damping parameter to the mode real part is calculated according to the partial derivative of the impedance matrix element to the damping parameter, which is used as the quantitative characterization basis of the mode dragging of the damping parameter.

[0111] The basic functions and principles of the active damping control module of the static synchronous machine in the control algorithm software are as follows:

[0112] The oscillation frequency online detection module provides the oscillation information and the main oscillation frequency. Based on the measurement values of the three-phase voltage and current instantaneous values of the high-voltage side of the substation step-up transformer, the frequency spectrum distribution of the system is obtained by fast Fourier transform, and it is determined whether the system is oscillating according to the set threshold value. If it is oscillating, the dominant frequency is extracted;

[0113] The virtual resistance control module is used to improve the system damping at the oscillation frequency. Based on the obtained oscillation information, a virtual resistance loop is added to the original control loop of the static synchronous machine, and the resonance frequency of the virtual resistance loop is dynamically adjusted based on the main oscillation frequency;

[0114] The power grid short-circuit ratio measurement module is used to monitor the strength of the power grid. According to the set measurement frequency band, a disturbance signal is generated and superimposed on the control reference of the internal control loop of the static synchronous machine. Based on the three-phase voltage and current measurement values of the high-voltage side of the step-up transformer, the disturbance injection component and its feedback component are extracted through signal analysis, and the equivalent resistance R and inductance parameter L of the power grid are further obtained through curve fitting.

[0115]

[0116] In the formula, ω p is the disturbance frequency, V and I are the voltage and current disturbance components respectively.

[0117] The present application can adjust the key damping parameters of each unit according to the real-time operating state of each unit to realize the stable control of the substation, and can realize oscillation suppression by actively injecting damping through the static synchronous machine after oscillation occurs in the substation, which helps to improve the overall damping of the main power type wind-solar substation and reduce the harm of oscillation, and has good practicability.

[0118] The above is the basic embodiment of the present application, and the technical solutions of the present application will be further described through a preferred embodiment.

[0119] Example 1

[0120] Referring to Figure 2 Fig. 1 shows a topology and electrical parameters of a certain actual wind farm adopted, located in the south-north wind farm of Ganhe River, mainly including 32 doubly-fed wind turbine generators (with a capacity of 3 MW) adopting self-synchronous voltage source control method, and a static synchronous machine (with a capacity of 10 Mvar) also adopting self-synchronous voltage source control, connected to the side of a 35 kV bus. For this system, wind farm damping cooperative control is constructed and carried on the farm algorithm server; active damping control of the static synchronous machine is constructed, in which the oscillation detection and grid short-circuit ratio detection module is carried on the farm algorithm server, and the virtual resistance control is carried on the static synchronous machine controller.

[0121] Based on the real-time working point information of each unit provided by the energy management system server, and the grid short-circuit ratio detection result of the static synchronous machine, the system stability is determined by the farm stability analysis module. Referring to Figure 3 Fig. 2a shows that the modal impedance resonance peak of the system is analyzed first, and it is found that there are three relatively obvious resonance peaks. The characteristic mode is solved near the frequency point corresponding to the resonance peak, as shown in Figure 3 Fig. 2b, the dominant characteristic mode of the system is obtained, and the following mainly describes the damping control thereof.

[0122] For the above-mentioned characteristic mode closest to the imaginary axis, the mode traction of each control parameter is calculated, as shown in Figure 4 Fig. 2a. It can be seen that the real axis sensitivity of the virtual synchronous ring is the largest, in which the inertia coefficient J and the damping coefficient D are the key parameters dominating the mode. For this mode, a damping improvement degree of 2% is set, and through the real axis sensitivity obtained by the above-mentioned solving, the new inertia coefficient and damping coefficient can be calculated, as shown in Figure 4 Fig. 2b. Based on the per-unit parameter, the inverse per-unit is carried out according to the output level of each unit, so as to obtain the corresponding damping parameter adjustment amount, and the adjustment amount distribution result of the 32 units is shown in Figure 4 Fig. 2c.

[0123] Based on the damping parameter adjustment amount obtained above, the damping parameters of each unit are updated, and the stability analysis module of the farm is called again to obtain the mode distribution as shown in Figure 5 Fig. 3. It can be seen that through the online adjustment of the damping parameters, the initial characteristic mode of the system can be moved to the desired position, and the distance from the imaginary axis is increased, so as to improve the stability of the main power supply wind and light farm.

[0124] Referring to Figure 6As shown, an oscillation is excited in the wind farm, and after 0.5s, the static synchronous compensator detects the oscillation and the corresponding oscillation frequency, at which time the virtual resistance loop is put into active damping, and the resonance frequency of the virtual resistance loop is the detected oscillation frequency (15.6Hz). It can be seen that after active damping, the oscillation is suppressed, and the system returns to a stable state.

[0125] Those skilled in the art understand that, in addition to implementing the system provided by the present application and each device, module and unit thereof in the form of pure computer readable program code, the system provided by the present application and each device, module and unit thereof can also be implemented in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers and embedded microcontrollers, etc. by logically programming the method steps to achieve the same functions. Therefore, the system provided by the present application and each device, module and unit thereof can be considered as a hardware component, and the devices, modules and units included therein for achieving various functions can also be considered as structures within the hardware component; the devices, modules and units for achieving various functions can also be considered as both software modules for implementing methods and structures within hardware components.

[0126] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0127] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other without conflict, provided that the combination does not conflict.

Claims

1. An online damping control system for a main power source type wind and solar power station, characterized in that: include: Control algorithm software and controller hardware; The control algorithm software includes: The damping coordinated control module of the wind and solar power stations is used for multi-machine stability analysis and damping parameter allocation; Active damping control module for static synchronous machines, for impedance measurement, oscillation detection, and virtual resistance control; The controller hardware includes: The wind and solar power generation unit controller is equipped with a self-synchronous voltage source grid-connected control algorithm, receives damping parameter control instructions, and sends the grid-connected active / reactive power, voltage RMS, and damping parameters of the current wind and solar power generation unit; The static synchronous generator controller is deployed on high-voltage direct-mounted energy storage and is equipped with a self-synchronous voltage source grid-connected control algorithm. It receives oscillation frequency detection values ​​and damping injection instructions, and sends the current static synchronous generator's grid-connected active / reactive power, voltage RMS, and damping parameters. The site algorithm server, equipped with an online damping control algorithm, receives the grid-connected active / reactive power, voltage RMS, and damping parameters of each wind / solar power generation unit and static synchronous machine, as well as the three-phase voltage and current instantaneous values ​​on the high-voltage side of the site's step-up transformer, and the number of wind / solar power generation units in operation. It also sends damping parameter control instructions for each wind / solar power generation unit, oscillation frequency detection values ​​and damping injection instructions for static synchronous machines, as well as grid short-circuit ratio identification values ​​and disturbance signal injection information. The energy management system server is used as a data transfer station to receive and send control instructions from the station algorithm server, operating point information of wind and solar power generation units and static synchronous machines, and three-phase voltage and current measurements on the high-voltage side of the station's step-up transformer; The host computer sets the configuration parameters of the wind and solar power stations and static synchronous damping control, and displays the control command values ​​and instantaneous electrical quantities of the system; Real-time data transmission between the control algorithm software and the controller hardware is completed based on Ethernet switches and optical fibers.

2. The online damping control system of the main power source type wind and solar power station according to claim 1 is characterized in that: The damping coordinated control module of the wind-solar station includes a multi-machine stability analysis module and a damping parameter allocation module; The multi-machine stability analysis module includes calculating the characteristic mode of wind and solar power stations and building a multi-machine dynamic aggregation model; substituting the real-time operating point of each power generation unit and the short-circuit ratio of the power grid into the model, calculating the characteristic polynomial and characteristic mode of the dynamic aggregation model, and realizing a quantitative assessment of system stability; The damping parameter allocation module includes adjusting the damping parameters of each unit; determining the key damping parameters in the wind and solar power generation units based on the obtained characteristic mode, further calculating the traction of the aggregated damping parameters on the real part of the characteristic mode, and calculating the damping parameter adjustment amount based on the real part improvement: Where k PF (λ,ρ D ) represents the aggregate damping parameter ρ D For the control traction of the characteristic mode, Δσ ref represents the set real part lift, ζ 聚合 is the adjustment amount of the aggregate damping parameter; According to the output level of each unit, calculate the corresponding damping parameter adjustment of each unit: Where, ζ 机,j Represents the damping parameter adjustment of the jth unit, P 机,j Represents its output level.

3. The online damping control system of the main power source type wind and solar power station according to claim 2 is characterized in that: The active damping control module of the static synchronous machine includes an oscillation frequency online detection module, a virtual resistance control module and a grid short-circuit ratio measurement module; The oscillation frequency online detection module includes providing oscillation information and its main oscillation frequency; obtaining the system's spectrum distribution through fast Fourier transform based on the measured values ​​of the three-phase voltage and current instantaneous values ​​on the high-voltage side of the station step-up transformer; determining whether the system is oscillating based on a set threshold, and if oscillating, extracting the dominant frequency; The virtual resistance control module includes increasing the system damping at the oscillation frequency; based on the obtained oscillation start information, adding a virtual resistance loop to the original control loop of the static synchronous machine, and dynamically adjusting the resonant frequency of the virtual resistance loop based on the main oscillation frequency; The grid short-circuit ratio measurement module includes monitoring the grid strength; generating an injection disturbance signal based on a set measurement frequency band and superimposing it on the control reference of the static synchronous machine's internal control loop; extracting the disturbance injection component and its feedback component through signal analysis based on the three-phase voltage and current measurements on the high-voltage side of the step-up transformer; and further obtaining the equivalent resistance R and inductance L of the grid through curve fitting: Where, ω p is the disturbance frequency, V and I are the voltage and current disturbance components respectively.

4. The online damping control system of the main power source type wind and solar power station according to claim 2 is characterized in that: The construction of a multi-machine dynamic aggregation model includes: Based on the capacity equivalence aggregation principle, the aggregate parameters of the main circuit parameters of each unit are obtained according to the number of power generation units in the station and their respective capacities. The control parameters of each controller are per-unit scaled and then de-scaled according to the aggregated capacity to obtain the aggregate parameters of each control parameter. For a wind-solar power generation unit, the impedance modeling method is used to establish the AC side impedance model, and the aggregation parameters are substituted to obtain the station single-unit aggregation frequency domain model: Among them, N ∑ Represents the number of wind and solar units in operation at the station, P ∑ represents the aggregate capacity, Represents the parameters of the power generation unit; Based on the principle of energy conservation, calculate the equivalent total impedance Z of the station collection network Line (s), and thus the aggregate frequency domain model Z of the wind and solar power station is obtained F (s):

5. The online damping control system of the main power source type wind and solar power station according to claim 4 is characterized in that: The characteristic polynomial and characteristic pattern of the computational dynamic aggregation model include: Ignore the real part and substitute s=jω to transform the multi-machine frequency domain aggregation model from the symbol matrix Z F (s) is converted into a numerical matrix: Z F (jω),ω∈[2πf1,2πf2]; Among them, f1 and f2 represent the starting range of the frequency band under consideration; To Z F (jω) Perform eigendecomposition to obtain the trajectory of the modal impedance with respect to ω, determine the resonant peak of the modal impedance, and determine the potential oscillation frequency of the system; Compute the zeros of the reciprocal of the determinant to obtain the characteristic modes: Here, σ represents the real part of the characteristic mode, and ω represents the imaginary part of the characteristic mode.

6. The online damping control system of the main power source type wind and solar power station according to claim 5 is characterized in that: The calculation of the aggregate damping parameter for the traction of the real part of the characteristic mode includes: Based on the obtained characteristic pattern, extract the corresponding pattern real part: Substitute the above pattern into the dynamic aggregation model Z F In (s), the left and right eigenvector information of the numerical matrix is ​​obtained through frequency domain modal decomposition, and the characteristic sensitivity matrix is ​​formed based on the left and right eigenvectors. Further, according to the partial derivatives of the impedance matrix elements with respect to the damping parameter, the sensitivity of the damping parameter to the real part of the mode is calculated, which is used as a quantitative characterization basis for the mode traction of the damping parameter.

7. An online damping control method for a main power source type wind and solar power station, based on the online damping control system of the main power source type wind and solar power station according to any one of claims 1 to 6, characterized in that: include: Step S1: Adjust the parameters of the control algorithm software; Step S2: Based on the control algorithm software, the multi-machine stability analysis module calculates the characteristic mode of the wind and solar power station; Step S3: Calculating the mode traction of each control parameter based on the characteristic mode, and calculating the per-unit adjustment of the damping parameter based on the mode traction; Based on the per-unit adjustment of the damping parameter, perform de-per-unit calibration according to the output level of each unit to obtain the actual damping parameter adjustment corresponding to each unit; Step S4: Based on the obtained damping parameter adjustment amount, the damping parameters of each unit are updated, and the multi-machine stability analysis module of the station is called again to complete the online damping control; Step S5: If the damping parameter adjustment fails and the system oscillates, the oscillation frequency is sensed by the static synchronous machine, and centralized damping injection is performed to suppress the oscillation.

8. The online damping control method for a main power source type wind and solar power station according to claim 7 is characterized in that: The step S2 includes constructing a multi-machine dynamic aggregation model; substituting the real-time operating point of each power generation unit and the short-circuit ratio of the power grid, calculating the characteristic polynomial and characteristic mode of the dynamic aggregation model, and realizing a quantitative assessment of system stability.

9. The online damping control method for a main power source type wind and solar power station according to claim 8 is characterized in that: The step S3 includes determining the key damping parameters in the wind-solar power generation unit according to the obtained characteristic mode, further calculating the traction of the aggregated damping parameters to the real part of the characteristic mode, and calculating the damping parameter adjustment amount according to the real part improvement: Where k PF (λ,ρ D ) represents the aggregate damping parameter ρ D For the control traction of the characteristic mode, Δσ ref represents the set real part lift, ζ 聚合 is the adjustment amount of the aggregate damping parameter; According to the output level of each unit, calculate the corresponding damping parameter adjustment of each unit: Where, ζ 机,j Represents the damping parameter adjustment of the jth unit, P 机,j Represents its output level.

10. The online damping control method for a main power source type wind and solar power station according to claim 8, characterized in that: The construction of a multi-machine dynamic aggregation model includes: For a wind-solar power generation unit, the impedance modeling method is used to establish the AC side impedance model, and the aggregation parameters are substituted to obtain the station single-unit aggregation frequency domain model: Among them, N ∑ Represents the number of wind and solar units in operation at the station, P ∑ represents the aggregate capacity, Represents the parameters of the power generation unit; Based on the principle of energy conservation, calculate the equivalent total impedance Z of the station collection network Line (s), and thus the aggregate frequency domain model Z of the wind and solar power station is obtained F (s):

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