Online damping control system and method for main power supply type wind and light station

Abstract

The invention provides an online damping control system and method for a main power supply type wind and light field station. The method comprises the steps that S1, parameters of control algorithm software are adjusted; s2, enabling a multi-machine stability analysis module to calculate a characteristic mode of the wind and light field station; s3, calculating mode traction of each control parameter according to the characteristic mode to obtain a corresponding damping parameter adjustment amount; s4, the damping parameters of all the units are updated, the multi-unit stability analysis module of the station is called again, and online damping control is completed; and S5, if the damping parameter adjustment fails and the system oscillates, sensing the oscillation frequency through the static synchronous machine, and performing concentrated damping injection to suppress oscillation. The damping of the whole station can be improved and the oscillation risk can be reduced under the condition that the running state of each unit in the main power supply type wind and light station changes at any time; after the system oscillates, through concentrated damping injection of the static synchronous machine, rapid suppression of the oscillation is realized, and the duration of the oscillation is reduced.

Description

Technical Field

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

[0002] At present, wind and solar power stations mainly work in the grid-connected power generation mode, which can adapt to few operating conditions and lack the ability to operate flexibly in multiple scenarios. The early wind and solar power grid-connected control methods were mainly based on passive tracking of the voltage at the grid connection point, and the main goal was rapid power response. It was difficult to cope with the grid support needs when the proportion of wind and solar power increased significantly. Self-synchronous voltage source control has become a key technology for expanding the multi-scenario operation capabilities of wind and solar power stations and enabling them to operate as the main power source due to its inherent active grid support, weak grid stability, and black start capabilities.

[0003] However, while self-synchronous voltage source control improves the station's networking capabilities, it also strengthens the power connection between the units. Under the influence of time-varying parameters such as source-end input fluctuations (such as wind speed, light fluctuations, etc.) and grid strength changes, there is a risk of power oscillation. It is urgent to consider the station damping control and stability improvement methods that take into account the multi-machine interaction characteristics. Summary of the invention

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

[0005] According to the present invention, an online damping control system of a main power source type wind and solar power station includes:

[0006] Control algorithm software and controller hardware;

[0007] The control algorithm software includes:

[0008] The damping coordination control module of the wind and solar power stations is used for multi-machine stability analysis and damping parameter allocation;

[0009] Active damping control module for static synchronous machines for impedance measurement, oscillation detection and virtual resistance control;

[0010] The controller hardware includes:

[0011] 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;

[0012] The static synchronous machine controller is deployed in high-voltage direct-mounted energy storage, equipped with a self-synchronous voltage source grid-connected control algorithm, receives oscillation frequency detection values ​​and damping injection instructions, and sends the current static synchronous machine's grid-connected active / reactive power, voltage RMS, and damping parameters;

[0013] The station algorithm server is equipped with an online damping control algorithm, which receives the grid-connected active / reactive power, voltage RMS, damping parameters of each wind and 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 station step-up transformer and the number of wind and solar power generation units in operation; it sends the damping parameter control instructions, oscillation frequency detection values, grid short-circuit ratio identification values, damping injection instructions and disturbance signal injection information of each wind and solar power generation unit;

[0014] Energy management system server, used as a data transfer station, receives and sends control instructions from the station algorithm server, wind and solar power generation units, working point information of static synchronous machines, and three-phase voltage and current measurement values ​​on the high-voltage side of the station step-up transformer;

[0015] 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;

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

[0017] Preferably, the damping coordinated control module of the wind-solar station includes a multi-machine stability analysis module and a damping parameter allocation module;

[0018] The multi-machine stability analysis module includes calculating the characteristic mode of wind and solar power stations and constructing a multi-machine dynamic aggregation model; substituting the real-time working 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 quantitative evaluation of system stability;

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

[0020]

[0021] In the formula, k PF (λ,ρ) represents the aggregate damping parameter ρ D For the control traction of the characteristic mode, Δσ ref represents the set real part lift, ζ is the adjustment of the aggregate damping parameter;

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

[0023]

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

[0025] Preferably, the active damping control module of the static synchronous machine includes 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 includes providing oscillation information and its main oscillation frequency; obtaining the spectrum distribution of the system through fast Fourier transform based on the measured values ​​of the instantaneous values ​​of the three-phase voltage and current on the high-voltage side of the station step-up transformer; judging whether the system oscillates according to the set threshold, and if so, extracting the dominant frequency;

[0027] The virtual resistance control module includes improving the system damping at the oscillation frequency; adding a virtual resistance loop to the original control loop of the static synchronous machine based on the obtained oscillation information, and dynamically adjusting the resonant frequency of the virtual resistance loop based on the main oscillation frequency;

[0028] The grid short-circuit ratio measurement module includes monitoring the grid strength; generating an injection disturbance signal according to a set measurement frequency band and superimposing it on the control reference of the internal control loop of the static synchronous machine; extracting the disturbance injection component and its feedback component through signal analysis based on the three-phase voltage and current measurement values ​​of the high-voltage side of the boost transformer; and further obtaining the equivalent resistance R and inductance parameters L of the grid through curve fitting:

[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 a multi-machine dynamic aggregation model includes:

[0032] Based on the capacity equal value 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 standardized and reversed according to the aggregate capacity to obtain the aggregate parameters of each control parameter;

[0033] 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:

[0034]

[0035] 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;

[0036] Based on the principle of energy conservation, the equivalent total impedance Z of the station collection network is calculated. Line (s), and thus the aggregate frequency domain model Z of the wind and solar power stations is obtained F (s):

[0037]

[0038] Preferably, the characteristic polynomial and characteristic pattern of the computational dynamic aggregation model include:

[0039] 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:

[0040] Z F (jω),ω∈[2πf1,2πf2];

[0041] Among them, f1 and f2 represent the starting range of the frequency band under consideration;

[0042] Z F (jω) Perform eigendecomposition to obtain the trajectory of the modal impedance about ω, determine the resonant peak of the modal impedance, and determine the potential oscillation frequency of the system;

[0043] Compute the zeros of the reciprocal of the determinant to obtain the characteristic modes:

[0044]

[0045] Here, σ represents the real part of the characteristic mode, and ω represents the imaginary part of the characteristic mode.

[0046] Preferably, the calculation of the traction of the real part of the characteristic mode by the aggregated damping parameter comprises:

[0047] Based on the obtained characteristic pattern, extract the corresponding pattern real part:

[0048]

[0049] 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 by frequency domain modal decomposition, and the characteristic sensitivity matrix is ​​formed based on the left and right eigenvectors. The sensitivity of the damping parameter to the real part of the mode is further calculated according to the partial derivatives of the impedance matrix elements with respect to the damping parameter, which is used as a quantitative characterization basis for the mode traction of the damping parameter.

[0050] According to the present invention, an online damping control method for a main power source type wind and solar power station is provided, comprising:

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

[0052] Step S2: Based on the control algorithm software, the multi-machine stability analysis module is instructed to calculate the characteristic mode of the wind and solar power station;

[0053] Step S3: Calculate the mode traction of each control parameter according to the characteristic mode, and calculate the per-unit adjustment amount of the damping parameter based on the mode traction; Based on the per-unit parameter, perform reverse per-unit calibration according to the output level of each unit to obtain the actual damping parameter adjustment amount corresponding to each unit;

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

[0055] Step S5: If the damping parameter adjustment fails and the system oscillates, the oscillation frequency is sensed by the static synchronous machine, and concentrated damping injection is performed to suppress the oscillation.

[0056] Preferably, 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 evaluation of system stability.

[0057] Preferably, 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 aggregate damping parameter for the real part of the characteristic mode, and calculating the damping parameter adjustment amount according to the real part lifting amount:

[0058]

[0059] In the formula, k PF (λ,ρ) represents the aggregate damping parameter ρ D For the control traction of the characteristic mode, Δσ ref represents the set real part lift, ζ is the adjustment of the aggregate damping parameter;

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

[0061]

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

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

[0064] 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:

[0065]

[0066] 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;

[0067] Based on the principle of energy conservation, the equivalent total impedance Z of the station collection network is calculated. Line (s), and thus the aggregate frequency domain model Z of the wind and solar power stations is obtained F (s):

[0068]

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

[0070] 1. The present invention can improve the damping of the entire station and reduce the risk of oscillation when the operating status of each unit in the main power source type wind and solar station changes all the time; after the system oscillates, the centralized damping injection of the static synchronous machine can be used to achieve rapid suppression of the oscillation and reduce the duration of the oscillation.

[0071] 2. The present invention can adjust the key damping parameters of each unit online according to the real-time operating status of each unit to achieve stable control of the station. After oscillation occurs in the station, the static synchronous machine actively injects damping to suppress oscillation, which helps to improve the overall damping of the main power source type wind and solar station and reduce the harm of oscillation.

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

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

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

[0075] Figure 2 Schematic diagram of actual wind farm topology and electrical parameters in an embodiment of the present invention.

[0076] Figure 3 Schematic diagram of the effect of the multi-machine stability analysis module in an embodiment of the present invention.

[0077] Figure 4 It is a schematic diagram of the effect of the damping parameter allocation module in an embodiment of the present invention.

[0078] Figure 5 This is a diagram verifying the damping cooperative control effect in an embodiment of the present invention.

[0079] Figure 6 This is a diagram verifying the effect of active damping control in an embodiment of the present invention. DETAILED DESCRIPTION

[0080] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0081] Reference Figure 1 As shown, an online damping control system of a main power source type wind and solar power station includes:

[0082] Control algorithm software: including damping coordination control of wind and solar power stations and active damping control of static synchronous machines. The damping coordination control of wind and solar power stations includes multi-machine stability analysis and damping parameter allocation, and the active damping control of static synchronous machines consists of online detection of oscillation frequency, virtual resistance control and grid short-circuit ratio measurement;

[0083] Controller hardware: including wind and solar power generation unit controller, static synchronous machine controller, site algorithm server, energy management system server, host computer, Ethernet switch and optical fiber.

[0084] Among them, 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 current grid-connected active / reactive power, voltage effective value and damping parameters;

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

[0086] The algorithm server of the station is equipped with an online damping control algorithm, which receives the grid-connected active / reactive power, voltage RMS and damping parameters of each wind and solar power generation unit and static synchronous machine, as well as the instantaneous values ​​of the three-phase voltage and current on the high-voltage side of the station step-up transformer, and the number of wind and solar power generation units in operation in the entire field; it sends the damping parameter control instructions, oscillation frequency detection values, grid short-circuit ratio identification values, damping injection instructions and disturbance signal injection information of each wind and solar power generation unit;

[0087] The energy management system server acts as a data transfer station, receiving and sending control instructions from the station algorithm server, the operating point information of the wind and solar power generation units and static synchronous machines, and the three-phase voltage and current measurement values ​​on the high-voltage side of the station step-up transformer;

[0088] The host computer is responsible for setting the configuration parameters of the wind and solar power stations and static synchronous damping control, such as damping boost, disturbance injection frequency band, short-circuit ratio detection rate, etc., and displays the control command value and system instantaneous electrical quantity;

[0089] Ethernet switches and optical fibers are responsible for real-time data transmission between controller software and hardware, mainly including site algorithm servers, energy management system servers, wind and solar power generation unit controllers, static synchronous machine controllers and host computers.

[0090] The basic functions and principles of the damping coordinated control module of the wind and solar power stations in the control algorithm software are as follows:

[0091] The multi-machine stability analysis module is used to calculate the characteristic mode of wind and solar power stations. Based on the offline multi-machine dynamic aggregation model, by substituting the real-time working point of each power generation unit and the short-circuit ratio of the power grid, the characteristic polynomial and characteristic mode λ of the dynamic aggregation model are calculated to achieve quantitative evaluation of system stability.

[0092] The modeling steps of the dynamic aggregation model of wind and solar stations are mainly:

[0093] Firstly, based on the capacity equal value aggregation principle, the aggregate parameters of the main circuit parameters of each unit (AC filter parameters, capacitor parameters, etc.) are obtained according to the number of power generation units in the station and their respective capacities; the control parameters of each controller are standardized, and then reversely standardized according to the aggregate capacity to obtain the aggregate parameters of each control parameter;

[0094] Considering a detailed wind-solar power generation unit, the impedance modeling method is used to establish the AC side impedance model. Substituting the above aggregation parameters, the station single-machine aggregation frequency domain model can be obtained. Where N ∑ Represents the number of wind and solar units in operation at the station, P ∑ represents the aggregate capacity, Represents the power generation unit parameters.

[0095] Based on the principle of energy conservation, the equivalent total impedance Z of the station collection network is calculated. Line (s), and thus the aggregate frequency domain model Z of the wind and solar power stations is obtained F (s), as follows:

[0096]

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

[0098] First, ignore the real part and substitute s = jω to transform the above multi-machine frequency domain aggregation model from the symbol matrix Z F (s) is transformed 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] Z F (jω) Perform eigendecomposition to obtain the trajectory of the modal impedance about ω, determine the resonant peak of the modal impedance, and determine the potential oscillation frequency of the system;

[0100] In the vicinity of the oscillation frequency obtained above, the zero point of the inverse of the determinant is calculated to obtain the characteristic mode:

[0101]

[0102] The damping parameter allocation module is used to adjust the damping parameters of each unit. Based on the characteristic mode obtained above, the key damping parameters in the wind and solar power generation units are determined, and the traction of the aggregate damping parameters for the real part of the characteristic 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) represents the aggregate damping parameter ρ D For the control traction of the characteristic mode, Δσ ref represents the set real part increase, ζ is the aggregate damping parameter adjustment. Then, according to the output level of each unit, the damping parameter adjustment 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 of the jth unit, P 机,j Represents its output level.

[0107] The control traction of the damping parameters on the characteristic mode can be calculated based on the following steps:

[0108] Based on the characteristic patterns calculated above, extract the corresponding real part of the pattern:

[0109]

[0110] Substitute the above pattern into the dynamic aggregation model Z FIn (s), the left and right eigenvector information of the numerical matrix is ​​obtained by frequency domain modal decomposition, and the characteristic sensitivity matrix is ​​formed based on the left and right eigenvectors. The sensitivity of the damping parameter to the real part of the mode is further calculated according to the partial derivatives of the impedance matrix elements with respect to the damping parameter, which is used as a quantitative characterization basis for the mode traction 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 its main oscillation frequency. Based on the measured values ​​of the instantaneous values ​​of the three-phase voltage and current on the high-voltage side of the station step-up transformer, the spectrum distribution of the system is obtained through fast Fourier transform, and the system is judged whether it is oscillating according to the set threshold. 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 oscillation information obtained above, a virtual resistance loop is added to the original control loop of the static synchronous machine, and the resonant frequency of the virtual resistance loop is dynamically adjusted based on the main oscillation frequency;

[0114] The grid short-circuit ratio measurement module is used to monitor the strength of the grid. According to the set measurement frequency band, an injection 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 ​​on 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 parameters L of the 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 invention can adjust the key damping parameters of each unit online according to the real-time operating status of each unit to achieve stable control of the station. After oscillation occurs in the station, the static synchronous machine actively injects damping to suppress the oscillation, which helps to improve the overall damping of the main power source type wind and solar station and reduce the harm of oscillation, and has good practicality.

[0118] The above is a basic embodiment of the present invention. The technical solution of the present invention is further described below through a preferred embodiment.

[0119] Example 1

[0120] Reference Figure 2The figure shows the topology and electrical parameters of a real wind farm, located in the Ganhekou North and South Wind Farm, which mainly includes 32 doubly-fed wind turbines (with a capacity of 3MW) using the self-synchronous voltage source control method, and a static synchronous machine (with a capacity of 10Mvar) also using the self-synchronous voltage source control, connected to the 35kV bus side. For this system, the wind farm damping coordinated control is constructed and installed in the site algorithm server; the static synchronous machine active damping control is constructed, in which the oscillation detection and grid short-circuit ratio detection modules are installed in the site algorithm server, and the virtual resistance control is installed on the static synchronous machine controller.

[0121] Based on the real-time operating point information of each unit provided by the energy management system server and the short-circuit ratio detection results of the static synchronous machine, the system stability is determined through the station stability analysis module. Figure 3 As shown in a, we first analyze the modal impedance resonance peak of the system and find that there are three obvious resonance peaks in the system. We solve the characteristic mode near the frequency point corresponding to the resonance peak, as shown in Figure 3 As shown in b, the dominant characteristic mode of the system is obtained, and the damping control is mainly carried out as follows.

[0122] For the characteristic mode closest to the imaginary axis, the mode traction of each control parameter is calculated, such as Figure 4 As shown in a. It can be seen that the real axis sensitivity of the virtual synchronization ring is the largest, among which the inertia coefficient J and the damping coefficient D are the key parameters that dominate this mode. For this mode, a 2% damping increase is set. Through the real axis sensitivity obtained by the above solution, the new inertia coefficient and damping coefficient can be calculated, as shown in Figure 4 Based on the normalized parameters, the output level of each unit is reversed to obtain the corresponding damping parameter adjustment. The adjustment distribution results of the 32 units are shown in Figure 4 As shown in c.

[0123] Based on the damping parameter adjustment obtained above, the damping parameters of each unit are updated, and the stability analysis module of the station is called again to obtain the following: Figure 5 The mode distribution is shown in Figure 2. It can be seen that by adjusting the damping parameters online, the initial characteristic mode of the system can be moved to the desired position, and the distance from the imaginary axis is increased, thereby improving the stability of the main power source wind and solar power station.

[0124] Reference Figure 6 As shown in the figure, an oscillation is excited in the wind farm. After 0.5s, the static synchronous machine detects the oscillation of the system and the corresponding oscillation frequency. At this time, a virtual resistance loop is put into use for active damping, where the resonant 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 know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0126] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0127] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

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 coordination 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 machine controller is deployed on the high-voltage direct-mounted energy storage, equipped with a self-synchronous voltage source grid-connected control algorithm, receives the oscillation frequency detection value and damping injection command, and sends the current static synchronous machine's grid-connected active / reactive power, voltage RMS, and damping parameters; The station algorithm server is equipped with an online damping control algorithm, which receives the grid-connected active / reactive power, voltage RMS, damping parameters of each wind and 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 station step-up transformer and the number of wind and solar power generation units in operation; it sends the damping parameter control instructions, oscillation frequency detection values, grid short-circuit ratio identification values, damping injection instructions and disturbance signal injection information of each wind and solar power generation unit; Energy management system server, used as a data transfer station, receives and sends control instructions from the station algorithm server, wind and solar power generation units, static synchronous machine operating point information, and three-phase voltage and current measurement values ​​on the high-voltage side of the station 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 control algorithm software and 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 constructing a multi-machine dynamic aggregation model; substituting the real-time working 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 quantitative evaluation of system stability; The damping parameter allocation module includes setting the damping parameters of each unit; determining the key damping parameters in the wind and solar power generation units according to the obtained characteristic mode, further calculating the traction of the aggregate damping parameters for the real part of the characteristic mode, and calculating the damping parameter adjustment amount according to the real part improvement: In the formula, k PF (l,r) represents the aggregate damping parameter r D For the control traction of the characteristic mode, Ds ref represents the set real part lift, z is the adjustment amount of the aggregate damping parameter; According to the output level of each unit, calculate the damping parameter adjustment corresponding to each unit: In the formula, 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 power grid short circuit ratio measurement module; The oscillation frequency online detection module includes providing oscillation information and its main oscillation frequency; obtaining the spectrum distribution of the system through fast Fourier transform based on the measured values ​​of the instantaneous values ​​of the three-phase voltage and current on the high-voltage side of the station step-up transformer; judging whether the system oscillates according to the set threshold, and if so, extracting the dominant frequency; The virtual resistance control module includes improving the system damping at the oscillation frequency; adding a virtual resistance loop to the original control loop of the static synchronous machine based on the obtained oscillation information, 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 according to a set measurement frequency band and superimposing it on the control reference of the internal control loop of the static synchronous machine; extracting the disturbance injection component and its feedback component through signal analysis based on the three-phase voltage and current measurement values ​​of the high-voltage side of the boost transformer; and further obtaining the equivalent resistance R and inductance parameters L of the grid through curve fitting: In the formula, w 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 equal value 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 standardized and reversed according to the aggregate 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, the equivalent total impedance Z of the station collection network is calculated. Line (s), and thus the aggregate frequency domain model Z of the wind and solar power stations 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 = jw to transform the multi-machine frequency domain aggregation model from the symbolic 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; Z F (jω) Perform eigendecomposition to obtain the trajectory of the modal impedance about 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 by frequency domain modal decomposition, and the characteristic sensitivity matrix is ​​formed based on the left and right eigenvectors. The sensitivity of the damping parameter to the real part of the mode is further calculated according to the partial derivatives of the impedance matrix elements with respect to the damping parameter, 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: adjusting the parameters of the control algorithm software; Step S2: Based on the control algorithm software, the multi-machine stability analysis module is instructed to calculate the characteristic mode of the wind and solar power station; Step S3: calculating the mode traction of each control parameter according to the characteristic mode, and calculating the per-unit adjustment amount of the damping parameter based on the mode traction; Based on the normalized parameters, the output level of each unit is reversed to obtain the actual damping parameter adjustment amount corresponding to each unit; Step S4: updating the damping parameters of each unit according to the obtained damping parameter adjustment amount, calling the multi-machine stability analysis module of the station again, and completing 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 concentrated damping injection is performed to suppress the oscillation.

8. The online damping control method of the 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 quantitative evaluation of system stability.

9. The online damping control method of the 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 aggregate damping parameters for the real part of the characteristic mode, and calculating the damping parameter adjustment amount according to the real part lifting amount: In the formula, k PF (l,r) represents the aggregate damping parameter r D For the control traction of the characteristic mode, Ds ref represents the set real part lift, z is the adjustment amount of the aggregate damping parameter; According to the output level of each unit, calculate the damping parameter adjustment corresponding to each unit: In the formula, z 机,j represents the damping parameter adjustment of the jth unit, P 机,j Represents its output level.

10. The online damping control method of the main power source type wind and solar power station according to claim 8 is 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, the equivalent total impedance Z of the station collection network is calculated. Line (s), and thus the aggregate frequency domain model Z of the wind and solar power stations is obtained F (s):

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