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CN-121710390-B - Distributed energy cooperative control method and device for photovoltaic power plant

CN121710390BCN 121710390 BCN121710390 BCN 121710390BCN-121710390-B

Abstract

The invention discloses a distributed energy cooperative control method and device for a photovoltaic power plant, and relates to the technical field of intelligent power grid control. The distributed energy cooperative control method and device for the photovoltaic power plant comprises the steps of S1, collecting inverter working data, preprocessing the inverter working data to obtain preprocessed inverter working data, S2, constructing an inverter set to be classified, extracting a reference sample, evaluating a grid withdrawal risk, outputting a grid withdrawal state label of the inverter to be classified, S3, identifying a power intervention candidate area, extracting an inverter which does not withdraw to construct a power compensation resource set, screening out a power regulation target, evaluating the regulation priority of the power regulation target, S4, calculating the power regulation step length of the power regulation target, carrying out power regulation, and constructing a feeder line regulation database after the regulation to realize closed-loop self-adaptive optimization of power control. The problem of the wrong judgement of the grid-withdrawal fault of the inverter caused by unrecognized voltage drop abnormality at the tail end of the feeder line is solved.

Inventors

  • Yu Zaichao
  • MA XIN
  • HAO XINTAO

Assignees

  • 国能(天津)大港发电厂有限公司

Dates

Publication Date
20260508
Application Date
20260211

Claims (9)

  1. 1. The distributed energy cooperative control method for the photovoltaic power plant is characterized by comprising the following steps of: S1, collecting inverter working data, and performing cycle integrity verification, trend segmentation, abnormal suppression and scale normalization on the inverter working data to obtain preprocessed inverter working data; S2, constructing an inverter set to be classified based on the inverter with the network to be classified, extracting a reference sample by combining with feeder line topology, evaluating the network to be classified risk based on the preprocessed inverter working data, outputting a network to be classified label of the inverter to be classified, and constructing an inverter network to be classified data set; the specific steps of constructing an inverter set to be classified based on the network-backed inverter and extracting a reference sample by combining a feeder line topology are as follows: For each inverter to be classified, identifying the feeder line according to the electric access topological relation, extracting other inverters without network withdrawal under the feeder line, and constructing a reference inverter set as a parallel comparison sample of the current inverter to be classified; Dividing the difference between the bus voltage and the inverter output voltage by the inverter output current to obtain a unit current voltage drop term, squaring the difference between the terminal box temperature and the environment temperature to obtain a thermal disturbance temperature difference term, squaring the unit current voltage drop term and adding the thermal disturbance temperature difference term to obtain a voltage drop temperature difference combined disturbance term, dividing the grid-connected restarting times by the grid-connected response time, adding a ratio and taking a natural logarithm to obtain a restarting response factor, multiplying the voltage drop temperature difference combined disturbance term by the restarting response factor to obtain a load coupling activation term, dividing the load coupling activation term by the sum of the photovoltaic direct current input power and a minimum term to obtain a grid-disconnected risk assessment value; s3, identifying a power intervention candidate area based on the network-quitting data set, extracting an unremoved inverter to construct a power compensation resource set, screening out a power regulation target, and evaluating the regulation priority of the power regulation target; S4, calculating the power adjustment step length of the power adjustment target, combining the alternating current output power to generate an active output instruction value after constraint verification, performing power adjustment, and constructing a feeder line adjustment database after adjustment to realize closed loop self-adaptive optimization of power control.
  2. 2. The method for cooperatively controlling distributed energy sources of a photovoltaic power plant according to claim 1, wherein the method is characterized by comprising the following specific steps of collecting inverter working data, performing cycle integrity verification, trend segmentation, abnormal suppression and scale normalization on the inverter working data, and obtaining the preprocessed inverter working data: setting a sampling period based on a fixed time window, and collecting inverter working data of each photovoltaic inverter in a power plant, wherein the inverter working data comprise inverter output voltage, inverter output current, bus voltage, ambient temperature, terminal box temperature, inverter grid-withdrawal times, grid-connected response time, grid-connected restarting times, photovoltaic direct current input power and alternating current output power; The method comprises the steps of performing periodic integrity check on inverter working data through a sampling stability analysis algorithm, identifying and removing break points and repeated fragments caused by communication interruption, data return delay and equipment instantaneous disconnection, performing multi-periodic steady-state segmentation processing on the inverter working data through a trend residual error subdivision algorithm, separating natural fluctuation and short-time abnormal jump in an operation stage, performing upper and lower limit pressing and data sparse restoration on the inverter working data through a grouping discrete abnormal pressing strategy to prevent a low-frequency event value from leading a regression result, performing range normalization processing on the inverter working data through a range linear mapping function, and mapping different physical dimension data to a unified standardized range.
  3. 3. The method for cooperatively controlling distributed energy sources of a photovoltaic power plant according to claim 1, wherein the specific steps of outputting the grid-withdrawal label of the inverter to be classified and constructing the grid-withdrawal data set of the inverter are as follows: Comparing the grid withdrawal risk evaluation value with a grid withdrawal risk threshold in real time, judging that the inverter to be classified is in a false report grid withdrawal state when the grid withdrawal risk evaluation value of the inverter to be classified is smaller than or equal to the grid withdrawal risk threshold, and removing a set to be classified; outputting a grid-withdrawal label of the inverter to be classified, and carrying out structural storage on the grid-withdrawal label and the corresponding inverter working data to construct an inverter grid-withdrawal data set.
  4. 4. The method for collaborative control of distributed energy sources of a photovoltaic power plant according to claim 1, wherein the specific steps of identifying power intervention candidate areas based on a grid-withdrawal data set, extracting an unremoved grid inverter to construct a power compensation resource set, and screening out a power adjustment target are as follows: line-type network-withdrawal behavior clustering is carried out on the inverter network-withdrawal data sets in the same period, the line-type network-withdrawal data sets are grouped according to the feeder numbers, the areas of the line-type network-withdrawal inverters meeting the set number of conditions at the tail end of the same feeder are screened, and the areas are marked as power intervention candidate areas; and in the power compensation resource set, selecting the inverter meeting the conditions that the ratio of the photovoltaic direct current input power to the alternating current output power is larger than an adjustment threshold value and the output current of the inverter is smaller than rated running current as a power adjustment target.
  5. 5. The method for cooperatively controlling distributed energy sources of a photovoltaic power plant according to claim 1, wherein the specific steps of evaluating the adjustment priority of the power adjustment target are as follows: The method comprises the steps of obtaining a photovoltaic direct current input power and alternating current output power, obtaining a power adjustment feasibility amount by squaring the difference between the photovoltaic direct current input power and the alternating current output power, obtaining a thermal coupling adjustment driving factor by multiplying the temperature control feasibility amount by the difference between the temperature of a terminal box and the ambient temperature serving as a temperature control deviation item, and obtaining a power adjustment priority evaluation value by dividing the thermal coupling adjustment driving factor by the product of an off-grid risk evaluation value and an inverter output current.
  6. 6. The method for cooperatively controlling distributed energy sources of a photovoltaic power plant according to claim 1, wherein the specific steps of calculating the power adjustment step size of the power adjustment target are as follows: For each power regulation target, a load regulation mapping relation is established based on the feeder line structure, photovoltaic direct current input power is subtracted by alternating current output power to obtain power regulation surplus, a current regulation coefficient is obtained by subtracting the ratio of inverter output current to rated operation current, the sum of the grid withdrawal risk evaluation value and the minimum term is taken as natural logarithm to obtain a risk regulation factor, and the power regulation surplus, the current regulation coefficient and the risk regulation factor are multiplied in sequence to obtain an output power regulation step length.
  7. 7. The method for cooperatively controlling distributed energy sources of a photovoltaic power plant according to claim 1, wherein the specific steps of generating the constrained and verified active output command value by combining the alternating current output power and adjusting the power are as follows: The method comprises the steps of calculating an active output instruction value of a power adjustment target by adopting a linear amplitude adjustment algorithm according to an output power adjustment step length and combining with real-time alternating current output power, carrying out constraint boundary check on the active output instruction value and rated output power, screening out an overrun instruction value, sequentially selecting the power adjustment target according to a descending order of a power adjustment priority evaluation value, and issuing a corresponding active output adjustment instruction to carry out power adjustment operation.
  8. 8. The distributed energy cooperative control method of a photovoltaic power plant according to claim 1, wherein the specific steps of constructing a feeder line adjustment database after adjustment and realizing closed-loop self-adaptive optimization of power control are as follows: and after the power adjustment is finished, monitoring the network-withdrawal behavior change condition of the other inverters in the corresponding feeder line, updating the network-withdrawal labels of the other inverters, and storing the output power adjustment step length, the active output instruction value and the network-withdrawal state label before and after the adjustment of the inverter in the corresponding feeder line in a structural association manner with the working data of the inverter to construct a feeder line adjustment database for supporting the self-adaptive optimization and strategy backtracking of the subsequent power adjustment.
  9. 9. The distributed energy cooperative control device for the photovoltaic power plant is characterized by comprising a data acquisition and preprocessing module, a risk assessment and state identification module, a power regulation target determination module and an active power regulation control module, wherein: The data acquisition and preprocessing module is used for acquiring inverter working data, and executing cycle integrity verification, trend segmentation, abnormal suppression and scale normalization processing on the inverter working data to acquire preprocessed inverter working data; the risk assessment and state identification module is used for constructing an inverter set to be classified based on the inverter which is already in the network, extracting a reference sample by combining with feeder line topology, assessing the network withdrawal risk based on the preprocessed inverter working data, outputting a network withdrawal state label of the inverter to be classified, and constructing an inverter network withdrawal data set; the specific steps of constructing an inverter set to be classified based on the network-backed inverter and extracting a reference sample by combining a feeder line topology are as follows: For each inverter to be classified, identifying the feeder line according to the electric access topological relation, extracting other inverters without network withdrawal under the feeder line, and constructing a reference inverter set as a parallel comparison sample of the current inverter to be classified; Dividing the difference between the bus voltage and the inverter output voltage by the inverter output current to obtain a unit current voltage drop term, squaring the difference between the terminal box temperature and the environment temperature to obtain a thermal disturbance temperature difference term, squaring the unit current voltage drop term and adding the thermal disturbance temperature difference term to obtain a voltage drop temperature difference combined disturbance term, dividing the grid-connected restarting times by the grid-connected response time, adding a ratio and taking a natural logarithm to obtain a restarting response factor, multiplying the voltage drop temperature difference combined disturbance term by the restarting response factor to obtain a load coupling activation term, dividing the load coupling activation term by the sum of the photovoltaic direct current input power and a minimum term to obtain a grid-disconnected risk assessment value; The power regulation target determining module is used for identifying a power intervention candidate area based on the network-quitting data set, extracting an unremoved inverter to construct a power compensation resource set, screening out a power regulation target, and evaluating the regulation priority of the power regulation target; The active power adjustment control module is used for calculating the power adjustment step length of a power adjustment target, generating an active output instruction value after constraint verification by combining the alternating current output power, carrying out power adjustment, and constructing a feeder line adjustment database after adjustment to realize closed loop self-adaptive optimization of power control.

Description

Distributed energy cooperative control method and device for photovoltaic power plant Technical Field The invention relates to the technical field of intelligent power grid control, in particular to a distributed energy cooperative control method and device for a photovoltaic power plant. Background In grid-connected operation of a photovoltaic power plant, an inverter is used as a key conversion unit, and a control strategy is directly related to grid-connected quality and system stability of the power plant. In the prior art, in order to improve the grid-connected performance and the exception handling capability of the inverter, various control methods and operation analysis models have been proposed. For example, the invention with the bulletin number of CN111030173B discloses a control method and device, an inverter and a medium of a grid-connected inverter of a new energy power plant. The control method of the grid-connected inverter of the new energy power plant comprises the steps of obtaining an input voltage measured value, an output voltage measured value and an output current measured value of the inverter, wherein the input voltage measured value is a busbar voltage measured value of a direct current busbar connected with the inverter, determining an active current given value of the inverter according to the input voltage measured value, determining a reactive current given value of the inverter according to the output voltage measured value and the output current measured value, and generating a PWM signal by utilizing the active current given value and the reactive current given value, wherein the PWM signal is used for controlling the working state of an IGBT of the inverter so that the output voltage of the inverter is close to a preset output voltage given value. For example, the invention with the bulletin number of CN117578405B discloses an abnormality analysis method and device for an inverter string of a photovoltaic power plant, which comprises the steps of collecting historical operation data of the inverter string for a period of time and a design strategy of the inverter string, preparing a volume ratio rule according to the historical operation data and the design strategy, establishing a volume ratio detection model according to the volume ratio rule and the historical operation data, collecting real-time operation data of the inverter string, inputting the real-time operation data into the volume ratio detection model, and judging whether the volume ratio of the inverter string is abnormal or not through the volume ratio detection model. The invention collects the operation data of the inverter group string and designs the detection model of the capacity ratio established by the strategy to judge whether the capacity ratio of the inverter group string is abnormal in real time, so as to prevent further loss or fault occurrence caused by the abnormality, greatly improve the monitoring efficiency and precision, ensure that the capacity ratio of the inverter group string can maintain the normal working state, and simultaneously improve the power generation efficiency and the operation stability of the photovoltaic power plant. However, although the technology has advanced to some extent in the aspects of current-voltage control and string abnormality identification of the inverter, the technology still has the following defects that firstly, multi-inverter state linkage judgment based on feeder topology is not realized, abnormal areas with cooperative grid withdrawal characteristics are difficult to identify, secondly, a quantitative modeling means for the fault state and operation data of the inverter is lacking, a targeted power regulation strategy is difficult to support, and thirdly, a closed loop feedback mechanism from state evaluation to regulation execution is not established, so that the technology cannot adapt to real-time optimization control under the condition of a dynamic power grid. Therefore, in view of the above problems, there is a need for a method and a device for controlling the distributed energy of a photovoltaic power plant. Disclosure of Invention Technical problem to be solved Aiming at the defects of the prior art, the invention provides a distributed energy cooperative control method and device for a photovoltaic power plant, which solve the problem of misjudgment of the grid-withdrawal fault of an inverter caused by unrecognized voltage drop abnormality at the tail end of a feeder line. Technical proposal The technical scheme includes that S1, inverter working data are collected, periodic integrity verification, trend segmentation, abnormal suppression and scale normalization processing are carried out on the inverter working data, preprocessed inverter working data are obtained, S2, an inverter set to be classified is built based on the existing network inverters, reference samples are extracted based on the preprocessed inverter working data, network