CN-121984091-A - Intelligent identification and smooth switching control method, system, equipment and medium for island operation mode of power distribution network

CN121984091ACN 121984091 ACN121984091 ACN 121984091ACN-121984091-A

Abstract

The invention discloses a method, a system, equipment and a medium for intelligent identification and smooth switching control of an island operation mode of a power distribution network, which belong to the technical field of operation and control of intelligent power distribution networks and comprise the steps of collecting real-time operation data of key nodes of the power distribution network, carrying out multiple quality check, extracting characteristic parameters, establishing an island identification classifier, judging island identification results, starting an island stable control strategy after confirming island formation, keeping island operation stable, detecting whether a main network is restored to supply power during the island stable operation, entering a grid-connected preparation stage, entering a grid-connected switching-on stage after synchronization is completed, sending a switching-on instruction for grid-connected switching, carrying out performance evaluation and off-line optimization, and obtaining optimal control parameters to be updated into a control system. The method and the device realize rapid and accurate identification of the island, quickly respond to unbalanced power in the island, improve the stability of island operation, realize smooth and impact-free grid connection, avoid impact on electrical equipment and improve the grid connection success rate.

Inventors

LI QINGSHENG
TAN ZHUKUI
WANG WEI
DING JIAN
ZHANG RUIFENG
ZHANG YAN
LUO NING
ZHANG YU
CHEN JULONG
LONG JIAHUAN
LI ZHEN
ZHANG ZHAOFENG
YANG JIERUI
TANG XUEYONG
XUE YI

Assignees

贵州电网有限责任公司

Dates

Publication Date: 20260505
Application Date: 20251211

Claims (10)

1. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network is characterized by comprising the following steps of, Collecting real-time operation data of key nodes of the power distribution network, and performing multiple quality checks on the collected data; Smoothing the checked data, filtering, extracting characteristic parameters and normalizing; Establishing an island identification classifier, judging island identification results, and recording island formation time; After the island formation is confirmed, starting an island stability control strategy, outputting and issuing an active output instruction of the distributed power supply, and keeping the island operation stable; during the stable operation of the island, detecting whether the main network recovers power supply, entering a grid-connected preparation stage after the main network recovers, and performing grid-connected synchronization to synchronously complete triggering grid-connected switching operation; And after synchronization is completed, a grid-connected switching-on stage is entered, a switching-on instruction is sent to perform grid-connected switching, performance evaluation and offline optimization are performed on island operation and grid-connected switching, and the optimal control parameters are updated into the control system.
2. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network according to claim 1, wherein the multiple quality checks comprise the steps of collecting real-time operation data of key nodes of the power distribution network, including electrical quantity information and switching value information, and setting data collection frequency; And performing multiple quality checks on the acquired data, wherein the multiple quality checks comprise data integrity check, data rationality check and data consistency check, and the data after triple checks is stored in a data cache area.
3. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network according to claim 2, wherein the characteristic parameter extraction comprises the steps of adopting a sliding window filtering method to carry out smooth processing on data; And forming a feature vector based on the feature parameters, and carrying out normalization processing on the feature vector.
4. The intelligent island operation mode identification and smooth switching control method of the power distribution network according to claim 3, wherein the establishing island identification classifier comprises the steps of utilizing the extracted feature vector and adopting a support vector machine algorithm to establish the island identification classifier; training samples of different scenes through historical operation data, and determining optimal parameters of a support vector machine; and judging an island identification result, identifying island identification zone bits, immediately triggering island stability control, and simultaneously recording island formation time.
5. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network according to claim 4, wherein the island stability control strategy comprises the steps of adopting self-adaptive droop control as a basic control strategy and introducing virtual inertia to improve dynamic response characteristics, wherein the basic control strategy comprises frequency-active droop characteristics and voltage-reactive droop characteristics of the self-adaptive droop control; Introducing virtual inertia control to improve dynamic response characteristics of island formation moment, and adding an inertia compensation term in a frequency control link: In the formula, The power is compensated for the inertia and, Is a coefficient of virtual inertia which is a coefficient of inertia, Is the rate of change of frequency; The final active output instruction of the distributed power supply is as follows: In the formula, In order to be an active force command, As a reference value for the frequency of the signal, For the adaptively adjusted droop factor, The command is sent to grid-connected inverters of all distributed power supplies in the island through a communication network, and the inverters adjust output power after receiving the command; continuously monitoring the voltage and frequency in the island, and calculating voltage deviation and frequency deviation: In the formula, As a percentage of the voltage deviation, the voltage deviation is, As a reference value for the voltage, the reference value, And after the island operation is judged to be stable, the stable control is continuously operated until the main network is detected to be recovered or a grid connection preparation instruction is received.
6. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network according to claim 5, wherein the grid-connected preparation stage comprises continuously monitoring the operation state of a main network side during the stable operation of the island, detecting whether the main network is powered back, and monitoring the voltage amplitude of the main network through a voltage sensor at the upstream side of a circuit breaker When detecting in 10 consecutive sampling periods When the main network is recovered, the main network recovery zone bit is judged Is set to be 1, wherein, Is the rated voltage of the power grid; After the main network is restored, entering a grid-connected preparation stage, and pre-judging the synchronous conditions of the island side and the main network side to calculate the voltage amplitude difference between the island side and the main network side Frequency difference And phase angle difference ; Defining grid-connected synchronization conditions as follows: when the synchronization condition is satisfied, the synchronization flag bit When the main network is recovered and the island is stable but the synchronization condition is not met, starting a bilateral synchronization control strategy, wherein the aim of synchronization control is to track the parameters of the main network by adjusting the voltage, frequency and phase of the island side and meet the synchronization condition; The frequency synchronous control adopts a proportional-integral controller, and the frequency adjusting instruction is as follows: In the formula, In order to be a frequency adjustment instruction, As a coefficient of proportionality of the frequency, The frequency adjustment instruction is added to the frequency control link, the frequency reference value is corrected, and the island frequency is the main network frequency through frequency adjustment; the voltage amplitude synchronous control also adopts a proportional-integral controller: In the formula, In order to provide a voltage regulation command, As a proportion coefficient of the voltage, the voltage is equal to the voltage, The voltage reference value is corrected by the voltage regulation command for the voltage integral coefficient; and a phase angle feedforward compensation strategy is adopted, and the phase of the island side is directly adjusted according to the phase angle difference: In the formula, To correct the island side phase angle, As a phase angle compensation coefficient, the phase angle adjustment is realized by modifying the reference signal phase of the grid-connected inverter; and continuously updating the synchronous control instruction, tracking the parameter change of the main network in real time, calculating the synchronous deviation, and judging whether the synchronization is completed.
7. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network according to claim 6, wherein the grid-connected switching-on stage comprises the following steps of When the method is used, a grid-connected switching-on stage is entered, switching-on impact is reduced by adopting a switching-on moment selection strategy, and the instantaneous value difference between the island side voltage and the main network side voltage is calculated: In the formula, As a result of the instantaneous voltage difference, And Monitoring zero crossing points of the instantaneous voltage difference to judge the optimal closing time; A closing instruction is sent to the grid-connected breaker at the optimal closing moment, the action time of the breaker is considered, and the action time of the breaker is advanced Sending a closing instruction: In the formula, The moment of sending out the closing instruction is given, For the predicted zero-crossing moment of the voltage, The intrinsic action time of the circuit breaker; after closing, monitoring the current of the grid connection point, calculating the impulse current multiple as an evaluation index of the control effect, and after closing, identifying the island identification zone bit Resetting to 0, and returning the system to a normal grid-connected operation state after exiting the island operation mode; performing performance evaluation on the whole island operation and grid connection switching process, and defining key performance indexes including island detection time, island operation stability, synchronization time and grid connection impact degree; Based on the key performance index, adopting a genetic algorithm to perform off-line optimization on key control parameters, wherein the key control parameters comprise sagging coefficients, virtual inertia coefficients and synchronous controller parameters, and the optimization objective function is as follows: In the formula, In order to integrate the performance index of the product, For the weight coefficients assigned to the different parameters, For the island detection time, As an index of the degree of stability, In order to synchronize the time of the day, And obtaining optimal control parameters by minimizing comprehensive performance indexes, and updating the optimal control parameters into an actual control system.
8. The intelligent identification and smooth switching control system for the island operation mode of the power distribution network is characterized by comprising a data acquisition and preprocessing module, a feature extraction module, an island intelligent identification module, an island stability control module, a synchronous control module and a grid-connected switching module, wherein the intelligent identification and smooth switching control system for the island operation mode of the power distribution network is applied to the intelligent identification and smooth switching control method for the island operation mode of the power distribution network according to any one of claims 1-7; the data acquisition and preprocessing module acquires real-time operation data of key nodes of the power distribution network and performs multiple quality checks on the acquired data; The feature extraction module performs smoothing treatment on the checked data, extracts feature parameters after filtering and performs normalization treatment; The island intelligent recognition module establishes an island recognition classifier, judges island recognition results and records island formation time; The island stability control module starts an island stability control strategy after confirming island formation, outputs and issues an active output instruction of the distributed power supply, and keeps island operation stable; the synchronization control module detects whether the main network recovers power supply or not during the stable island operation period, enters a grid-connected preparation stage after the main network recovers, and performs grid-connected synchronization to synchronously complete triggering grid-connected switching operation; And the grid-connected switching module enters a grid-connected switching-on stage after synchronization is completed, a switching-on instruction is sent to perform grid-connected switching, performance evaluation and offline optimization are performed on island operation and grid-connected switching, and optimal control parameters are obtained and updated into the control system.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the power distribution network island operation mode intelligent identification and smooth switching control method of any one of claims 1 to 7.
10. A computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the steps of the power distribution network island operation mode intelligent identification and smooth switching control method of any of claims 1 to 7.

Description

Intelligent identification and smooth switching control method, system, equipment and medium for island operation mode of power distribution network Technical Field The invention relates to the technical field of operation and control of intelligent power distribution networks, in particular to a power distribution network island operation mode intelligent identification and smooth switching control method, system, equipment and medium. Background As the permeability of the distributed power supply in the power distribution network is continuously improved, when the main network fails, the local area of the power distribution network containing the distributed power supply may form an island to continue to operate. The existing island operation control technology mainly has the following defects: The island detection speed is low and the accuracy is not enough, and the traditional island detection method mainly comprises two types of passive detection and active detection. The island is judged by the passive detection through monitoring the change of the electric quantity such as voltage, frequency and the like, but a detection blind area exists when the load is balanced with the distributed power supply power, and the detection failure rate is high. The island operation stability control capability is insufficient, namely after the island is formed, the voltage and the frequency in the island are easy to have larger fluctuation due to the loss of the support of the main network. The existing control method is mainly used for controlling sagging of a single distributed power supply and lacks of coordination and optimization of a plurality of distributed power supplies. And when the main network is recovered from faults, the island needs to be re-integrated into the main network. The traditional grid-connected method adopts simple voltage frequency detection, and is directly switched on when the voltage amplitude, phase and frequency of the island and the main network are close. Because of lack of accurate synchronous control, larger phase difference and frequency difference often exist at the moment of grid connection, obvious impact current is generated, the peak value can reach 3-5 times of rated current, impact is caused on electrical equipment, and the power supply reliability is affected. Disclosure of Invention The present invention has been made in view of the above-described problems. Therefore, the invention aims to realize rapid and accurate identification of the island, ensure stable voltage frequency during the operation of the island and realize smooth and impact-free grid connection of the island and the main network. In order to solve the technical problems, the invention provides the technical scheme that the intelligent identification and smooth switching control method for the island operation mode of the power distribution network comprises the following steps, The method comprises the steps of collecting real-time operation data of key nodes of a power distribution network, carrying out multiple quality verification on the collected data, carrying out smoothing treatment on the verified data, extracting characteristic parameters and carrying out normalization treatment after filtering, establishing an island identification classifier, judging island identification results, recording island formation time, starting an island stability control strategy after island formation is confirmed, outputting an active output instruction of a distributed power supply and issuing the active output instruction, keeping island operation stable, detecting whether a main network is restored to supply power during the island stability operation, entering a grid connection preparation stage after the main network is restored, carrying out grid connection synchronization, triggering grid connection switching operation after synchronization is completed, entering a grid connection switching stage, sending a switching-on instruction to carry out grid connection switching, carrying out performance evaluation and offline optimization on island operation and grid connection switching, and obtaining optimal control parameters to be updated into a control system. The intelligent identification and smooth switching control method for the island operation mode of the power distribution network is a preferable scheme, wherein the multiple quality check comprises the steps of collecting real-time operation data of key nodes of the power distribution network, including electrical quantity information and switching value information, and setting data collection frequency; And performing multiple quality checks on the acquired data, wherein the multiple quality checks comprise data integrity check, data rationality check and data consistency check, and the data after triple checks is stored in a data cache area. The intelligent identification and smooth switching control method for the island operation mode of the power