CN-122026366-A - Micro-grid fault self-healing control and recovery method

CN122026366ACN 122026366 ACN122026366 ACN 122026366ACN-122026366-A

Abstract

Sampling a busbar voltage waveform and calculating a real-time total harmonic distortion rate, and accordingly performing weight mapping on a predicted phase before failure and a current measured phase to output a reference phase vector; the method comprises the steps of calculating normalized physical conflict intensity, generating a switching decision variable based on deviation of the normalized physical conflict intensity and a preset threshold value, triggering characteristic current injection according to a jump state of the switching decision variable, identifying complex impedance characteristic values of ports of a distributed unit and generating a role grade index, configuring droop control gain according to the role grade index, and generating a power adjustment vector by combining frequency slippage rate. The method utilizes the logical evolution of physical characteristic quantity to replace communication message interaction and is used for self-healing control of the low inertia micro-grid under the communication interruption working condition.

Inventors

ZHAO XIN
CHEN BIN
ZHU WEIZHENG
WANG YINGHUI
ZHOU TAO

Assignees

西安西拓电气股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (6)

1. The self-healing control and recovery method for the micro-grid faults is characterized by comprising the following steps of: the phase characteristic capturing step comprises the steps of calculating real-time total harmonic distortion rate of a busbar voltage waveform after sampling and obtaining the busbar voltage waveform, and carrying out weight mapping on a predicted phase vector before failure and a current measured phase vector according to numerical distribution of the real-time total harmonic distortion rate to output a reference phase vector; The state arbitration step is that the reference phase vector is input into logic processing operation, normalized physical conflict intensity is calculated and obtained, and a switching decision variable is generated according to the deviation amount of the normalized physical conflict intensity and a preset threshold value; Triggering characteristic current injection operation according to the jump state of the switching decision variable, identifying complex impedance characteristic values of all distributed unit ports according to the acquired characteristic response current, sequencing the modulus values of all the complex impedance characteristic values, and generating corresponding role grade indexes; And a cooperative compensation step, namely configuring corresponding droop control gain according to the role grade index, and generating a power adjustment vector by combining the monitored frequency slip rate.
2. The method for self-healing control and restoration of a micro-grid fault according to claim 1, wherein in the state arbitration step, the switching decision variable The calculation formula of (2) is as follows: Wherein: for the normalized physical collision strength; for a suppression coefficient determined from the real-time total harmonic distortion rate, and Wherein -For said real-time total harmonic distortion rate; Is a preset safety constant; Is a preset action threshold value and meets ; In order to determine the sensitivity coefficient of the decision, Is a sensitivity factor; The normalized physical collision strength The calculation formula of (a) is specifically as follows: Wherein: For the angular offset of the reference phase vector relative to the reference vector, Is a rated phase reference value; for the instantaneous ripple amplitude vector of the bus voltage waveform, Is a rated voltage reference value; is a preset positive minimum constant without dimension.
3. The method for self-healing control and recovery of a micro-grid fault according to claim 1, wherein the specific way of generating the reference phase vector in the phase feature capturing step is as follows: When the real-time total harmonic distortion rate exceeds a preset threshold, the duty ratio of the pre-fault predicted phase vector in the weight mapping is increased, and the correction amplitude of the current measured phase vector to the reference phase vector is reduced.
4. The method for self-healing control and recovery of a micro-grid fault according to claim 1, wherein the feature identification step specifically comprises: when the switching decision variable exceeds the preset threshold value, driving the characteristic current injection operation; the obtained modular values of the complex impedance characteristic values are arranged in a descending order; And defining the node with the maximum modulus as a first control role, defining the rest nodes as a second control role, and generating the corresponding role grade index.
5. The method for self-healing control and recovery of a micro-grid fault according to claim 1, wherein the step of collaborative compensation specifically comprises: And when the absolute value of the frequency slip rate is monitored to be larger than a preset frequency protection threshold, adjusting the amplitude vector of the busbar voltage waveform.
6. The method for self-healing control and restoration of a micro-grid fault according to any one of claims 1 to 5, wherein the method is operated under the working condition that the message transmission of a communication link is interrupted or the transmission delay is greater than a preset time consumption threshold.

Description

Micro-grid fault self-healing control and recovery method Technical Field The invention relates to the technical field of distributed control of power systems, in particular to a micro-grid fault self-healing control and recovery method. Background As high-proportion power electronic equipment is connected into a micro-grid, the system presents the remarkable characteristics of low inertia and weak damping. The existing micro-grid self-healing technology is commonly built on an information layer-physical layer dual-coupling architecture, and highly depends on a high-speed communication network to realize state synchronization and control authorization among distributed units. The invention relates to a core technical problem that each distributed unit of a micro-grid loses the support of an external instruction and falls into a sensing island under the working condition that a communication link is interrupted due to extreme faults or logic messages are lost due to high-intensity electromagnetic interference. Due to the lack of a unified logic synchronization reference, physical uncertainty problems such as phase alignment deviation, master-slave control right conflict, power flow disturbance and the like can occur in each unit at off-grid moment and in the subsequent self-healing process, huge transient loop impact and frequency/voltage support collapse are extremely easy to be caused, self-healing attempt failure is caused, and system linkage collapse is caused. Disclosure of Invention The invention provides a self-healing control and recovery method for a micro-grid fault, which aims to solve the problem that each distributed unit of the micro-grid loses the support of an external instruction and falls into a perceived island under the working condition that a communication link is interrupted or a logic message is lost due to high-intensity electromagnetic interference caused by an extreme fault. In view of the above problems, the present invention provides a method for controlling and recovering a fault self-healing of a micro-grid, comprising the following steps: the phase characteristic capturing step comprises the steps of calculating real-time total harmonic distortion rate of a busbar voltage waveform after sampling and obtaining the busbar voltage waveform, and carrying out weight mapping on a predicted phase vector before failure and a current measured phase vector according to numerical distribution of the real-time total harmonic distortion rate to output a reference phase vector; The state arbitration step is that the reference phase vector is input into logic processing operation, normalized physical conflict intensity is calculated and obtained, and a switching decision variable is generated according to the deviation amount of the normalized physical conflict intensity and a preset threshold value; Triggering characteristic current injection operation according to the jump state of the switching decision variable, identifying complex impedance characteristic values of all distributed unit ports according to the acquired characteristic response current, sequencing the modulus values of all the complex impedance characteristic values, and generating corresponding role grade indexes; A cooperative compensation step of configuring corresponding droop control gains according to the role grade index, and generating a power adjustment vector by combining the monitored frequency slip rate; In the state arbitration step, the switching decision variable The calculation formula of (2) is as follows: Wherein: for the normalized physical collision strength; for a suppression coefficient determined from the real-time total harmonic distortion rate, and Wherein-For said real-time total harmonic distortion rate; Is a preset safety constant; Is a preset action threshold value and meets ;In order to determine the sensitivity coefficient of the decision,Is a sensitivity factor; The normalized physical collision strength The calculation formula of (a) is specifically as follows: Wherein: For the angular offset of the reference phase vector relative to the reference vector, Is a rated phase reference value; for the instantaneous ripple amplitude vector of the bus voltage waveform, Is a rated voltage reference value; is a preset positive minimum constant without dimension. Further, the specific way of generating the reference phase vector in the phase feature capturing step is as follows: When the real-time total harmonic distortion rate exceeds a preset threshold, the duty ratio of the pre-fault predicted phase vector in the weight mapping is increased, and the correction amplitude of the current measured phase vector to the reference phase vector is reduced. Further, the feature recognition step specifically includes: when the switching decision variable exceeds the preset threshold value, driving the characteristic current injection operation; the obtained modular values of the complex impedance characte