Partial discharge detecting system for all-fiber power transformer and detecting method thereof

Abstract

The invention relates to a partial discharge detecting system for all-fiber power transformer and a detecting method thereof. The system comprises a controller, a transmission device and a detecting device. The detecting device comprises four groups of fiber bragg grating F-P ultrasonic sensors, optical fiber delayers are arranged between every two fiber bragg gratings, and the four groups of fiber bragg grating F-P ultrasonic sensors and a fluorescent probe are in serial connection on an optical fiber. The transmission device is connected with the detecting device through a through part. The controller is connected with the transmission device. In the calculation processing end, the partial discharge position can be calculated and determined through the time difference for the four groups of sensors to receive sound wave and by taking time division multiplexing time error into consideration. According to the strength of stimulated emission light signals of the fluorescent probe, the apparent discharge magnitude of the partial discharge is calculated. Through the comparison between the ultrasonic sensors and the signals of the fluorescent probe, whether the system is interfered by external environment to cause error judgment is judged. Furthermore, false alarm of the system is avoided. The partial discharge detecting system has the advantages of being simple in structure, facilitating networking, resisting to electromagnetic interference and the like.

Description

technical field [0001] The invention relates to an on-line monitoring technology for partial discharge of a power transformer, in particular to an all-optical fiber power transformer partial discharge detection system and a detection method thereof. Background technique [0002] Large-scale high-voltage power transmission and transformation equipment, especially transformers, are the basis for ensuring the reliability of power supply and the fundamental guarantee for safe power production. With the continuous improvement of power transmission and transformation capabilities, the voltage level is also increasing, and the reliable operation and fault diagnosis of transformers are becoming more and more important. Partial discharge is the main cause of power transformer insulation aging and breakdown. The detection of partial discharge is based on various phenomena produced by partial discharge, and the state of partial discharge is characterized by the physical quantity that ...

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Problems solved by technology

[0004] The existing application number is 201010235704.9, and the title of the invention is "System and Method for Detecting Partial Discharge of Power Transformer Using Fluorescent Optical Fiber". The optical signal generated by partial discharge is used to detect partial discharge. This method has problems such as low sensitivity and inability to locate the discharge source. ; Chinese patent 201020302185.9, titled "Transformer Partial Discharge Optical Fiber Detection Device", uses acoustic emission technology to detect transformer partial discharge. This method has problems such as low sensitivity, easy to be interfered by external ultrasonic signals, and inability to measure apparent discharge volume; China Patent 201110266331.6, the name of the invention is "Fiber Bragg Grating-based Power Transformer Partial Discharge Detection System and Detection Method", which uses fiber Bragg gratings to detect transformer partial discharges. Since this method uses fiber Bragg gratings as the sensing unit, it is affected by the environment. The problem of large vibration impact is difficult to achieve application in the actual environment

[0005]In addition, the probability distribution of discharge signals and interference is generally not completely clear, and there are many interference factors in the actual environment that will interfere with partial discharge detection, resulting in false alarms

For example, a lightning strike in a thunderstorm will generate ultrasonic waves, resulting in false alarms from ultrasonic sensors

These uncertain factors reduce the reliability of the partial discharge monitoring system

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