Study On Discharge Detection Of High Voltage Electrical Equipment Based On Ultraviolet Signal

Nowadays human society needs more and more energy especially electricity with the rapid development of the national economy. However, the high voltage electrical equipment often occurs partial discharge phenomenon caused by the destruction of equipment insulation systems,which inevitably influenced by electric field, thermal field, mechanical stress, chemical corrosion and environmental conditions and other factors during the process of manufacturing, transportation, installation and operation of high voltage electrical equipment. According to the statistics, the insulation accidents are 1/3 of the total incidents of power system, only less than lightning strikes disaster. The main cause for the insulation deterioration of electrical equipment is the high-voltage discharge. Therefore, it is necessary to pay attention on discharge detection so we can discovery, location and treat the damage early, which has a very important practical significance in improving the safe and stable operation of power grids.The radiation mechanism of high voltage equipment discharge is discussed in detail in the paper. The paper summarizes and analyzes the characteristics of high voltage equipment discharge. It is summarized into electrometric methods and non-electrometric ones, mainly including pulse current method, ultrasonic method, infrared imaging method, ultra high frequency method, UV signal method based on the comparative analysis of both at home and abroad of high voltage electrical equipment discharge detection methods. Electrometric methods are vulnerable to some electric magnetic disturbance and have low sensitivity. The paper proposes a non-electrometric method: UV pulse method based on a solar blind ultraviolet sensor for the discharge detection, which effectively avoids the electric magnetic interference, but also eliminates the solar radiation as the external light interference. This paper has designed discharge detection system. The hardware system is mainly composed of photomultiplier tube(PMT) circuit based on a solar blind ultraviolet sensor:R7154, signal processing circuit(including the I/U conversion, amplification, etc.), the collection and storage circuit of discharge detection by using data acquisition card:USB_DAQ_PIC16F877_VO5, temperature and humidity acquisition circuit(using temperature sensor DS18B20 and humidity sensor DHT11), simulation and controlling discharge device of high voltage equipment, detection device platform, etc. The software parts of the system are designed for each hardware module to perform their respective functions. The data acquisition, storage and processing are realized by using LABVIEW and MATLAB. At last, this paper has designed a simple user interface.The validity of the UV pulse method system is tested by simulating the high voltage equipment discharge in the laboratory. The results show that the system can effectively detect the discharge, has a good sensitivity and accuracy. And the relationship between optical signal and the discharge signal is discussed. The detection system basically meets the design requirements.