163 / 2018-08-27 10:51:00

Study on Ultrasonic and UHF Combined Detection Method and Gas Production Characteristics of 220kV GIS Equipment Vibration Fault

ultrasonic detection method,UHF detection method,GIS equipment,vibration fault,gas production

GIS (Gas Insulated Switchgear) equipment has the advantages of safe and reliable operation, small size, long maintenance cycle and strong environmental adaptability, which is widely used in power grid. At present, the voltage level of GIS is getting higher and higher, and the volume is getting larger and larger. It has been widely used in UHV power grid. In order to ensure the stable operation of gas insulated combined electrical appliances, it is necessary to study and predict the detection methods of potential faults in GIS equipment. There are two main sources of GIS failure: first, the installation or improper operation of GIS equipment will lead to serious failure. Secondly, the long-term high-pressure environment of GIS equipment will lead to material deterioration. In the actual operation of GIS, besides discharge fault, mechanical fault is also a major cause of the accident. The long-term vibration of GIS results in bolt loosening, leakage, insulation accidents, damage to insulators and insulating columns, which affect the firmness of the shell grounding point. Once an accident occurs, it will cause large-scale blackouts, causing irreparable huge losses to the grid. Therefore, it is of great significance to strengthen the research on the mechanical fault detection of GIS to ensure the safe and stable operation of GIS and power grid.
In this paper, the characteristics of mechanical faults of 220 kV GIS equipment are studied and analyzed. The ultrasonic and ultra-high frequency characteristics of vibration signals, gas production characteristics was analyzed. Ultrasound detection showed that the effective value of partial discharge was 20 mV, the peak value was 56 mV, the correlation value of 50 Hz was 1.1 mV, the correlation value of 100 Hz was 2.4 mV, the maximum value of signal was located near the hand hole cover of C phase PB tank, and the detection pattern had vibration characteristics. No discharge characteristic was found in UHF partial discharge detection, and no discharge characteristic gas was detected by component detection of SF6 gas in this chamber. The above information suggests that there may be mechanical vibration defects. The vibration of the chamber may be caused by metal loosening. The maintenance personnel opened the warehouse for the 221PB C tank and found that the molecular sieve cover was loose. This case shows that the ultrasonic partial discharge detection technology in GIS can effectively detect the vibration defects in the GIS equipment. The comprehensive judgment and consideration are made by combining the ultra-high frequency partial discharge detection technology in GIS with the SF6 gas component detection technology and other live detection methods, which can provide more basis for the diagnosis and treatment of the internal defects in GIS.
Analyzing the characteristics of mechanical characteristics W and shell vibration signal in GIS is helpful to the research of mechanical fault detection and diagnosis in GIS. It can also be used as a reference for discharging faults. It provides a basis for condition-based maintenance of substation GIS equipment and improves the safety and stability of GIS equipment operation. The results of this paper provide an important guiding significance for the on-site use of ultrasonic discharge fault detection, and provide an important reference for the future analysis of typical defect spectrum for on-site test results.