Application and analysis of power supply fast switching device in gas purification plant substation

Author of the article:ZHU Tao1, CHEN Junhong1, XING Pengfei2, ZHU Wei1, XU Wenqiang1, LI Tao1

Author's Workplace：1. Northwest Sichuan Gasmine of PetroChina Southwest Oil and Gasfield Company, Jiangyou, Sichuan, 621700, China; 2. PetroChina Southwest Oil and Gasfield Company, Chengdu, Sichuan, 610017, China

Key Words：Single bus; Separate operation; Voltage loss startup; Fast switching; Synchronous capture switching

Abstract：The substations of natural gas purification plants often utilize dual circuit power supply and single bus segmented wiring. The usual operation mode involves one power supply with one transformer for operation, and the other power supply with another transformer for hot standby. The power supply switching commonly utilizes power supply fast switching devices. On December 20, 2021, when the differential protection of the 35 kV main transformer in a natural gas purification plant tripped, the power supply fast switching device failed to operate, resulting in an 11-minute power outage in the purification plant substation. This led to an unplanned shutdown of the natural gas purification plant and significant economic losses. By studying the operation principle of the power supply fast switching device, checking the wiring and setting value of the power supply fast switching device in the substation, it is found that the secondary circuit wiring terminal of the standby power supply incoming line voltage transformer of the power supply fast switching device was loose and improperly connected. This resulted in a low measurement voltage of the standby power supply incoming line, causing the power supply fast switching device to misjudge and fail to operate. Additionally, the research found defects in the wiring of the incoming voltage transformer and the functionality of the power supply fast switching device in the substation. A transformation scheme was proposed to optimize the wiring of the voltage transformer and improving the functionality of the power supply fast switching device. Through the analysis and application research of power supply fast switching device failure accident, this study can guide the management of operation and maintenance of substation automation devices, improve the accuracy of the 35 kV substation automation device operation, and enhance the reliability of power supply in natural gas purification plant.