Analysis of Misoperation of Main Transformer Gap Protection in a 220kV Intelligent Substation

The successful application of smart substations in China's power grid makes the operation of the power grid system more intelligent and visualized. However, the high degree of information integration of smart substations, complex equipment principles, and incomplete related technical means have caused a certain degree of difficulty in on-site operation and maintenance. Based on the analysis of a 220kV smart substation main transformer protection maloperation accident, it is concluded two main factors that affect the malfunction of protection. On the one hand, professionals lack understanding of the principles and treatment methods of the equipment, and it is difficult to find some hidden faults on site. On the other hand, in the process of equipment maintenance, the method and degree of safety measures are difficult to be accurately mastered, and it is easy to cause hidden faults. All of the above have caused hidden dangers to the safe and stable operation of the power grid. This requires operators and maintenance personnel to have an in-depth understanding of smart substation technology, improve the reliability of relay protection operations, and accurately isolate grid faults.