Study On Fault Diagnosis And Condition Assessment For Process Layer Of Smart Substation

With the large-scale construction of smart substations, operation and maintenance technology of substations face new opportunities and challenges. On the one hand, smart substations use intelligent secondary equipment, and adopt fiber-optic connections. Compared with traditional substations, the use of intelligent devices and fiber-optic can facilitate the realization of on-line condition monitoring, which has laid a good foundation for fault diagnosis and condition assessment of the protection system. On the other hand, traditional substations use cables for secondary system connections, which is clearly, independent, and easy for troubleshooting. In smart substations, the information transmission is highly integrated, making the maintenance relatively complex. From the operation perspective of smart substations, the vast majority of the faults occurs in the process layer, and there is no corresponding fault diagnosis methods.Meanwhile, with the rapid development of economy, the society demands increasingly high reliability of power supply. At present, a condition based maintenance of primary equipment has been developed to a higher level, while the secondary equipment started relatively late and its development is relatively slow. Therefore, the innovation research is needed from the aspects of maintenance, equipment, technology, strategy, mode, etc. so as to adapt to the rapid development of smart substations. Now, it is urgent to propose a fault diagnosis and condition assessment scheme for secondary equipment of smart substations.This paper aims at studying on the technology of rapid fault diagnosis in process layer of smart substations, putting forward a method for fast fault localization, improving the efficiency and quality of troubleshooting, and shortening the power cuts. At the same time, it is essential to realize accurate condition assessment and scientific maintenance decision-making, to deepen the condition based maintenance of smart substation relaying, and to maintain the safe and stable operation of smart substations.The main contents of this paper include:An on-line rapid fault diagnosis system of smart substations is designed, which realizes the condition monitoring of merging unit, intelligent terminals and relaying devices, and the on-line monitoring of the physical and logical loops. Through the condition monitoring of relay protections and its related devices and on-line monitoring of the secondary loops, the on-line fault diagnosis and localization of process layer is achieved.An off-line rapid fault diagnosis system of smart substations is designed, which adopts separate hardware. The detection terminal is used for fault analysis, loop generation and maintenance, results analysis, signal display, loop display, loop editing, and database maintenance. And the access device is used for network signal detection, facilitating the equipment installation and network debugging of smart substations. This system is easy to operate, and has good scalability and flexibility.The classification of smart substation condition information is studied, condition data of traditional and smart substations is compared, and additional condition information of smart substations is extracted. Meanwhile, the method of condition assessment of smart substations is proposed, and its mechanism and result are introduced.The application of this research in Ji’nan power grid has proved its practicability and availability.Research and implementation of this project takes advantage of the condition on-line monitoring of smart substations, to solve some of the problems of fault diagnosis and localization of process layer and sums to form a set of smart substation condition assessment system, which is conducive to implementation of the condition based maintenance of smart substation secondary equipment.