Application Of Online Monitoring To Substation Alternating And Direct Current System

With the extending scale of Zhongshan power grid and the increasing demand forelectricity, the power system requires a high-quality AC-DC system in the substations. If afault in the AC-DC system cannot be found and eliminated in time, the relay-protectionequipments or the automatic equipments will breakdown, fail to react, or exceed to trip, whichimpacts the safety and stability of power system severely. The application of AC-DC onlinemonitoring system in substations realizes the compatibility and the unification of all kinds ofintelligent watching-devices in a substation, and the IED of different factories in the samesubstation can realize the inter-operating and information-sharing by using a standard protocol.This is helpful for the reliability of the automatic equipments in the substation. It can providesstable and economic operation of the AC-DC system in substation, and produces great benefitin both economic and social area by analyzing and digging the data run-out from the AC-DConline-monitoring system, abstracting effective information and knowledge, assisting themanagers and the operators in decision-making and daily-operation, and integrating the dataprovided from all kinds of factories using the specially-designed expert-diagnosis analyzingmodule.First，this paper expounds the current situation, existing problems as well as possibleeffect of monitoring and maintaining the AC-DC system in substations, with an introductionof design theory, structure, functions and real application interface of AC-DC onlinemonitoring system in the substations of Zhongshan Power Supply Bureau. Based on thecommunication protocols of IEC60870-5-103and IEC61850, the operating information suchas telesignal data, telemetering data, definite values and recorded data of different systemslike AC system, DC system, and UPS system are transferred to external communicationservers, and then to the AC-DC web server (or AC-DC monitoring master station) in themanner of FTP/Socket. In this way, the system achieves online monitoring, analyzing,diagnosing the operating information of the AC-DC devices, and an early warning for thehidden danger of devices comes true, which provides scientific evidence on condition-basedmaintenance for the operating department, and ensures the safety and stability of the AC-DCsystem in substations, acting as a “bodyguard” for the power grid. The new system, which based on a series of stages of investigating, developing,debugging, applying and summarizing has been already used in practical work and hasachieved result, will provide the foundation for further improvement in future.