An intelligent monitoring and diagnosis system for 330kV oil-immersed power transformer

Power transformer plays a role of power transmit and distribution and is the key apparatus in power system. Monitoring and diagnosis system is of great importance for normal operation of power transformer. An online monitoring and diagnosis system referring to Dissolved Gas Analysis (DGA), Partial Discharge, winding Hot-Point Temperature, Core Grounding Current, Bushing Condition, Water in Oil, etc. is proposed in this paper. The collected data from monitoring devices, which are parts of Intelligent Electric Devices (IED), are sent to Primary IED according to IEC 61850 Protocol. The data can reflect status of monitoring devices in real time. Threshold values with the statistic method are used to decide whether the equipment is in good condition or not. Based on much useful information gathered in Primary IED, certain arithmetic is given to estimate real-time condition of power transformer. The arithmetic involves data preprocessing, pattern recognition, probability estimate of fault. This diagnosis system can provide not only separate diagnosis result which reflects the state of power equipment in one sense according to data given by different monitoring device, but also comprehensive diagnosis based on all data by different monitoring devices. Results indicate that it is comprehensive, accurate and effective than before.