Research On Partial Discharge Detecting Of Power Transformers Based On Optical Signal Characteristics

When the power transformer operate, internal partial discharge phenomenon might be lead to the transformer fault. Therefore, the detection of partial discharge during the transformer operation becomes extremely important. Optical detection method is a non-contact direct of partial discharge detection method rising in recent years which is directly determine partial discharge failure by analyzing the discharge process of the optical signal.In this paper, the different types of discharge in transformer was simulated based on the establishment of the real transformer fault model.The optical partial discharge detection system(OPDS) was established based on optical sensors in the shielded room for capturing optical effects of partial discharge. UHF method was used to comparative analysis with optical partial discharge detection system. In this research, partial discharge signal produced by the applied voltage to the surface discharge,suspended discharge and point discharge three typical defect model, two interference analog signal sources was simulate optical PD online monitoring interfering signals. The research findings conclude that:(1) The OPDS had a good consistency with UHF system. OPDS could be used to detect the emergence and development of internal partial discharge of transformer. OPDS could be used for on-line monitoring in the process of operation of the transformer device.(2) Discharge point number and energy acquired by the OPDS which could visually determine internal transformer partial discharge generation and discharge strength.(3) Compared with UHF system, the OPDS has higher sensitivitymeasurement and anti-interference ability.(4) When the discharge phenomenon stabilized, the phase of surface discharge mainly between 60°~150°and 240°~330°, the phase of suspended discharge mainly between 260°~320°. According to the phase characteristic of discharge pattern, the creeping discharge and suspended discharge phenomenon of transformer can be distinguished. It laid the foundation for the application of transformer optical partial discharge detection technology.