New-Style Dielectric Loss of Transformer Bushing On-line Monitoring Apparatus

Abstract

Abstract Transformer bushing dielectric loss factor (tanδ) is the reaction of the important parameters of the capacitor-type bushing insulation condition, the online monitoring is an effective means to determine the insulation condition. A new-style on-line monitoring apparatus of dielectric loss is designed. An approach using IRIG-B code to implement high-accuracy synchronization sampling in different places, combined with Harmonic analysis method. RS485-bus is used to implement communication between monitoring apparatus and bushing IED is presented .The sampling control of ADS8505 is realized by EP1C6Q240I7 that embedded soft-core processors Nios II Field Programmable Gate Array devices. The Fast Fourier Transform (FFT) processing of the signals is realized by Digital signal processing (DSP) device TMS320F28335. The digital information is transmitted by RS485-bus from monitoring terminal to bushing IED. Testing results show that the monitoring apparatus can improve the measurement of dielectric loss greatly with regard to accuracy and stability compared with conventional equipment. It is very useful and worth to promoting.