Study on High Frequency Capacitance of Coupling Capacitor Used in Carrier of Power Transmission Line

摘要

The high frequency capacitance of coupling capacitor with various dielectrics was studied in theoretical analysis, calculation and experiment. The experimental results show that the high frequency capacitance of coupling capacitor increased with the proportion of the non-polar dielectrics content in the capacitor increased in case the structure and inherent inductance of coupling capacitors were one and the same, and the high frequency capacitance might be as 150% high as the rated capacitance when the frequency being at 500kHz. However, when the dielectric of coupling capacitor is the paper/film complex, the high frequency capacitance will not be as 80% low as the rated capacitance at the working temperature range suggested in IEC358 and JB8169-1999. Based on the results acquired by the theoretical analysis, calculation and experiment conducted, it is suggested that the dielectric system with full pp (poly propylene) film immersed, in non-polar liquid dielectric does not satisfied with the requirement for the design of coupling capacitor for the carrier used in power transmission line.