Voltage measuring equipment in power grids often requires capacitive voltage dividers to realize conversion of high voltage electrical quantities to low voltage signal quantities.The new floating-ground capacitive vol...Voltage measuring equipment in power grids often requires capacitive voltage dividers to realize conversion of high voltage electrical quantities to low voltage signal quantities.The new floating-ground capacitive voltage divider(FG-CVD)can eliminate original lumped capacitors and its supporting insulation structures by adopting precisely designed parasitic capacitance as a high voltage arm capacitor,which can greatly save cost and volume.However,the utilization of parasitic capacitance not only makes FG-CVD sensitive to external conductor interference,but also causes transient waveform distortion,especially when the connecting lead between the FG-CVD and high-voltage conductor is lengthy.On the basis of transfer characteristic analysis,this paper proposes a complete parameter design method for FG-CVD to improve stability of its transfer ratio under interference of the external conductor.Moreover,by establishing a wideband equivalent model with lead inductance,the transient waveform distortion problem of FG-CVD is well explained,and a resistance compensation scheme is also proposed to reduce ratio error.Finally,a 500:1 FG-CVD prototype with a measurement bandwidth of 2MHz is developed.Experimental results show the prototype has high accuracy in both power frequency and lightning pulse voltage measurement,and ratio error decreases from 20.33%to less than 1.3%.展开更多
基金supported by the Science and Technology Project of SGCC under Contract 5500-202140126A-0-0-00.
文摘Voltage measuring equipment in power grids often requires capacitive voltage dividers to realize conversion of high voltage electrical quantities to low voltage signal quantities.The new floating-ground capacitive voltage divider(FG-CVD)can eliminate original lumped capacitors and its supporting insulation structures by adopting precisely designed parasitic capacitance as a high voltage arm capacitor,which can greatly save cost and volume.However,the utilization of parasitic capacitance not only makes FG-CVD sensitive to external conductor interference,but also causes transient waveform distortion,especially when the connecting lead between the FG-CVD and high-voltage conductor is lengthy.On the basis of transfer characteristic analysis,this paper proposes a complete parameter design method for FG-CVD to improve stability of its transfer ratio under interference of the external conductor.Moreover,by establishing a wideband equivalent model with lead inductance,the transient waveform distortion problem of FG-CVD is well explained,and a resistance compensation scheme is also proposed to reduce ratio error.Finally,a 500:1 FG-CVD prototype with a measurement bandwidth of 2MHz is developed.Experimental results show the prototype has high accuracy in both power frequency and lightning pulse voltage measurement,and ratio error decreases from 20.33%to less than 1.3%.
