Development of the 10 kV Wideband Combined Resistance-capacitance Voltage Divider Unit

Overvoltage monitoring is very important to analyzing the cause of the accident and improving the design technique for the insulation coordination. The wideband combined resistance-capacitance divider is a suitable sensor for these jobs. Normally, a high-voltage divider is composed of several divider units in series. Thus, the divider unit is the base for the development of voltage divider with high-voltage level. In this paper, based on the classic structure of combined resistance-capacitance divider, a 10 kV (under ac voltage) wideband voltage divider unit was developed. A series of resistors and capacitors with low temperature drift characteristics was chosen to form the high-voltage arm, and a PCB board with resistors and capacitors was used to make the low-voltage arm to limit the stray circuit inductance. The developed voltage divider unit had been tested under dc voltages, ac voltages, lightning impulse voltages and step voltages. The test results indicated that the voltage divider unit has a wide bandwidth covering from dc to approximately 3 MHz. This voltage divider unit will be the basic for developing the wideband voltage divider with a rated voltage of 100 kV and above.