An LCR Network for Current Limiting at Hundreds of kV and Tens of MHz

This paper describes an LCR network for isolating a HV power supply from the load in case of the latter sparking. Electromagnetic simulations analyze field distribution in a solenoid at different frequencies illustrating difficulty to build a current limiter (CL) capable to cope with hundreds of kV at MHz. As an alternative, CL in a form of an LCR network was designed and built in such a way as to provide close to uniform voltage distribution between the limiter components at high frequency. Circuit simulations of equivalent circuit were made along with electrostatics simulation for shaping the limiter electrodes, grading the field and optimizing parasitic capacitances. On the base of the simulations, CLs, 350-mm-long, 180mm in diameter, operating in oil were built. Laboratory tests allowed direct measurement of HV across CL, at subscale voltages. Longterm field operation confirmed the device reliability at voltages estimated at up to 350kV, 20MHz.