Patent ID: 6433557
Filing Date: 2002-08-13
Classification: G01R,H02B

Abstract:
A partial discharge determination system for an electrical system which includes a conductor at a given voltage potential, electrical insulation disposed proximate said conductor, insulator capacitance in said insulation which conducts a partial discharge radio frequency electrical current and a power frequency current component:a sensor current transformer, said sensor current transformer having a sensor current transformer primary winding and a sensor current transformer secondary winding, said sensor current transformer primary winding having a sensor current transformer primary winding first end and a spaced sensor current transformer primary winding second end, said sensor current transformer secondary winding having a sensor current transformer secondary winding first end and spaced current transformer sensor secondary winding second end; a sensor capacitor shunt, said sensor capacitor shunt having a sensor capacitor shunt first end and a spaced sensor capacitor shunt second end; said sensor current transformer primary winding first end being connected electrically to said insulator capacitance in said insulator to conduct said partial discharge electrical current through said sensor current transformer primary winding; said sensor current transformer primary winding second end, said sensor current transformer secondary winding second end, and said sensor capacitor shunt first end being connected together electrically; a coaxial cable, said coaxial cable having an inner conductor, said inner conductor having an inner conductor first end and a spaced inner conductor second ends, said coaxial cable having an outer conductor, said outer conductor having an outer conductor first end and a spaced an outer conductor second end; said coaxial cable inner conductor first end being connected electrically to said sensor current transformer primary winding first end; a monitoring power frequency capacitor having a monitoring power frequency capacitor first end and a spaced monitoring power frequency capacitor second end; a monitoring radio frequency isolation transformer having a monitoring radio frequency isolation transformer primary winding and a monitoring radio frequency isolation transformer secondary winding, said monitoring radio frequency isolation transformer primary winding having a monitoring radio frequency isolation transformer primary winding first end and a spaced monitoring radio frequency isolation transformer-primary winding second end, said monitoring radio frequency isolation transformer secondary winding having a monitoring radio frequency isolation transformer secondary winding first end and a spaced monitoring radio frequency isolation transformer secondary winding second end; a monitoring choke coil, said monitoring coil having a monitoring coil first end and a spaced monitoring choke coil second end; said monitoring choke coil first end, and said monitoring power frequency capacitor first end being interconnected electrically with said coaxial conductor inner conductor second end; said monitoring radio frequency isolation transformer primary winding first end being interconnected electrically with said monitoring power frequency capacitor second end; a monitoring surge arrester, said monitoring surge arrester having a monitoring surge arrester first end and a spaced monitoring surge arrester second end; said monitoring choke coil first end, said monitoring surge arrester first end, and said monitoring power frequency capacitor first end being interconnected electrically with said coaxial conductor inner conductor second end; said monitoring radio frequency isolation transformer primary winding second end being interconnected electrically with said coaxial conductor outer conductor second end; a first signal representative of said partial discharge electrical current power frequency current component existing between said monitoring choke coil second end and said monitoring surge arrester second end; and a second signal representative of said radio frequency current component existing between said monitoring radio frequency isolation transformer secondary winding first end and said monitoring radio frequency isolation transformer secondary winding second end.