Patent ID: 6927562

Claim:
A low voltage system for measurement of power factor to enable diagnosis of the condition of high power stand off insulators which include a roll of insulating material around a central HV conductor in a hollow rigid insulator body in a power system while the power system is in use and subject to full voltage, comprising: coupling means providing a capacitive voltage divider with a tap near the lowest voltage point on the conductor wrapped within the insulator structure, a ground connector and an external lower voltage connector proximate to the insulator surface; an intermediate voltage reduction circuit connected and spanning space between the lower voltage connector and an output terminal which carries voltage reduced to a computer compatible level, which output terminal is fixed in position spaced sufficiently far from the insulator and other high voltage associated parts to assure no danger to testing personnel taking measurements, which voltage reduction circuit is connected to the external connector of the coupling means for that one insulator and left attached to the external connector for use upon demand without disconnecting the tested equipment from service level HV; portable computer means connectable to the output terminal of the voltage reduction circuit and containing software to convert a received analog signal to digital and subjecting the digital signal to an AST Fourier transform analysis to produce an output signal representative of power factor.