Systems and methods for measuring the integrity of insulation components in electrical systems. In preferred embodiments, an active sensor is coupled to a test tap of a bushing, the active sensor having an electrical circuit electrically coupled to the test tap, and wherein the electrical circuit includes a high pass filter that divides the electrical circuit into a high frequency bus and a power frequency bus. A grounded high frequency voltage is injected into the test tap via the frequency bus circuit. Resulting voltages and currents may be measured and compared to a reference voltage to determine capacitances and power factors for both the inner and outer sections of the bushing. Once the capacitances and power factors of the bushings are known, grounded and ungrounded high frequency voltages may be injected to determine capacitances and power factors of a connected transformer or reactor.