POWER LINE IMPEDANCE DETERMINATION USING THE 'THREE VOLTMETER' MEASUREMENT METHOD.

One of the problems associated with power line filter specifications is adequate knowledge of the source impedance into which the filter should be designed. In order to establish an average impedance with high and low bounds, a number of measurements have been made at various Navy installations. The procedure used to determine source impedances utilizes an adaptation of the three voltage method. A known impedance is placed in series with the desired impedance and a measurement voltage, tuned to the test frequency of interest. The magnitude of the impedance is found by comparison of the voltages across the known and unknown impedances. Phase information is obtained by construction of a vector diagram made up of the voltages measured across the known and unknown impedances and the measurement voltage. Author