High-Voltage Bridge for Measurements of Cables with Grounded Sheaths

This paper describes a bridge that is adapted to making dielectric measurements of cables whose sheaths are in electrical contact with the ground. A balance to adjust the bridge to the system losses to ground is first made with the test cable disconnected; the bridge is then balanced with the test cable connected. The cable properties such as power loss, power factor and capacitance are then determined directly from this bridge balance. Certain precautions, however, are necessary such as the method of substituting the test cable in circuit and the elimination of the ground currents which may come from the low-voltage system.