Abstract :
This report gives directions for the application of the Schering bridge to the measurement of the power factor of the insulation of cables at power frequencies and at voltages up to 200 kV. Details are given in Appendices, of the principles of design of the air condenser recommended as a standard of reference, of subsidiary methods of power-factor measurement, and of the effect of wave-form. The standardization of the Schering bridge method, as described, is recommended, and full details are given of the elaborate precautions necessary for shielding the cable and apparatus. The standard method provides for the measurement of power factors of the order of 0.01 to an accuracy of 0.0001 at a frequency of 60 cycles per sec, and at voltages up to 200 kV. If one of the subsidiary methods is employed, the steps described herein should be taken to secure that the results agree with those obtained by the recommended standard method.
