Method for simultaneous measurement of current and voltage on high-voltage lines using optical techniques

Abstract

A laboratory device for the simultaneous measurement of current and voltage on a high voltage busbar has been constructed. A laser beam may be directed upwards from the ground to interrogate a passive optical transducer attached to a high-voltage busbar. Real and reactive power indications can also be obtained from the output, thus providing complete simultaneous information on the line state. The device uses a combination of magneto-optic and electrogyration effects in crystalline α-quartz. The latter effect has only recently been discovered and should lead to a device with small temperature dependence. The measurement transducer operates in a differential mode and the light beam passes through the quartz at a chosen angle to the optic axis. Quartz is a rugged material, very suitable for use in a transducer. A more highly developed version of the device should provide a convenient, portable, large bandwidth, research tool for diagnostic use. Eventual development could lead to an acceptable instrument for long-term operational use on the power system. Such an instrument would offer the advantages of considerably improved performance over conventional devices, at much lower cost.