EPRI's Non-Contact, Portable Polyphase Current Sensor.

摘要

EPRI has been testing and evaluating a pre-prototype, non-contact, portable sensor that can remotely measure line currents flowing in a polyphase transmission line by means of measuring the external magnetic fields emanating from the line. The geometry of the power line is assumed to be known to an accuracy that can be readily determined from mechanical drawings with the exception that the vertical height of the power lines to ground will be considered to be an unknown. Presently, the system is designed to monitor only the 60 Hz component of line current. However, other harmonics of the fundamental power system and signals propagating on the power system could be readily obtained as well. The constraints on the final sensor system are that it must be field portable, setup time must be short (less than 30 minutes) with minimal setup tool utilization, accuracy should be better than 5%, and actual currents flowing through a transmission line cannot be used to calibrate the proposed sensor. To quantitatively evaluate the feasibility of the concept, the sensor was placed under a 230 kV transmission line that was instrumented at the nearby substation to measure 60 Hz current flowing through each phase. Our paper will describe in detail the sensor, the test setup, and the final results.