Master-slave fiber optic current sensors for differential protection schemes

摘要

A master-slave current sensor system for measuring, for example, differential current on a transmission line is described. The slave current sensor can be periodically recalibrated (or have a compensation value re-calculated) based on the master sensor's average output, and the slave sensor can be unpowered and remote from an electronics box which receives its measurements. Health monitoring and fault location can also be performed using the master-slave optical current sensor system, optionally in conjunction with one or more voltage sensors.

主权项

1. A method for measuring differential electrical current in a transmission line using master and slave current sensors, the method comprising the steps of:
measuring a first electrical current value at a first location of said transmission line using a master current sensor; measuring a second electrical current value at a second location of said transmission line using a slave current sensor, wherein at least one of said master current sensor and said slave current sensor is an optical current sensor; determining said differential electrical current based on said first electrical current value and said second electrical current value; and recalibrating an output of said slave current sensor based on an output of said master current sensor, wherein said step of recalibrating further comprises:
recalibrating said output of said slave current sensor by multiplying said output of said slave current sensor by a ratio of an average output of said master current sensor to an average output of said slave current sensor.