Fault detection for n phase electrical measurement - using two sets of metering one set of comparators and two sets of homopolar units

摘要

Electrical quantities such as voltage are metered for each phase of a system by a set of meters (A1) (A2) (A3). One set of check meters (B1) (B2) (B3) are also installed and comparators (CP1, CP2, CP3) check that both meters on each phase agree. A homopolar unit (HA) (HB) produces the vector sum of each set of meter readings and compares the result with preestablished values. Operation of a comparator (CP) for a particular phase together with operation of one homopolar unit for a particular set of metering identifies one meter uniquely as faulty. ADVANTAGE - Combination of comparators and homopolar units enables benefits of triple redundancy to be obtained with only two sets of metering.