Automatic testing and lifetime management of protection relays-an REC experience

The authors describe how the use of automatic testing within a Regional Electricity Company has enabled relay testing times to be considerably reduced. This reduction has been achieved by removing the `learning curve´ effect when new relays have been introduced and by providing software specifically written for each relay type. Testing errors and various test methods which previously produced incorrect fault simulation, particularly for distance protection relays, have been obviated. Experience gained to-date indicates considerable savings in revenue expenditure by reducing testing times and deskilling the testing procedures. The proposal to establish a central database for protection relay test results is expected to aid decision making in respect of maintenance frequency and relay life span