Design and evaluation of a current differential protection scheme incorporating a fiber optical current sensor

The paper describes the design and operating performance of a current differential protection scheme that include a fibre optical current transducer (FCOT). Computer simulation techniques were used as the tool for carrying out the scheme modelling design analysis and performance evaluation. Fault current waveform encountered on a 33 kV distribution system and measured using the FCOT are used to evaluate the operating performance of protection scheme. The results are analysed and compared with those obtained for the protection tested using data derived from conventional CTs. Conclusions are drawn based on the advantages and disadvantages between FCOTs and CTs when used within a current differential protection scheme.