Limitations of current limiting protectors for expansion of electrical distribution systems

Application of current limiting protectors (CLPs) has been recommended in the existing literature to retain underrated medium voltage circuit breakers of lower short-circuit ratings in service, when the distribution systems are expanded and the short-circuit currents increase. However, the existing published literature does not describe the limitations of CLPs from system separation and loss of protective device coordination conditions, nor does it provide an analysis of short-circuit duties of medium voltage circuit breakers used with CLPs. The paper shows how these evaluations can be carried out. Considerations of high cost of replacements, the far greater loss of production due to lack of coordination and availability of a proven alternate solution should be included in an informed decision to use CLPs. `CLP´, `triggered fault current limiter (TCL)´, `CLIP´, and `I_s Limiter´ are synonymous