Some Engineering Features of Petersen Coils and Their Application

Service experience with Petersen coils on transmission systems and networks in this country has demonstrated conclusively certain facts concerning these protective devices which may be stated as follows: 1. There is definitely a place for Petersen coils in American system-protective practice. 2. The Petersen coil will prevent the interruptions to service usually associated with transitory flashovers to ground. 3. The Petersen coil may be applied to any system insulated for full neutral displacement. 4. Petersen coils do not lose their effectiveness if used on a system when different sections are switched out of service unless the system capacitance is changed more than 25 to 30 per cent. 5. Surges during switching operations encountered on the first Petersen-coil application have not recurred in later applications. 6. By the use of Petersen coils, it is possible that from 70 to 80 per cent of all faults may be cleared without the opening of a single oil circuit breaker, and without any dip in the phase-to-phase voltage, thus improving system stability and service continuity.