AEP System Research Articles

Frequency Actuated Load Shedding and Restoration Part I - Philosophy

During the last few years, there has been expanded effort throughout the country to install frequency actuated load shedding programs for the purpose of providing means to safeguard a power system should a condition of declining frequency occur. Hand in hand with a load shedding program a convenient means must be provided for restoring load after the system returns to a normal state. In this series of papers, the authors will present some of the basic principles which should be considered in the application of a load shedding and load restoration program and will describe the philosophy which led to the frequency actuated load shedding and load restoration program being implemented on the American Electric Power System. As part of this presentation, the various analytical studies which were carried out to determine the load management programs for the AEP system will be described in detail. In addition, the method of program implementation and management is presented in a companion paper.

American Electric Power 765-kV Transmission Line Project

In 1966 the design of a 765-kV transmission line network was instigated in the AEP System. This construction project was started in 1967 and is to be completed by 1972. The overall development, design, and construction features of this project, to date, are reviewed.

Field Tests on a 345-Kv High-Capacity Oil Circuit Breaker at Philip Sporn Power Plant

1. A 345-kv OCB rated 25,000, was tested extensively at the Philip Sporn Station of the AEP system for performance on both line-dropping and fault-interruption duty. 2. The full-scale tests demonstrated the adequacy of the breaker over an extremely wide range of fault conditions and for line-charging current-switching duty up to and beyond the present maximum lineswitching requirements of the AEP system at 345 kv. 3. The line-dropping tests were free of the high transient overvoltages which accompany severe restrikes. In 57 3 phase tests at currents up to 226 amperes, there were three single restrikes with maximum transient voltages lower than those accompanying normal fault interruptions. 4. Fault duty tests included singlephase as well as both grounded and ungrounded 3-phase faults, high-speed reclosing, and a 4-operation AEP reclosing duty cycle at fault duties between 1,160 and 13,380 mva. The tests confirmed the usefulness of field tests and inspired confidence in the results of laboratory tests previously reported.2 5. The field tests also demonstrated the more severe duty imposed on a circuit breaker by 3-phase ungrounded faults. Arcing times for 3-phase ungrounded faults were found to be approximately one half-cycle longer than for grounded faults because of the higher power-frequency recovery voltage across the first pole to clear. Because of the rarity of 3-phase ungrounded faults in service, it is the opinion of the authors that industry standards should recognize a longer applicable rated interrupting time for this type of fault for breakers intended for application on effectively grounded systems.