A study on the effect of distribution circuit loading on air conditioner motor stall using a real time simulator

It has been shown that high seasonal energy efficiency ratio (SEER) air conditioner compressor motors will stall during a voltage sag of 30 % or greater such as during a sub-transmission fault. When these motors stall, they draw two to three times their rated current and reactive power. The motor stall affects the entire power system beyond the duration of voltage drop of the fault resulting in a system-wide impact. This phenomenon is known as fault induced delayed voltage recovery (FIDVR) or slow voltage recovery (SVR). The FIDVR or SVR event is not only influenced by the air conditioner motor penetration but also by the voltage sensitivity of the load composition in the distribution system. In this study, the singlephase induction machine model that is available in the real time digital simulator (RTDS) is used to simulate the stall nature of these high SEER machines. This paper also addresses the effect of distribution system loads on FIDVR and analyzes the effect using RTDS. A group of the machine models are installed in a test power system along with constant impedance (Z), constant current (I), and constant power (P) load models to study the effect of these loads on the stall nature of the single phase induction machines.