Effect of Prime Mover's Characteristics on the Survivability of a Synchronous Generator-Based Distributed Energy Resource During Transient Overload Conditions

Recently, prime-mover stalling phenomenon was observed in a synchronous generator-based distributed energy resource (DER) for large step load changes during experimental testing at the Consortium for Electric Reliability Technology Solutions Microgrid. It is found to highly impact the generator's survivability during transient overload conditions. The stalling occurs in synchronous generator-based DER because of a sustained imbalance between electrical load demand and mechanical power available from the prime mover, thus depleting the generator's stored kinetic energy. In particular, mechanical power capability of the prime mover and stored kinetic energy in the rotating mass are the causal factors. This article evaluates two different types of prime movers-reciprocating engine and combustion gas turbine-for the DER survivability. The characteristics of these two commonly used prime movers are investigated during transient overload conditions by simulation case studies using PSCAD/EMTDC software.