Novel control of a PV solar system as STATCOM (PV-STATCOM) for preventing instability of induction motor load

摘要

This paper presents a new control of PV solar system as a STATCOM, termed PV-STATCOM, for faster post-fault voltage recovery, thereby avoiding the voltage instability of a neighboring critical induction motor load. Distributed Generators (DGs), such as PV solar systems, are typically required to disconnect upon detection of fault according to the current grid code of DG interconnection. Although, the preferred industry trend is to allow them to remain connected with Low Voltage Ride Through (LVRT) capabilities. In this paper, a case study is presented where an induction motor close to a PV solar system becomes unstable due to slow post fault voltage recovery. A fast fault detection control strategy is utilized in the PV solar system to disconnect the PV solar panels and convert the PV solar system inverter into a STATCOM, thereby providing rapid reactive power support to stabilize the voltage. This novel control strategy of utilizing the PV solar farm temporarily as a STATCOM after the fault prevents a critical induction motor from becoming unstable.