In power systems, Single-Line-to-Ground (SLG) faults are the most common type of fault. When a three-phase four-wire system supplied by an ungrounded synchronous generator is subjected to SLG fault.
What is transient overvoltage (Tov)?
Abstract: Transient overvoltage (TOV) is an important design consideration for interconnecting inverter-based generation resources to a four-wire distribution system.
During the fault and its recovery, AC transient low voltage and transient overvoltage (TOV) will occur in the sending‐end system. The TOV has the risk of triggering the disorderly off‐grid of the nearby renewable power generations. Besides, in a serious situation, it will threaten the power system to maintain a secure and steady operation.
Can external grounding transformers reduce overvoltage in inverter based systems?
Transient overvoltages during single-line-to-ground faults are often mitigated by introducing external grounding transformers in traditional synchronous generator based power systems. These external grounding transformers are relatively ineffective for mitigating overvoltages in inverter based systems.
What is a fast overvoltage protection mechanism?
Inverters, whether used for photovoltaic (PV) systems or energy storage facilities, typically include internal fast overvoltage protection mechanisms designed primarily to protect the inverter itself from damaging transients.
The TOV has the risk of triggering the disorderly off‐grid of the nearby renewable power generations. Besides, in a serious situation, it will threaten the power system to maintain a secure and steady operation. Therefore, the authors analyse the mechanism involved in the AC transient voltage during the AC fault and the recovery period first.
Similarly, Fig. 14(b) demonstrates the overvoltages when the load pf is 0.9 and the apparent power is 463 kVA. This yields an active power output of 416.6 kW, and a GLR of 1.2 if the inverter output is kept constant at 500 kW. The observed maximum overvoltage in these experiment was close to 29%.