Voltage Sag Assessment in Distribution System with Neutral Grounding Resistance by Methods of Fault Position and Monte Carlo Simulation

Voltage sag is one of the most common power quality disturbances in overhead distribution systems. The typical cause of voltage sag is faults or short circuits. The impacts of voltage sags depend on the magnitude of the voltage sag and clearing time of the associated protective devices. These two factors allow us to determine the depth and the duration of voltage sags. With reference on the ITIC curve, we can determine whether the sensitive equipment connected to the bus of interest is able to operate properly. Because the neutral grounding resistance can limit ground fault level, voltage sag events due to ground faults are expected to decrease. This paper presents voltage sag assessment in distribution system with neutral grounding resistance using methods of fault position and Monte Carlo simulation. The proposed method is tested with two 22 kV distribution systems of Provincial Electricity Authority (PEA).