Impact of delayed fault clearance on the load in Indian Power System

Induction motor loads constitutes the major portion of the various types of the loads in any of the power grid across the world. Various control modes of induction motor along with its speed variability based on the slip provides its usage for versatile application. However, these induction motor based loads are affected by the voltage observed at their node during the constant torque mode due to their inherent characteristic. Such loads tend to stall/stop during voltage dip observed in the system. During any severe fault near to load centers with voltage suppression, a large amount of these load stall/stop as per their characteristic resulting in loss of a large amount of load from the grid. Further, they also recover quickly after the clearance of the fault by drawing large reactive power and current from the system causing delayed voltage recovery. Such phenomenon is also called as fault induced delayed voltage recovery in power system. These events are further accentuated under the condition of delayed fault clearance. This paper presents various such case studies on the impact of delayed fault clearance on the load in the Indian Grid.