Voltage Stability Assessment of Dubai Power Grid Using a Detailed Load Model

Abstract

Voltage stability problem has become one of the major concerns for power utilities in recent years. This is due to the exponentially growing demands and the associated stress on the power transmission resources. Moreover, voltage instability has been responsible for severe network collapses world-wide and subsequently, the possible threat of voltage instability is becoming more pronounced in power utilities. Dubai Power Grid is undergoing similar circumstances. The increased stress on the power resources in addition to the high proportion of motor driven loads, embedded in Air Conditioning (AC) appliances, have raised the necessity to assess the voltage stability of Dubai Power Grid. During large system disturbances, the transmission system voltage can fall below a critical threshold, resulting in induction motors stalling or tripping depending on several factors such as motor type, size and control. The severity increases during peak load conditions, when the system load is dominated by AC appliances. Recently, Dubai Power Grid had experienced several system disturbances that were accompanied by small/large voltage variations. These variations were followed by inadvertent disconnection of load. The existing Dubai Power Grid load model is not capable of reflecting the actual system behavior following the experienced disturbances. Having an accurate load model capable of capturing load behavior during system disturbances is crucial in voltage stability assessment. This thesis presents a detailed load model for Dubai Power Grid and validates it against recorded disturbances. The updated load model will be used to assess voltage stability margin against the increasing use of power transmission resources, growing demand and associated stress on available and planned active and reactive power resources.