Early warning and prevention of potential wide-area voltage instability problem

Nowadays, there is a must to operate the power system close to its security limit due to current economic growth and the difficulties to upgrade the existing grid infrastructure. With the sudden increment of demand, the voltage instability problem has become a main concern to the power system operator. Hence, methods for early warning of voltage instability are required to prevent the power system from a collapse. This paper describes the use of real-time voltage instability predictors for the load areas in the Tenaga Nasional Berhad (TNB) network based on measurement from Phasor Measurement Units (PMUs) placed at the boundary of the load center. The voltage instability predictor calculates the power margin and compares to the pre-set margin threshold. Finally, the stability of the system is based on the comparison between the margin and pre-set threshold.