Application of voltage stability analysis in the South region of the Libyan transmission network

In sparsely connected power systems one of the most common problems detected is reduction of power transfer capabilities between the parts of transmission network related to the voltage stability problems. This paper presents one approach to analyze these problems using voltage stability analysis of current operating conditions of Libyan power system, specifically in the South region. There is a transmission corridor consisting of two 220 kV double circuits and one 400 kV transmission line interconnecting the South region with the rest of the system. The length of the lines is over 400km and there is no local generation in this region. Different operating conditions of Libyan transmission system were studied, by utilizing voltage stability tools in PSS/E software. This analysis has shown that the maximum power transfer is significantly less than the thermal capacity of the transmission corridor. The Q-V analysis showed that the Static VAr Compensator (SVC) of 300MVAr was recommended for installation in Sebha substation and a capacitor bank of 50MVAr in GMMR2 substation. The conclusion was that the significant increase of consumer load in the South area cannot be met with the existing transfer capabilities, even with 350MVAr of static VAr compensators. New transmission capacities or power generation in this area are recommended in case of a significant increase in consumer load.