Application of FACTS to Enhance the Performance of Power System with Growing Wind Power Penetration

Abstract

Wind generation connection to a power system affects its steady state and transient stability. This effect increases with the increase of wind penetration in generation capacity. In this work, optimal location of FACTS devices is carried out by using genetic algorithm to cover the problem associated with wind penetration in power systems. The proposed method in this work is applied to the modified IEEE 39-bus system and to another higher wind penetration system as IEEE 9-bus system. First part of study in this thesis is for selection of suitable FACTS type and ranking method. Two methods of lines ranking are studied. The first one is according to the minimum voltage and the other method is according to the lines over load. Results show that TCSC with capacitive range is the best solution for this problem where it can keep the system operate without power, voltage and power angle limits violated. Also it reduces the total loss of the system which gives wind generator more spare to cover its generation variation. Also it increases the minimum voltage to acceptable limit which is considered as an improvement in voltage profile. Results also proved that the ranking according to the minimum voltage made better cost saving and better power system performance than the other method of ranking. After selection is carried out, another part (is to try to maximize the wind penetration of the system by using TCSC) is performed under several topologies of system on the first model of wind (the wind generator can be considered as a generator produces active power and generates reactive power within 33% of the active power). Three cases in the system are studied: system without change; system with reduction of the impedance of the lines connected to wind generator by 50% and system with the location of wind generator transferred to another location which has more interconnection with the network. Finally 100% increase of wind generation is done by another way, by adding new wind generator at the bus which has more interconnection in the system. Results show that optimal TCSC allocation with reduction of the impedance of the line connected to wind generator by 50% has increased the wind power penetration by 170 % of its normal generation without system parameter violated. It is also shown that multi location of wind generation, if possible, is better than wind generation penetration in same location. Other studies are carried out to increase wind penetration of second and third model of wind (a generator produces active power and doesn’t inject any reactive power to the network and a generator produces active power and consumes reactive power respectively). Results show that TCSC with capacitive range is the best solution for this problem. It can cover the required reactive power by the wind with keeping the system operates without power, voltage and power angle limits violated. Moreover, reactive power needed according to the grid code can be covered by using TCSC. Furthermore TCSC can carry out good cost saving in addition to the enhancement of operation of wind generator. Finally, in model 3 of wind, studies are carried out on modified IEEE 9-bus system which has higher wind penetration more than before, with change in reactive power injection to wind bus from the network. Results verify that TCSC with capacitive range is still the best solution for the problems associated with wind penetration.