Improving the power quality in real network by using fault current limiter and determination of optimum impedance by the proposed algorithm

Increasing development of interconnected electrical networks may result in increased level of short circuits in electrical transmission substations with regard to breaking current of circuit breakers and their related equipments. One of the appropriate approaches to tackle the problem is to use fault current limiters (FCL). In the present paper, through studying Yazd electrical network, we initially identify critical buses in terms of the level of short circuit current and try to resolve the problem by using fault current limiters. To this end, the optimum FCL impedance is calculated by the proposed algorithm through modeling the FCL in the network and determining the most suitable place for it to be installed, with the purpose of causing the highest reduction in level of fault current in all critical buses. Afterwards, we investigate the effect of installing the FCL on decreasing the level of short circuit current, changes in voltage level of buses at the fault time, and its role in improvement of power quality. Simulations are made in DigSilent software. Finally, the computational results are compared and evaluated by DigSilent software.