Optimal Power Flow for Reactive Power Compensation Increasing the Cross-Border Transmission Capacity

Increasing the Net Transfer Capacity (NTC) of tie-lines between different grid areas may lead to a decrease in the cost to generate electricity in one area if this cost is more expensive than the cost of importing power from neighbouring areas over those tie-lines. An effective means to increase the cross-border transmission capacity is by installing reactive power compensation devices. In this paper, a multi-objective optimization is devised that optimally locates and sizes reactive compensation devices in a grid, so that the net benefit of increasing the NTC value of a tie-line is maximized and the maximum voltage stability indicator (L-index) in the grid area is minimized, indicating there is enough voltage stability margin. The genetic algorithm NSGA-II is implemented to perform the optimization. The IEEE 30-bus and 14-bus test grids are used as two interconnected areas.