A new method of congestion management based on power flow tracing

Nowadays, with the competition and optimization of resource's allocation being introduced into the power market, the problem of transmission congestion also emerges. In power systems, lines and transformers transmiss energy which is a comprehensive reflection of the active power and reactive power, thus the causes of congestion should include the active and reactive power. The results of sensitivity analysis method may be inaccurate because only the effect of active power is considered. A new congestion management method which considers the linkage characteristic of active and reactive power is proposed in this paper. When there exists congestion, the analytical relationships between the line power and generator outputs can be obtained by power flow tracing. Then the power vectorgraph could be made and congesiton can be eliminated effectively by adjusting relevant power components in four quadrants. The correctness and effectiveness of the new method can be verified by a numerical example.