Explore the Limit Operation State of Power System by Optimal Power Flow Calculation

In order to explore the limit operation state of power system by optimal power flow (OPF) analytical tool, the complicated OPF model considering fuel cost and valve-point cost of generators is constructed, and a heuristic intelligent optimization algorithm, called human learning optimization algorithm (HLO), is employed to solve the OPF problem under different conditions. For one thing, we explore the limit operation state by expanding maximal times of load; For another, based on the solution obtained by HLO algorithm under the limit operation state, some comprehensive information can be referenced for other algorithms to also find solutions, such as particle swarm optimization algorithm (PSO) and genetic algorithm (GA). Simulation results show that HLO algorithm has the advantage of convergent property compared to PSO and GA. It is feasible way to obtain a more secure, stable and economic operation mode under the limit operation state by adding shunt capacitor on the vulnerable node, where amplitude of node voltage is close to the security constraint boundary, and by increasing capacity of transmission line, where congestion occurs on some line branches.