Weak Link System Voltage Stability

Connection of power system is good for the economy of operation and the security of power supply, but it also brings challenge to the voltage stability problem. The heavy load needs to be transmitted in long distance, which adds the difficulty of maintaining the nomal voltage of the system. In networks of weak connections, power transformation would be caused by faults or repairs of system components and line switching, so would the reavtive power. It results in an easier voltage instability in power system which has weak networks and heavy power transmission. Now voltage stability problem in weak connection system arouses people's attentions more and more.The paper first studies the primary analyse method of static voltage stability problem such as continuous power flow (CPF), sensitivity analysis and eigenvalue structure analysis. And it introduces their theories, characteristics and their effects in voltage stability analysis respectively.Secondly, this paper analyzes the static voltage stability problem in view of Wenzhou network's weak connection situation. CPF is used to calculate the voltage stability margin index. Sensitivity analysis and the eigenvalue structure analysis are introduced to analyze the weak nodes and areas of the network. Finally, some control measures are introduced to enhance the safety and stability of the network.A method based on the genetic algorithm (GA) and CPF is proposed to calculate the system's maximum voltage stability margin index. It can also work out an integrated control strategy by calculate the optimum value of node voltages, SVC and ULTC, which is advantageous to propose the appropriate control measure of the system.