Online voltage security assessment using multiple dynamic decision tree

Power system online dynamic security is assessed by data mining, which can provide decision-making guidance for system operation and prevent continuous system security problems. An online voltage security assessment algorithm based on phasor measurement unit (PMU) was proposed in this paper: by establishing the voltage security evaluation decision tree using existing grid offline database, and updating the tree according to the real-time sampled data regularly, the online dynamic decision tree was formed and the voltage security was monitored. In addition, using different attribute set, an alternative to build multiple decision trees instead of original single decision tree was introduced, which greatly improved the accuracy of decision tree classification and evaluation of the reliability. Using IEEE 57-bus test system, the multiple dynamic decision tree method and the model were presented. Simulation results show that multiple dynamic decision tree based on PMU is a kind of feasible method for online voltage security assessment.