Simultaneous prediction of voltage and frequency stability based on game theory

Abstract

Disturbances in the power system may lead to changes in the Voltage and Frequency Stability (VFS) status since they have a lot of parameters in common. Therefore, it is critical to predict these two aspects of power system stability simultaneously, while appropriate protection operations can be taken to improve VFS status. Furthermore, the VFS assessments can be more accurate and faster by eliminating improper statuses in prediction. This paper proposes a novel method for predicting the VFS status using the online measurements of the weak bus based on the theory of Mixed Strategy Games (MSGs). In MSG, the voltage and frequency represent the players, while the stability status is considered as the players’ strategy. The Equilibrium Points (EPs), which are obtained from the strategies of the two players, are mapped once the system is subjected to the disturbances. Also, the strategies without EPs are excluded from the game. The probability of each of the players’ strategies is evaluated by drawing a game tree. Finally, the EP of the game with the highest probabilities is determined for two players to predict VFS using the Nash Equilibrium (NE). This method involves high levels of accuracy and speeds up real-time prediction using online measurements since it considers the interdependencies effect of these two aspects on each other, elimination of impossible status, certainty in choosing the best solution. The simulations are carried out on IEEE 14-bus, New England 39-bus, and 118-bus systems using MATLAB and DIgSILENT software. The obtained results are compared with the findings of other methods.