Study On Secondary Voltage Coordinated Control Based On Multi-Intelligent System

Along with the development of power grid and the problem of voltage stability, more and more attention has been paid to coordinated automatic voltage/var control. Voltage hierarchical control is an efficient way to coordinate the voltage control, and the control strategy for the secondary voltage control is the critical part of the voltage hierarchical control.Because the control devices of the secondary voltage control have devices of continuous regulation and discrete regulation, the improved discrete model for secondary voltage control system has been built firstly in this paper. Discrete regulation devices, such as on-load tap changers, have been added to the model. Taking into account the effect of the secondary voltage control regions and the departure value of reactive power control device terminal voltage, the model is more in line with the actual power system.This paper uses a new swarm intelligent algorithm--Bacterial ColonyChemotaxis (BCC) algorithm to solve the objective function of the improved control strategy for secondary voltage control.The simulation result shows that compared to the traditional secondary voltage control, this method can achieve great controlling effect by using discrete regulation devices such as on load tap change transformers. In addition, BCC algorithm can handle the issue of discrete variables, with fast convergence, high precision and low resource occupancy.BCC algorithm is easy to fall into a local optimal solution because of the over-reliance on group interaction.To solve the problem, this paper structures a newalgorithm--Bacterial Colony Chemotaxis algorithm based on multi-agent (MABCC)combined with the main features of multi-agent system (MAS). Through the competition and collaboration among the bacteria Agent, this algorithm weakens its dependence on the group information. As a result, the bacteria converge more accurately to the global optimal solution.Finally, this paper puts forward a coordinated strategy of secondary voltage control based on multi-agent used in emergency. The strategy can eliminate the over-limit voltage rapidly by coordinating controlling with the voltage control device of different response speed.The improved secondary voltage control based on BCC algorithm is used for corrective control in emergency. When the system is restored from a state of emergency, conventional secondary voltage control based on MABCC algorithm is been used. The simulation results show that the control strategy not only eliminate the over-limit voltage rapidly, but also makes the pilot nodes and over-limit nodes recover the reference value given by tertiary voltage control via conventional secondary voltage control.