Research On The Method Of Electromechanical Transient Simulation Based On Power Network Partitioning

As the scale of power network is dramatically expanding, the difficulty of power system transient simulation has been gradually improving. Therefore, it is significant for modern power system to study on the method of electromechanical transient simulation based on network partition. The deep study and analysis has been worked for the method of electromechanical transient simulation based on constant-impedance type loads with two partition algorithms which are region segmentation and generator-net partition, respectively.A generator equivalent model for power system electromechanical simulation has been built by numerical integration method based on the generator practice model. The variables of the equivalent model are terminal voltage and current of the generator. The admittance in the equivalent model is related to the power angle in the x-y coordinates, which makes the coefficient matrix of the network change due to the power angle leading to the increase of calculation. Therefore, a generator approximate equivalent model which is has been built in order to eliminate the effect of the change of the admittance in the generator equivalent model and deduce the calculation.The generator-net partition algorithm for electromechanical simulation has been proposed based on the power network with constant-impedance type loads. Power system is divided into generator subsystem and net subsystem which is constituted with constant-impedance type loads, through the incision on generators and power network. A simple net model has been built by the equivalence algorithm of linear network based on the net equation. The algorithm of interconnect power system has been studied respectively based on that the net model collocates the generator equivalent model and that the net model collocates the generator approximately equivalent model.Region segmentation is partitioning the power system by splitting node method considering the regional characteristics of the power system. Region subsystems are made up with generators and constant-impedance type loads. The equivalent model of subsystem has been built by equivalence algorithm of linear network combining the generator equivalent model and the generator approximate equivalent model. Further on, electromechanical simulation algorithm of the interconnect system has been proposed.With the case of the New England 39 bus system, the equivalent models and the algorithm of the interconnect system which are respectively used for generator-net partition and region segmentation have been simulated constituted by constant-impedance type loads, and the results of the simulation have been analyzed. The equivalent models and the algorithm of the two partition method have been simulated under different fault types in the case and the result s of the simulation verified the validity and effectivity of the proposed models and algorithm. Additionally, the simulation results of different integration steps ha ve been analyzed and they show that the proposed models and algorithm have the satisfactory simulation stability and are easily used for parallel calculation.