Research Of Interconnected Fower Systems With Time Delay

Along with the rapid development of power industry, the degree of interconnection between the regional power grids is increasingly. The modern power grids have become the interconnected power system, which consists of many control areas. The realization of large scale power system interconnection, on the one hand, it brings a lot of benefits for the power system; on the other hand, it introduces time delay to the system. Therefore, in this paper, interconnected power systems with time delay is studied.Firstly, we give the concepts of interconnected power system and make a detailed introduction for control area, In addition, flat frequency control strategy^flat tie-line control strategy and tie-line bias frequency control are given. The mathematical expressions of frequency deviation and tie-line power switching deviation are derived under different conditions.Secondly, linear active disturbance rejection control technology (LADRC) is applied to deal with the time delay, which is transmitted from the control center to individual generation units based on the interconnected power system. The delay is time variable instead of constant time delay. LADRC can estimate real-time disturbance and compensate it quickly via making the two inputs from LESO synchronously. As a result of the active disturbance rejection controller needs to set a large number of parameters, more serious is the setting number of parameters will be very large in the multi area interconnected power systems. So the genetic algorithm (GA) is used for self-tuning those parameters, which can calculate the optimal value after several iterations. This method was applied to a single area and a four-areas power systems under deregulated. The results show that it can provide good control effect.Thirdly, in the actual process, the communication of the interconnected power system is packet transmission method. When the network node failure, it will cause the data packet dropout、disorder、nonresponse and other issues, the network communication delay will form. Based on these above considerations, we proposed a state space model on the networked interconnected power systems with time delay. This model completely descript the coupling and nonlinear perturbations, and also consider the time delay from plant to controller.