The Research Of Distribution Network Controlled Series Compensation Device Control System

Thyristor Controlled Series Compensation is relatively mature and widely used as a technology of Flexible AC Transmission the System. By quickly and accurately controlling the size of the angle of the thyristor, in order to adjust the equivalent reactance flexibly for improving the performance of the power system. It is of great significance for the development of power system.Based on the reasons for economic benefits of high/medium voltage distribution system reactive power compensation far less than the low-voltage distribution lines, the research of reactive power compensation techniques applied to the distribution network has been a concern. At present, in order to improve the power quality of distribution network and reduce line losses, the parallel reactive compensation technology has been widely used in domestic power distribution system. However, due to the limitations of the line power flow control capability, resulting only in the node and its nearby areas have a significant compensation effect. Therefore, in the distribution network, the application of parallel compensation technique is not the only way to solve power quality problems. TCSC device of simple structure and low cost, It has many functions such as improving the trend of distribution of distribution lines, transmission capacity of distribution lines, and system transient stability, damping line power oscillations and the suppression of sub-synchronous oscillation. Therefore, application of TCSC in the power distribution system which will be further research.The paper described the development, research and application of FACTS technology and its TCSC technology, summed up the basic structure and working principle of TCSC, and analyzed the fundamental frequency impedance characteristics. Through the establishment of an accurate mathematical model of TCSC and the analysis of resonant point, derived the TCSC simulation curve of relationship between fundamental impedance and trigger angle a. The paper studied and analyzed the TCSC operating characteristics and temporary/steady-state characteristics, established the simulation model of the TCSC, and detailed Simulated and analyzed the steady state characteristics of the TCSC in the four work mode, the transient characteristics of capacitive range and mode switching process. The article described the control system of TCSC, summed up the layers of control strategies, and specifically described the impedance control strategy. By establishing impedance of the conventional PID controller model and combining with the fuzzy theory, the TCSC fuzzy PID impedance controller model is designed. By comparing simulation results, it is obtained:in response to a variety of impedance step command, compared with conventional PID control, fuzzy PID control has better tracking performance, smaller overshoot and faster response to prove the basic realization of the optimal control of the system.At last, the paper established two kinds of system simulation models of single phase/three phase power distribution power systems with excluding TCSC and containing TCSC, and detailed simulated temporary/steady-state process, in order to study the impact of the introduction of TCSC on the power system of the distribution network. Through modeling and simulation analysis, it can be obtained:TCSC can not only increase the transmission capacity of distribution lines, and have a significant role in damping power oscillations and improving system transient stability, and prove that it can meet the demand of distribution network of power system. At the same time, the summary of this paper points out the shortcomings which provides a reference for future in-depth study.