Study On The Control System And Experiments On Voltage Compensation Type Active Superconducting Fault Current Limiter

With the development of the society and the economy, demands to energy increased greatly have been leading to the rapid development of modern power system. Power systems are becoming more and more complex, and the short circuit capacity becomes a serious limiting factor to it. Once the amplitudes of short-circuit current exceed the interrupting capacities of existing circuit breakers, the fault cannot be cleared effectively, and the power equipments may be threatened seriously. In order to reduce the damage to the power system, a protection system to limit the short current to a safe level as quickly as possible is required. Among the proposed current-limiting technologies, SFCL, which has some merits, such as low loss, small volume, auto trigger and auto recovery, has been the current-limiting technical field's main research direction.The voltage compensation type active superconducting fault current limiter (SFCL) is composed of an air-core superconducting transformer, PWM converter and an energy storage module. This type SFCL makes use of the characteristic of the superconductor's high-density current-carrying capacity, and then the modern control theory and power electronics technology are adopted to achieve rapid response, flexible control and active current-limitation. This paper studies the proposed voltage compensation type active SFCL.In this paper, the parameter design of energy storage module and control system is studied, including the issues of theoretical analysis, the parameter design of energy storage module, the control system, performance comparison, prototype development and short-circuit test in a dynamic simulation power system.In chapter 2, the structure and principle of the SFCL are firstly introduced. The parameter design of energy storage module, the pulse-width modulation (PWM) converter, the Bi-Directional DC/DC converter and monitoring&control system are proposed in chapter 3 and 4.The author participated in the research on the SFCL supported by the 863 program, and took charge of power system short-circuit test-platform design, dynamic experiments. In chapter 5, the configuration of the SFCL and the test results are presented. In the dynamic simulated experiment of power system, the SFCL prototype can effectively suppress the fault current. In addition, there is no overvoltage during the current-limiting process.