The New Solid-state Limiting The Practical Study

Along with the expanding power network, the fault current has increased greatly. It will bring hidden troubles to the security, stability, credibility of the power system. Conventional current limiters gradually show their limitation and can't fit the request of high power quality. The fault current limiting technology has become a hotspot of fault protects research.This disquisition focuses on the topology of the transformer coupling solid state fault current limiter with bypass inductance. In this paper, through experiments on the model system and simulations, the author validates the correctness of hardware and software used by fault current limiter controller, design and realizes man-machine conversation system for fault current limiter, and expatiates on the effects taken by fault current limiter.First, the paper expatiates on the damages caused by faults and makes a summary on some existing FCL technologies. Then, the author experiments on the transformer coupling solid state fault current limiter with bypass inductance. In order to evaluate control strategy and working effects of the prototype, SFCL with bypass inductance in 10kV/500A/2500A(maximal virtual value of fault current),we design corresponding experimental model in 50V/1A/5A. Based the strategy, we have experimented on the model in different short circuit faults. The results of experiments indicate that the mixed-mode inversion and subsequent flow strategy ,used by SFCL ,not only limit the short circuit current to proposed level ,but also has many advantages ,such as that control method is simple and reliable ,fault types can be judged exactly ,the load of fly-wheel thyristors T7, T8 can be decreased to a low level in course of limiting or disconnecting short circuit current and so on. The third, the author introduces hardware and software design proposal of man-machine conversation system, including circuit design, the menu frameworks and serial communication. Finally, the author discusses the application of FCL in the power system. Using simulator software, characteristic of FCL affecting to voltage sags due to short fault is analyzed. In addition, harmonic effects and protection on asynchronous electromotor are appraised by simulation. The author then particularly analyses the locations a FCL may be set in the system and their function and correlative effects. Expressly, the author indicates that FCL is good for protecting the fault occurred on high voltage side of generator equipped newly in system.