Research On The Installation Location And Fault Diagnosis Of SSFCL

The electric power industry is the basic industry of the national economy. The safe and steady operation of power system is an important prerequisite to maintain a sustained, rapid and sound development of the national economy and relates to social progress and people's living standards improvement. With the rapid development of China's electric power construction, large power grids' interconnection is in progress, electric power plants and dynamos' unit capacity is growing, low-impedance and high-capacity transformers are used more and more in low voltage distribution system. All of these cause power system short-circuit capacity and short-circuit current increasing year by year. What's worse, it is even more than the switching equipment breaking capacity. Large short-circuit current not only directly affects the choice and safe operation of electrical equipment and to the security and stability of power system. Therefore, it is significant to take effective measures for the purpose of limiting short-circuit current to a reasonable and low level. After years of research and experimentation, Zhejiang University proposed SSFCL which based on power electronic technology. SSFCL can quickly limit the steady-state short-circuit current to required level, meanwhile, it has many advantages such as fault isolation, network protection, power quality improvement and so on. Thus it certainly has a good application prospect.This paper theoretically analyzes the limiting effect when SSFCL is installed in different positions of power system and simulates combining with the actual structure and operation conditions of 220kV substation in Zhongshan power supply bureau. At the same time as electrical equipment, SSFCL itself may be also out of order in the running process. And in the event of failure it not only can not achieve the purpose of limiting current, but also affect the security and stability of the whole system. So it is necessary to study SSFCL running dynamic monitoring method and corresponding protection measures. This paper proposes an improvement scheme based on literature 1 which further reduces the monitoring points. It can achieve fault diagnosis and fault location by monitoring the current of DC inductance and a specific branch and analyzing current waveform's Fourier transform. This method can reduce monitoring points, get more concise criterions of fault types and has many other advantages when it is used to on-line monitor and diagnose SSFCL bridge arm fault.