Abstract. With the rapid development of the power electronic technology and control technology, the use of the IGBT, IGCT full controlled devices consisting of a voltage source converter (voltage source converter, VSC) in the DC transmission system has been widely used. However, rapid response of power electronic devices and control systems, protective properties of the AC system impact. Study of DC system in DC interconnected system on the protection of AC system effects have important theoretical significance and practical value. Based on the output characteristics in a comprehensive grasp of the AC distribution network protection, feeder automation and flexible loop network control device fault, in-depth analysis of its access to distribution network in different position, different types of fault when fault characteristics and the traditional AC power distribution of the difference between, on the basis of study the applicability of traditional AC distribution line protection strategy and improvement strategy.
IntroductionWith the rapid development of the power electronic technology and control technology, the IGBT, IGCT, full control type components of voltage source converter is widely used in DC power transmission system, and successfully applied in many fields, due to power electronic devices and the control system of the fast response should be, relay protection device of the AC system impact. Power system relay protection device is an important part of the power system. It plays an important role in ensuring the safe operation of the system when the system is in trouble and is not in normal operation. Therefore, it is of great theoretical significance and practical value to study the influence of DC system on AC relay protection device in AC / DC interconnected system. It is necessary to fully grasp the flexible loop network control device fault output characteristics based on the in-depth analysis of its access to distribution network in different position, different types of faults, the difference between fault characteristics and the traditional AC power distribution network, based on research on the applicability of traditional AC distribution line protection strategy and improvement strategy. The different control strategies of different topologies of AC / DC hybrid distribution network under various fault conditions are analyzed by literature [1-2]. The literature [3] in the AC side voltage occurs asymmetric fault, according to the characteristics of zero sequence current path failures in the system and put forward the fault system of positive, negative and zero sequence controller and the system active power control strategy. The literature [4] for converter station of the lock up period power module capacitor voltage gradually diverge and eventually lead to AC circuit breaker tripping problem, put forward the fault through the period, the converter is in a controllable state, to avoid the divergence of capacitor voltage, without the need to shut off the cross connect DC system, can immediately ...
