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Shunt reactor with auxiliary winding system can compensate line capacitive reactive power and provide power for switching station. There is large air gap in the iron core, thus the coupling relationship between shunt reactor winding and auxiliary winding is weak. According to the special structure of shunt reactor with auxiliary winding system, equivalent circuit of shunt reactor with auxiliary winding system is researched in this paper. Shunt reactor with auxiliary winding system inter-turn protection based on zero sequence differential current is proposed, on the basis of fixed relationship between shunt reactor winding zero sequence current and auxiliary winding zero sequence current when fault occurred outside the zone. The conclusion of prototype protection device dynamic simulation test shows that this protection principle is current protection without voltage information and voltage transformer, and protection setting doesn’t need manual calculation work, and has high sensitivity for slight inter-turn fault.

This paper presents the impact of distributed generator (DG) accessing to distribution network on protective relaying at home and abroad, according to the current situation of experimental research analysis the necessity of test method research. Set up electromagnetic transient model of three common distributed power photovoltaic (PV), doubly-fed induction generators (DFIG) and permanent magnet synchronous generator (PMSG) on PSCAD/EMTDC platform; Set up physical model of three common distributed power photovoltaic (PV), doubly-fed induction generators (DFIG) and permanent magnet synchronous generator (PMSG) in dynamic simulation laboratory. Comparing simulation results of distributed generators electromagnetic transient model and physical model under the same fault conditions and control strategy, verified the validity of the laboratory physical model. On the basis of the physical model, construct dynamic test system to test protective relaying for distributed generators access to distribution network, which can realize closed loop for relay protection device from every manufacturer. At the same time test results laid the foundation for the improvement of the existing distributed power relay protection device and put forward the new principle of relay protection.

Testing the protection equipment on dynamic simulation test systems is very valuable not only for finding software bugs and design deficiencies of protection but also for performance and characteristics understanding. To strictly test different kinds of protection relay, the test systems must been designed carefully by selecting the connection and parameters of the system. The test items are designed specially for every kind of protection. This paper introduces some special technical requirements in China, and important test items for different protection schemes. Several ideas and algorithms of some protections are also compared in this paper, such as power swing blocking methods in line protection, current transformer saturation countermeasures in transformer and busbar protection, inrush currents, blocking methods in transformer protection, current transformer single-phase open detection methods, etc. Several problems appeared in the test and the reason of these problems are described and analyzed in this paper.