Analysis of Turn-to-turn Short Circuit Magnetic Field of Dry-type Air-core Reactor

Reactor is a very important primary high voltage installations in power system, which is mainly used for limiting short circuit current, reactive power compensation, filtering out high-order harmonics and so on. Dry-type Air-core Reactors (DAR) are extensively used in power transmission lines because of their simple structure, low loss, easy installation and maintenance, and many other advantages. They are generally installed outdoors and have a harsh working environment, which is prone to serious accidents such as fire caused by inter-turn short circuit fault. Therefore, it is very important to con-figure a highly sensitive rapid detection system to detect the abnormal state of the reactor and take measures in time. Firstly, the structure of the DAR and the equivalent circuit model (ECM) under normal and interturn short circuit are analyzed. Then the simulation model of the DAR is established by using finite element software, and the change of the whole magnetic field inside the reactor is simulated and analyzed. The simulation results indicate when the reactor is short-circuited between turns, the magnetic field at the fault location will be distorted, and the overall distribution of the magnetic field inside the reactor will change, which will affect the stable operation of the reactor. The change of magnetic field can be used as the criterion to detect whether the reactor fails, so that the reactor can run safely and stably.