The utility model discloses a varistor resistance depressor carries out the integrated design with current limiting reactor with the transformer, moves mechanism controls reactor switching through fast switch and behaviour. The normal during operation of transformer, the reactor is in short -circuit state, and the transformer loss does not increase, when short -circuit fault takes place for the transformer, the circuit of reactor input transformer, the impedance that improves the transformer, restriction short -circuit current realizes independently adjusting the impedance, reduces short -circuit current and reaches the impact in fortune to the transformer, alleviates the burden of cut -offfing of subordinate's circuit breaker. The utility model discloses not only can be used to the transformer of new production, also can be used to simultaneously promote at fortune transformer short -circuit resistant ability and transform.