PROBLEM TO BE SOLVED: To provide a digital type protection relay capable of preventing an error operation of a breaker which may be generated when performing a soundness confirmation of a breaker trip circuit.SOLUTION: A digital type protection relay comprising a soundness test function of a breaker trip circuit for a breaker operation provided to a power system, comprises: an opening/closing part that is serially connected to the breaker trip circuit and opens/closes a current path; a switching part that switches a first connection point connected to the opening/closing part to a second connection point or a third connection point on the current path when protecting the power system; a resistance element that is connected to between the first connection point and the second connection point or an electric power wire to which the breaker trip circuit is connected; a current detection part that outputs a detection signal when conducting a parallel current path to the switching part connecting between an opening/closing part end part opposite to the side of the switching part and the third connection point; and a control part that determines interruption/continuation of a soundness test on the basis of the presence of the detection signal when controlling a scheduled operation to the opening/closing part and the switching part at the time of the soundness test.SELECTED DRAWING: Figure 1
展开▼
