Novel surge protection device

The invention relates to a novel surge protection device which mainly comprises a lightning protection element, a current sensor, a relay, a heat protection device, an over-current protection device, a current limiter and a housing. The lightning protection element is connected with the over-current protection device in series to form a surge discharge closed circuit; the heat protection device is positioned on an electrode of the lightning protection element; the current sensor is sleeved on the surge discharge closed circuit, and is connected with the relay; and a normally-open contact of the relay and the current limiter are connected in series and then connected to the two sides of the lightning protection element in parallel. The power frequency current flowing through the lightning protection element can be sensed by the current sensor, the normally-open contact of the relay is enabled to be closed, the power frequency current flows through the over-current protection device, and the over-current protection device is enabled to be switched off. According to the novel surge protection device, the problem of power frequency current protection dead zones of a protection device of a conventional surge protection device is effectively solved.