Phase failure alarm device

The utility model provides a phase failure alarm device for electric power substation, which comprises a casing, a three phase power supply switch, a power indicator, a phase failure alarming fault display device, a fuse plug, a capacitance, an alarm lamp and an alarm electric cell. The phase failure alarming fault display device and the alarm lamp are arranged on the casing; other devices are arranged in the casing; the incoming line of the power switch is 380 V alternating current three-phase power supply of the quadratic side (low voltage) of a transformer; the lower side of the power switch is connected with the power indicator and the phase failure alarming fault display device. Three fuse plugs and three capacitors are respectively connected with the three phases in the phase failure alarming fault display device in series. The three phases in the capacitor are connected into one point. The neutral point of a three phase power supply system is led out; the lower side of the neutral point is connected with the alarm lamp. An electric bell is connected in parallel beside the alarm lamp. The indicating lamp is grounded with the other side of the electric bell. The electric power substation phase failure alarm device can rapid and accurately judge the fusing failure of the fuse plug of a voltage mutual inductor or the phase failure accident. As the power supply of the phase failure is taken from the quadratic side of the transformer, monitoring can be carried out on the three phase winding of the transformer. After the winding of the transformer breaks, the alarm device can also alarm.