Pump pit alarm system

The utility model relates to the technical field of power plant safety, in particular to a pump pit alarm system, which comprises a probe mounted above a pump pit and suitable for transmitting sound waves into the pump pit and receiving sound waves reflected by a blocking surface in the pump pit so as to obtain a first height from the probe to the blocking surface in the pump pit; the blocking surface is a pump pit water surface or a pump pit bottom surface; the central control room host is in signal connection with the probe and is suitable for obtaining a third height from the water surface of the pump pit to the bottom surface of the pump pit; the first alarm is in signal connection with the central control room host and is suitable for giving an alarm when the third height exceeds a preset value; according to the technical scheme, the height information of the water surface of the pump pit is obtained through the probe, then the depth, namely the third height, of water in the pump pit is obtained through