Fault traveling wave collecting device and system for medium voltage distribution network

The invention discloses a fault traveling wave collecting device and system for a medium voltage distribution network. The fault traveling wave collecting device is provided with a low-speed phase voltage collecting circuit and a trigger circuit to detect whether a power transmission line is in fault or not at the sample rate of 2 kHz, and after the line is in fault, a high-speed traveling wave signal collecting circuit is used for collecting the current and voltage signal of the traveling wave at the sample rate of 1 MHz, and therefore, the device and the system can ensure high precision and high integrity for the traveling wave collection by ensuring high traveling wave sample rate, and at the same time, the requirements for the capacity of processing, storing and transferring data for the device are reduced, and the problem of the contradiction between the collecting requirements of high integrity and high precision of the traveling wave signal and large data size at the high-speed collecting speed in the prior art is solved. The fault traveling wave collecting system disclosed by the invention can utilize the multi-port traveling wave distance measuring method in the medium voltage distribution network, the problem of extremely complicated network of the power distribution network is solved, and the distance measuring precision of the traveling wave is greatly improved.