FTU is the abbreviation of "distribution automation terminal", also known as "feeder terminal equipment". Its main function in the power distribution system is to collect local AC measurement (such as voltage, current, power, etc.) (such as switch performance, etc.), and execute remote control commands (such as jumping and closing switches). The middle section of distribution automation is widely used in 10kV distribution lines, and can monitor load switches, sectionalizers, ring network contact switches, etc. The FTU can be installed on the outdoor wire pole, and can be used for single-wire control or double-wire control erected on the same pole.

(1) Remote signaling function. The FTU should be able to collect important state variables such as the current position of the switch on the pole, whether the communication is normal, and the completion of energy storage. If the FTU itself has a microcomputer relay protection function, it should also respond to the remote signaling of the protection action.

(2) Telemetry function. The FTU should be able to collect analog quantities such as the voltage of the line, the load current experienced by the switch, active power, and reactive power. Generally, the fault current of the line is much larger than the normal load current, and the dynamic range of the input current must be relatively large to collect fault information. The purpose of measuring the fault current is to carry out relay protection and judge the fault section. Therefore, the measurement accuracy is not high, but the response speed is required to be fast, and the fundamental wave signal must be filtered out.