Good explosion-proof performance, advanced technologies, stable and reliable protection performance, compact structure, easy for maintenance and overhaul.

The overall structure of the protective case consists of the explosion-proof chamber and wiring chamber.

1. The explosion-proof chamber consists of the front door, chamber, rear explosion-proof flange and so on.

a) The Chinese display observation window convenient for observation and operation buttons of closing, opening, resetting, overload, electric leakage, displacement, confirm and adjustment are arranged on the front door.

b) PLC protection device and various protections signal sampling elements are installed in the chamber.

c) The explosion-proof chamber at the rear of the explosion-proof chamber can be subject to flange connection with the wiring chamber of the mobile substation (dry transformer).

2. Three terminals of the main circuit and two seven-core terminals for control loop wiring shall be installed in the wiring chamber. There are two pressure plate type cable lead-in device at the left and right sides of the wiring chamber respectively, two M42 compression nut lead-in device is installed in front of the wiring chamber, which can be used for external control wiring.

3. The door opening mode of the protective case has the quick-open structure, and the safe mechanical locking device is arranged.

a) Release locking before door opening, turn off the isolating switch to cut off the working power, the vacuum circuit breaker at the high voltage side is tripped, and the next operation can be conducted.

b) Power transmission work can be conducted after door closing.

4. The full Chinese backlit LCD shall be adopted in the protective case, and parameter setting, data monitoring, historic record query and other operation can be conducted through the operation button installed on the front door.

V. Electrical features

Three-phase current signal, system voltage signal and additional DC voltage signal are directly connected with PLC. PLC analyzes and processes the digital signals of three-phase current, system voltage and insulation resistance according to the parameters preset, so as to complete short circuit, overload, electric leakage locking, leakage protection, overvoltage, undervoltage and other protection actions.

The protective case shall send the signal of normal and abnormal operation at the low voltage side to the vacuum switch at the high voltage side through closing and opening of PLC output relay Q0.0, so as to realize control of the mobile substation.