ASK-411 digital the PT monitoring and control switching device, the main achievement of the two sets of bus PT automatically switch remote switching function as a subsystem of the integrated substation automation. The device can be in a group of PT exit running under another group PT voltage automatic switch, low-voltage protection action to avoid the protection device, PT parallel can also be achieved by remote control or manually. Main functions: protection function a) PT automatically switch function PT remote control switch function; b) over-voltage, low-voltage, zero sequence overvoltage alarm or trip; c) bus PT the disconnected, insulation monitoring functions. The device self-test function, a) the device automatically detecting RAM, ROM, A / D, and the power disappears, such as failure; b) automatically detects the fixed value, configuration, coefficient parameters. The event log a) record the content of the event, including the the protection action events, device self-test failure; b) record the type of protection action events, action moments and operating parameters of the protective action; recording device self-test failure event type and time of occurrence. Communication functions a) means to upload real-time data, including the measurement data, failure, an alarm signal, and all of the protection setting value, configuration, coefficients. Setting and cast-off protection function can be remotely modified online; b) receive higher fat control commands, including: system, given the value of the tuning and data read and write commands. Monitoring function a) measuring voltage, frequency analog telemetry device; b) acquisition disconnector position signal and switch signal remote signaling function. The function of a) Chinese character LCD status indicator and keyboard operation, measurement tracking and monitoring can be easily modified online setting or vote back protection functions, and reversion keys or distant control reversion fault indicator panel.