Turbine-generator shaft system torsional vibration protection method and device

Provided is a turbine-generator shaft system torsional vibration protection method and device. The method includes the steps of collecting shaft system torsional vibration signals, determining the threat situation of the torsional vibration on the safety of units through a fatigue inverse time limit criterion (protection criterion I), a static instability criterion (protection criterion II) and a quick operation criterion (protection criterion III), and performing protection trip and warning to avoid more damage of the torsional vibration to a turbine-generator shaft system. The torsional vibration protection device comprises a speed sensor, a pulse input module (PI), a main control module (CM), a digital input module (DI), an analog input module (AI), a digital output module (DO) and a power supply module (POW). The speed sensor is connected to the pulse input module of the protection device through a cable. The protection device is in communication with a human machine interface (HMI) of a master station through Ethernet.