Method of coordinated operation for turbine-generator shafts torsional vibration protection

A coordinated control method of steam turbine generators' torsional stress relay (TSR) in large power plant, this method will connect TSR in different generators of the same power plant to form a coordinated control group, the coordinated control group can be divided into 2 layers:

• a TSR layer and a coordinated control master station (Tmaster) layer;
• each TSR implements a supervisory works of a units' shaft torsional oscillation and a shaft fatigue real-time calculation independently;
• TSR will judge whether to send a “trip” command according to its criterion and fixed value;
• Tmaster will implement a real-time monitoring of each generator's operation status and output, Tmaster can also real-time generate optimized trip strategy online, utilize a selective trip implemented by a coordinated action of equipments in 2 layers, this method includes:
• 1) Each generator's TSR will send 2 messages to Tmaster, these messages are:
• “trip” command, unit's shaft torsional oscillation mode, when Tmaster receives the “trip” command form TSR, Tmaster will trip the units according to a real-time generated optimized trip strategy;
• 2) After Tmaster receives a first “trip” command, it will trip a unit which has a highest priority, then wait for the message which represents a shaft torsional oscillation mode that is in divergence or not during a period of “Tset”, where “Tset” is a fixed value of latency period, which usually is set as 0.5S˜1S;
• 3) If the shaft torsional oscillation still exists after Tmaster has tripped a first unit, Tmaster will trip another unit that has the highest priority of the remaining units, then TSR will judge whether the unit shaft torsional oscillation mode is in divergence during another period of “Tset”;
• 4) if the shaft torsional oscillation still exists after Tmaster has tripped a second unit, Tmaster will keep the unit which has a lowest priority running, and trip all other units if their shaft torsional oscillation mode is in divergence.