We knowgenerator setDEHbeunifyIn overspeed protection, it is divided into103 actions(professionally referred to asOPC action, hereinafter referred to as OPC action）Compared to the 110 overspeed protection action, perhaps everyone can understand that the fixed values of these two protections will be different. So, what are the objects of these two overspeed protection actions and how are they implemented? Today, we will explain in detail:

One OPC protection action

belowconditionTriggered when any condition is metOPC action：

(1) When the unit transitions from grid connected state to disconnected state,DEHThe lower computer sends a trip signal through the oil switchjudgmentOutput DO pointThis premise is that it was not activated during the ETS protection actionOil switch trippedIn this case, if the protection is activated, the AST solenoid valve will immediately shut down

（2）When in the DEH system3 of themDetected separately by servo cardsspeed probespeedExceeding 3090r/min, output 2 DO points through hard circuit 3;

(3) In the disconnected state, the DEH lower computer uses three speed analog signals to determine overspeed3090r/minOutput DO point.

When the OPC action is triggered, it is necessary to quickly unload the load, power on the OPC solenoid valve, release the oil pressure of the hydraulic engine, and quickly close the high-pressure valve; Wait for the unit speed to drop to 2950r/minWhen the OPC action is reset, the oil pressure is established again,The high-profile door opens againThe speed control PID will be3000r/minTo accelerate the target speed again, quicklyspeedMaintain in3000r/min， Re load.

so-calledThe only martial arts in the world are fast and unbreakable.The key to OPC action is to be fast, which belongs toA typical open-loop control requires fast closing and opening, and also has high requirements for the oil system. For DEH commands, it needs to respond quickly, indicating which to hit which to hitThe delay rate is very unfavorable for the operation of the steam turbine. The larger the delay rate, the greater the fluctuation of the turbine speed, which will destroy the single value correspondence between speed and frequency.

In the debugging process of small domestic units, the dynamic 103 experiment is basically conducted in the unit disconnection state. After grid connected operation, the unit frequency follows the large grid, and there is basically no situation where the single machine frequency exceeds 51.5Hz.

2、 110 overspeed protection action

For 110 overspeed protection, two protection systems need to be set up. Generally, the unit has seven speed probes,One of them enters the boot disk3 into DEH, 3 into TSI:

(1) DEH overspeed protection:When in the DEH system3 of themDetected separately by servo cardsspeed probespeedExceeding 3300r/min,3 of themServo cardOutput 3 DO points separately into the hard circuit for a 2 out of 3 judgment,Determine the output DO and input it into the ETS protection system；

（2）TSIspeedingprotect：whenTSIin the system3 of themSpeed cardDetected separatelyspeed probespeedExceeding 3300r/min, to be done by TSI itself3 out of 2 judgment，Determine the output DO and input it into the ETS protection system；

When the ETS system receives either of the above two signals,ETSTurn on the switch and directly perform a power-off operation on the AST solenoid valve, thereby releasing safety oil, closing the main steam valve, and shutting down the unit. The ETS system operation screen will display the first outputDEHOverspeed shutdown orTSIspeedingshutdown