RB control strategy of thermal power unit and matters needing attention in its test

Abstract: The information on the RB control strategy of thermal power units and the matters needing attention in the test is provided by the excellent flowmeter and flowmeter manufacturers and quotation manufacturers. 1. RB control function The basic mode of RB control is that after the occurrence of RB, the unit control is switched from the coordinated control mode to the steam turbine tracking (TF) mode, and the sliding pressure operation mode is automatically put into operation, the boiler main control is switched to the manual control mode, and the fuel main control is maintained. Automatic controller. You are welcome to inquire for more flowmeter manufacturers to select models and price quotations. The following are the details of the RB control strategy for thermal power units and the precautions in the test. 1. RB control function The basic mode of RB control is that after the occurrence of RB, the unit control is switched from the coordinated control mode to the steam turbine tracking (TF) mode, and the sliding pressure operation mode is automatically put into operation, the boiler main control is switched to the manual control mode, and the fuel main control is maintained. In the automatic control mode, the output of the coal feeder is the fuel amount corresponding to the target load in the RB state, and the steam turbine side should maintain the RB target load through the main control of the steam turbine. If the control system has a digital electro-hydraulic control system (DEH) RB interface logic, the opening degree of the steam turbine regulating valve is adjusted according to the main steam pressure setting value and its pressure deviation. After the RB process is over, the control remains in the TF mode (most control systems use this mode, and individual control systems use input coordination control or the main control of steam turbine and boiler are switched to manual control mode). The control functions of all units RB are basically realized by the analog control system (MCS) and the burner management system (BMS). The BMS adjusts the fuel quantity according to the RB control request. Usually, MCS includes RB signal generation, state end logic, maximum output calculation of unit, calculation of fuel amount corresponding to target load, coordinated control mode switching, main steam pressure control mode switching, load/pressure relationship curve setting, main (re) steam Calculation of temperature drop rate (used to block the change of main steam pressure setting value), calculation of feed-forward amount of the baffle of the blower/draught fan, prevention of overcurrent of the blower/draught fan motor, blocking and opening logic, and shielding each subsystem after the occurrence of RB (supply If the deviation of the control signal of air, induced air, primary air, water supply) is large, switch to the manual control mode logic, the furnace load blocking reduction command shielding logic, the forced closing logic of the superheater desuperheating regulating valve and the shut-off valve control circuit etc. RB control loop. 2. RB control strategy 1. Balance control of blower/draught fan The blower RB or induced draft fan RB has 2 control strategies. The supply/induced fan trips and the interlock trips the same side induced/supplied fan, and the output of the unit is reduced to 50%. After the supply/induced fan RB occurs, the supply/induced fan will rapidly increase its output through the balance logic on the original output, so as to ensure the air supply volume. Under the premise of maintaining the stability of the negative pressure of the furnace; the trip of the supply/induced fan is not interlocked and the same side of the induced/supplied fan is tripped. After the occurrence of the blower RB, the adjustment mechanisms of the two operating induced draft fans are overridden and reduce the opening according to a certain proportion. The adjustment mechanism of a single blower is overridden to open (the RB control of the induced draft fan is the same) to ensure the stability of the negative pressure of the furnace. The ratio selection of the overriding action of the blower/induced fan and the speed limit and the maximum opening limit of the overrunning baffle opening of the regulating mechanism of a single fan should be avoided under the premise of ensuring the fan output (MFT). 2. Override control of feed water pump and primary fan is in the control of feed pump RB and primary fan RB, which requires a single running feed pump to quickly increase the output, and quickly open the single running primary fan adjustment mechanism to maintain the pressure of the primary air main pipe to avoid Running the pulverizer tripped. Usually, the balance logic designed by the output command of the regulator or the feedback of the actuator opening is used to override the actuator of a single running feed pump and a primary fan after RB occurs. In addition, some units adopt the state switching control mode of the regulator. When RB occurs, the output of the regulator quickly turns on the single running feed pump and primary fan actuator with a fixed opening command.

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