SU613194A1 - Device for automatic control of pressure in deaerators with common steam mains - Google Patents

Description

REGULATION OF PRESSURE IN DEAERATORS WITH A GENERAL STEAM HIGHWAY

which connects unit 15 for comparing relative increments of sampling from the turbip 11, 12, connected to units 16, 17 for determining the relative increments, and through them with pressure sensors 18 and 19 in selections for turbines I and 12 and switches 20 for the operating mode of turbines.

To the output of the selection unit 14, control action switching units 21, 22 are connected. The actuator 6 is coupled to a control valve 23.

The device works as follows.

Sensor 24 measures the pressure in the common steam line 13 of deaerators 4 and issues signals to the main pressure regulator 1, which, through the block of selection of regulatory actions, outputs the output signal to the slave regulators 2 or 3. The choice of regulator 2 or 3 in block 14 of selection of regulatory actions carried out according to a predetermined algorithm or according to the results of the calculation of the bcr If it is known that the turbine 12 is the most economical, the block for selection of regulatory actions generates a signal to the slave controller 3, which acts on the actuator 6, which closes or opens the control valve 23, depending on the pressure in the common steam line 13. The steam flow sensor 25 gives feedback signal to slave controller 3, and it stabilizes the steam flow at a given level. If the steam consumption from the selection of turbine 12 is insufficient and its possibilities are exhausted, block 14 issues a signal to the slave controller 2, and the control valve 26 opens it through the actuator 5. The missing part of the steam from the selection of turbine 11 enters the common steam line 13 and the pressure rises. If there is an excess of steam, at the command of the main controller 1, the Decrease block 14 commands the slave controller 2, which acts on the isolating mechanism 5, and it closes the valve 26. The device regulates further changes in steam consumption from the selection of the turbine 12.

Thus, depending on the input signal, the device 9 implements an algorithm for selecting one circuit of the automatic control system (ACS) vapor pressure for operation in the regulating mode, the other in the standby mode.

In order to increase the reliability of regulation, the device is equipped with control switching units 21, 22 and a pulse action unit 27. The use of these blocks allows simultaneous switching in the backup and working circuits of the SAR and provides non-transition from one circuit to another according to the setting of the block 27 taking into account sufficiently small disturbances. In the current SAR circuit, the commands of unit 14 connect the main controller 1 to the slave controller 3 (if the selection of the turbine 12 has the maximum increase), and the latter through the block 22 to the actuator 6. In the backup loop, the connection from the unit 27 to the the actuator 5 through the block 21. At the same time, the latter turns off the influence of the slave controller 2 on the recovery mechanism 5. In block 27, the selection of the duty cycle –y-pulses and the duration of the period of the output signal is performed Taking into account the application of sufficiently small perturbations. In the case of the maximum loading of the selection of the turbine 12, fixed by the sensor 25, or the exhaustion of the control range determined by the position of the actuator 6, the signals arrive at the input of the unit 14, which gives commands to rebuild the modes of the ATS circuits. In this case, in the previously isolated circuit of the SAR, the effects of the main controller 1, the updated controller 3, and the block 27 through block 22 on the actuator 6 are removed. A backup SAR circuit is additionally included in the adjustment mode. Signals of influence of the main regulator 1

through blocks 14 and 21 and the slave controller 2 through block 21 are fed to the actuator 5. When the signals from the sensor 28 disappear or the actuator 5 moves by the command of the block

14, the circuit comes to its initial position with the selection of the SAR circuit, which acts on the control valve 23 on the heating steam line from the selection of the turbine 12 with the maximum increase. Another ATS circuit

the command of block 27 is put into reserve.

As you know, when working on the thermal schedule of the turbines, it is advisable to achieve the maximum of the cogeneration power generation, and the electrical schedule - the maximum efficiency from the combined generation of electricity and heat. The device performs automatic pressure control in deaerators taking into account the vapor pressures in the selections, schedule and mode

work turbines.

The signals from the pressure sensors 18 and 19 go to the relative gain units 16 and 17, respectively, which also receive signals from the switch 20

turbine operation modes corresponding to the “Thermal Load Schedule” mode or “Electrical Load Schedule. In blocks 16 and 17, the values of the relative increments of the heat generation power generation during the operation of turbines according to the heat schedule or the determination of the relative gains of heat savings in the combined power generation based on the heat supply from the corresponding selection to the deaerators take place. The values of the resulting signals from the output of blocks 16 and 17 are received in block 15 of the relative gains comparison, which gives the comparison results to block 14. The latter, depending on the input, implements an algorithm for selecting one SAR circuit for operation in the regulating mode, the other in the standby mode. When switching the turbine operation mode, the automatic control system reorganization takes place according to signals from block 15.

Thus, the device has the opportunity to increase the use of those selections of turbine units that provide either a maximum of cogeneration power generation (when operating on a heat schedule) or maximum heat savings from combined power generation associated with selective heat for deaerators (when operating on an electrical schedule). This in turn leads to lower fuel consumption for the supply of electricity, which increases the efficiency of the station.

Claims (2)

1. Author's certificate of the USSR № 313028, cl. F22D 11/00, 1970. 2. Shalman MP Automation of large thermal power plants. M., “Energy 1974, with. 116, fig. 5-18.