SU436325A1 - SYSTEM FOR AUTOMATIC LIMITATION OF POWER TURBO GENERATOR - Google Patents

Description

one

The invention relates to the field of automatic control of turbomachines and emergency control equipment.

Devices are known for automatically limiting the power of a turbo-generator, mainly in emergency conditions, containing integral and proportional correctors connected to the corresponding inputs of the amplifier covered by a feedback circuit consisting of a null indicator, a relay, a drive electric motor, an executive unit of a synchronizer and a sensor. , with the output of the amplifier through an electro-hydraulic converter connected to a device draining the liquid from the impulse line, the shaft rotation speed sensor, connected to the input of the prolortional equalizer, sensors of active turbogenerator power and pressure in the intermediate superheat pipeline.

The disadvantages of the known devices are the low quality of the transient process with arbitrary unloading of the unit, the false operation of the equalizer due to the slow power change during its operation in the mode of comparing the setpoint with the current power of the turbogenerator.

The frequency corrector used in the devices for the adopted circuit is forcedly performed slow-acting, which does not fully compensate for the action of the speed controller caused by a change in the speed of rotation of the shaft and leads to additional error.

The second applied generator power corrector removes the error only between the signal from the executive part of the synchronizer and the power in the initial mode and between the setpoint and the power iB in the post-emergency mode and is turned off at the first moment of time. As a result, due to the mismatch of pressure in the intermediate reheat line of the steam after the emergency power value, which is determined by the setpoint, the corrector does not cope with the compensation of this error in case of significant power drops.

The aim of the invention is to improve the processing accuracy without reducing the power of the turbo-generator.

To achieve this, a signal forcing circuit is connected to the additional feedback circuit of the amplifier; in this case, a relay is inserted into the system, through which the amplifier output, the turbogenerator active power sensor and the pressure sensor in the intermediate superheat pipeline are connected to the integral corrector, to the proportional corrector A corrector integrator feedback is connected.

The drawing is principled

a system diagram for automatically limiting the power of the turbogenerator, where I, II are the groups of inputs along which the system is started up; III - an additional input from an external device; 1, 2 - contacts through which the groups I and I are turned on; 3 - elements of the setpoint; 4 shows a diode pattern for selecting the maximum signal; 5 - power; 6 - relay; 7 - capacity; 8 - integral slow-acting corrector; 9 - proportional high-speed corrector; 10 is a forced signal circuit; 11 - position sensor of the executive unit; 12 - synchronizer executive unit; 13 - drive motor; 14 - zero indicator; 15 - electro-hydraulic converter; 16 - device draining the liquid; 17, 18 - diodes; 19 - relay; 20 - time relay; 21 - relay with zone and time delay for actuation; 22, 23 - time relay; 24 - relay with actuation zone; 25 - resistor; 26 - zener diode; 27 - capacity; 28 - time relay; 29 - resistor; 30 - high-speed amplifier; 31 - integrator; 32 - adder; 33 - relay; 34 is the equivalent of turbine control insensitivity; 35 - adder; 36, 37 - integrators of negative and positive values of the signals at the output of the adder; 38 - integrator; 39 - resistor; 40 - time relay; 41 - sensors, to the active power of the turbogenerator; 42 - pressure sensor in the intermediate reheat pipeline; 43 - shaft speed sensor.

The system works in the following way.

The system is started up from an external circuit that is not part of the device, which includes two groups I and II of functional inputs pins 1 and 2 (it is assumed that the external circuit has a lock that turns off the signal of group II - slow unloading via a synchronizer - if necessary. The bridges of unloading through an electro-hydraulic converter are based on signals from group I and simultaneously including the signal from group II, the necessary channel of group I).

Contacts 1 (t 1, 2 ...) connect elements 3 of the settings in the form: 1 - Y ,. where Y is the set point after-fault power, through a diode circuit 4 for extracting the maximum signal to the input of amplifier 5, in parallel with which relays 6 used in protection and control, capacitance 7 for reducing the exponential signal when the limit channel is turned off, as well as the equalizer input eight.

To the input of the amplifier 5, their integral slow-acting 8 and proportional high-speed 9 correctors according to technological parameters and the signal forcing circuit 10, which are interconnected, are connected by their outputs.

To the input of the amplifier, in addition, is connected to the sensor 11 position executive

block synchronizer 12 with the drive motor 13.

The signal at the output of amplifier 5 is formed by the relation:

h 1 +; ga; 9, where 3 ,,, 1-У, „,„

where is the minimum of the simultaneously connected settings; Hz - sensor signal 11 Executive unit; Xs -signal slow-acting corrector; Hell is a high-speed corrector signal. The output of the amplifier 5 is connected to the input of the equalizer 8, the input of the circuit 10 forcing a signal, an indicator indicator 14, which fixes the occurrence of positive signals, and an electro-hydraulic converter 15, the output signal of which provides the opening of the drain device 16 from the pulse line proportionally

signal fed to its input.

For additional input of signals from external devices, an additional input 111c diode 17 and diode 18 is provided at the amplifier output, excluding the passage

signals to the amplifier from this input. In the circuit in front of the converter 15, the contacts of the relay 19 are installed, disconnecting the amplifier from the converter when performing slow unloading through the synchronizer, i.e.

signal to group II on the relay 19.

From the null indicator 14, the signal is applied to

motor 13 downwards

power. The circuit of this signal closes the time relay 20, whose contacts are bounded by the contacts of the relay 19, which ensures

the assembly of this circuit when the relay is triggered 19.

Relay 21 with zone and time delay on

triggering monitors the occurrence of input and output signal mismatch

amplifier, time relay 22 controls the duration of the pulse signals and time relay 23 prevents continuous unloading through the synchronizer. All protection relays are self-locking, manually deactivated with the common button K.

The signal forcing circuit 10 is triggered by a signal at the amplifier output from a relay 24 having a pickup zone. The relay reconfigures the positive feedback element of the amplifier by connecting it to the output of the amplifier through a series-connected resistor 25 and a group consisting of a zener diode. 26 and capacitance 27. As a result, the signal is

the output increases in proportion to the increase in the gain of the amplifier 5 (determined by the resistance of the resistor 25), and the capacitance is charged to a predetermined level determined by the zener diode 26. Turning off

a positive feedback element is provided by a time relay 28, with a setting of a few tenths of a second, which is connected to the output of the relay 24 and determines the duration of the force signal. Recovery

The initial position of the contacts of the relay 24 leads to connection via a resistor 29 of the ground 26, 27 with a change in the polarity of the connection, which provides a sharp decrease in the signal to the level determined by elements 26 and 29, and a further decrease in its exponent determined by the capacitance 27 and the resistance of the resistor 29. The high-speed corrector 9 dries, compensates for the Impact of the speed controller, caused by a change in the speed of turn, of the shaft of the turbogenerator. An input signal proportional to the deviation of the speed of the shaft, from the nominal co, is fed to the fast-acting amplifier 30, covered by the slow-acting integrating feedback of the integrator 31, which is turned off by the signal from the null indicator 14. The correction signal is formed from the sum of the negative output signal amplifier 30 and the feedback signal for element 31. As a result, K0 | rekretsi the effect of changing the speed of rotation of the shaft in the original mode, when the signal behind the amplifier 5 is not there is. When the system is working, only a decrease in the rotational speed is corrected, i.e. an increase in power is prevented, which is provided by a diode in front of the adder 32. A positive value of the signal in front of the adder (increase in speed) is fixed by the relay 33, the signal of which is used to turn off the corrector 8 in this mode. The output of the equalizer is set to element 34 - the equivalent of insensitive turbine control. Slow-acting corrector 8 is used to eliminate the mismatches, for which, at its input adder 35, signals from sensors of the active power of the RG generator and pressure in the intermediate-temperature pipeline p are connected. The signal from the adder 35 is supplied to the integrators of negative 36 and positive 37 values of the signals at the output of the adder, which control integrator 38 with a constant time G 15–40 s, covered by negative negative feedback, the coefficient of which is determined by element 39, for example, a resistor. At the output of the offset, an element is installed with which you can change the gain coefficient of the offset (not shown). The signal at the output of the adder 35 in the initial mode is formed according to the ratio r - 1 - -Pr - and (see p. 5, 7), which ensures the elimination of the mismatch between PJ. and 11, i.e. between signals proportional to the power of the generator and the turbine. At the time of actuation, a normally closed contact of the null indicator disconnects the output of amplifier 5 from the equalizer, and a relay with a zone of operation (using relay 24) connected to the output of the amplifier disconnects the active power signal of the generator g, turns on the negative feedback of the integrator 38 with the resistor 39 and connects a signal proportional to the pressure p. As a result, the signal at the output of the corrector is determined by the relation: X ,. -f p-1 p - Y /, where Xi is the signal behind diode 4, with the statistics defined by the resistor 39, the value of which is chosen the smaller, the greater the power of the part of the turbine behind the intermediate superheater of the turbine installation. After a predetermined time of operation of the forcing circuit, time relay 40 connects to the adder 35 a signal proportional to the generator power P ,. , turns off the signal rio pressure p. and turns off the negative feedback resistor 39. As a result, the corrector eliminates the inconsistency of the relation: V, l-p - p V t f - r. Further, if the limit signal does not disappear, the corrector continues to operate in this mode due to the fact that the output of the amplifier 5 is disconnected from the corrector ). In order to prevent false correction of the corrector in the case of unloading through the synchronizer, relay 19 disconnects the output of the accumulator from integrators 36, 37 in the event that relay 24 has triggered, which compensates for the error signal with the corrector only after the amplifier reaches the values specified by the relay trigger zone 24. In order to prevent false triggering of the corrector, when the rotational speed of the shaft increases, a relay 33 installed in the corrector 9 disconnects the integrator 36 with its contacts and decreasing the corrector signal in the case of the system, fixed by null indicator. Such blocking ensures normal operation of the corrector when a signal is received from the relay 33, if the turbogenerator is not relieved. When the turbo generator is quickly unloaded to the statute value, the external circuit by contacts 1 includes one of the channels of the first group, which is when the turbine power is greater than the set value Vi, determined by the connected element of task 3; , provides turbine unloading for the difference: An - 1 - Xs RG - 1 - (I - Y) - Y i through electro-hydraulic converter 15. Due to the operation of relay 24, if the signal at the output of amplifier 5 is greater than the specified value, a forced signal with amplitude is applied ( Rg-U /) K, where (K - gain factor). Its boosting part disappears at the time determined by time relay 28, and further reduction to value P - W / occurs according to the exponent determined by resistor 29 and capacity 27. After a predetermined time, relay 20 switches on the synchronizer circuit

in the direction of decreasing the power, the signal at the output of the amplifier 5 is replaced by a signal of the synchronizer position sensor. In the case of connection during the operation of the system of another element of the task with a lower power setting, the settings are replaced without applying an accelerated signal. After the replacement of the signal at the amplifier output by the synchronizer, the system continues to monitor the specified maximum allowable power level, replacing the newly generated signal at time intervals defined by the relay 20. When the limit signal disappears, if the synchronizer does not replace the signal, the system provides power to the original . When performing fast unloading, the slow-acting corrector 8, it was stated, switches successively to the three modes of operation listed above: comparison of synchronizer signals and power, pressure and setpoint, power and setpoint. If the limitation is made in the control mode of the post-emergency power after the operation, the relay 24 does not work and the corrector operates continuously in the mode of comparison of the Vi setpoint with the power of the RG by disconnecting the signal 6 from the amplifier 5 to the equalizer input. When the system is working, the corrector 9 by a null indicator switches to the correction mode of the current negative change 0) due to the disconnection of the integrating feedback with element 31. If the shaft speed increases, the signal at the output of the corrector does not change, which ensures a reduction in power speed controller action account. In this case, the relay 33 eliminates the possibility of adjusting the decrease in power produced by the speed controller from the side of the corrector 8 by turning off the integrator 36.

When a slow discharge system is implemented, the operation of the circuit is basically the same as the previous one. The difference lies in the fact that the relay 19 bypasses the relay 20, providing the possibility of immediate discharge through the synchronizer when the elements of task 3i are connected. In this case, until the signal at the amplifier output decreases to the set value of the relay 24, the corrector 8 is turned off by the contacts of the relay 19, which eliminates the correction due to the inconsistency of the WG and Y signals caused by a slow change in power. If the signal at the amplifier output exceeds the setpoint value of the relay 24, then the force circuit is started and its operation is ensured as described above.

The supply of pulse signals through diode 17 does not lead to any disturbances of the elements of the system under consideration, i.e. completely independent control of these signals is carried out.

A different combination of signals applied to the inputs of groups I and II allows the power to be changed according to the following laws:

1. A sharp drop in power to a predetermined level while ensuring optimum quality.

transient process regardless of the magnitude of the output power (input group I).

2.Rough short-term power shedding by an amount proportional to the setpoint

with the subsequent restoration of the power to a value equal to the initial one (for a short time the input of group I).

3. Similarly, p. 2, followed by slow unloading to the set point through the synchronizer (inputs of groups I, II).

4. A sharp drop in power to a predetermined level, ensuring optimum quality of the transient process and with restoration

power up to a value greater than the setpoint (group I input for a given time t).

5. Slow unloading and loading of the unit while maintaining the specified power level in the post-accident control mode

values (group I input).

Subject invention

System for automatic limiting

turbo-generator power, containing integral and proportional correctors, connected to the corresponding inputs of the amplifier covered by the feedback circuit; consisting of a null indicator, a relay, a drive electric motor, a synchronizer actuator unit and a sensor, the amplifier output being connected via an electro-hydraulic converter to a device for draining liquid from a pulse line, a speed sensor

rotation of the shaft, connected to the input of the proportional corrector, sensors of the active power of the turbogenerator and pressure in the intermediate superheat pipe system, characterized in that, in order to increase the accuracy

power reduction, in the additional feedback circuit of the amplifier. a signal forcing circuit is connected, a relay is inserted into the system, through which contacts the amplifier output, an active power sensor

the turbogenerator and the pressure sensor in the intermediate overheating pipe are connected to the integral equalizer, the integrator feedback corrector is connected to the proportional corrector.