SU1513159A1 - Method of controlling turbine plant - Google Patents

Abstract

The invention relates to a power system and can be used in the automation of turbine control. The steam turbine control method is aimed at increasing the durability of the power unit and reducing its downtime by reducing the number of protection actions of the capacitor. The steam turbine unit 1 is controlled by adjusting the power of the turbine 3 in accordance with the setpoint and simultaneously adjusting the level of condensate in the condenser 9 of the exhaust steam of the turbine, with the unit stopped when the level of condensate is outside the allowable level range. At the same time, pre-emptive thresholds are set for raising and lowering the level and when the current level goes beyond these thresholds they form the setpoint for power control of the turbine 3 as the setpoint difference at the time the level goes beyond the pre-emptive thresholds and a signal proportional to the current rate of level change. 1 il.

Description

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The invention relates to a power system and can be used in the automation of turbine control.

The purpose of the invention is to increase the durability of turbine equipment by reducing the number of protection trips.

The drawing shows a device for carrying out the proposed method.

The control unit of the steam turbo (control) input forces the output from the first input to the output and remains in this state until the signal arrives at the second input. Switch 19, when there is a signal at its control input, passes a signal from the second input to the output, and in the absence of a signal at the control input, passes a signal from the first input to the output. The threshold element set as the limiter 7 installation, when

the installation 1 contains the regulator 2 of the power output of the input signal from the permissibility of the turbine 3 (at the input of which the variable range fixes the control valve 4 of the steam flow to the turbine), the setting unit 5

power connected to the first input

output signal on the achieved limiting value. The trigger 20 in the initial state does not generate an output signal, power regulator 2, power sensor 6, When it arrives at the first control-limiter 7 of the setpoint (for example, a threshold signal does not form an output element), the controller 8 - a signal (or generates a zero output sat in capacitor 9 (at the output of which the signal), and after the termination of the flow control valve 10 is installed or to the input of the control signal of the form-condensate from the condenser), the sensor 11 outputs the output signal, for example nsata in condenser 9, first 20 ny. When a signal arrives at the second threshold element 12, the output of which sv - input trigger 20 passes into the initial zone with the system 13 of the emergency control automation of the power unit. The device has a second threshold element 14, a differentiator 15, a comparison element 16, an element 5 of memory 17 and 18, a switch 19 and a trigger 20. The dial 5 is connected to the first inputs of the memory element 17 and switch 19. The output of the regulator 2 power connected to flow control valve 4

standing

Approximately the relationship between the level and the power L can be represented as

Tu +,

where Yu is the gain factor;

T - constant time.

Therefore, the proportionality coefficient / (in the differentiator 15 can be chosen experimentally by measuring

the pair, and the input is connected through a limited set of corresponding values

A 7 is connected to the output of the memory element 18, the first input of which is connected to the output of the switch 19, and the second input of which is connected to the output of the trigger 20. The output of the level controller 8 is connected to the control valve 10 of the condensate flow. 35 thresholds for raising and lowering

y by ratio

t / cT and / VycT by ratio

l / VycT / i CT,

Knowing the maximum possible rate of change of the level to increase (y) + max and decrease () 1chax, set the proactive

40

The sensor And the level is connected to the inputs of the level controller 8, the first threshold element 12, the differentiator 15 and the second threshold element 14, the output of which is connected to the second (control) input of the memory element 17, the control input of the switch 19 and the first input of the trigger 20. A second trigger input 20 is associated with an operator. The inputs of the comparison element 16 are connected to the outputs of the memory element 17 and the differentiator 15, and the output is connected to the 45 second input of the switch 19. The first threshold element 12 generates a signal when the level is output from a predetermined change range, which corresponds to the maximum allowable level change range

+

Mlxt

y y -T- (y) y un + T- (y) „, where (/ vi /„ - respectively the upper and lower limits of the maximum allowable range of changes in the level of condensate in the condenser.

The method is carried out as follows.

The steam turbine unit 1 is controlled by adjusting the power of the turbine 3 by means of the power regulator 2, to which the turbine power signal is received from the power sensor 6, in accordance with the pre-condensate formed by the unit 5. The second threshold element 1450 is limited by admissible diaforming of the output signal if the input range of the power variation in the limit signal is outside the specified range 7 of the setpoint. Simultaneously regulate

for changes limited by the anticipating level of condensate in the condenser 9 by the railways to increase and decrease the level of the steam of the turbine 3 by means of a regulating condensate. Differentiator 15 forms a torus of level 8, which receives

with a given ratio proportional to the 55 signal at the level of condensate from sensor 11

K signal on the rate of change of level. When the output signal level

input signal. Elements 17 and 18 of the memory of the condensate outside the permissible range of the moment the signal arrives at the second zone of the level change, the first threshold

the (control) input forces the output from the first input to the output and remains in that state until the signal goes to the second input. Switch 19, when there is a signal at its control input, passes a signal from the second input to the output, and in the absence of a signal at the control input, passes a signal from the first input to the output. The threshold element set as the limiter 7 installation, when

the input signal from the allowable range of change fixes on its

ny. When a signal arrives at the second input, the trigger 20 goes to the initial co

standing

Approximately the relationship between the level and the power L can be represented as

Tu +,

where Yu is the gain factor;

T - constant time.

Therefore, the proportionality coefficient / (in the differentiator 15 can be chosen experimentally by measuring

thresholds for raising and lowering

t / cT and / VycT by ratio

l / VycT / i CT,

Knowing the maximum possible rate of change of the level to increase (y) + max and decrease () 1chax, set the proactive

y by ratio

0

five

+

Mlxt

y y -T- (y) y un + T- (y) „, where (/ vi /„ - respectively the upper and lower limits of the maximum allowable range of changes in the level of condensate in the condenser.

The method is carried out as follows.

Steam turbo unit 1 is controlled by adjusting the power of turbine 3 using power regulator 2, which receives a turbine power signal from power sensor 6, in accordance with the setpoint set by unit 5, additional element 12 forms a signal to system 13 of the automatic control of the power unit, which causes the latter to stop. This protects the capacitor 9 from the accident. In the differentiator 15, the rate of change of the level of the condensate is constantly determined and a signal proportional to the current rate of change of the level is formed at the input of the comparison element 16. When the current level for proactive

and taking the necessary measures) will not generate a control signal to the second input of the trigger 20, thereby resetting it to the initial state.

Thus, when the current level of condensate reaches the preemptive thresholds, the turbine power is changed so as to stabilize the level in the condenser m and return it to the allowable range of change. This leads to a reduction in the number of servo thresholds (increase or decrease), protection of the capacitor and, as a result, set in the second threshold effect, increase in the durability of the energy element 14, the second threshold element 14 generates a signal to the control inputs of the memory element 17 , switch 19 and trigger 20. At the same time, switch 19 .. c passes to element 18 a signal at the setpoint of the turbine 3 power control, formed by the comparison element 16 as the difference of the signal at the set point at the moment the level goes beyond the forward thresholds

block and reduce its downtime.

Claims (1)

Invention Formula Steam turbine control method by adjusting the turbine power in accordance with the setpoint and the permissible range of power variation and adjusting the level of condensate in the condenser to form m. the memory element 17 and the signal proportional to the protective signal when the level of the current speed changes outside its permissible level range, from the differentiator 15. The trigger 20 does not receive a control signal to memory element 18, therefore, the last operation, characterized in that, in order to increase the durability of the equipment of the turbine installation by reducing the number of interruptions and taking necessary measures, will not generate a control signal to the second input of the trigger 20 . Thus, when the current level of condensate reaches the preemptive thresholds, the turbine power is changed so as to stabilize the level in the condenser m and return it to the allowable range of change. This leads to a reduction in the number of protection actions of the capacitor and, consequently, to an increase in the durability of the power unit and a decrease in its downtime. Invention Formula Steam turbine control method by adjusting the turbine power in accordance with the setpoint and the permissible range of power variation and adjusting the level of condensate in the condenser to form m.  protective signal when the level goes beyond its acceptable range change, characterized in that, in order to increase the durability of the equipment of the turbine installation by reducing the number of Allows the input signal through the protection limitations; additionally, the set 7 is set to the power regulator 2. When the level returns to the area bounded by the preemptive thresholds, the control signal to the first input of the trigger 20 stops, causing the rate of change of the condensate level to form, set the preemptive thresholds downwards within the acceptable range of the level change and when the level goes beyond one of the preemptive thresholds the last of the output control ZO is its setpoint for adjusting the power of the torsion signal to the memory element 18, which captures at its output a signal according to the set value reached. Correspondingly, regulator 2 stabilizes the turbine power at the setpoint level and the ostabin system leads by the difference in the value of this setpoint at the moment the level goes beyond the threshold and a signal proportional to the rate of change of the level, and after the level returns to the area bounded ahead of time then, as long as they are, they record what was achieved at the time of the carrier (by removing the setpoint value for the causes of the emergency situation). protection is additionally determined the rate of change of the condensate level; within the allowable range of the level change, the anticipatory thresholds decrease and when the level goes beyond one of the forward thresholds of the shape of the turbine lead by the difference of this setpoint at the time the level leaves the threshold and the signal proportional to the rate of change of the level, and after return level in the area bounded by preemptive