JP2011052553A - Apparatus and method of controlling steam turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow smooth attainment of a setting rotation speed by reducing the variation of turbine rotation speed in a turbine setting process after the operation of a power load unbalance circuit. <P>SOLUTION: An apparatus of controlling a steam turbine includes the power load unbalance circuit 50 operating to self-hold and generate a power load unbalance signal 50s when a difference 51s between steam turbine output 19s and power generator output 20s is a predetermined set value or more 52s and a decrease rate 53s of the power generator output is a predetermined value or more 54s. The apparatus has a circuit 512, 513 including: a turbine rotation speed rising rate determination means 59 detecting that a rising rate 58s of the turbine rotation speed becomes a predetermined value or less 59s; and a turbine rotation speed detection means 510 detecting that the turbine rotation speed becomes a predetermined value or less 510s, detects that both the turbine rotation speed rising rate determination means 59 and the turbine rotation speed detection means 510 operate and resets the operation of the power load unbalance circuit. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steam turbine control device and a steam turbine control method that can reduce fluctuations in turbine rotation speed in a turbine settling process after operation of a power load unbalance circuit and can smoothly reach a settling rotation speed.

  In general, a steam turbine controller detects an unbalanced state between the generator load and the turbine output in order to avoid an overspeed state of the turbine at the time of load interruption or a system fault. Thus, the main steam valve is closed for a certain period of time to limit the steam flowing into the turbine, and a power load unbalance function and an intercept valve abrupt closing function for suppressing overspeed are provided (for example, see Patent Document 1). ).

  FIG. 7 is a schematic system diagram of a general steam turbine plant described in Patent Document 1, and FIG. 8 is a schematic control block diagram of a conventional steam turbine control device. FIG. 9 is an operation diagram of the turbine settling process by the conventional steam turbine control device when power load imbalance occurs.

First, a schematic system diagram of the steam turbine plant of FIG. 7 will be described.
In FIG. 7, the steam from the steam generator or boiler 1 flows into the high-pressure turbine 5 through the main steam stop valve 3 and the steam control valve 4 provided in the main steam pipe 2, where the work is performed and the turbine shaft is moved. Rotate. The high-pressure exhaust steam that has finished its work in the high-pressure turbine 5 is guided to the reheater 7 by the low-temperature reheat pipe 6, reheated here, and then reheated steam stop valve 9 provided in the high-temperature reheat pipe 8 and It is supplied to the intermediate pressure turbine 11 through the intercept valve 10.

  The steam supplied to the intermediate pressure turbine 11 is exhausted after performing work here, and flows into the low pressure turbine 13 through the crossover pipe 12. Then, after performing the work here, the water is condensed and condensed in the condenser 14 and then returned to the steam generator or the boiler 1 again through a water supply system (not shown).

  When the turbine shaft is rotated by using steam energy in the high-pressure turbine 5, the intermediate-pressure turbine 11, and the low-pressure turbine 13 as described above, the generator 15 directly connected to the turbine shaft is driven to cut off the generated power. The power is transmitted to the transmission line 17 of the power system via the device 16.

  Reference numeral 18 denotes a turbine rotational speed detector provided on the turbine shaft, and reference numeral 19 denotes a steam pressure detector for detecting the pressure of the high-pressure exhaust steam or the reheat steam obtained by reheating the high-pressure exhaust steam that is proportional to the turbine output. It is. Depending on the power plant, a steam pressure detector may be installed downstream of the intercept valve 10 and upstream of the intermediate pressure turbine 11.

  Reference numeral 20 denotes a generator current transformer for detecting transmission power from the generator 15 to the transmission line 17 (this is referred to as a generator load amount). Reference numeral 21 denotes a valve opening detector that detects the valve opening of the steam control valve 4, and reference numeral 22 denotes a valve opening detector that detects the valve opening of the intercept valve 10.

Next, functions will be briefly described based on a schematic control block diagram of a conventional steam turbine control apparatus 100T shown in FIG.
The conventional steam turbine control device 100T shown in FIG. 8 is roughly classified into components, and a speed control circuit 30, a load control circuit 40, a power load unbalance circuit 50T, a valve opening control circuit 60, and an intercept valve. And a quick closing circuit 70. All of these components are known, but an outline will be described below.

  First, the speed control circuit 30 obtains a speed control signal 30 s obtained by multiplying the deviation between the rated speed that is the target speed and the actual turbine speed 18 s detected by the turbine speed detector 18 by a control gain. Is output to the load control circuit 40.

  Next, the load control circuit 40 integrates the deviation between the output setting designation 80s set by the operator or the like and the load setting signal of the built-in load setting device (integrating element), and then inputs from the speed control circuit 30. The load request command signal 44s is obtained by adding the speed control signal 30s, and a low value signal is selected from the load request command signal 44s and the load limit setting signal, and the valve is opened as the steam control valve flow command signal 40s. It is configured to output to the degree control circuit 60.

Next, the valve opening degree control circuit 60 will be described.
Valve opening degree control circuit 60, the steam control valve valve opening control circuit 60 _-1 for controlling the valve opening of the steam control valve 4, intercept Benben opening control circuit 60 for controlling the valve opening degree of the intercept valve 10 are composed of two systems of _-2, of which, the steam control valve valve opening control circuit 60 _-1, the steam control valve 4 from the load control circuit 40 to input steam control valve flow command signal 40s A valve opening command is determined according to the “flow rate-valve opening characteristic”, and a value obtained by multiplying a deviation between the valve opening command and the actual valve opening 21 s of the valve opening detector 21 by a control gain is servoed. It is configured to output as a command signal.

On the other hand, the intercept Benben opening control circuit 60 _-2 inputs the load request command signal 44s output from the load control circuit 40, to the load request command signal 44s, steam control valve droop and intercept valves regulating After multiplying by a gain determined by a constant rate, a bias value (100%) for fully opening the intercept valve 10 is added to obtain an intercept valve flow rate command signal, and according to the “flow rate-valve opening characteristic” of the intercept valve 10 A value obtained by multiplying the deviation between the determined valve opening command and the actual valve opening 22s of the valve opening detector 22 by the control gain is output as a servo command signal.

Next, the power load unbalance circuit 50T will be described.
The power load unbalance circuit 50T functions to eliminate an overspeed state of the turbine by detecting an unbalanced state between the generator load and the turbine output caused by load interruption or a system fault. Steam pressure proportional to the turbine output, for example, a turbine output signal 19s which is an output signal of the reheat steam pressure detector 19 for detecting the reheat steam pressure, and a generator load detected by the generator current transformer 20 The signal 20s is input, the rate of change of the generator load signal 20s (a decrease amount per unit time), and the deviation between the turbine output signal 19Ts and the generator load signal 20s are monitored, respectively, and the rate of change of the generator load 20s Is a preset value (for example, -40% / 10 msec) or more, and the deviation between the turbine output signal 19s and the generator load signal 20s is predetermined. When detecting a state in which the set value (for example, + 40%) or more is detected, a signal 50Ts is output and at the same time the steam control valve 4 is rapidly fully closed by a rapid operation solenoid valve (not shown) of the steam control valve 4. The output of the load setting device built in the load control circuit 40 is forcibly set to zero.

  This operation is continued until the deviation between the turbine output signal 19s and the generator load signal 20s is less than the set value (40%), and when the deviation is less than the set value (40%), the rapid operation (not shown) is performed. Simultaneously with the release of the operation of the operating solenoid valve, the output of the load setting device in the load limiting circuit 40 is set to the value of the no-load rated rotational speed.

  Moreover, under the situation where the power load unbalance circuit 50T is operated, the intercept valve rapid closing circuit 70 is also operated, and the rapid operation electromagnetic valve of the intercept valve 10 is operated to rapidly fully close the intercept valve 10.

Finally, the intercept valve rapid closing circuit 70 will be described.
The intercept valve rapid closing circuit 70 has a turbine output 19s of a predetermined value (for example, 15%) or more and a load control signal for the intercept valve in order to eliminate the overspeed state of the turbine caused by load interruption or system fault. The valve opening command of the intercept valve 10 calculated from the state is a value lower by, for example, 5% or more than the actual valve opening, that is, the deviation between the intercept valve valve opening command and the actual opening of the intercept valve is − The intercept valve 10 is configured to be fully closed by detecting the condition of 5% or less and operating the quick-acting solenoid valve of the intercept valve 10 for a certain period of time.
In addition to the above two conditions, the intercept valve rapid closing circuit 70 also has an interlock condition that the valve opening command of the intercept valve 10 is not more than a fully open value.

  When the power load unbalanced state occurs and the turbine rotation speed 18 s rises to the operating rotation speed range of the intercept valve 10, the fully opened intercept valve 10 starts to operate in the closing direction, resulting in a large closing direction deviation. 10 is fully closed by the operation of the quick action solenoid valve. When the intercept valve 10 is fully closed, the large deviation in the closing direction is eliminated, and the turbine rotational speed determined by the speed regulation rate of the intercept valve 10 in the process of decreasing the turbine rotational speed (for example, the intercept valve regulation rate is 2%). For example, the intercept valve 10 shifts from the fully closed state to the fully open state between the rated speed and 102%.

FIG. 9 is an operation diagram of a turbine settling process when power load imbalance occurs in the conventional apparatus.
When an unbalanced state between the generator load and the turbine output occurs due to load interruption or a system fault, the power load unbalance circuit 50T operates (ON) at time t1, and at the same time, the turbine speed is the rated speed. It rises rapidly from (100%).

Then, when the turbine speed increases and becomes equal to or higher than the blowdown speed (at 102% if the intercept valve speed adjustment rate is 2%) at time t2, the intercept valve rapid closing circuit 70 is turned on at time t2. It operates (ON), and the valve opening degree of the intercept valve 10 is suddenly throttled from the valve opening degree of 100% so far to be fully closed (0%).
When the opening degree of the intercept valve 10 is fully closed, the intercept valve rapid closing circuit 70 returns to the OFF state again.

The turbine rotation speed continues to increase for a while due to inertia immediately after the steam amount to the high-pressure turbine 5 and the intermediate-pressure turbine 11 suddenly decreases, and reaches a peak value and starts to decrease.
Thereafter, when the turbine rotational speed decreases to the blowdown rotational speed (102% rotational speed) at time t3, the valve opening of the intercept valve 10 starts to gradually open from the fully closed (0%) state.

  When the turbine rotation speed further decreases and the turbine rotation speed decreases to 101% at time t4, the power load unbalance circuit 50T is reset (OFF), and at the same time, the valve opening degree of the intercept valve 10 is further increased.

As a result, the turbine rotation speed increases again from time t4 and exceeds 102%.
At time t5, the intercept valve abrupt closing circuit 70 operates again (ON), so that the valve opening of the intercept valve 10 is again controlled to the fully closed (0%) state. Since the opening degree of the intercept valve 10 is fully closed, the intercept valve rapid closing circuit 70 returns to the OFF state again (time t6). When the turbine rotational speed decreases to 102%, the intercept valve 10 starts to open again according to the valve opening characteristic of the function generator 67. After the rotational speed reaches 101% at time t7, the intercept valve 10 opens at a large rate of change. Return to the fully open (100%) state at t8. The turbine rotation speed at this time is 100%.

  The turbine speed continues to decrease thereafter, and settles to a speed much lower than the rated speed (100%) at time t9.

JP-A-5-18207

  As can be seen from the characteristic diagram of FIG. 9, in the conventional steam turbine control device 100T, the turbine rotational speed is lowered (turbine settling) at the timing when the operations of the power load unbalance circuit 50T and the intercept valve rapid closing circuit 70 are reset. There may be fluctuations in the rotational speed in the process.

That is, in the conventional steam turbine control device,
(I) When the reheat bowl pressure after the intercept valve is used as the steam pressure proportional to the turbine output, when the intercept valve 10 is operated and the intercept valve 10 is fully closed (0%) Since the turbine output also becomes zero, an off-delay timer is added to continue the operation of the power load unbalance circuit for a certain period of time.

  In this case, since the timer time is set assuming that the increase in the number of revolutions during rated load operation is the largest, if the power load imbalance is activated during partial load operation, the timing for resetting the operation is too late. There is a drawback that the turbine rotational speed undershoots from the rated rotational speed.

(Ii) In the turbine settling process, when the turbine rotation speed becomes equal to or less than the blowdown rotation speed (102% if the intercept valve speed adjustment rate is 2%), the intercept steam is blown to blow down the residual steam in the reheater. The valve 10 starts to open (time t3 in FIG. 9). The occurrence of the secondary peak of the rotational speed (time t4-t6 in FIG. 9) in the turbine settling process is caused by the operation timing and reset timing of the power load unbalance circuit and the intercept valve rapid closing circuit in the vicinity of the blowdown rotational speed.

(Iii) Since the load setting device of the load control circuit 40 is set to the value of the no-load rated speed when the power load unbalance circuit 50T is reset, the final turbine settling speed is almost the rated speed. In some cases, it may deviate from the rated speed due to the steam conditions during settling.

  Accordingly, the present invention has been made to solve the above-described problems, and is a steam that reduces fluctuations in the turbine rotational speed in the turbine settling process after the power load unbalance operation and can smoothly reach the settling rotational speed. It is an object to obtain a turbine control device and a steam turbine control method.

  Another object of the present invention is to increase the turbine speed by opening the intercept valve or to undershoot from the rated speed by making the timing to reset the power load unbalance operation appropriate. It is an object of the present invention to provide a steam turbine control device and a steam turbine control method that can be prevented.

  In order to achieve the above object, an invention according to claim 1 is directed to a speed control circuit that outputs a speed control signal obtained from a deviation between a target rotational speed and an actual turbine speed, and a load set by a load setting device. Either of a load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between a setting signal and an output setting command, or a load limit setting signal set by a load limit setting device A load control circuit that selects the lower value and outputs it as a steam control valve flow command signal, and determines a valve opening command based on the steam control valve flow command signal from the load control circuit, A steam control valve opening control circuit that outputs as a servo command signal based on the deviation from the actual valve opening, and a steam control valve adjustment rate and intercept valve control to the load request command signal input from the load control circuit After multiplying the value determined by the rate, add the bias value to fully open the valve to obtain the intercept valve flow command signal, and set the intercept valve flow command signal to the function generator flow rate-opening An intercept valve valve opening control circuit that obtains a valve opening command by inputting into a characteristic and outputs a value obtained from a deviation between the valve opening command and the actual valve opening as a servo command signal, a generator load, and a turbine A power load unbalance circuit that, when detecting an unbalanced state with the output, operates a quick-acting solenoid valve to fully close the steam control valve, and self-holds this operating state until the unbalanced state is resolved; When it detects that the intercept valve opening command is lower than the actual valve opening by a predetermined value or more, it operates the rapid action solenoid valve for a certain period of time to fully close the intercept valve. In the steam turbine control device comprising: a sept valve rapid closing circuit, the power load unbalance circuit includes a turbine rotational speed increase rate determining means for detecting that the turbine rotational speed increase rate is equal to or less than a predetermined value, and a turbine Turbine rotational speed detection means for detecting that the rotational speed has become a predetermined value or less is added, and the turbine rotational speed increase rate determination means and the turbine rotational speed detection means are reset under the condition that both operate. .

  According to a second aspect of the present invention, there is provided a speed control circuit that outputs a speed control signal obtained from a deviation between the target rotational speed and the actual turbine speed, a load setting signal set by a load setting device, an output setting command, The load request command signal obtained by adding the speed control signal input from the speed control circuit to the deviation of the load and the load limit setting signal set by the load limit setter is selected as one of the low values. A load control circuit that outputs as a steam control valve flow rate command signal, a valve opening command is determined based on the steam control valve flow command signal from the load control circuit, and a deviation between the valve opening command and the actual valve opening A steam control valve opening degree control circuit that outputs as a servo command signal based on the load control command, and a load request command signal input from the load control circuit is determined by a steam control valve regulation rate and an intercept valve regulation rate Then, add the bias value for fully opening the valve to obtain the intercept valve flow rate command signal, and input this intercept valve flow rate command signal to the flow rate-opening characteristics of the valve set in the function generator. An intercept valve valve opening control circuit that obtains an opening command and outputs a value obtained from a deviation between the valve opening command and the actual valve opening as a servo command signal, and an unbalanced state between the generator load and the turbine output Is detected, the rapid operation solenoid valve is operated to fully close the steam control valve, and the power load unbalance circuit that self-maintains this operating state until the unbalanced state is resolved, and the intercept valve valve opening command An intercept valve quick-close circuit that operates a rapid-acting solenoid valve for a certain period of time to fully close the intercept valve when a state is detected that is lower than the actual valve opening by a predetermined value or more. In the steam turbine control device, the intercept valve opening degree control circuit includes an opening speed limiting means for limiting an operating speed of the intercept valve when the intercept valve opens by resetting the intercept valve suddenly closing. It is characterized by having.

  According to a fourth aspect of the present invention, there is provided a speed control circuit that outputs a speed control signal obtained from a deviation between the target rotational speed and the actual turbine speed, a load setting signal set by a load setting device, an output setting command, The load request command signal obtained by adding the speed control signal input from the speed control circuit to the deviation of the load and the load limit setting signal set by the load limit setter is selected as one of the low values. A load control circuit that outputs as a steam control valve flow rate command signal, a valve opening command is determined based on the steam control valve flow command signal from the load control circuit, and a deviation between the valve opening command and the actual valve opening A steam control valve opening degree control circuit that outputs as a servo command signal based on the load control command, and a load request command signal input from the load control circuit is determined by a steam control valve regulation rate and an intercept valve regulation rate Then, add the bias value for fully opening the valve to obtain the intercept valve flow rate command signal, and input this intercept valve flow rate command signal to the flow rate-opening characteristics of the valve set in the function generator. An intercept valve valve opening control circuit that obtains an opening command and outputs a value obtained from a deviation between the valve opening command and the actual valve opening as a servo command signal, and an unbalanced state between the generator load and the turbine output Is detected, the rapid operation solenoid valve is operated to fully close the steam control valve, and the power load unbalance circuit that self-maintains this operating state until the unbalanced state is resolved, and the intercept valve valve opening command An intercept valve quick-close circuit that operates a rapid-acting solenoid valve for a certain period of time to fully close the intercept valve when a state is detected that is lower than the actual valve opening by a predetermined value or more. In the steam turbine control device, the load control circuit is configured to change the output of the load setting device so that the set rotational speed after resetting the operation of the power load unbalance circuit matches the rated rotational speed. It has an output control means.

Further, the invention according to claim 6 is a speed control circuit that outputs a speed control signal obtained from a deviation between the target rotational speed and the actual turbine speed, a load setting signal and an output setting command set by a load setting device, The load request command signal obtained by adding the speed control signal input from the speed control circuit to the deviation of the load and the load limit setting signal set by the load limit setter is selected as one of the low values. A load control circuit that outputs as a steam control valve flow rate command signal, a valve opening command is determined based on the steam control valve flow command signal from the load control circuit, and a deviation between the valve opening command and the actual valve opening A steam control valve opening control circuit that outputs a servo command signal based on
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening Is detected as a servo command signal, and when an unbalanced state between the generator load and the turbine output is detected, the rapid operation solenoid valve is operated to fully close the steam control valve. The power load unbalance circuit that self-maintains this operating state until the equilibrium state is eliminated, and the intercept valve opening command is a value lower than the actual valve opening by a predetermined value or more. In a steam turbine control method, wherein a steam turbine is controlled with an intercept valve rapid closing circuit that operates a rapid operation solenoid valve for a certain period of time to fully close an intercept valve when a state is detected. The power load unbalance operation is reset when a condition where the rate is equal to or lower than a predetermined value and a condition where the turbine rotational speed is equal to or lower than the predetermined value are satisfied at the same time.

  Further, the invention according to claim 7 is directed to a speed control circuit that outputs a speed control signal obtained from a deviation between the target rotational speed and the actual turbine speed, a load setting signal set by a load setting device, and an output setting command. The load request command signal obtained by adding the speed control signal input from the speed control circuit to the deviation of the load and the load limit setting signal set by the load limit setter is selected as one of the low values. A load control circuit that outputs as a steam control valve flow rate command signal, a valve opening command is determined based on the steam control valve flow command signal from the load control circuit, and a deviation between the valve opening command and the actual valve opening A steam control valve opening degree control circuit that is output as a servo command signal based on the load control command, and a load request command signal input from the load control circuit is determined by a steam control valve regulation rate and an intercept valve regulation rate. After multiplying the value, add the bias value to fully open the valve to obtain the intercept valve flow command signal, and input this intercept valve flow command signal to the flow rate-opening characteristics of the valve set in the function generator An intercept valve opening control circuit that obtains a valve opening command and outputs a value obtained from a deviation between the valve opening command and the actual valve opening as a servo command signal, and an imbalance between the generator load and the turbine output When a state is detected, a power load unbalance circuit that operates the quick-acting solenoid valve to fully close the steam control valve and self-holds this operation state until the unbalanced state is resolved, and the intercept valve opening degree An intercept valve abrupt closing circuit that operates a quick-acting solenoid valve for a certain period of time to fully close the intercept valve when it detects that the command is lower than the actual valve opening by a predetermined value or more. A steam turbine control method for controlling a steam turbine to limit an increase rate of a valve opening command of the intercept valve when the intercept valve opens by resetting the intercept valve It is characterized by that.

  Furthermore, the invention according to claim 8 is directed to a speed control circuit that outputs a speed control signal obtained from a deviation between the target rotational speed and the actual turbine speed, a load setting signal set by a load setting device, and an output setting command. Select a low value from the load request command signal obtained by adding the speed control signal input from the speed control circuit to the deviation from the load limit setting signal set by the load limit setting device A steam control valve flow rate command signal, and a valve opening command is determined based on the steam control valve flow command signal from the load control circuit, and the valve opening command and the actual valve opening Steam control valve opening control circuit output as servo command signal based on deviation, and load request command signal input from the load control circuit is determined by steam control valve regulation rate and intercept valve regulation rate Then, add the bias value for fully opening the valve to obtain the intercept valve flow rate command signal, and input this intercept valve flow rate command signal to the flow rate-opening characteristics of the valve set in the function generator. An intercept valve opening degree control circuit that outputs a value obtained from a deviation between the valve opening degree instruction and the actual valve opening degree as a servo instruction signal, and the difference between the generator load and the turbine output. When an equilibrium state is detected, a rapid operation solenoid valve is operated to fully close the steam control valve, and a power load unbalance circuit that self-maintains this operation state until the unbalanced state is resolved, and an intercept valve open. Intercept valve abruptly closing the intercept valve by operating the rapid operation solenoid valve for a certain period of time when the degree command is lower than the actual valve opening by a predetermined value or more In the steam turbine control method to control the steam turbine and a road, the settling speed after resetting the operation of the power load imbalance circuit and controls to match the rated speed.

  According to the steam turbine control device and the steam turbine control method of the present invention, the timing for resetting the self-maintenance of the power load unbalance operation is determined based on the turbine rotational speed and the amount of change thereof, so the reset timing is too early. Thus, it is possible to prevent a problem that the turbine rotational speed increases due to the opening operation of the intercept valve, or the reset timing is too late and the turbine rotational speed undershoots from the rated rotational speed.

  Further, according to the steam turbine control device and the steam turbine control method of the present invention, it is possible to reduce the fluctuation of the turbine rotational speed in the turbine settling process after the power load unbalance operation, and to smoothly reach the settling rotational speed.

1 is a schematic control block diagram of a steam turbine control device according to a first embodiment of the present invention. FIG. 3 is an operation diagram of a turbine settling process when a power load imbalance occurs in the steam turbine control device of the first embodiment. The schematic control block diagram of the steam turbine control apparatus which concerns on Embodiment 2 of this invention. FIG. 6 is an operation diagram of a turbine settling process when a power load imbalance occurs in the steam turbine control device of the second embodiment. The schematic control block diagram of the steam turbine control apparatus which concerns on Embodiment 3 of this invention. FIG. 9 is an operation diagram of a turbine settling process when a power load imbalance occurs in the steam turbine control device of the third embodiment. The schematic system diagram which shows a steam turbine plant. The general | schematic control block diagram which shows the conventional steam turbine control apparatus. The operation | movement figure of the turbine settling process at the time of the conventional power load imbalance generation | occurrence | production.

  Hereinafter, an embodiment of a steam turbine control device according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component through each figure, and it omits suitably so that it may not become a duplicate description.

(Embodiment 1)
FIG. 1 is a control block diagram of the steam turbine control device according to the first embodiment of the present invention, and FIG. 2 is an operation diagram of a turbine settling process when power load imbalance occurs according to the first embodiment.

(Constitution)
In FIG. 1, a steam turbine control device 100 according to the first embodiment is similar to a conventional steam turbine control device 100T in that a speed control control circuit 30, a load control circuit 40, a power load unbalance circuit 50, a valve opening control. The circuit 60 and the intercept valve rapid closing circuit 70 are different from the conventional apparatus 100T in that the power load unbalance circuit 50 is improved.

  Hereinafter, the internal configuration from the speed control circuit 30 to the intercept valve rapid closing circuit 70 will be described in detail.

First, the speed control control circuit 30 will be described.
The speed control control circuit 30 is detected by a rated speed setting device 31 for setting the turbine rated speed, a rated speed setting value 31 s of the turbine rated speed setting device 31 and the turbine speed detector 18 (FIG. 7). The rotation speed deviation signal 32s is calculated by matching the turbine actual rotation speed 18s, and a gain adjuster 33 that multiplies the rotation speed deviation signal 32s by a necessary control gain. The output 30s of the gain adjuster 33 is output to the load control circuit 40 at the next stage as a speed control signal.

Next, the load control circuit 40 will be described.
The load control circuit 40 is constituted by an integral element, and a load setting unit 43 that forms a first-order lag circuit by feeding back an output signal to the input side, and an output setting set by an operator or the like on the input side of the load setting unit 43 An adder 41 that calculates a deviation signal 41 s between the command 80 s and the load setting signal 43 s and a load setting value 43 s output from the load setting unit 43 are forced to zero by the operation of the power load unbalance circuit 50 described later. The setting switch 42 to be set and the load control value 30s output from the speed control control circuit 30 is added to the load setting value 43s obtained by integrating the deviation signal 41s with the load setting unit 43, thereby adding a load. An adder 44 for obtaining a request command signal 44s, a load limit setting unit 45, a load request command signal 44s output from the adder 44, and the previous Enter the restriction signal 45s from the load limit setting device 45, and a one to select the low value of the signal output as steam control valve flow rate command 40s low value selector 46.

Next, the power load unbalance circuit 50 will be described.
The power load unbalance circuit 50 according to the first embodiment calculates the amount of change in the turbine rotation speed within a predetermined time, that is, the turbine rotation speed change rate, and the increase rate becomes equal to or less than a predetermined value (for example, 0%) ( Condition 1) and a function to detect that the turbine rotation speed has become a predetermined value (for example, 101%) or less (condition 2) and reset the operation state (OFF) are added to the conventional power load unbalance circuit 50T. is doing.

That is, the power load imbalance circuit 50 according to Embodiment 1, the first protection circuit 50 _-1 corresponding to the power load imbalance circuit 50T according to Figure 8 of the prior art mainly includes the first protection circuit 50 The second protection circuit _50-2 releases or resets the self-holding when the above two conditions are satisfied when the _-1 operates and is self-holding.

First, the first protection circuit 50 _-1, generator load signal detected by the turbine output signal 19s and the generator current the current transformer 20 is the output signal of the reheat steam pressure detector 19 is proportional to the turbine output An adder 51 that compares 20s and calculates the deviation signal, and the deviation signal 51s of the adder 51 is input, and the magnitude of the deviation is equal to or greater than a preset value (for example, + 40%). If the difference is greater than or equal to the set value, a comparator 52 that outputs a signal 52 s that is a logical signal “1”, a differentiator 53 that calculates the rate of change of the generator load 20 s, and the differentiator 53 are output. When the generator load change rate 53s decreases to a predetermined change rate rate (as an example, −40% / 10 msec) or more, the comparator 54 outputs a signal 54s that is a logical signal “1”, and the comparator 52 Output signal While 52s is the first input signal, the output signal 54s of the comparator 54 is the second input signal 55s via the OR operator 55, and the AND condition of both the input signals 52s and 55s is satisfied. The AND operator 56 outputs a logic signal “1”.

  In the case where the reheat steam pressure detector 19 described above is not installed upstream of the reheater 7 but downstream of the intercept valve 10, in order to prevent immediate reset due to full closure of the intercept valve 10. An OFF delay timer is provided after the AND operator 56 to delay the reset timing by a certain time.

Next, the second protection circuit _50-2 receives the actual turbine speed 18 s detected by the turbine speed detector 18, and calculates the rate of increase of the actual turbine speed change rate calculator 58. It is determined whether or not the rate of increase of the turbine rotational speed obtained by the change rate calculator 58 is equal to or less than a predetermined set value (for example, 0%). When the rate is 0% or less, a logic signal “1” is output. A comparator 59 is provided. Here, the meaning that the set value is 0% or less includes the case where the rate of increase of the turbine speed is negative.

Further, the second protection circuit 50 _-2, (as one example, 101%) settings turbine actual rotational speed 18s is predetermined to determine whether a following logic signal when: 101% "1" AND circuit that outputs the logical signal “1” when both AND signals 59s and 510s are input and the AND condition is satisfied, and the logical signal “0” is output when the AND condition is not satisfied. A child operator 511, a NOT operator 512 that inverts the logical output “1” or “0” of the AND operator 511 and outputs an output signal 512 s of “0” or “1”, and an output of the NOT operator 512 a signal 51 s, the output 56s inputs the signal 57s obtained via the OR operator 57 of the first protection circuit _{50 -1} aND operator 56, both input signals 512s, 57s of the aND condition is And a AND operator 513 outputs a rapid closing command 50s to the steam control valve 4 upon.

The power load unbalance circuit 50 is configured to input the output signal 50 s of the AND operator 513 to the input terminal of the OR operator 57 so that the first protection circuit _50-1 once holds once it operates. is doing.

Thus, turbine power load imbalance circuit 50 of the first embodiment is that the first protection circuit 50 _-1, which corresponds to a conventional power load imbalance circuit 50T, detected by turbine speed detector 18 The rotational speed 18 s is input, and the comparator 59 detects that the rate of increase of the turbine rotational speed in the settling process calculated by the change rate calculator 58 has become a set value of 0% or less, and the turbine at this time When the comparator 510 detects that the rotation speed 18s is equal to or less than the set value of 101% and the AND condition of the signals 59s and 510s output from both the comparators 59 and 510 is satisfied, the power load unbalance circuit 50 A second protection circuit _50-2 for resetting the operation state is added.

Next, the valve opening degree control circuit 60 will be described.
The valve opening control circuit 60 mainly includes a steam control valve valve opening control circuit 60 _-1 for controlling the valve opening of the steam control valve 4, intercept Benben opening for controlling the valve opening degree of the intercept valve 10 It consists of two systems with the degree control circuit _60-2 .

Steam control valve valve opening control circuit 60 _-1, the steam control valve 4 which the load control circuit 40 inputs a steam control valve flow rate command signal 40s is preset "flow rate command - the valve opening instruction conversion characteristics" According to the function generator 61 for determining the valve opening command 61s, an adding unit 62 for calculating a deviation signal 62s between the valve opening command 61s and the actual valve opening 21s, and a predetermined control gain for the deviation signal 62s. And a gain adjuster 63 that outputs a value obtained by multiplication as a servo command signal.

On the other hand, the intercept Benben opening control circuit 60 _-2 enter the load request command signal 44s output from the adder 44 of the load control circuit 40, and the steam control valve droop to the load request command signal 44s intercept A gain adjuster 64 that multiplies a control gain determined by the valve regulation rate, a value 64s obtained by multiplication by the gain adjuster 64, and a bias value for fully opening the valve set by the bias setting unit 65 ( 100%) An adder 66 for adding 65 s to obtain an intercept valve flow command signal 66 s, and inputting the intercept valve flow command signal 66 s, according to a predetermined “flow-valve opening characteristic” of the intercept valve A function generator 67 for determining the opening command 67s, and a deviation 68s between the valve opening command 67s and the actual valve opening 22s is obtained. An adder 68 and a gain adjuster 69 that outputs a value obtained by multiplying the deviation 68s by the control gain as a servo command signal _60-2s .

Further, the intercept valve rapid closing circuit 70 will be described.
The intercept valve suddenly closed circuit 70, the intercepted Benben enter the intercept Benben opening instruction 67s from the function generator 67 of the opening degree control circuit 60 _-2, if the valve opening command 67s is less than fully open value to a comparator 71 which outputs a logic signal "1" signal serving 71s, enter the deviation 68s output from the adder 68 of the intercepting Benben opening control circuit 60 _-2, the deviation 68s predetermined value (e.g. , −5%) or less, a comparator 72 that outputs a signal 72s that is a logical signal “1” and a turbine output signal 19s from the reheat steam pressure detector 19 are input, and this is a predetermined value (for example, 15%), a comparator 73 that outputs a signal 73s that is a logical signal “1”, and output signals 71s, 72s, and 73s of the comparators 71, 72, and 73 are input. Detecting the AND condition, and a AND operator 74 for outputting an AND condition is satisfied results in the intercept valve 10 as steep close instruction 70s.

  As described above, the operating condition of the intercept valve quick closing circuit 70 is that the turbine output 19s is equal to or greater than a predetermined value (for example, 15%), and the intercept valve opening command and the intercept valve calculated from the intercept valve speed load control signal. The deviation from the opening is a predetermined value (for example, -5%) or less, that is, the deviation in the closing direction is large, and the valve opening command of the intercept valve 10 is not more than the fully opened value.

(Function)
Next, the operation of the steam turbine control device 100 according to the first embodiment will be described.
(I) Steady state (state where steam turbine output and generator output are balanced)
The speed control circuit 30 adjusts a deviation signal 32 s between the rated speed setting signal 31 s and the turbine speed signal 18 s to a preferable gain by the gain adjuster 33, and outputs it to the load limiting circuit 40 as the speed control signal 30 s.

  This speed control signal 30 s is added to the load setting signal 43 s in the load limiting circuit 40 to be sent to the low value selector 46 as a load request command signal 44 s. The low value selector 46 is preliminarily input with a load limit set value 45s, and the lower one of the load request command signal 44s and the load limit set value 45s is selected and the steam valve flow rate command signal 40s is selected. And output to the valve opening control circuit 60.

In steam control valve valve opening control circuit 60 _-1 valve opening degree control circuit 60, by entering the steam control valve flow rate command signal 40s output from the load limiting circuit 40 to the function generator 61 of the steam control valve 4 " The valve opening command 61 s is determined according to the “flow rate command-valve opening command conversion characteristics”, and the valve opening command 61 s detected by the adding unit 62 and the valve opening signal detected by the valve opening detector 21 of the steam control valve 4. A deviation 62 s from 21 s is calculated, and the deviation 62 s is multiplied by an adjustment gain by a gain adjuster 63, and then a servo command signal 60 _{−1 s} is sent to a steam control valve driving device (not shown). The steam control valve 4 supplies high-pressure steam corresponding to the servo command signal _60-1s to the high-pressure steam turbine 5.

Also, intercepting the Benben opening degree control circuit 60 _-2, wherein the load control load request command signal 44s output from the adder 44 of the circuit 40 is input to gain controller 64, steam control valve droop and intercept valve A value determined by the adjustment rate is multiplied to obtain a multiplied value 64s, and a bias value (100%) 65s for fully opening the intercept valve 10 is added to the multiplied value 64s to obtain an intercept valve flow rate command signal 66s. Input to the function generator 67. This function generator 67 generates a valve opening command 67 s according to the input, calculates a deviation 68 s from the detection signal 22 s of the valve opening detector 22, and multiplies the adjustment gain by a gain adjuster 69. The servo command signal _60-2s is sent to the intercept valve driving device that does not. The intercept valve 10 supplies intermediate pressure steam corresponding to the servo command signal _60-2s to the intermediate pressure steam turbine 11.

  In this way, in the steady state of the power system, even when the generator load fluctuates, the valve openings of the steam control valve 4 and the intercept valve 10 are controlled so that the generator speed is maintained at the rated speed. ing.

Since the steam turbine output 19s in the steady state of the electric power system and the generator output 20s are balanced, the deviation signal 51s of the first protection circuit 50 _-1 of the adder 51 of the power load imbalance circuit 50 compares The signal output from the comparator 52 is a logical value “0” because it is sufficiently smaller than the set value of the comparator 52, and the generator output change rate 53 s obtained from the differentiator 53 is also higher than the set value of the comparator 54. Is sufficiently small, the signal output from the comparator 54 is a logical value “0”. As a result, the first protection circuit _50-1 does not operate and the power load unbalance circuit 50 does not operate.

  Since the power load unbalance circuit 50 does not operate, the setting switch 42 of the load control circuit 40 does not operate to force the setting value of the load setting unit 43 to zero. For this reason, the intercept valve rapid closing circuit 70 also does not operate.

(Ii) Steam turbine output and generator output are in an unbalanced state. This is because the circuit breaker 16 was shut off due to a system fault or the like, or the load was shut off in a power system (not shown). When the generator output 20s rapidly decreases, the rotational speed of the steam turbine, which is the prime mover, increases according to the decrease in the generator output 20s.

In the first protection circuit _{50 -1} power load imbalance circuit 50, a predetermined value reduction rate 53s of the generator output 20s obtained by the differentiator 53 is set to the comparator 54 (e.g., -40% / 10 msec ) AND operator that the decrease 51 s and the deviation 51 s between the turbine output signal 19 s and the generator load signal 20 s exceeds a predetermined value (for example, + 40%) set by the comparator 52 Detect at 56. Then, a signal 56 s having a logical value “1” is output from the AND operator 56 to one input terminal of the AND operator 513 via the OR operator 57.

At this time, the second protection circuit 50 _-2 power load imbalance circuit 50, increase in the turbine speed 18s rate calculated while the turbine settling process in the power load imbalance caused by the change rate calculator 58 58s, the comparison Since it is not less than a predetermined value (for example, 0%) set in advance in the unit 59 and exceeds 0%, the comparator 59 outputs a signal 59s having a logical value “0”.

  Further, the turbine speed 18 s is not less than a predetermined value (for example, 101%) set in advance in the comparator 510 and is larger than 101%, so that the comparator 510 outputs a signal 510 s having a logical value “0”. The In this state, the AND condition of the AND operator 511 is not satisfied, and a signal 511 s having a logical value “0” is output from the AND operator 511 to the NOT operator 512. The NOT operator 512 inverts the signal 511 s having the logical value “0” and inputs the signal 512 s having the logical value “1” to the other input terminal of the AND operator 513.

  As a result, in a state where the load is interrupted due to a system fault or the circuit breaker 16 is interrupted and the generator output 20 s becomes zero or rapidly decreases, both input signals are “1” in the AND operator 513. Thus, the power load unbalance circuit 50 operates.

When the power load unbalance circuit 50 is operated, a rapid closing command 50 s is given to a rapid operation solenoid valve (not shown) of the steam control valve 4 to rapidly fully close the steam control valve 4, and at the same time, it is built in the load control circuit 40. The output of the load setting unit 43 is forcibly set to zero via the setting switching unit 42.
This operation is continued until the logic value "0" as the signal 512s from the comparator 59 and the comparator 510 are both operated NOT operator 512 of the second protection circuit _{50 -2} is output.

Forcibly result of setting to zero the output of the load setting device 43, as described above, the load request command signal 44s output from the addition unit 44 outputs to a low value to intercept Benben opening control circuit 60 _-2 Is done. Therefore the intercept Benben opening degree control circuit 60 _-2, the output signal 66s of the adder 66 becomes smaller than that in the healthy state, output from the function generator 67 was intercepted Benben opening command 67s also fully open value ( 100%).

Then, in the intercept valve rapid closing circuit 70, the comparator 71 operates. In this case, intercepting Benben opening control circuit ₆₀ deviation 68s also a constant value obtained in ₂ (e.g., 5%) because hereinafter comparator 72 also operates, the turbine output 19s is a constant value (e.g., 15%) Since it is the above size, the comparator 73 also operates.

  For this reason, the input condition of the AND operator 74 of the intercept valve rapid closing circuit 70 is satisfied, and a rapid closing command 70s is given to a rapid operation electromagnetic valve (not shown) of the intercept valve 10 to rapidly increase the valve opening degree of the intercept valve 10. To fully close.

Immediately after the power load imbalance circuit 50 and the intercept valve rapid closing circuit 70 are operated, the turbine rotational speed increases due to inertia, and after reaching a peak value, starts to decrease. The turbine rotational speed 18s decreases from a peak value to a predetermined value (for example, 101%) or less, and the rate of increase of the turbine rotational speed calculated by the change rate calculator 58 at this time is a predetermined value (for example, 0%) or less, since the comparator 510 and the comparator 59 of the second protection circuit _{50 -2} to output a logic signal "1" in operation respectively, the signal becomes a logical value "1" from the aND operator 511 511S Is output. As a result, the output signal 512 s from the NOT operator 512 is inverted from the previous logical value “1” to “0”, the self-holding of the operation of the power load unbalance circuit 50 is reset, and the rapid operation of the steam control valve 4 is performed. The operation of the solenoid valve is canceled, and the output of the load setting unit 43 provided in the load control circuit 40 is set to the value of the no-load rated rotational speed.

Thus, the power load imbalance circuit 50 according to Embodiment 1, the first protection circuit 50 _-1, which corresponds to a conventional power load imbalance circuit 50T, turbine speed increase rate is a predetermined value (e.g. , 0%) or less, and resetting the self-holding of the operation of the power load unbalance circuit 50 when two conditions are detected that the turbine rotational speed 18s is less than a predetermined value (for example, 101%). Since the second protection circuit _50-2 is added, the operation of the rapid operation solenoid valve of the steam control valve 4 is canceled in a state where the turbine rotational speed is higher than that of the conventional one, and the output of the load setting device 43 of the load control circuit 40 is Set to the value of the no-load rated speed.

  FIG. 2 illustrates the operation of the first embodiment from the operation (ON) time to the reset (OFF) time of the power load unbalance circuit 50 in comparison with the operation of the conventional device. FIG. FIG. 2B shows an example of the response in the example, and FIG. 2B shows the response in the first embodiment.

In the conventional power load imbalance circuit, since the second protection device _50-2 of the first embodiment is not provided, it is unavoidable to determine operation and reset only by the power load imbalance circuit 50T. As shown in FIG. 2A, the power load imbalance circuit 50T is reset at time t8 when the turbine speed decreases from the peak value to the rated speed (100%). The return timing of the circuit is too late, and the turbine rotational speed undershoots from the rated rotational speed (100%) and becomes a settling rotational speed at a considerably low rotational speed. DS2 represents the difference between the settling speed and the rated speed.

On the other hand, in the first embodiment, by adding the second protection device _50-2 to the power load unbalance circuit 50, the turbine rotational speed is rated from the peak value as shown in FIG. The power load unbalance circuit 50 is reset by determining the rate of change of the rising rate at the time tx when the rotational speed is decreased to a rotational speed higher than the rotational speed (for example, 101%) or less, which is more appropriate than in the past. The settling speed can be brought close to the rated speed at the timing. If the difference between the settling speed and the rated speed in this case is DS1, DS1 can be made smaller than DS2 of the conventional example.

  As described above, according to the first embodiment, the timing for resetting the self-holding of the operation of the power load unbalance circuit is determined based on the turbine speed and the amount of change thereof. At time t4-t5, the reset timing is too early and the turbine speed increases due to the opening operation of the intercept valve 10, or the reset timing is too late and the turbine speed is at the rated speed as at time t8-t9. The problem of undershooting from the number can be prevented.

(Embodiment 2)
Next, the steam turbine control device of the second embodiment will be described with reference to FIGS. 3 and 4.
FIG. 3 is a control block diagram of the steam turbine control device according to the second embodiment of the present invention, and FIG. 4 is an operation diagram of a turbine settling process when a power load imbalance occurs according to the second embodiment.

  The steam turbine control device 100A of the second embodiment is different from the steam turbine control device 100 of the first embodiment described above in that some of the internal configurations of the power load unbalance circuit 50 and the valve opening control circuit 60 are changed. In other words, the other constituent elements are the same as those in the first embodiment, and a duplicate description will be omitted as appropriate.

That is, the power load unbalance circuit 50 according to the second embodiment is configured by removing the second protection circuit _50-2 from the power load unbalance circuit 50 in FIG. 1 and only the first protection circuit _50-1 as in the related art. It is said.

The valve opening control circuit 60 of the second embodiment, between the interception Benben opening degree control circuit 60 _-2 function generator 67 and the adder unit 68, abrupt closing of the reset of the intercept valve 10 (OFF ) Is provided with an opening operation speed limiting means for limiting the operation speed when the intercept valve 10 opens, in other words, the rate of increase of the valve opening command.

  This opening speed limiting means is provided with a rate of change limiter 610 that limits the rate of change in the increasing direction of the valve opening degree command 67s, which is the output of the function generator 67, between the function generator 67 and the adder 68. Further, the output signal 67 s from the function generator 67 is switched to the output signal 610 s from the change rate limiter 610 until the turbine is set after the power load unbalance circuit 50 and the intercept rapid closing circuit 70 are operated. And a signal switching device 611 for outputting.

  In the second embodiment configured as described above, the intercept valve 10 is in a period from when the power load unbalance circuit 50 and the intercept rapid closing circuit 70 are operated due to the occurrence of power load unbalance until the turbine is stabilized. An output 610 s of the change rate limiter 610 is selected by the signal switcher 611 as the valve opening command, so that the increase rate of the valve opening command is limited.

  In accordance with the change in the limited valve opening command, the intercept valve 10 is gradually opened until the turbine is set. After the turbine rotational speed has settled, the output of the function generator 67 is switched again as a valve opening command by the signal switch 611.

  FIG. 4 shows the turbine settling process at the time of occurrence of power load imbalance according to the second embodiment and the conventional turbine settling process, and FIG. 4A is the same as FIG. The process is shown, and FIG. 4B shows how the intercept valve opening degree and the turbine rotational speed of the second embodiment change.

Intercept Benben opening control circuit 60 _-2 change rate limiter 610, in the case of the prior art without a signal switch 611, as shown in FIG. 4 (a), the process of the intercept valve 10 is gradually opened ( At time t4-t6), there is a problem that the turbine rotational speed starts to increase, and thereby the intercept valve rapid closing circuit 70 operates again (time t5-t6).

On the other hand, in the case of the second embodiment, as shown in FIG. 4B, the change rate limiter 610 changes the valve opening command of the intercept valve 10 until the turbine rotational speed is stabilized. By restricting and gently opening the intercept valve 10, the disturbance applied to the turbine speed can be reduced.
As described above, according to the second embodiment, the influence of the opening operation of the intercept valve 10 on the fluctuation of the turbine rotational speed can be reduced.

(Embodiment 3)
Next, the steam turbine control device of the third embodiment will be described with reference to FIGS. 5 and 6.
FIG. 5 is a control block diagram of the steam turbine control device according to the third embodiment of the present invention, and FIG. 6 is an operation diagram of a turbine settling process when a power load imbalance occurs according to the third embodiment.

  The difference between the steam turbine control device 100B of the third embodiment and the steam turbine control device 100 of the first embodiment is that some of the internal configurations of the power load unbalance circuit 50 and the load control circuit 40 have been changed. Since the other constituent elements are the same as those in the first embodiment, a duplicate description will be omitted as appropriate.

That is, in the present embodiment 3, the power load imbalance circuit 50, only the first protection circuit 50 _-1 from the power load imbalance circuit 50 of FIG. 1 by removing the second protection circuit 50 _-2 That is, the conventional technique and It has the same configuration.

  In addition, the load control circuit 40 resets the power load unbalance circuit 50 from the operating state between the adder 41 that calculates the deviation between the output setting command 80 s and the output 43 s of the load setting device 43 and the load setting device 43. Later, load setter output control for controlling the settling speed of the turbine to match the rated speed is added.

  This added load setting device output control means inputs the turbine rotation speed 18s and calculates a deviation 48s from the rated rotation speed setting device 47 (a setting device equivalent to the rated rotation speed setting device 31 of the speed control circuit 30). An adder 48, a gain adjuster 49 that adjusts and outputs the deviation 48s, and an input signal to the load setting unit 43 is gain adjusted from a deviation 41s between the output setting command 80s and the output 43s of the load setting unit 43. And a signal switching unit 410 for switching to the output of the unit 49.

  In the third embodiment configured as above, after the power load unbalance circuit 50 is reset from the operating state and the turbine is set, the signal switcher 410 responds to the deviation between the rated speed and the actual set speed. A value is input to the load setting unit 43. Since the load setter 43 is an integral element as described above, until the deviation between the rated rotational speed and the actual settling speed is canceled, that is, until the turbine rotational speed matches the rated rotational speed, The output 43s is changed. After the turbine rotational speed 18 s returns to the rated rotational speed, the signal switching unit 410 switches the output to a deviation signal between the original output setting command 80 s and the output value 43 s of the load setting unit 43.

  FIG. 6 shows the turbine settling process when power load imbalance occurs according to the third embodiment and the turbine settling process of the prior art, and FIG. 6 (a) is the same as FIG. The settling process is shown, and FIG. 6 (b) shows how the turbine speed of the third embodiment changes.

  In the case of the conventional example in which the gain adjuster 49 and the signal switching unit 410 are not added to the load control circuit 40 as shown in FIG. 8, the steam condition at the time of settling is performed after time t9 in FIG. The final turbine settling speed may deviate from the rated speed.

  On the other hand, in the third embodiment, since the deviation between the settling rotational speed and the rated rotational speed is integrated in the load setting device 43 by the signal switching device 410, as after time t11 in FIG. 6B. The turbine rotational speed can be controlled to coincide with the rated rotational speed after settling.

  As described above, according to the third embodiment, the settling speed after the operation of the power load unbalance circuit can be prevented from greatly deviating from the rated speed, so that the subsequent turbine operation operation can be performed smoothly. Can do.

DESCRIPTION OF SYMBOLS 1 ... Steam generator or boiler, 2 ... Main steam pipe, 3 ... Main steam stop valve, 4 ... Steam control valve, 5 ... High pressure turbine, 6 ... Low temperature reheat pipe, 7 ... Reheater, 8 ... High temperature reheat pipe, DESCRIPTION OF SYMBOLS 9 ... Reheat steam stop valve, 10 ... Intercept valve, 11 ... Medium pressure turbine, 12 ... Crossover pipe, 13 ... Low pressure turbine, 14 ... Condenser, 15 ... Generator, 16 ... Circuit breaker, 17 ... Electric power system , 18 ... turbine speed detector, 19 ... reheat steam pressure detector, 20 ... current transformer for generator current, 21 ... valve opening detector for steam control valve, 22 ... valve opening detector for intercept valve, 80 ... Output setting command, 30 ... Speed control circuit, 31 ... (Turbine) rated speed setting device, 32 ... Adder, 33 ... (For speed control) gain adjuster, 40 ... Load control circuit, 41 ... Adder, 42 ... (Load setter output forced) Setting changer, 43 ... Load setter, DESCRIPTION OF SYMBOLS 5 ... Load limit setting device, 46 ... Low value selector, 47 ... (turbine) rated rotation speed setting device, 48 ... Adder, 49 ... Gain adjuster, 410 ... Signal switching device, 50 ... Power load unbalance circuit, _50-1 ... 1st protection circuit, _50-2 ... 2nd protection circuit, 51 ... Adder, 52 ... (Turbine output-generator load deviation) comparator, 53 ... (For generator load) differentiator, 54 ... (Generator load change) comparator, 55 ... OR operator, 56 ... AND operator, 57 ... OR operator, 58 ... (turbine rotational speed) change rate calculator, 59 ... (turbine rotational speed change rate) comparator , 510 ... (turbine speed) comparator, 511 ... AND operator, 512 ... NOT operator, 513 ... AND operator, 60 ... Valve opening control circuit, 60-1, 60-2, 61 ... Steam control valve Function generation for 4 flow rate command-valve opening command conversion , 62... Adder, 63... Gain adjuster for valve opening control of steam control valve 4, 64... (Intercept valve speed regulation rate) gain adjuster, 65... (Intercept valve full open bias) setter, 66. , 67 ... (Intercept valve flow rate command-valve opening degree command conversion) function generator, 68 ... Adder, 69 ... (Intercept valve opening degree control) Gain regulator, 610 ... (Intercept valve opening degree) Command) change rate limiter, 611... Signal switcher, 70... Intercept valve rapid closing circuit, 71... (Interval valve opening command) comparator, 72... (Intercept valve opening command-actual valve opening) ) Comparator, 73 ... (turbine output) comparator, 74 ... AND operator.

Claims (8)

A speed control circuit that outputs a speed control signal obtained from the deviation between the target rotational speed and the actual turbine rotational speed;
A load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between the load setting signal set by the load setting device and the output setting command, and a load set by the load limit setting device A load control circuit that selects any one of the lower limit setting signals and outputs it as a steam control valve flow command signal;
A steam control valve opening control that determines a valve opening command based on a steam control valve flow command signal from the load control circuit and outputs it as a servo command signal based on a deviation between the valve opening command and the actual valve opening Circuit,
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening An intercept valve opening control circuit that outputs a servo command signal,
When an unbalanced state between the generator load and the turbine output is detected, the rapid load solenoid valve is operated to fully close the steam control valve, and the power load that self-maintains this operating state until the unbalanced state is resolved An unbalanced circuit;
An intercept valve rapid closing circuit for operating the rapid operation solenoid valve for a certain period of time to fully close the intercept valve when detecting that the intercept valve valve opening command is a value lower than the actual valve opening by a predetermined value or more;
In a steam turbine control device comprising:
The power load unbalance circuit is
A turbine rotational speed increase rate determining means for detecting that the turbine rotational speed increase rate has become a predetermined value or less, and a turbine rotational speed detection means for detecting that the turbine rotational speed has become a predetermined value or less; A steam turbine control device, which is reset under a condition in which both the turbine rotational speed increase rate determination means and the turbine rotational speed detection means operate. A speed control circuit that outputs a speed control signal obtained from the deviation between the target rotational speed and the actual turbine rotational speed;
A load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between the load setting signal set by the load setting device and the output setting command, and a load set by the load limit setting device A load control circuit that selects any one of the lower limit setting signals and outputs it as a steam control valve flow command signal;
A steam control valve opening control that determines a valve opening command based on a steam control valve flow command signal from the load control circuit and outputs it as a servo command signal based on a deviation between the valve opening command and the actual valve opening Circuit,
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening An intercept valve opening control circuit that outputs a servo command signal,
When an unbalanced state between the generator load and the turbine output is detected, the rapid load solenoid valve is operated to fully close the steam control valve, and the power load that self-maintains this operating state until the unbalanced state is resolved An unbalanced circuit;
An intercept valve rapid closing circuit for operating the rapid operation solenoid valve for a certain period of time to fully close the intercept valve when detecting that the intercept valve valve opening command is a value lower than the actual valve opening by a predetermined value or more;
In a steam turbine control device comprising:
The intercept valve opening degree control circuit has an opening operation speed limiting means for limiting an operation speed of the intercept valve when the intercept valve opens by resetting the intercept valve abruptly closing. Control device.   The opening speed limiting means for limiting the operating speed of the intercept valve includes a rate-of-change limiter that limits the rate of change in the increasing direction of the valve opening command that is an output of the function generator, the power load unbalance circuit, A signal switch for switching the output signal from the function generator to the output signal from the change rate limiter until the turbine settles after the intercept quick-close circuit operates. The steam turbine control device according to claim 2, wherein: A speed control circuit that outputs a speed control signal obtained from the deviation between the target rotational speed and the actual turbine rotational speed;
A load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between the load setting signal set by the load setting device and the output setting command, and a load set by the load limit setting device A load control circuit that selects any one of the lower limit setting signals and outputs it as a steam control valve flow command signal;
A steam control valve opening control that determines a valve opening command based on a steam control valve flow command signal from the load control circuit and outputs it as a servo command signal based on a deviation between the valve opening command and the actual valve opening Circuit,
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening An intercept valve opening control circuit that outputs a servo command signal,
When an unbalanced state between the generator load and the turbine output is detected, the rapid load solenoid valve is operated to fully close the steam control valve, and the power load that self-maintains this operating state until the unbalanced state is resolved An unbalanced circuit;
An intercept valve rapid closing circuit for operating the rapid operation solenoid valve for a certain period of time to fully close the intercept valve when detecting that the intercept valve valve opening command is a value lower than the actual valve opening by a predetermined value or more;
In a steam turbine control device comprising:
The load control circuit includes:
A steam turbine control device comprising load setter output control means for changing the output of the load setter so that the settling rotational speed after resetting the operation of the power load unbalance circuit matches the rated rotational speed .   The load setter output control means includes a gain adjuster that adjusts and outputs a deviation between a turbine speed and a rated speed, and inputs the load setter to the output setting command and the output of the load setter. The steam turbine control device according to claim 4, further comprising: a signal switcher that switches to a gain adjuster output from the deviation of the gain adjuster. A speed control circuit that outputs a speed control signal obtained from the deviation between the target rotational speed and the actual turbine rotational speed;
A load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between the load setting signal set by the load setting device and the output setting command, and a load set by the load limit setting device A load control circuit that selects any one of the lower limit setting signals and outputs it as a steam control valve flow command signal;
A steam control valve opening control that determines a valve opening command based on a steam control valve flow command signal from the load control circuit and outputs it as a servo command signal based on a deviation between the valve opening command and the actual valve opening Circuit,
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening An intercept valve opening control circuit that outputs a servo command signal,
When an unbalanced state between the generator load and the turbine output is detected, the rapid load solenoid valve is operated to fully close the steam control valve, and the power load that self-maintains this operating state until the unbalanced state is resolved An unbalanced circuit;
An intercept valve rapid closing circuit that operates a rapid operation solenoid valve for a certain period of time to fully close the intercept valve when detecting that the intercept valve valve opening command is a value lower than the actual valve opening by a predetermined value or more. In a steam turbine control method comprising a control of a steam turbine,
Steam turbine control characterized by resetting a power load unbalance operation when a condition in which the rate of increase in turbine rotation speed falls below a predetermined value and a condition in which the turbine rotation speed falls below a predetermined value are satisfied simultaneously Method. A speed control circuit that outputs a speed control signal obtained from the deviation between the target rotational speed and the actual turbine rotational speed;
A load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between the load setting signal set by the load setting device and the output setting command, and a load set by the load limit setting device A load control circuit that selects any one of the lower limit setting signals and outputs it as a steam control valve flow command signal;
A steam control valve opening control that determines a valve opening command based on a steam control valve flow command signal from the load control circuit and outputs it as a servo command signal based on a deviation between the valve opening command and the actual valve opening Circuit,
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening An intercept valve opening control circuit that outputs a servo command signal,
When an unbalanced state between the generator load and the turbine output is detected, the rapid load solenoid valve is operated to fully close the steam control valve, and the power load that self-maintains this operating state until the unbalanced state is resolved An unbalanced circuit;
An intercept valve rapid closing circuit that operates a rapid operation solenoid valve for a certain period of time to fully close the intercept valve when detecting that the intercept valve valve opening command is a value lower than the actual valve opening by a predetermined value or more. In a steam turbine control method comprising a control of a steam turbine,
A steam turbine control method, wherein an increase rate of a valve opening command of an intercept valve is limited when the intercept valve opens by resetting the intercept valve suddenly closing operation. A speed control circuit that outputs a speed control signal obtained from the deviation between the target rotational speed and the actual turbine rotational speed;
A load request command signal obtained by adding a speed control signal input from the speed control circuit to a deviation between the load setting signal set by the load setting device and the output setting command, and a load set by the load limit setting device A load control circuit that selects any one of the lower limit setting signals and outputs it as a steam control valve flow command signal;
A steam control valve opening control that determines a valve opening command based on a steam control valve flow command signal from the load control circuit and outputs it as a servo command signal based on a deviation between the valve opening command and the actual valve opening Circuit,
After multiplying the load request command signal input from the load control circuit by the value determined by the steam control valve regulation rate and the intercept valve regulation rate, the bias value for fully opening the valve is added to obtain the intercept valve flow rate command signal. This intercept valve flow rate command signal is input to the flow rate-opening characteristics of the valve set in the function generator to obtain the valve opening command, and the value obtained from the deviation between this valve opening command and the actual valve opening An intercept valve opening control circuit that outputs a servo command signal,
When an unbalanced state between the generator load and the turbine output is detected, the rapid load solenoid valve is operated to fully close the steam control valve, and the power load that self-maintains this operating state until the unbalanced state is resolved An unbalanced circuit;
An intercept valve rapid closing circuit that operates a rapid operation solenoid valve for a certain period of time to fully close the intercept valve when detecting that the intercept valve valve opening command is a value lower than the actual valve opening by a predetermined value or more. In a steam turbine control method comprising a control of a steam turbine,
A steam turbine control method comprising: controlling a settling rotational speed after resetting an operation of a power load unbalance circuit so as to coincide with a rated rotational speed.

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