JPH062505A - Turbine control device - Google Patents

Abstract

PURPOSE:To ensure safe selective operation by deducting the positional deviation of a component selected with a position instruction signal, when a non-selection component is changed over for operation, regarding a device where a governor and a load limiter are selectively operated, and the position thereof is PI controlled with a position instruction signal. CONSTITUTION:Regarding output signals from a load limiter 1 and a governor 2, a lower value is inputted to a governing valve via a low value priority mechanism 3. An amount of steam generated in a boiler 5 is thereby controlled, and the output of a turbine 7 and a generator 8 is adjusted. On the other hand, a subtracter 11 operates a deviation between a position instruction signal and a position signal for the load limiter 1 or the governor 2, thereby driving each of actuators 12 and 13, and maintaining the output of the generator 8 constant. In this case, an multiplier 16 adjusts a deviation for the control of generator output, and this adjusted deviation is added to the output of a selector 15 via an adder 17. Then, when the output signal of the multiplier 16 overrides the output signal of the selector 15, the governor moving down begins to reverse a direction, and moves upward, thereby opening the governing valve 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a turbine generator having a mechanical turbine control mechanism.

[0002]

2. Description of the Related Art When controlling a steam turbine, there are two types depending on the operating mechanism: an EHC (electric / hydraulic control) system and an MHC (mechanical / hydraulic control) system. In the case of the former EHC method, both the governor and the load limiter are electrically processed, so that the switching can be accurately switched. However, in the latter case of the MHC system, the governor and the load limiter are the machine itself, and it is not easy to switch this positional relationship to shockless. This is because it is not enough to detect the mechanical position by providing a position detector at each position and confirming the position. That is, the governor constantly changes while being influenced by the rotational speed of the turbine, and this change becomes a disturbance and the positional relationship cannot be confirmed well.

For this reason, in the case of mechanical switching, it is necessary to push in the person who wants to switch until it can be confirmed, and then it is necessary to wait for confirmation. As a result, the output fluctuation of the turbine appears, and in some cases, this output fluctuation affects the operation of the plant.
The operation had to be very careful because it could cause trouble.

A conventional turbine control device will be described with reference to the drawings. FIG. 5 is a system diagram of a conventional turbine control device. In the figure, the outputs of the load limiter 1 and the governor 2 are controlled by the low value priority mechanism 3, and whichever is lower, the steam control valve 6
The steam amount generated in the boiler 5 is adjusted to adjust the output of the turbine 7 and the generator 8. The auxiliary pilot valve 4 mechanically compares the outputs of the load limiter 1 and the low value priority mechanism 3 and outputs the difference.

For the machine side configured as described above, the difference between the generator output command SV and the generator output PV is usually calculated by the subtractor 11, and the PI control unit performs PI calculation to obtain a position command signal. The subtracter 11 calculates the deviation between this position command signal and the position signal of the load limiter 1 or the governor 2 and supplies it as a position control deviation signal to the actuator 12 or 13 to drive the load limiter 1 or the governor 2. By doing so, the generator output is controlled to be kept constant. Whether the turbine is controlled by the load limiter 1 or the governor 2 is selected by the selection step 101a or 102a.

By the way, in the state of FIG. 5, the load limiter side is selected through the contacts 15b1 and 15b2. When the governor selection step 102a is selected from this state, the switching device 15 operates to output a lowering signal to output the contact 15b2.
Start lowering the governor 2 through the. As the governor 2 is lowered, the output of the auxiliary pilot valve 4 becomes smaller, and the polarity reverses over time. The switching device 15 determines the switching point based on this polarity and connects the contacts 15a1 and 15a2,
The contacts 15b1 and 15b2 are separated. As a result, the position control deviation signal (output of the subtractor 11) is given to the governor 2 through the contact 15a2, and the governor 2 controls the generator output. Immediately after this switching, the switching device 15 outputs a raising signal to the load limiter through the contact 15a1 so that the output of the auxiliary pilot valve 4 becomes the specified position.

When determining the switching point, the governor 2
Output fluctuates depending on the turbine speed, that is, the generator frequency, and the time limit request is made to detect that the governor is reliably switched to, so the governor is lowered for that time. Therefore, the steam control valve 6 is the governor 2 selected by the low price priority mechanism 3.
Is narrowed down by the output signal of, and finally the generator output is narrowed down.

Further, as shown in the operation mode switching operation of the turbine control of FIG. 7, the position signal of the load limiter 1 before switching and the position signal of the switched governor 2 do not have the same electric position, and accordingly, the position is changed. A position control deviation occurs between the command signal and the position signal of the governor 2, and this position control deviation increases the output of the governor 2 and increases the generator output. Then, after the switching is performed, it is returned to the original value by the generator output control again.

The process of switching from the load limiter to the governor has been described above. However, the same operation is performed when switching from the governor to the load limiter, and the description thereof will be omitted.

[0010]

In this way, the load limiter and the governor are switched to each other to operate, but the generator output fluctuation at this time is not limited to the above-mentioned time limit request, but the auxiliary pilot. The output of the valve 4 actually becomes a mechanical operation as shown in FIG. 6, and this mechanical operation is converted into an electric signal by the position detector (differential transformer in this figure) and used. The output fluctuation of the generator may further increase due to detection error, conversion error, or the like.

Further, in the case of a steam turbine, the amount of steam supplied from the boiler 5 is separately controlled by a boiler control device so as to correspond to the amount of power generation, but if the change of the steam control valve 6 is large, the control becomes difficult. As a result, the pressure and temperature of the steam may fluctuate, and the operation of the plant itself may become unstable, leading to the inability to operate itself.

The present invention has been made to solve these problems, and an object thereof is to provide a turbine control device capable of safely switching operation modes (switching between governor and load limiter) without fluctuations in the output of the generator. To provide.

[0013]

In order to achieve the above object, the first aspect of the present invention is directed to a position control by a PI control which can automatically switch between a governor and a load limiter depending on the operating condition of the plant. In a turbine control device that performs control, when the non-selected side is switched to the operating side, the position deviation of the selected side is subtracted from the position command signal. According to claim 2 of the present invention, in a turbine control device capable of automatically switching between a governor and a load limiter depending on an operating state of a plant, the reduction signal when switching the non-selected side to the operating side It is characterized in that the control deviation on the selection side of is added like a bias.

[0014]

According to the turbine control device of the present invention, the operation mode can be switched by the governor and the load limiter, in which the output fluctuation of the generator is extremely small, and the turbine control can be carried out without affecting the boiler control. it can.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a system diagram of one embodiment of the present invention. The difference between the turbine control device of the present embodiment and the conventional example of FIG. 5 already described is that a multiplier 16 and an adder 17 are added, It is only a point that the down signal is automatically changed to the up signal when the output of the generator drops by adjusting and adding the deviation amount of the generator output control to the down signal during switching. The same parts as those in FIG.

Next, the operation of this embodiment will be described.
As described above, when the operation mode is switched and the governor 2 is lowered and the power generation output starts to fall, the output of the subtractor 11 becomes a + (plus) signal, and the load limiter is operated by the actuator 12 through the contact 15b1. However, since the steam control valve 6 is selected on the governor side by the low value priority mechanism 3, the load limiter cannot return the power generation output.

When the multiplier 16 adjusts the deviation amount of the generator output control and the adder 17 adds it to the output of the switch 15, when the output signal of the multiplier 16 overcomes the output signal of the switch 15. The output signal of the adder 17 becomes a + signal, and the governor, which has been moving in the downward direction until now, starts moving in the upward direction, and opens the steam control valve 6. As a result, the power generation output is pulled back. Since the output (deviation) of the subtractor 11 disappears when the power generation output is pulled back, the multiplier 16
, The output signal of the adder 17 becomes a-(minus) signal again, and the governor is again lowered.
Then, the power generation output starts to drop again, and similarly the deviation of the power generation output control becomes +, and the same movement as above is repeated thereafter. While moving in this way, the load limiter moves more and more upward, so the governor and the load limiter are completely switched. The output change of the generator at this time is minute, and this change amount can be adjusted by the multiplier 16. While operating in this manner, the switching contacts (15a1, 15b1, 15a2, 15b2) are switched by the switching device 15.
) Is switched, the load limiter that has already escaped to the upper side is raised to the specified value, and switching is completed.

The process of switching the operation mode is shown in FIG. 2. As can be seen from this figure, according to the present embodiment, the operation mode can be switched by the governor and the load limiter, which have very little fluctuation in generator output. It is possible to provide a very safe turbine control device that does not affect the boiler control.

FIG. 3 is a system diagram of another embodiment of the present invention. Differences from the conventional example of FIG. 5 are the subtracter 16 and the memory 1.
7 and a subtracter 18 are additionally provided.
As a result, during operation mode switching, the deviation between the position command signal and the position signal of the load limiter 1 or the governor 2 is subtracted from the position command signal so that the position control deviation signal given to the actuator 12 or the actuator 13 is set to zero and switched. It was designed to eliminate the shock of time.

Next, the operation mode switching operation according to this embodiment will be described with reference to FIG. When the switching occurs and the governor 2 is lowered as described above, the output of the auxiliary pilot valve 4 becomes small, and the polarity is reversed in the meantime. The switch 15 determines the switching point based on this polarity, and the contact 15
a1 and 15a2 are connected and contacts 15b1 and 15b2 are disconnected. Further, when the governor 2 is lowered, the deviation between the position command signal and the position signal of the governor 2 (output of the subtractor 11) becomes a + (plus) signal, and this position control deviation signal is applied by the actuator 13 through the contact 15a2 to the governor 13. 2 is operated to increase the generator output.

When the switching occurs here, the subtractor 16 calculates the deviation between the position command signal and the position signal of the governor 2, the switching contact 15a4 is closed, and the subtracter 18 through the memory 17 causes the deviation from the position command signal. Deduct. As a result, the position control deviation signal (output of the subtractor 11) given to the actuator 13 becomes zero, the output of the governor 2 does not change, that is, the output fluctuation of the generator disappears. While moving in this way, the load limiter moves upward and higher, so the governor and the load limiter are completely switched. When the switching is completed, the switching contact 15a4 is opened, the memory 17 retains the previous value, the normal position control is performed, and the shock after the switching is eliminated. The output change of the generator at this time is very small.

While operating in this way, the switching device 1
Switching contacts (15a1, 15b1, 15a2, 5
15b2, 15a3, 15b3) are switched, and the load limiter which has already escaped to the upper side is raised to the specified value, and the switching is completed. The process of this switching is shown in FIG.

[0023]

As described above, according to the present invention, the operation mode can be switched by the governor and the load limiter, in which the output fluctuation of the generator is extremely small, the boiler control is not affected, and the turbine control device is extremely safe. Can be provided.

[Brief description of drawings]

FIG. 1 is a system diagram of a turbine control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an operation mode switching operation of FIG.

FIG. 3 is a system diagram of a turbine control device according to another embodiment of the present invention.

FIG. 4 is a diagram showing an operation mode switching operation of FIG.

FIG. 5 is a system diagram showing an example of a conventional turbine control device.

6 is a diagram showing an example of detection of the machine position of FIG.

FIG. 7 is a diagram showing an operation mode switching operation of a conventional turbine control device.

[Explanation of symbols]

1 ... Load limiter, 2 ... Governor, 3 ... Low value priority mechanism, 4
... Auxiliary pilot valve, 5 ... Boiler, 6 ... Steam control valve,
7 ... Turbine, 8 ... Generator, 9 ... Subtractor, 10 ... PI controller, 11 ... Subtractor, 12 ... Actuator, 13 ... Actuator, 15 ... Switcher, 16 ... Subtractor, 17 ...
Memory, 18 ... Subtractor, SV ... Generator output command, PV ...
Generator output, 101a ... Load limiter selection step, 10
2a ... Governor selection step.

Claims (2)

[Claims] 1. A turbine control device that performs position control by PI control that automatically switches between a governor and a load limiter depending on the operating state of a plant, and when switching the non-selected side to the operating side, position control is performed. A turbine control device characterized in that the position deviation of the selected side is subtracted from a command signal. 2. In a turbine control device capable of automatically switching between a governor and a load limiter depending on the operating state of a plant, the current selection side is used as a reduction signal when switching the non-selection side to the operation side. The turbine control device is characterized in that the control deviation of the above is added in a bias manner.