JPH04214907A - Turbine controlling device - Google Patents

Abstract

PURPOSE:To control a turbine inlet steam pressure stably by outputting a turbine trip signal corresponding to a steam regulation valve closure trouble signal when a nuclear reactor output is a load more than a partial capacity given to a turbine bypass valve. CONSTITUTION:A turbine controlling device is provided with a steam regulation valve closure trouble detector 24 for detecting an abnormality in a closing action of a steam regulation valve. A turbine bypass valve opening set changing part 25 is provided for changing a turbine bypass valve opening jack setter 19 to a turbine bypass valve forced opening by a signal v19 outputted at this time. A turbine trip changing part 36 is provided for outputting a turbine trip signal based on the signal v19 outputted from the steam regulation valve closure trouble detector 24. For a load under a partial capacity given to a turbine bypass valve 6, the turbine bypass valve 6 is forcedly opened when the steam regulation valve 3 is failed as it is closed.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine control system for a nuclear power plant.

0002

2. Description of the Related Art FIG. 5 shows an example of a turbine system in a nuclear power plant.

In FIG. 5, steam generated in a nuclear reactor 1 flows into a turbine 4 through a main steam stop valve (hereinafter referred to as MSV) 2 and a steam control valve (hereinafter referred to as CV) 3. - Drives the bottle and condenses it in the condenser 5. Further, some of the steam passes through a turbine bypass valve (hereinafter referred to as TBV) 6 from before the MSV 2, bypasses the turbine 4, and flows into the condenser 5. Always keep MSV2 fully open and CV
The turbine speed and turbine inlet steam pressure are controlled by adjusting the valve openings of TBV 3 and TBV 6.

In this case, the turbine inlet steam pressure and the turbine speed are detected by a pressure detector 7 provided in front of the MSV 2 and a speed detector 8 attached to the turbine shaft, respectively.

[0005] In the new type of reactor, the reactor dome pressure is detected instead of the turbine inlet steam pressure to determine CV3 and TBV6.
The turbine speed and reactor dome pressure are controlled by adjusting the valve opening. A functional block diagram of a conventional turbine control device is shown in FIG.

In FIG. 6, the set speed v1 set by the speed setter 9 and the actual speed v2 detected by the speed detector 8
is subtracted from the adder 10, and the speed deviation v3 (=v1
-v2) is output as the speed control command value. On the other hand, the set pressure v4 set by the pressure setting device 11 and the actual pressure v5 detected by the pressure detector 7 are subtracted by the adder 12, and the pressure deviation v6 (=v5 - v4) is the maximum that limits the reactor maximum flow rate. Pressure command value v via flow restrictor 13
It is output as 7.

The speed deviation v3 and pressure command value v7 are input to the low value selector 14, and the lower command value is selected and output as the CV opening command value v8, which is detected by the valve position converter 15. The adder 16 compares the valve opening v9 of CV3 with the opening deviation v10 (=v8-v9
) controls the valve opening degree of CV3 via the valve drive unit 17 with respect to the opening degree command value v8. Further, a plurality of CV3s are usually installed, and the same CV opening command value v8 is outputted to all CVs, and all CVs are controlled to the same opening degree.

On the other hand, the pressure control signal v7 and the CV opening command value v8 are subtracted by an adder 18, and the difference v7 is
~v8 is output as the TBV opening deviation v11. Bypass valve - T set with opening jack setting device 19
The BV set opening degree v12 is input to the high value selector 20, the higher value is selected and outputted as the TBV opening command value v13, and the actual opening degree v14 of the TBV6 detected by the valve position converter 21 is added to the adder. 22 and its opening deviation v15 (
=v13-v14) controls the valve opening of the TBV6 via the valve driver 23 in accordance with the opening command value v13. Using the above control device, the following pressure control operation is normally performed.

In the pressure control operation, the set speed v1 is set lower than the limit value of the maximum flow rate limiter 13, and the speed control command value v3 is set to be slightly higher than the pressure control command value v7. is selected to be a low value and becomes the CV opening command value v8.

Therefore, the pressure control command value v7 = CV opening command value v8, and the TBV opening deviation v11 becomes zero, and the bypass valve opening jack setting device 19 is always set to zero. , zero is selected as a high value by the high value selector 20 to become the TBV opening command value v13, the TBV 6 is fully closed, and pressure control is performed only by CV3.

When the actual speed v2 increases during pressure control operation, the speed control command value v3 decreases, and the speed control command value v
3 is lower than the pressure control command value v7, the CV opening command value v8 becomes the speed control command value v3, and the CV opening is controlled in the closing direction. At this time, pressure control command value v7
>CV opening command value v8, so TBV opening deviation v
11>0, and the TBV is controlled in the opening direction. That is, the amount of steam flowing into the turbine 4 decreases by closing the CV3, the surplus steam flows to the TBV6, and the steam flow rate as seen from the reactor 1 remains constant.

As described above, during normal pressure control operation, even if the actual speed and actual pressure vary, the turbine inlet pressure is controlled to be constant by controlling the opening degrees of CV3 and TBV6.

[0013]

[Problem to be Solved by the Invention] As mentioned above, during normal pressure control operation, the opening degrees of CV3 and TBV6 are controlled even if the actual speed and actual pressure fluctuate, and the steam pressure at the turbine inlet is controlled to be constant. Therefore, no problem will occur, but the CV
If the actual pressure v5 increases due to a closing failure, the following problem will occur. In addition, here, multiple CV3s are installed.
Assume that there is a closed fault.

At a load below the partial capacity of the TBV 6, the amount of steam flowing into the turbine 4 decreases due to a CV closing failure, and as the actual pressure v5 increases, the CV opening command value v8 increases, and the CV The opening degree is controlled in the opening direction.

When the actual pressure v5 further increases, pressure control command value v7 > speed control command value v3, CV flow rate command value v8 = speed control command value v3 = constant, and v
8 is suppressed to v3, and the CV opening degree is controlled to be constant. At this time, TBV opening deviation v11 = pressure control command value v7
- Speed control command value v3 >0, and the TBV opening degree is controlled in the opening direction. On the other hand, if the load exceeds the partial capacity of the TBV6, the reactor pressure will rise due to excess steam, which may cause the reactor protection interlock to operate and lead to a reactor scram.

An object of the present invention is to safely scram the reactor before the reactor protection interlock is activated, thereby preventing an increase in turbine inlet steam pressure or reactor dome pressure, and Bin inlet steam pressure or reactor door
An object of the present invention is to provide a turbine control device that can achieve stable control of turbine pressure. [Structure of the invention]

[0017]

[Means for Solving the Problems] In order to achieve the above object, the present invention bypasses a plurality of steam control valves and a plurality of turbines that regulate the flow rate of steam led from a nuclear reactor to a turbine. The opening of the partial capacity turbine bypass valve, which regulates the flow rate of steam to be
In a turbine control device that controls the steam pressure at the bin inlet or the reactor dome pressure, a steam regulating valve closing failure is detected based on the sum of the actual opening degrees of multiple steam regulating valves, and a steam regulating valve closing failure signal is output. The turbine bypass valve opening degree is determined by the steam regulating valve closing failure detection unit that switches the setting value of the turbine bypass valve opening jack setting device to the turbine bypass valve forced opening degree based on the steam regulating valve closing failure signal. a setting switching section, and a turbine trip switching section that outputs a turbine trip signal in accordance with a steam control valve closing failure signal when the reactor output is a load greater than the partial capacity given to the turbine bypass valve. It is characterized by the fact that it has been provided.

[0018]

[Operation] As a result, if the load is less than the partial capacity given to the TBV, the TBV will be forcibly opened even if the CV fails to close, and if the load is more than the partial capacity given to the TBV, the turbine will be tripped. Reactor protection interface
By scramming the reactor before the lock is activated, an increase in turbine inlet steam pressure or reactor dome pressure can be prevented.

[0019]

[Embodiment] An embodiment of the present invention is shown in FIG.

In FIG. 1, the number of installed CV3s is n. The CV failure detection unit 24 detects the first CV actual opening degree v16 and the second CV failure detection unit 24.
Input the CV actual opening degree v17 and the nth CV actual opening degree v18, and generate the CV closing failure signal v based on the rate of change of the total of these actual opening degrees.
output 19

The TBV opening degree setting switching unit 25 is composed of a turbine bypass valve forced opening degree setting 26 and a relay contact 27, and when the load is less than the partial capacity given to the TBV 6,
Relay contact 27 is closed by CV closing fault signal v19. The setting value of the bypass valve opening jack setting device 19 is always zero, and the relay contact 27 is closed by the CV closing failure signal v19, so that the bypass valve is opened.
The turbine bypass valve forced opening degree setting 26 is input to the opening jack setting device 19, and the bypass valve opening jack setting value is switched to the turbine bypass valve forced opening degree.

The turbine trip switching unit 36 is composed of a TBV partial capacity or higher load detector 37, a relay contact 38, and a timer relay 39. The TBV partial capacity or higher load detector 37 receives a generator output signal v29. , turbine inlet steam flow rate signal v30, and reactor feed water flow rate signal v31 are input, and when the load exceeds the partial capacity given to TBV6, the relay
Contact 38 trips turbine 4 to safely scram the reactor before the reactor protection interlock is activated.

The timer relay 39 detects that the turbine trip contact is not operating transiently but continues for several seconds in order to prevent malfunction of the turbine trip. If CV3 has 4 valves, CV closed failure detector 24 is shown in Figure 2.
An example is shown below.

[0024] First CV actual opening degree v16 and second CV actual opening degree v
17 is subtracted by the adder 28, and the deviation v17-v1
6 is input to the comparator 29, and when the deviation is greater than or equal to the specified value, the comparator 29 outputs the first/second CV abnormal signal v20.

Similarly, the first CV actual opening degree v16 and the third CV
The actual opening degree v21 is subtracted by an adder 32, and the deviation v2
1-v16 is input to the comparator 31, and when the deviation is greater than the specified value, the comparator 31 outputs the first/third CV abnormal signal v22.
is output.

Similarly, the first CV actual opening degree v16 and the fourth CV
The actual opening degree v23 is subtracted by the adder 32, and the deviation v2
3-v16 is input to the comparator 33, and when the deviation is greater than the specified value, the comparator 33 outputs the first/fourth CV abnormal signal v24.
is output.

Each abnormal signal v20, v22, v24 is input to a 2-out-of-3 logic 34 for detecting false detection due to an erroneous signal, and the 2-out-of-3 logic 34 detects one of the abnormal signals v20, v22, v24. When two or more are established, a logic signal of the first CV closed fault v25 is output.

[0028] Second CV closed fault v26 created in the same manner
, the logic signals of the third CV closed fault v27 and the fourth CV closed fault v28 are input to the OR logic 35;
A CV closing failure signal v19 is output.

As described above, during normal pressure control operation, the bypass valve opening jack setting device 19 is set to zero, and at this time, the TBV 6 is held fully closed and pressure control is performed only by the CV 3.

Assuming that a pressure control operation failure occurs, T
When the load is less than the partial capacity of BV6, the CV closing failure detector 24 detects the CV close almost at the same time as the actual pressure v5 starts to rise.
When a closing failure is detected, the set value of the bypass valve opening jack setting device 19 is switched to the turbine bypass valve forced opening/closing degree, and the TBV 6 is forcibly opened.

By setting the turbine bypass valve forced opening degree setting 25 to be the steam flow rate generated by the reactor 1 + the steam flow rate at the forced opening degree of TBV6, CV3 and TBV
6, all of the reactor generated steam can flow, so an increase in the turbine inlet steam pressure or the reactor dome pressure is prevented.

[0032] Furthermore, the amount of steam generated in the reactor 1<the amount of steam at the maximum opening of CV3 at the time of a CV closing failure+the steam flow rate at the time of forced opening of TBV6, and the flow rate of steam of CV3 at the time of a failure in closing the CV=steam generated in the reactor 1. Quantity - Steam flow rate at TBV6 forced opening degree, so CV3 steam flow rate at CV closing failure <C at CV closing failure
V3 is the steam flow rate at maximum opening, and CV6 is the pressure command value v
7 In other words, pressure control is performed quietly following the actual pressure v5.

If a CV closing failure occurs during pressure control as described above, the CV closing failure is detected by the CV closing failure detection unit 24, and the TBV 6 is forcibly opened, thereby reducing the turbine inlet steam pressure or the reactor. Dome pressure is prevented from increasing. Furthermore, control of the turbine inlet pressure or reactor dome pressure of the TBV forced opening degree is stably performed by CV6.

On the other hand, when the load exceeds the partial capacity given to TBV6, it is not possible to prevent the reactor dome pressure from rising, so the turbine is tripped and the reactor protection interlock is activated. This prevents the reactor dome pressure from rising by scramming the reactor safely. FIG. 3 shows an embodiment of the TBV partial capacity or higher load detector 37.

Since the generator output signal v29 has a characteristic that is almost proportional to the reactor output, the comparator 40 presets T.
By setting the generator output value that becomes the BV partial capacity and inputting the generator output signal v29, when the load becomes more than the TBV partial capacity, the comparator 40 outputs the generator output TBV partial capacity or more load signal v32. Ru.

Similarly, since the main steam flow rate signal v30 has a characteristic that is almost proportional to the reactor output, a main steam flow rate value corresponding to the TBV partial capacity is set in advance in the comparator 41, and the main steam flow rate signal v30 is inputted. By doing so, when the load exceeds the TBV partial capacity, the main steam flow rate TB is determined by the comparator 41.
A load signal v33 greater than or equal to the V partial capacity is output.

Similarly, since the feed water flow rate signal v31 has a characteristic that is almost proportional to the reactor output, by setting the feed water flow rate value that becomes the TBV partial capacity in the comparator 42 in advance and inputting the feed water flow rate signal v31, , when the load exceeds the TBV partial capacity, the comparator 42 outputs the water supply flow rate TBV partial capacity or higher load signal v34.

Each TBV partial capacity or higher load signal v32,v
33, v34 is 2 to detect false detection due to false signals.
Input to out of 3 logic 43, 2 out of 3
Logic 43 outputs each TBV partial capacitance or higher load signal v32,
If two or more of v33 and v34 are true,
The logic signal v35 of load greater than or equal to TBV partial capacity is established, and C
When the V closed fault signal v19 occurs, the turbine is tripped as described above to safely scram the reactor before the reactor protection interlock is activated.

Note that the CV closing failure detector 24 may be as shown in FIG. That is, the first CV actual opening degree v1
6. The second CV actual opening degree v17 and the nth CV actual opening degree v18 are taken out by the adder 44 as a total CV actual opening degree v36, and added to the input terminal of the differentiator 45. A differentiator 45 determines the rate of change of the total CV actual opening v36, which is output to one input terminal of a comparator 46 and compared with a set value derived from a setter 47 to the other input terminal of the comparator 46. , at this time, if the rate of change is large, it is output as a CV closing failure signal v19.

[0040]

[Effects of the Invention] As explained above, according to the present invention, C
Even if a V-closing failure occurs, an increase in turbine inlet steam pressure or reactor dome pressure is prevented;
Provides stable control of the bin inlet steam pressure or reactor dome pressure, and trips the turbine before the reactor protection interlock operates at loads greater than the partial capacity given to the TBV. By safely scramming the reactor, a rise in reactor dome pressure is prevented.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing an embodiment of a steam turbine control device according to the present invention.

FIG. 2 is a functional block diagram showing an embodiment of the steam control valve closing failure detection section according to the present invention.

FIG. 3 is a functional block diagram showing an embodiment of the TBV partial capacity or higher load detection section according to the present invention.

FIG. 4 is a functional block diagram showing another embodiment of the present invention.

FIG. 5 is a configuration diagram showing a general configuration of a conventional turbine plant.

FIG. 6 is a functional block diagram showing an example of a conventional turbine control device.

[Explanation of symbols]

3...Steam control valve 4...
Turbine 6...Turbine bypass valve 10, 12, 16, 18, 22, 28, 30, 32...Adder 23...Low value selector 19...Bypass valve opening jack setting device 20...High value selector 24...CV
Closed failure detector 25...TBV opening setting switching section
36...Turbine trip switching unit 37...TBV partial capacity or higher load detector

Claims (1)

[Claims] Claim 1: A plurality of steam control valves and a plurality of turbines that adjust the flow rate of steam led from the reactor to the turbine.
Turbine speed and turbine speed are controlled by controlling the opening of both turbine bypass valves, which regulate the flow rate of steam bypassing the turbine.
In a turbine control device that controls the steam pressure at the bottle inlet or the reactor dome pressure, a steam regulator valve closing failure is detected based on the sum of the actual opening degrees of the multiple steam regulator valves, and a steam regulator valve closing failure signal is generated. The steam control valve close failure detection section outputs
A turbine bypass valve opening setting switching unit that switches the setting value of the punning jack setting device to the turbine bypass valve forced opening, and a load where the reactor output is greater than the partial capacity given to the turbine bypass valve. and a turbine trip switching section for outputting a turbine trip signal in accordance with the steam control valve closing failure signal.