JP2668143B2 - Steam turbine control device and control method therefor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine control device and a control method thereof suitable for maintaining a rated load of a turbine when seawater temperature changes in summer and winter.

[Conventional technology]

Generally, in a thermal or nuclear power generation system, as shown in FIG. 5, a turbine 2 having a generator 1 and a boiler 4 are connected, and a regulating valve 3 is provided therebetween. The control valve 3 controls the flow rate of the main steam flowing from the boiler 4 into the turbine 2 and is connected to the load limiter 5 and the governor 8 via a cam mechanism and a hydraulic mechanism. Load limiter 5
Is driven by the load limiter motor 6, and the position at that time is detected by the load limiter position detector 7. The governor 8 is driven by a governor motor 9, and the position at that time is detected by a governor position detector 10.

The power generation system is provided with a load limiter follower 11 that automatically controls the position of the load limiter 5 by giving the opening of the control valve 3 driven by the governor 8 an arbitrary constant width. The load controller follower 11 includes a load limiter follower width setter 12, an adder 13, a load limiter position upper limiter 14, a row selector 15, and a comparison detection amplifier.
16 are built-in. Here, the adder 13 is a load limiter tracking width setting device for the detection signal from the governor position detector 10.
The signal of arbitrary fixed width from 12 is added, and the position of the load limiter 5 is set. The row selector 15 takes in the signals from the adder 13 and the load limiter position upper limiter 14, selects the lower one of the signals, and outputs the selected signal to the comparison detection amplifier 16. The comparison detection amplifier 16 compares the signal of the load limiter position setting from the row selector 15 with the detection signal from the load limiter position detector 7 to amplify the deviation, and makes the load limiter position have a fixed width with respect to the governor position. A drive signal is output to the load limiter motor 6 so that The above is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-3406.

[Problems to be solved by the invention]

By the way, the output P _G of the turbine generator can be expressed as follows: P _G = kw · Δi where k: constant w: main steam flow rate Δi: heat head enthalpy, and the heat head enthalpy Δi is the condenser vacuum Depends on the degree.

The condenser vacuum is increased or decreased, if the heat drop enthalpy Δi is changed, in order to hold the output P _G of the generator constant, it is necessary to change the main steam flow rate w. Especially when the seawater temperature rises in summer and the condenser vacuum level drops, the governor motor controls the opening and closing of the control valve to control the main steam flow
Have to do more. In this case, since the load limiter follow-up device controls the load limiter by giving a certain width to the governor motor position (adjustment valve opening), it becomes impossible to secure a certain width due to the upper limiter.

Also, when the condenser vacuum degree decreases, the governor motor position attempts to rise above the load limiter motor position, but the control valve opening degree driven by the governor motor becomes the control valve opening degree controlled by the load limiter motor, The rated load cannot be secured due to insufficient main steam flow.

In other words, the load limiter tracking device determines the condenser based on the detection signals from the load limiter position detector and the governor position detector, and the load limiter tracking width setting device and the load limiter position upper limit setting signal inside the device. Vacuum (NV
When the condenser vacuum degree changes due to the load calculation at the time of C), as shown in FIGS. 6 and 7, the main steam flow rate w and the control valve opening CV change, respectively, as shown in FIGS. I do.

Then, when the condenser vacuum is reduced by −ΔVC from the specified vacuum (NVC) at a constant load, the main steam flow rate w needs to be + Δw in order to keep the load constant. + ΔCV must be opened. However, if the load limiter upper limit setting LLM LIM is at the position shown in the figure, the opening / closing valve CV will reach the upper limit of the load limiter.
-C-B does not change, but A-C-D changes and ΔCV is insufficient. For this reason, there is a problem that the rated load cannot be secured because the main steam flow rate w also lacks Δw.

An object of the present invention is to secure the rated load of the turbine generator by controlling the load limiter to an appropriate position with high accuracy even when the seawater temperature rises in summer and the degree of vacuum of the condenser decreases. It is an object of the present invention to provide a steam turbine control device and a control method thereof.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a control valve capable of adjusting a flow rate of steam flowing into a turbine, a governor for controlling an opening of the control valve, and a load for restricting an opening of the control valve to a predetermined range. Detect the limiter and the position of the governor,
Adding means for adding a signal having an arbitrary constant width to the detection signal and outputting the signal; load limiter position upper limit setting means for setting an upper limit value of the load limiter position; and load limiter position upper limit setting means. Low-value selecting means for taking in the signal of the load limiter position upper limit value and the signal from the adding means, and selecting and outputting the lower one of the taken-in signals, and outputting from the low-value selecting means. In the steam turbine control device configured to automatically follow and control the position of the load limiter according to the detected signal, while detecting the degree of vacuum of the condenser connected to the turbine, based on the detected value, the load A correction means is provided for correcting the load limiter position upper limit value set by the limiter position upper limit setting means.

Further, according to the present invention, in the steam turbine control device having the above-described configuration, a heat drop enthalpy between an inlet and an outlet of the turbine is detected, and a load set by the load limiter position upper limit setting unit based on the detected value. It is characterized in that correction means for correcting the upper limit value of the limiter position is provided.

Further, a power generation system of the present invention includes a turbine whose operation is controlled by any one of the steam turbine control devices described above, and a generator that is rotationally driven by the turbine.

Further, according to the present invention, there is provided a regulating valve capable of adjusting a flow rate of steam flowing into the turbine, a governor for adjusting the opening of the regulating valve, and a load limiter for limiting the opening of the regulating valve to a predetermined range. If the position of the governor is detected, a signal of an arbitrary constant width is added to the detection signal, and an upper limit value of the position of the load limiter is set,
The lower signal is selected from among the signals obtained by adding the signal of the set load limiter position upper limit value and the signal of an arbitrary constant width, and the position of the load limiter is automatically controlled by the selected signal. In a turbine control method, a vacuum degree of a condenser connected to the turbine is detected, and the load limiter position upper limit value is corrected based on the detected value.

[Action]

According to the above configuration, when the temperature of the seawater increases and, for example, the vacuum degree of the condenser decreases, the upper limit of the load limiter position setting signal is increased, and the temperature of the seawater decreases and the vacuum degree of the condenser increases. In that case, the upper limit of the load limiter position setting signal is lowered. Thereby, the main steam flow rate that matches the rated load can be maintained.

Also, since the condenser vacuum degree and the heat drop enthalpy are in a proportional relationship, the value of the heat drop enthalpy is detected instead of the condenser vacuum degree, and the value of the load limiter position setting signal is changed according to the change in the value. Even if the lower limit is corrected, it is possible to maintain the main steam flow rate commensurate with the rated load in the same manner as described above.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. The same parts as those of the conventional technique are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a conceptual diagram of a power generation system to which a steam turbine control device of the present invention is applied. As shown in the figure, a characteristic part of the present invention is that a computing unit 17 and a correction value function generator 18 are provided in a load limiter tracking device 11, and the correction value function generator 18 is connected to a condenser 20 in a condenser 20. That is, it is connected to the vacuum detector 21.
Then, the condenser vacuum detector 21 detects the degree of vacuum in the condenser 20 and outputs a detection signal to the correction value function generator 18. The correction value function generator 18 outputs a load limiter upper limit correction signal to the calculator 17 based on the detection signal from the condenser vacuum detector 21. Further, the arithmetic unit 17 takes in the correction signal from the correction value function generator 18 and the setting signal from the load limiter position upper limit setting unit 14, sets the load limiter upper limit based on those signals, and Output to the row selector 15. In this embodiment, the arithmetic unit 1
7. The correction value function generator 18 and the condenser vacuum degree detector 21 constitute a correction means.

According to the steam turbine control device having the above configuration,
The load limiter upper limit can be set according to changes in the condenser vacuum degree. The principle will be described below.

FIG. 2 is a characteristic diagram of load limiter upper limit setting correction with respect to the condenser vacuum degree. When the condenser has a specified vacuum (NVC), the correction value is fixed to 0 and set. When the condenser vacuum changes by -ΔVC, the correction value becomes + ΔMW.
By increasing the load limiter upper limit setting by MW,
The main steam flow rate w and the control valve opening CV with respect to the condenser vacuum change as shown in FIGS. 3 and 4, respectively. In other words, when the condenser vacuum degree changes from −NVC to −ΔVC, the control valve opening CV corresponding to the rated load changes to AB,
The main steam flow w will increase and flow by + Δw.
That is, even if the degree of vacuum of the condenser is reduced, it is possible to secure the following width up to the rated load of the generator.

In the above description, the case where the seawater temperature is increased and the condenser vacuum degree is reduced has been described. However, even when the seawater temperature is decreased and the condenser vacuum degree is increased, the steam turbine control device of the present invention is also described. Can of course be applied.

〔The invention's effect〕

As described above, according to the present invention, the upper limit value of the load limiter position is corrected based on the degree of vacuum of the condenser or the amount of change in the heat drop enthalpy between the inlet and the outlet of the turbine. Thus, even if the seawater temperature rises in the summer, a main steam flow rate that matches the rated load of the turbine generator can be secured. As a result, a highly reliable power generation system can be realized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a power generation system in which a steam turbine control device of the present invention is installed, FIG. 2 is a characteristic diagram of a load limiter upper limit correction with respect to a condenser vacuum degree according to the present invention, and FIG. Of the main steam flow rate against the vacuum degree of the vessel,
FIG. 4 is a characteristic diagram of a control valve opening degree with respect to a condenser vacuum degree according to the present invention, FIG. 5 is a conceptual diagram of a power generation system provided with a conventional steam turbine control device, and FIG. Fig. 7 is a characteristic diagram of the main steam flow rate with respect to the degree, and Fig. 7 is a characteristic diagram of the control valve opening degree with respect to the degree of vacuum of the condenser according to the prior art. 1 ... Generator, 2 ... Turbine, 3 ... Regulator, 4 ... Boiler, 5 ... Load limiter, 6 ... Load limiter motor, 7 ... Load limiter position detector, 8 ... Governor, 9 ...... Governor motor, 10 ...... Governor position detector, 11 ...... Load limiter tracking device, 12 …… Load limiter tracking width setting device, 13 …… Adder, 14 …… Load limiter position upper limit setting device, 15 …… Low selector, 16: Comparison detection amplifier, 17: Operation unit, 18: Correction function generator, 20: Condenser, 21: Condenser vacuum detector.

Claims (4)

(57) [Claims] 1. A control valve capable of adjusting a flow rate of steam flowing into a turbine, a governor for controlling an opening of the control valve, a load limiter for restricting an opening of the control valve to a predetermined range, and a position of the governor. Adding means for detecting the detected signal, adding a signal having an arbitrary constant width to the detection signal, and outputting the signal; load limiter position upper limit setting means for setting an upper limit value of the position of the load limiter; and load limiter position upper limit setting means Low-value selection means for taking in the signal of the load limiter position upper limit value set in the above and the signal from the adding means, and selecting and outputting the lower one of the taken-in signals, In a steam turbine control device configured to automatically follow and control the position of the load limiter based on a signal output from a selection unit, the steam turbine control device includes a condenser connected to the turbine. While detecting the degree of vacuum, when the detected degree of vacuum falls below the specified degree of vacuum, based on the detected value, the load limiter position upper limit value set by the load limiter position upper limit setting means adjusts the valve opening direction. A steam turbine control device, characterized in that a correction means for correcting the temperature is provided. 2. A control valve for adjusting a flow rate of steam flowing into a turbine, a governor for adjusting an opening of the control valve, a load limiter for restricting an opening of the control valve to a predetermined range, and a position of the governor. Adding means for detecting the detected signal, adding a signal having an arbitrary constant width to the detection signal, and outputting the signal; load limiter position upper limit setting means for setting an upper limit value of the position of the load limiter; and load limiter position upper limit setting means Low-value selection means for taking in the signal of the load limiter position upper limit value set in the above and the signal from the adding means, and selecting and outputting the lower one of the taken-in signals, In a steam turbine control device configured to automatically follow and control the position of the load limiter based on a signal output from a selection unit, a heat drop between an inlet and an outlet of the turbine is provided. While detecting the difference enthalpy, when the detected heat drop enthalpy falls below a specified value, based on the detected value, the load limiter position upper limit value set by the load limiter position upper limit setting means is increased / decreased in the valve opening direction. A steam turbine control device, characterized in that a correction means for correcting the temperature is provided. 3. A power generation system comprising: a turbine whose operation is controlled by the steam turbine control device according to claim 1; and a generator that is rotationally driven by the turbine. 4. A control valve for controlling the flow rate of steam flowing into the turbine, a governor for controlling the opening of the control valve, and a load limiter for restricting the opening of the control valve to a predetermined range. In this case, the position of the governor is detected, a signal having an arbitrary constant width is added to the detection signal, and an upper limit value of the position of the load limiter is set. The lower signal is selected from the signals obtained by adding the signals of a certain width,
In the steam turbine control method of automatically following and controlling the position of the load limiter according to the selected signal, a vacuum degree of a condenser connected to the turbine is detected, and the detected vacuum degree is equal to or less than a specified vacuum degree. Wherein the upper limit value of the load limiter position is corrected in the opening direction of the control valve based on the detected value.