JP2515797B2 - Turbin controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a turbine control device for a steam generating plant, and more particularly to a turbine control device suitable for application to a boiling water reactor.

[Conventional technology]

The load setter of the turbine control device of the conventional nuclear power plant uses the base load signal and the Automatic Frequency Control (AFC) signal from the central power supply command center as input signals, and these signals and the load setter bias signal. In this configuration, the addition signal of and is used as the load setter output signal.
In addition, the AFC signal is amplitude-limited and rate-of-change limited.
It may be used as the input signal of the load setting device instead of the FC signal. The turbine output control device is composed of a pressure control system for controlling the reactor pressure and a speed control system for controlling the turbine speed. The addition signal of the output signal of the speed control system and the output signal of the load setter, and the pressure controller. The output signal of is the input signal of the low value selection circuit. The output signal of the low value selection circuit controls the turbine control valve, and the deviation of the output signal of the pressure control system from the output signal of the low value selection circuit controls the turbine bypass valve. Normally, because of the load setting device bias signal, the sum signal of the speed control system output signal and the load setting device output signal has a higher value than the pressure control system output signal. For this reason, the low value selection circuit selects the output signal of the pressure control system to give priority to the reactor pressure control, and in this case, the turbine bypass valve does not operate.

Control of the reactor output is achieved by driving the recirculation flow rate control device by the deviation between the addition signal of the base load signal and the AFC signal and the generator output signal.

As an example of this type of turbine control device, there is, for example, Japanese Patent Laid-Open No. 59-54997, "Output control device for boiling water nuclear power plant".

[Problems to be solved by the invention]

The above-mentioned conventional technology relates to a load setting device necessary for setting the reactor output when performing load following operation in a nuclear power plant, but has the following problems. That is, normally, the low value selection circuit selects the output signal of the pressure control system because of the load setter bias signal of 10%, but the variation range of the reactor output with respect to the AFC signal of ± 5% is 10%.
% And there is a response delay in the reactor output change, that is, the pressure control system output change, the sum signal of the speed control system output signal and the load setter output signal has a low value due to the pressure control system output signal. There are times when Since the turbine bypass valve operates by the deviation between the output signal of the pressure control system and the output signal of the low value selection circuit, the low value selection circuit selects the addition signal of the speed control system output signal and the load setter output signal. If so, the turbine bypass valve will operate. Such operation of the turbine bypass valve during load following operation is unnecessary and not preferable.

When the AFC signal, which is the input signal of the load setting device, is subjected to amplitude limit and rate of change limit, the change in the reactor output is suppressed and the change in the pressure control system output is reduced. Although the required operation can be prevented, there is a problem that the load following property is deteriorated.

An object of the present invention is to provide a turbine control device capable of preventing unnecessary operation of a turbine bypass valve during load follow-up operation without reducing load followability.

[Means for solving problems]

In order to achieve the above object, the addition signal of the base load signal and the AFC signal and the load setter bias signal is output to the steam generator output control device, and phase compensation calculation is performed on the addition signal. The point is that the addition signal of the signal and the output signal of the speed controller is input to the low value selection circuit.

[Action]

By the means for solving the above-mentioned problems, for the added signal of the signal for which the phase compensation calculation (for example, the first-order delay calculation) which is one input signal of the low value selection circuit is performed and the output signal of the speed controller, The output signal of the pressure controller, which is the other input signal of the low value selection circuit, can be set to a low value. That is, during the normal load following operation, the low value selection circuit selects only the output signal of the pressure controller, so the turbine bypass valve does not operate. Also,
Since the AFC signal and the load setter bias signal are added to the base load signal as the output signal to the steam generator output control device, the load followability is not deteriorated.

〔Example〕

Hereinafter, a turbine control device for a steam generating plant, which is a preferred embodiment of the present invention, will be described in detail with reference to FIGS. 1 and 2.

The present embodiment is intended for a boiling water reactor plant as a steam generation plant. An outline of a boiling water reactor plant will be described based on FIG. The steam generated in the reactor pressure vessel 1 passes through the main steam pipe 2 and is guided to the turbine 4 via the steam control valve 3 to rotate the turbine 4. The reactor pressure vessel 1 of a boiling water reactor plant is a kind of steam generator. The generator 8 coupled to the turbine 4 by the rotation of the turbine 4 generates electricity and supplies the electricity to a power system (not shown). The steam that rotates the turbine 4 is condensed into water by the condenser 5. This condensed water is boosted as feed water by the condensate pump 6 and the feed water pump 7, and is returned to the reactor pressure vessel 1 through the feed water pipe 23. The turbine bypass pipe 24 is connected to the main steam pipe 2 on the upstream side of the steam control valve 3 and is connected to the condenser 5. Turbine bypass valve 9 is turbine bypass piping 24
It is provided in. When the rotation speed of the turbine 4 suddenly rises due to a power system accident or the like, the turbine control device 11 acts to restrict the turbine control valve 3 to protect the turbine 4 and restrict the supply of steam to the turbine 4. , Prevent the turbine 4 from overspeeding. Further, in order to prevent the pressure rise in the reactor pressure vessel 1 due to the throttle of the turbine control valve 3, the turbine control device 11 opens the turbine bypass valve 9 and the excess steam is directly condensed through the turbine bypass pipe 24 into the condenser. Lead to 5.

A pressure gauge 10 for detecting the steam pressure discharged from the reactor pressure vessel 1 is provided in the main steam pipe 2, and a tachometer 25 for detecting the rotation speed of the turbine 4 is provided.

The turbine control device of the steam generation plant of the present embodiment,
It has a turbine output control device 11 and a load setting device 16 which are shown in detail in FIG.

The load setting device 16 has a load setting adjuster 17 and adders 26A and 26B. The load setting adjuster 17 is connected to the adder 26A via the adder 26B.

The turbine output control device 11 includes a pressure controller 18, a speed controller 19, a low value selection circuit 20, a speed signal adjuster 21, and an adder 27A.
Has ~ 27F. The pressure controller 18 is connected to the pressure gauge 10 via the adder 27A, and the speed controller 19 is connected to the tachometer 25 via the adder 27B. The output end of the speed controller 19 is
It is connected to the low value selection circuit 20 via the adder 27C and to the adder 27D via the speed signal adjuster 21. The other input end of the adder 27C is connected to the load setting adjuster 17 of the load setting device 16. The other input end of the adder 27D is connected to the output end of the adder 26B of the load setting device 16. The output end of the pressure controller 18 is connected to the recirculation flow rate controller 12 via the adder 27E, to the low value selection circuit 20, and further to the adder 27F. The input end of the adder 27E is also connected to the output end of the adder 27D. The output terminal of the low value selection circuit 20 is connected to the regulator valve drive device 14 and the adder 27E. The output end of the adder 27F is connected to the bypass valve drive device 15. The recirculation flow controller 12 is connected to the motor of the recirculation pump 13. The recirculation pump 13 is installed in the recirculation pipe 28 connected to the reactor pressure vessel 1.

The operation of the turbine control device having such a configuration will be described below.

The load setter 16 inputs an automatic frequency control (AFC) signal S7 and a base load signal S8 from a central power supply command center (not shown), and outputs a load setter output signal S11 and a load setting adjuster output signal S12. To do. That is, the adder 26A, which receives the input AFC signal S7 and the input base load signal S8, adds these signals and outputs the load setting request signal S9. Adder 26B
Is the load setting bias signal to this load setting request signal S9.
The load setter output signal 11 is output by adding S10. Normally, the load setter bias signal S10 is set to 10%. The load setting device output signal S11 becomes an input signal of the load setting adjuster 17. The load setting adjuster 17 performs gain / phase compensation calculation on the input load setting device output signal S11 and outputs a load setting adjuster output signal S12. As the gain / phase compensation calculation performed by the load setting adjuster 17, any one of a delay calculation such as a first-order lag and a second-order lag, a change rate limit calculation, and a delay calculation for delaying an output with respect to an input. Is used. Load setting adjustment output signal S1
2 is output to the adder 27C of the turbine output control device 11. Further, the load setting device output signal S11 is output to the adder 27D of the turbine output control device 11.

The turbine inlet pressure signal S1 output from the pressure gauge 10 is
It is input to the adder 27A of the turbine output control device 11. The deviation between the turbine inlet pressure signal S1 and the pressure setting signal S17 obtained by the adder 27A is input to the pressure controller 18 as a pressure deviation signal S18. The pressure controller 18 performs lead / lag compensation calculation and multiplication calculation of the reciprocal of the pressure regulation rate on the input pressure deviation signal S18, obtains the total steam flow rate request signal S19, and outputs this signal. On the other hand, the turbine speed signal S2 output from the tachometer 25 is input to the adder 27B. The deviation between the turbine speed signal S2 and the speed setting signal S15 obtained by the adder 27B is used as the speed deviation signal S16 and the speed controller
Entered in 19. The speed controller 19 multiplies the input speed deviation signal S16 by the reciprocal of the speed adjustment rate to obtain the speed controller output signal S13, and outputs this signal. The speed signal adjuster 21 outputs a speed signal adjuster output signal S20 based on the input speed controller output signal S13. The speed signal adjuster 21 takes out a signal in a predetermined frequency band to be sent to the recirculation flow rate control device 12, that is, the speed signal adjuster output signal S20 by a low frequency filter or the like.

The adder 27D adds the load setter output signal S11 output from the load setter 16 and the speed signal adjuster output signal S20, and outputs a load request signal S21. Also, the adder 27C is
The modified load request signal S14 is output by adding the load setting adjuster output signal S12, which is the other output of the load setting device 16, and the speed controller output signal S13. Correction load request signal S14
Is input to the low value selection circuit 20.

The total steam flow rate request signal S19, which is the output of the pressure controller 18,
The load follow-up error signal S5, which is a deviation signal obtained by the load request signal S21 and the bias signal S22 corresponding to the load setter bias signal S10, is sent to the recirculation flow rate controller 12 by the adder 27. The recirculation flow rate control device 12 controls the rotation speed of the recirculation pump 13 based on the input load following error signal S5 to adjust the flow rate of the cooling water supplied to the core. The reactor output is controlled by adjusting the flow rate of the cooling water. The recirculation flow rate control device 12 is a kind of steam generator output control device, and the recirculation pump 13 is a reactor output (steam generator output) control means.

The total steam flow rate request signal S19 is input to the low value selection circuit 20, similarly to the modified load request signal S14. The low value selection circuit 20 is
Input total steam flow rate request signal S19 and corrected load request signal S
A signal having a lower value out of 14 is selected, and this is output as the adjustment valve opening degree request signal S3. Control valve opening request signal S3
Is transmitted to the regulator valve drive device 14. Adjustable valve drive device 14
Controls the opening degree of the steam control valve 3 based on the signal S3.

Further, the adder 27F inputs the total steam flow rate request signal S19, the regulating valve opening request signal S3 which is the output of the low value selection circuit 20, and the chattering prevention bias signal S23 to obtain the deviation of these signals, and Is output as a bypass valve opening request signal S4. The bypass valve opening request signal S4 is transmitted to the bypass valve drive device 15. The bypass valve drive device 15 controls the opening degree of the turbine bypass valve 9 based on the signal S4.

The turbine control device having the load setting device 16 described above has the functions of suppressing fluctuations in the reactor pressure (steam generator output), setting the reactor output, and protecting the turbine 4 when the load is cut off. First, the function of suppressing reactor pressure fluctuations will be described. This is achieved by setting the total steam flow rate request signal S19 to be lower than the modified load request signal S14 by a value corresponding to the load setter bias signal S10. Therefore, since the low value selection circuit 20 normally selects the total steam flow rate request signal 19, the steam control valve 3 performs a control operation of suppressing fluctuations in turbine inlet pressure, that is, reactor pressure fluctuations.

Next, the function of setting the reactor power will be described. This setting is based on the base load signal S8 and the AFC signal S8 in the load setter 16.
Set according to 7. That is, the base load signal S8, the AFC signal S7 and the load setter bias signal S10 is a load setter output signal S11, which is a setting signal of the reactor output, and based on this set signal Performs furnace power control. At this time, the load setting adjuster 17 is configured such that the load setting adjuster output signal S12 changes according to the change in the total steam flow rate request signal S19 accompanying the response of the reactor output. Therefore, the total steam flow rate request signal S19 becomes lower than the modified load request signal S14 by a value corresponding to the load setter bias signal S10.

Lastly, protection of the turbine 4 in load shedding etc. will be described. This protection is dealt with as follows. That is, if the turbine speed S2 suddenly rises above the load setter bias signal S10 equivalent due to load shedding, etc., the modified load request signal S14 will decrease, and the total steam flow rate request signal S
Lower than 19 Therefore, the low value selection circuit 20 switches from the reactor pressure fluctuation suppression function to the turbine overspeed protection function, and thus selects the modified load request signal S14. That is, in order to suppress turbine speed fluctuations, the opening of the steam control valve 3 is reduced by the modified load request signal S14 to prevent the turbine 4 from overspeeding. Further, in order to prevent the reactor pressure from rising due to excess steam in the reactor pressure vessel due to this, based on the deviation between the total steam flow rate request signal S19 and the turbine control valve opening request signal S3, that is, the modified load request signal S14. The opening degree of the turbine bypass valve 9 is controlled by the bypass valve opening degree request signal S4, and excess steam is discharged by bypassing the turbine 4.

FIG. 3 shows the control characteristics of the turbine control device of this embodiment. 80% of base load signal S8, AFC signal S7
The control characteristics in the case where is set to ± 5% as shown in FIG. 3 (A) will be described. However, the speed controller output signal S13 is "0".
And At this time, the load request signal S21 becomes higher than the load setting request signal S9 by an amount corresponding to the load setter bias signal S10. The load setter bias signal S10 is removed by subtracting the bias signal S22 from the load request signal S21. Therefore, the recirculation flow controller 12 limits the amplitude,
The reactor output is controlled based on the load setting request signal S9 that does not limit the rate of change. Therefore, the total steam flow rate request signal S19, which is a signal corresponding to the reactor output, shows a response to the load setting request signal S9. Further, the control valve opening / closing request signal S3 is determined in correspondence with the response of the total steam flow rate request signal S19, and the load followability does not deteriorate 12 compared with the conventional technique.

Further, when the load setting adjuster 17 is composed of the first-order delay calculation element, the load setting adjuster output signal S12 is the load setting adjuster output signal S11 (here, the load request signal S21 and the load request signal S21 as shown in FIG. 3B). Equivalent) first-order lag signal. This is the load setter bias signal S
It is almost the same as the signal with 10 added. That is, the total steam flow rate request signal S19 becomes lower than the modified load request signal S14 by a value corresponding to the load setter bias signal S10 (10%). Therefore, the low value selection circuit 20 selects the total steam flow rate request signal S19, and the total steam flow rate request signal S19 is the control valve opening degree request signal S19.
It becomes 3 (Fig. 3 (C)). At this time, the bypass valve opening request signal S4 becomes "0" (FIG. 3 (D)), and the turbine bypass valve 9 does not operate. This corresponds to the case where the load setting adjuster output signal S12 is the same signal as the load request signal S21 in the load setting device of the conventional turbine control device. That is, the modified load request signal S14 becomes the same as the load request signal S21, and depending on the response of the total steam flow rate request signal S19, there occurs a time zone in which the modified load request signal S14 has a low value. During this time period, the turbine bypass valve 9 operates based on the deviation between the total steam flow rate request signal S19 and the modified load request signal S14. However, in the load setting device 16 of the turbine control device of the present embodiment, the turbine bypass valve 9 which is originally unnecessary in such load following operation is used.
Does not occur.

As described above, with respect to the setting of the reactor output, which is the function of the turbine control device having the load setting device 16, the present embodiment has the preferable control characteristics as compared with the prior art. It is obvious that the function of suppressing the reactor pressure fluctuation is equivalent to that of the prior art. Further, regarding the turbine protection function in load shedding, etc., the total steam flow rate request signal S19 is lower than the modified load request signal S14 by the load setter bias signal S10, so there is no difference from the prior art.

Further, the load setting device 16 of the turbine control device of the present embodiment
Although the base load signal is given as one of the input signals of the above, it is obvious that a similar load setting device can be configured even with the output of the load pattern generating device or the load pattern correcting device. It is also clear that the same control operation can be obtained even if the speed controller output signal is not "0".

In the load setting device 16 of the turbine control device of this embodiment, the load setting device bias signal S10 was set to 10% and the AFC signal was set to ± 5%. This load setter bias signal S10
Shows the degree of turbine speed increase required for switching the control of the opening degree of the steam control valve 3 from suppression of reactor pressure fluctuation to suppression of turbine speed fluctuation. Therefore, the turbine 4 against the increase in turbine speed due to load shedding, etc.
The load setter bias signal
S10 can be increased. This can reduce unnecessary operation of the turbine bypass valve 9 during load following operation, but by combining with the load setting device of the turbine control device of the present embodiment, unnecessary turbine bypass valve 9 can be prevented. The operation can be further prevented.

FIG. 4 shows another embodiment of the turbine control device. The present embodiment is different from the embodiment of FIG. 1 in that an adder 27G is provided and the load request signal S21, the generator output signal S24, and the bias signal S22 corresponding to the load setter bias signal S10 are adjusted by the adder 27G. This is the point that this deviation is used as the load following error signal S5 and is used as the input signal to the recirculation flow rate control device 12. This is because the load request signal S21 is a generator output request signal, so the actual generator output signal S24
Is fed back to the load request signal S21 to obtain the required generator output.

The present invention may be applied to a steam generation plant other than a boiling water reactor plant, that is, a pressurized water reactor plant and a fast breeder reactor plant having a steam generator, and a thermal power plant having a boiler that is a steam generator. it can. A steam generator output control device in a pressurized water reactor plant and a fast breeder reactor plant operates a control rod that is output control means. A steam generator output control device in a thermal power plant adjusts a governor of a boiler, which is steam generator output control means.

〔The invention's effect〕

According to the turbine control device of the present invention, during load following operation, without lowering the load following performance,
Unnecessary operation of the turbine bypass valve can be prevented without degrading the function of the turbine output control device.

[Brief description of drawings]

FIG. 1 is a detailed block diagram of a turbine controller which is a preferred embodiment of the present invention applied to a boiling water reactor plant, and FIG. 2 is a boiling water reactor to which the embodiment of FIG. 1 is applied. FIG. 3 is a configuration diagram showing an outline of the plant, FIG. 3 is an explanatory diagram showing control characteristics in the embodiment of FIG. 1, and FIG. 4 is a configuration diagram of another embodiment of the present invention. 1 ... Reactor pressure vessel, 3 ... Steam control valve, 4 ... Turbine, 8 ... Generator, 9 ... Turbine bypass valve, 10 ...
… Pressure gauge, 11 …… Turbine output control device, 12 …… Recirculation flow rate control device, 13 …… Recirculation pump, 16 …… Load setting device, 17 …… Load setting adjuster, 18 …… Pressure controller, 19 ……
Speed controller, 20 ... low value selection circuit, 21 ... speed signal adjuster, 25 ... tachometer.

Claims (1)

(57) [Claims] 1. A steam generator, a turbine, and steam piping for guiding steam generated by the steam generator to the turbine,
A condenser that condenses the steam exhausted from the turbine;
A bypass pipe connecting the steam pipe and the condenser, a steam flow control valve provided in the steam pipe at a downstream side of a branch point with the bypass pipe, and a bypass valve provided in the bypass pipe. In the turbine control device of the steam generation plant, which comprises an output control means for adjusting the output of the steam generator, a means for detecting the pressure of steam introduced to the turbine, a means for detecting the rotation speed of the turbine, First addition for adding a pressure controller for inputting the output of the pressure detecting means, a speed controller for inputting the output of the rotation speed detecting means, and an automatic frequency control signal and a base load signal and a load setter bias signal Means, load adjusting means for inputting the output of the first adding means and performing phase compensation, and means for adding an output signal of the load adjusting means and an output signal of the speed controller 2 addition means, low value selection means for selecting a low-value output signal of the output signals of the pressure controller and the second addition means as the opening control signal of the steam flow control valve, and the opening control signal Based on the input means for adjusting the opening of the steam flow control valve, the means for adjusting the opening of the bypass valve based on the output signal of the pressure controller, and the output signal of the first adding means A turbine control device for a steam generating plant, comprising: a control unit that operates the output control unit.