JPS62293003A - Feedwater controller for steam generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a water supply control device for a steam generator that uses a high-temperature heat medium as a heating source, such as an atomic couplant. .

[Prior Art] A plurality of steam generators are used in a PWR plant, an FBR plant, etc., each steam generator forms a loop, and each loop has a water control system.

The steam/water circulation system in each loop is composed of a water supply pipe, a steam generator, a steam pipe, and a steam turbine. It is adjusted by the control 31.

The opening degree of the meteor control valve is controlled by a water supply flow rate control device that includes a water level controller and a flow rate controller.

Basically, the water level controller included in the water supply control device is given a steam generator water level deviation signal as a control input signal, and performs a proportional-integral (PI) calculation on this steam generator water level deviation signal to generate a water level controller signal. Output.

In addition, the nine flow rate controllers included in the water supply flow rate control device basically receive a steam flow rate signal and a water supply flow rate signal in addition to the water level controller signal from the water level controller, and perform PI calculations on these signals to determine the flow rate. Outputs a control signal.

[Problem to be Solved by the Invention 1 In the above steam generator water supply control device, conventionally, the control system parameters are set as constants, and within the range of automatic control, the set constants are maintained at any load. It was being driven. The plant characteristics of the steam generator's water supply system vary depending on the load, and the optimal control system parameters will naturally vary accordingly. Therefore, there was room for improvement in controllability.

[Means for Solving the Problems] Therefore, the object of the present invention is to provide water supply control for a steam generator that further improves plant controllability by making control system parameters variable depending on the plant condition. Another object of the present invention is to provide a water supply control device suitable for computer control of a plant.

In order to achieve this object, the present invention provides a water supply control device that adjusts the flow rate of water supply to a steam generator using a high-temperature heat medium as a heating medium, which inputs a steam generator water level deviation signal and a load signal, a water level controller that performs a PI calculation on the function of the steam generator water level deviation signal using the function of the load signal as a control system parameter and outputs a water level controller signal; the water level controller signal, the steam flow rate signal, the feed water flow rate signal; A turbine load signal is input, and a function of the feedwater flow rate signal and the turbine load signal is used as a control system parameter, and a PI calculation is performed by subtracting the feedwater flow rate signal from the sum of the water level controller signal and the steam flow rate signal. Provided is a water supply control device for a steam generator, comprising: a flow rate controller that outputs a flow rate control signal;

[Operation] Since the characteristics of the steam generator are controlled by the load, the water level controller is given a load function as a control system parameter.

As the load signal, the difference between the inlet-side piping temperature and the outlet-side piping temperature of the high-temperature heating medium is used to provide loop specificity. In this way, the water level controller is given a function of the load signal as a control system parameter in addition to the steam generator water level deviation signal, thereby converting the steam generator water level deviation signal into the PI
Calculate and output water level controller signal.

Furthermore, since the 1i characteristic of the water supply system is controlled by the water supply flow rate, the flow rate control signal is given a function of the water supply flow rate as a control system parameter. Thereby, the flow rate controller performs a PI calculation on a signal obtained by adding the deviation between the steam flow rate signal and the water supply flow rate signal to the water level controller signal, and outputs a flow rate control signal.

The functions of each control system parameter given to the water level controller and the flow rate controller are set so as to enable the best control in each plant state.

[Example 1] Hereinafter, an example of the present invention will be described based on the attached drawings. [Z shows a block circuit diagram showing the feed water control 'A position of a steam generator according to the present invention applied to a PWR plant main feed water control system, and includes a water level controller 1 and a flow rate controller 2. It is shown.

The water level controller 1 includes a nonlinear gain 11, a first variable gain 12, an integral hold 13, a variable integral time constant 14, a first multiplier 15, a first divider 16, a first integrator 17, and a first 1 adder 18 is included. With this configuration, the water level controller 1 inputs the steam generator water level deviation signal 1a and the load signal 1b as a control system parameter, and outputs the water level controller signal 1f.

The flow rate controller 2 also includes a second variable gain 21, a one-shot signal generator 22, a switch 23, a second adder 24,
Second multiplier 25, second divider 26, second integrator 2
7, and a third adder 28. With this configuration, the flow rate controller 2 receives the water level controller signal 1r from the water level controller 1, the steam flow rate signal 2a representing the steam flow rate output from the steam generator, and the water supply from the meteor control valve provided in the water supply pipe. A water supply flow rate signal 2b representing the water supply flow rate and a turbine load signal 2c are inputted to output a flow rate control signal 2g.
1. The first variable gain 12, the integral hold 13, and the variable integral time constant 14, and in the KLJti, II controller 2, the second variable gain 21, the one-shot signal generator 22, and the switch 23 according to the present invention. R11u added by
It is.

In the above configuration, the steam generator (sG) water level deviation signal 1a, which is input to the water level controller 1 and represents the difference between the measured water level and the set water level, is first processed with a nonlinear gain of 1 prior to PI calculation.
1, and this nonlinear gain 11 outputs a different gain depending on the input deviation according to a function graphically displayed inside the block. In other words, the deviation is small -D.

If the value is between +D1 and and outputs a signal with increased input deviation. The role of this nonlinear gain 11 prior to the PI calculation is as follows:
When a large deviation in the water level of the steam generator occurs, the water level controller signal 1f is increased and output in order to quickly bring the deviation to a close.

The first variable gain 12 controls the signal IC as a control system parameter, which is multiplied by the multiplier 15 by the output signal of the nonlinear gain 11 prior to PI calculation, so that the best controllability can be obtained for each plant load. In addition, the program is set according to the plant load.

In a PWR plant, a loop is constructed for each number of steam generators, and a main water supply control system is applied to each loop. Coolant inlet side (high temperature fIl!I)
T is the difference between the piping temperature and the outlet side (low temperature side) piping temperature.
Signal 1b is used.

As shown in the figure, the first variable gain 12 outputs the value CI as a signal IC when T to the load signal is less than T, and outputs the value 02 when it is greater than T2, and when ΔT is greater than When it is smaller than 8T2, C+ + (MuT-Δ”r+)・(C2-CI)/(8T2-ΔT
, ) is output. When the load increases, the response typically becomes slower due to the increase in capacity, but by multiplying the output of the nonlinear gain 11 by a larger value C2,
Furthermore, it becomes possible to match the characteristics of the steam generator, and the stability and responsiveness of control are improved.

The first multiplier 15 multiplies the deviation signal from the nonlinear gain 11 and the gain rZ signal 1c from the first variable gain 12 to output a signal 1e, and this signal 1e is
Calculated.

In PI operation, integral hold 13 receives signal 1e from multiplier 15 and provides its output to divider 16. This integral hold 13 is provided to avoid overshoot caused by integrating an excessive SG water level deviation, and when the absolute value of the signal 1e is less than D2, the input signal is passed through the output as it is, but the absolute value D2 For an excessive SG water level deviation exceeding , the input to the integrator 17/\ is set to zero, thereby speeding up the settling of the water supply system.

The divider 16 divides the output from the integral hold 13 by the signal 1d from the variable integral time constant 14, and outputs the quotient to the integrator 17.

Like the first variable gain 12, the variable integral time constant 14 is used to program the integral time constant signal 1d depending on the plant load.

That is, input T to the plant load signal, output cs-+al-ΔT (lal is slope) as signal 1d,
This allows adjustment to be made to obtain the best controllability for each load. In this way, the variable integral time constant 14 can provide control system parameters that match the characteristics of the steam generator, improving control stability and responsiveness.

The integrator 17 integrates the value from the divider 16 and outputs it to the adder 1.
8, and the adder 18 adds this refined signal and the signal 1e from the first multiplier 15 to perform water level control: Jg2''
A y signal 1r will be output.

In the flow rate controller 2, since the plant performance of the water supply system is controlled by the water supply flow rate, a signal programmed from the water supply flow rate is used as a control system parameter.

The second adder 24 adds the steam flow rate signal 2a and the water level controller signal 1f described above, subtracts the water supply flow rate signal 2h, and outputs the result to the second multiplier 25. The second multiplier 25 adds, in addition to the signal from the second adder 24,
A gain signal 2d programmed by the second variable gain 21 is also received from the water supply flow rate signal 2b, and both are multiplied to output a signal 2f, which will be subjected to PI calculation below.

The gain signal 2d from the second variable gain 21 is C4 (C4C5
)・F/F, "(" is set to decrease and become a constant value C2 at 21 or more.

The role of the second variable gain 21 is to consider the influence of heat, which has not been considered in the past because the flow rate of water supply and the flow rate of steam are based on mass. In other words, the feed water enters the aJi steam generator at a substantially constant temperature lower than the temperature inside the steam generator, and its temperature rises within the steam generator. This is what we are trying to adjust. This makes it possible to provide control system parameters tailored to the characteristics of the water supply system, improving control stability and responsiveness.

The integration time constant signal 2e in the PI calculation is used by switching between two integration time constants TPC+ and TPC2 depending on the blunt state. The one-shot signal generator 22 inputs the turbine load signal 2c and changes the transition of the switch 23 from TFcl to T for a certain period of time only when the load changes rapidly.
Operates to switch to FCa. In other words, when the load changes rapidly, T is used instead of TFcl as the integral time constant.
One TFC2, in which PC2 is used, is set to be smaller than TFcl, so that fluctuations in the control signal 2g due to load fluctuations are quickly matched to the equilibrium value, and plant stabilization is accelerated.

The PI calculation for the signal 2' is performed by dividing the signal 2f by the integration time constant signal 2e in the second divider 26, and then
The divided signal output from the divider 26 of
7 and the signal 2f are added to the third adder 2.
This is done by adding at 8. Third adder 28
A flow rate control signal 2g is obtained from .

[Effects of the Invention] As described above, according to the present invention, in the steam generator water supply control device that performs PI calculation of the steam generator water level deviation signal and the steam flow rate signal, the load signal is further added as a control system parameter. 1b, the water supply 'ajt signal 2b, and the load signal 2C are set to match the water supply system of the plant, resulting in the effect that the control characteristics of the plant are greatly improved as shown below.

1) Due to the non-linear gain of the water level controller, a large deviation in the steam generator water level can be quickly converged 9 2) The first variable gain 12 and the variable integral time constant 14 of the water level controller allow the steam generator to It is possible to provide control system parameters that match the characteristics of the control system, thereby improving control stability and responsiveness.

3) Integral hold of the water level controller makes it possible to avoid excessive integral operation of the water level controller and speed up settling.

4) The variable gain of the flow rate controller can provide control system parameters that match the characteristics of the water supply system, improving control stability and responsiveness.

5) A switch for the integral time constant of the flow rate controller speeds up the settling time of the water supply system during load fluctuations.

[Brief explanation of the drawing]

The figure is a block circuit diagram showing a water level control device for a steam generator according to an embodiment of the present invention. In figure 0, 1 is a water level controller, 1a is a steam generator water level (I difference signal, 1b is a load signal, 1f is a water level controller signal, 2 is a flow rate controller, 2a is a steam flow rate signal, 2b is a feed water flow rate signal, 2c is a turbine load signal, 2g is a flow rate control signal, 11 is a nonlinear gain, 1
2 is the first variable gain, 13 is the integral hold, 14 is the variable integral time constant, 15 is the first multiplier, 16 is the first divider, 1.7 is the first integrator, and 18 is the first adder, 21
is a second variable gain, 22 is a one-shot signal generator,
23 is a switch, 24 is a second adder, 25 is a second multiplier, 26 is a second divider, 27 is a second integrator, and 28 is a third adder. Patent applicant: Mitsubishi Heavy Industries, Ltd. 5-ku

Claims (1)

[Scope of Claims] A water supply control device that adjusts the water supply flow rate of a steam generator using a high-temperature heat medium as a heating medium, the device comprising: inputting a steam generator water level deviation signal and a load signal; and controlling a function of the load signal. a water level controller that performs a PI calculation on a function of the steam generator water level deviation signal as a system parameter and outputs a water level controller signal; inputting the water level controller signal, the steam flow rate signal, the feed water flow rate signal, and the turbine load signal; Using a function of the feed water flow rate signal and the turbine load signal as a control system parameter, a PI calculation is performed on the sum of the water level controller signal and the steam flow rate signal minus the feed water flow rate signal, and a flow rate control signal is output. A water supply control device for a steam generator, comprising: a flow rate controller for controlling the flow rate;