JPH04175401A - Steam turbine output controller - Google Patents

Abstract

PURPOSE:To make a control amount of a generator output slow in response to a change in the opening of a governor to restrain errors in the generator output and quickly perform the output control by the use of the generator output by utilizing plant condition amounts such as the opening of the governor, pressure in a steam reheater, etc. CONSTITUTION:An integration feedback means 2 inputs an output setting value 29 and generator output signal 20 to a difference calculator 6 to calculate a deviation from the set value of the generator output. The integration feedback signal 14 makes the generator output signal 20 coincide with an output set value signal 29. A condition feedback means 3 consisting of counters 9-11 and an adder 12 inputs an A valve opening signal 17, B valve opening signal 18 and steam reheater pressure 19 of conditional amounts of a plant. A condition feedback signal 15 compensates for the delay of the generator output slow in response to provide a conforming property and safety. Further, an adding means 4 consisting of an adder 13 adds said both feedback signals 14, 15 to output a governor opening commanding signal 16 which controls the opening of a governor 36.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a self-control device used in a power generation steam turbine such as a PWR (pressurized water reactor).

[Prior Art] The output of a steam turbine is adjusted by controlling the flow rate of steam flowing into the steam turbine by opening and closing a flow control valve called a governor.

A steam turbine will be briefly explained with reference to FIG. The steam generated by the steam generator is passed through the steam pipe 25 to the governor 3.
6. The governor 36 is constructed by connecting a plurality of valves in parallel. Although the number of valves is usually four, only two, valve A 23 and valve B 24, are shown here for simplicity. The steam whose flow rate is adjusted by the governor 36 first flows into the high pressure turbine 26 . The steam that has done work in the high-pressure turbine 26 has a high humidity, so it is heated in a steam reheater 37, and is led to the low-pressure turbine 27 after the humidity becomes low. The steam that has done work in the low pressure turbine 27 is discharged to the condenser. High pressure turbine 26 and low pressure turbine 27
The power generated is transmitted to the generator 28 and converted into electric power.

Next, a conventional output control method will be explained.

Since the delay in steam flow in the steam reheater 37 is large, the time constant from when the steam flow rate is adjusted by the governor 36 until the generator output changes is as long as about 5 seconds.

Therefore, rapid output control is difficult if the generator output, which has a slow response, is fed back.

In conventional plants, control performance has been improved by feeding back steam flow rate, which has a quick response, instead of generator output. This is because the steam flow rate and the generator output almost match each other during settling, so the generator output can be controlled by controlling the steam flow rate. Since the steam flow rate is proportional to the pressure at the seventh stage of the turbine blade row of the high-pressure turbine 26, the steam flow rate signal 30 can be easily obtained by measuring the pressure there with the pressure sensor 38.

The conventional output control device calculates the deviation of the steam flow rate signal 30 with respect to the output setting value 29 using a differentiator 31, performs a proportional integral calculation on this deviation using a proportional integral controller 32, and transmits a governor opening command signal 34. . The governor opening command signal 34 is
It is transmitted to the A valve 23 and B valve 24 of the governor 36. In response to this governor opening command signal 34, the opening of each valve 23, 24 changes.

[Problems to be Solved by the Invention] Conventional output control devices attempt to improve performance by feeding back the steam flow rate, which has a faster response than the generator output, but sufficient performance has not yet been achieved. not present. This is because the steam flow rate signal 30 is delayed by about 0.4 seconds compared to the actual steam flow rate due to the measurement delay of the pressure sensor 38.
This is because control performance deteriorates.

In addition, the steam flow rate and generator output are almost the same at the time of settling, but if the steam pressure in the steam pipe 25 fluctuates for some reason, the efficiency of the turbine is also affected by the steam pressure, so the steam flow rate and generator output are An error occurs between the two. Conventional output control methods control the steam flow rate to keep it constant.
If an error occurred between the steam flow rate and the generator output, the generator output could not be maintained at the desired value.

The present invention has been made in view of the above points, and an object of the present invention is to provide a steam turbine output control device that can perform quick output control using the generator output.

[Means for Solving the Problems] A steam turbine output control device according to the present invention generates an integral feedback signal by integrating the deviation between the output of a generator driven by a steam turbine and a set value of the output. an integral feedback means, a state feedback means for generating a state feedback signal by multiplying a plant state quantity such as the degree of opening of a governor or a pressure of a steam reheater by a preset coefficient, and an integral generated by the integral feedback means. The apparatus further includes an adding means for adding the feedback signal and the state feedback signal generated by the state feedback means to generate a governor opening command signal for controlling the opening of the governor.

[Function] According to the above configuration, by using plant state quantities such as the governor opening and the pressure of the steam reheater, it is possible to use the generator output, which has a slow response to changes in the governor opening, as a controlled variable. Errors in generator output can be suppressed.

[Embodiment] Hereinafter, a steam turbine output control device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing its configuration. In FIG. 1, the output control device 1 is composed of integral feedback means 2, state feedback means 3, and addition means 4.

Note that the configuration of other parts is the same as in Figure 2, so
The explanation thereof will be omitted here.

The integral feedback means 2 inputs the output set value 29 and the generator output signal 20 to the differentiator 6, and calculates the deviation of the generator output from the set value. The deviation calculated by the difference unit 6 is multiplied by a preset coefficient Kl by the coefficient unit 7, and then
It is transmitted to the integrator 8. Integrator 8 integrates the transmitted signal and issues an integral feedback signal 14 . This integral feedback signal 14 is a signal for making the generator output power signal 20, which is the original control amount, coincide with the output setting value signal 29.

The state feedback means 3 consists of coefficient multipliers 9, 10° 11 and an adder 12, and inputs the A valve opening signal 17, the B valve opening signal 18 and the steam reheater pressure 19, which are state variables of the plant. The coefficient unit 9 multiplies the A valve opening signal 17 by a preset constant KIA. The coefficient unit 10 multiplies the B valve opening signal 18 by a preset constant KgB. The coefficient unit 11 uses a constant K preset to the steam reheater pressure signal.
Multiply by MSR. Adder 12 includes coefficient units 9, 10.11
, and outputs a state feedback signal 15'. This status feedback signal 15 is a signal for compensating for a delay in the output of the generator, which is slow in response, and for obtaining prompt response and stability.

The adding means 4 includes an adder 13 and adds the integral feedback signal 14 and the state feedback signal 15 to output a governor opening command signal 16. This governor opening command signal 16 is a signal for controlling the opening of the governor 36.

In the output control device 1 configured in this way,
By using plant state variables such as the governor opening signal 17.18 and the steam reheater pressure signal 19, it is possible to control the generator output, which previously had a large time delay in response to changes in the governor opening and was difficult to control quickly. This allows rapid control. That is, since the plant state quantity has a smaller delay in response to changes in the governor opening than the generator output, quick control can be achieved by using these signals.

Furthermore, the constants of the coefficients of the state feedback means 3 and the integral feedback means 2 can be determined relatively easily by using optimal regulator logic.

[Effects of the Invention] As described above, according to the present invention, it is possible to use the generator output, which responds slowly to changes in the governor opening, as a controlled variable. Therefore, it is possible to reduce to zero an error with respect to the set value of the generator output, which conventionally occurs when the turbine efficiency changes due to fluctuations in the steam pressure of the steam pipe or the like.

Furthermore, by using the governor valve lift, which has a faster response based on the steam flow rate signal that was conventionally used, it becomes possible to control the generator output more quickly than before.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an output control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of a conventional output control device. DESCRIPTION OF SYMBOLS 1... Output control device, 2... Integral feedback means, 3... State feedback means, 4... Addition means, 6... Differentiator, 7, 9-11... Coefficient unit, 7 ．．
8... Integrator, 12.13... Adder, 14...
Integral feedback signal, 15... Status feedback signal, 16... Governor opening command signal, 17... A
Valve opening signal, 18... B valve opening signal, 19... Steam reheater pressure signal, 20... Generator output signal, 23...
・A valve, 24...B valve, 25...steam pipe, 26...
・High pressure turbine, 27...Low pressure turbine, 28...
Generator, 29... Output setting signal, 36... Governor,
37...Steam reheater. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] Integral feedback means for generating an integral feedback signal by integrating the deviation between the output of a generator driven by a steam turbine and a set value for the output; a state feedback means for generating a state feedback signal by multiplying a plant state quantity such as pressure by a preset coefficient; an integral feedback signal generated by the integral feedback means; and a state feedback signal generated by the state feedback means. 1. An output control device for a steam turbine, comprising: an adding means for adding up a governor opening command signal for controlling an opening degree of the governor.