JPS58133505A - Controller for feed pump - 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 The present invention provides a water supply pump control device which is configured to control a plurality of water supply pumps that supply water to a steam generator in a power plant or the like based on a predetermined operation command. Regarding equipment.

The conventional water pump control device of this type inputs a predetermined operation command into a control circuit when water is supplied using a water pump with a KII number of steam generators in a power generation plant, etc., and this control circuit controls the water pump. It was configured to control driving. To be more specific, a water supply pump that supplies water to a steam generator is used in a typical power generation plant.

an electric motor-driven water pump as a starting water pump;
Two turbine-driven water supply pumps are used as water supply pumps for normal operation after startup, with each suction side and each discharge side connected in common. Above water supply pump Fi
%At the time of initial start-up, the electric motor-driven water feed pump is operated, and when the pressure from the steam generator reaches a predetermined pressure, the turbine-driven water feed pump is operated.
Its operation was controlled. This speed increase control XIFi of the turbine-driven water supply pump was a control method that smoothed and determined the rotational speed of the driving turbine and increased it to the 9th constant speed. In order for the discharge pressure to overcome the water supply pressure in the piping after the water pump discharge side confluence point, it became necessary to increase the rotational speed to the point where the turbine-driven water pump started supplying water.

As a result, the disadvantage is that it is not easy to shift to water supply control using a turbine-driven water supply pump.

FIG. 1 is a characteristic diagram showing the relationship between the flow rate Q and the discharge pressure HK of the water supply system, with the horizontal axis representing the flow rate Q and the vertical axis representing the discharge pressure H. In addition, in Figure 1, N, , Nt and N
, Fi, the rotation speed of the water supply pump, h, indicates the system head characteristics of a constant pressure operation plant, and hT indicates the system head characteristics of a variable pressure operation plant. In the case of a constant-pressure operation plant, as shown in the figure, the system head curve h1 is flat, so the change in discharge pressure due to changes in the rotation speed of the turbine-driven water pump is small, and the rotation speed target is maintained as in the conventional control system. Even if the value is set to a constant value, the effect of the above drawback is small. However, in the case of a variable pressure operation plant, the main steam pressure changes depending on the load, so the system head of the water supply system h! When the system head 11sK of a constant pressure operation plant changes significantly, it becomes . Therefore, especially in the case of a variable pressure plant, the rotational speed corresponding to the water supply start point of the turbine-driven water supply pump is not uniformly determined, and it is not preferable to set the rotational speed target value to a constant value. For this reason, the control of the water pump.

The disadvantage is that it is difficult.

The object of the present invention is to overcome the drawbacks of the prior art described above.

KTo provides a water supply pump control device that can perform stable and smooth water supply control regardless of changes in the system head of the water supply system.
Ru.

In order to achieve the above object, the present invention obtains the rotation speed corresponding to the water supply start point of the water supply pump based on the differential pressure between the discharge pressure of the turbine-driven water supply pump and the pressure at the water supply pump discharge side confluence point, and The rotation speed of the water supply pump is controlled accordingly.

One embodiment of the present invention will be described below with reference to the drawings.

Figure 2 is a system diagram showing the schematic configuration of a power generation plant to which the feed water pump control device according to the present invention is applied.
Th, the boiler IOK as a steam generator is configured to be supplied with feed water 100 from turbine-driven feed water pumps 12 and 14 and an electric motor-driven feed water pump 16, and the boiler IOK is supplied with fuel from a fuel pump (not shown). At the same time, air is supplied from the fan. This boiler 10 converts feed water 100 into steam 102 according to the combustion of the fuel, and converts this into steam 102.
The turbine 2011'C is supplied through the two control valves 18. This turbine 20 is configured to generate rotational work according to the steam 102A controlled by the control valve 18, and is configured to be able to transmit the rotational work to the generator 22. This generator 20 is configured to be able to generate electric power according to its work.

Additionally, the turbine 20 is configured to send most of its steam 102A to the double water tank 24, which in turn sends most of its steam 102A to the pumps 12, 14 and 16 as steam 102At-double water 104. -ru.

The suction sides of the water supply pumps 12, 14 and 16 are common, and their discharge sides are connected to check valves 26, 30 and 3.
4 and stop valves 28, 32 and 36 are connected in series to the confluence point as shown in the figure, and are supplied to the boiler 10 as water supply 100. Additionally, a turbine-driven water pump 12. and 14
is adapted to drive the turbines 42 and 44 to rotate by controlling the bleed air 106 from the turbine 20 with respective control valves 38 and 40. Rotation detectors 46 and 48 are provided to detect the rotational speed of these water supply pumps 12 and 14Kus.

Note that 50 is powered by an electric motor. Furthermore, 52 and 54 are
Top and 56 are pressure detectors provided on the discharge sides of the turbine-driven feedwater pumps 12 and 14, respectively. Further, the water supply pipe is provided with a flow rate detector 58 for detecting the flow rate of the water supply 100, and the steam pipe is further provided with a flow rate detector 60 and a pressure detector 62 for detecting the flow rate and pressure of the steam 102. is provided. In addition, generator 2
A detector 64 for detecting the amount of power generated is provided at the second output.

A control circuit 66 controls the power generation plant.

Various commands for power generation 68 and various detectors 46.4g.

Detection signals from 52, 54, 56, 58, 60, 64 are taken in, and based on these, the control valve 18 and regulating valves 38 and 40 are controlled to control the amount of generated power. ing.

The power generation plant configured as described above is
When the control circuit 66 controls combustion of the boiler 10 based on the control circuit 66, the control valve 18 is controlled to control the rotation of the turbine 20 and the amount of power generated by the generator 22. At this time, the control circuit 66 performs various detections based on various commands 68.
, 54, 56° 58, 60, 62 and 64 to control the control valve 18, adjusting valves 38 and 40, and other operating parts.

The specific configuration of the water supply pump control device applied to the above-mentioned power generation plant is shown in FIG.
Since this is an enlarged view of the practical part of FIG. 2, the same reference numerals are given, and the explanation of the structure will be omitted, and only a brief explanation of the reference numerals will be given. 12 and 14 are turbine-driven water pumps, and steam turbines 42 and 44
Driven by. Further, reference numeral 16 denotes an electric motor-driven water supply pump, which is driven by an electric motor 50. 26.30 and 28.32 are check valves and stop valves for the turbine-driven water pumps 12 and 14, respectively, and 34 and 36 are check valves and stop valves for the motor-driven water pump 16.

When starting up the plant, water is supplied to the motor-driven water supply pump 16 for the boiler, and after reaching the specified load, the turbine-driven water supply pump 12 is started, and the water supply load is transferred to the turbine water supply pump 12.
Alternatively, the turbine-driven water supply pump 1492 is added to the 14 side, but when starting the turbine-driven water supply pump 12 or 14, as described above, the rotation speed is increased to the rotation speed equivalent to the water supply start point and the turbine drive water supply pump 14 is placed on standby. It is desirable to maintain a state in which the system can smoothly transition to water supply control.
And, 52, 54 and 56 are the ninth pressure detectors that perform this, and the detection signals from these pressure detectors 52, 54 and 56 are transferred to the control circuit 66Km! 0 is included to perform the above control.

FIG. 4 is a block diagram showing this embodiment of the control circuit 66. In FIG. 4, a detection signal 70 from the pressure detector 52 and a detection signal 72 from the pressure detector 56 are input into a subtractor 74, and this subtractor 74 is used to generate a differential pressure signal ()P).
76. This differential pressure signal 7
6 into the subtractor 78 and the % target differential pressure command 68A.
The signal from . This differential pressure deviation 8G is taken into the proportional integral calculator 82,
This calculation 4e! 82 to form a rotational speed set value 84. The actual rotational speed signal 86 from the rotational speed detector 46 is input into a subtracter 88 together with the rotational speed set value 84, and a rotational speed deviation 90 is formed in the arithmetic unit 88. This rotational speed deviation 90 is supplied to a low value selector 94 via a proportional calculator 92.
Further, the signal from the acceleration rate setting 68B can be taken in, and the lower value can be outputted and supplied to the proportional-integral calculator 96. This proportional-integral calculator 96 is designed to control the regulator valve 38 of the turbine 42.

The operation of the control circuit configured as described above will be explained next.

In FIG. 4, signal 90 indicates turbine-driven water pump 1
The actual rotational speed signal 86 detected by the rotational speed detector 46 which detects the rotational speed of 2 and the rotational speed set value 84 are calculated by a subtractor 88 to give 9 deviations. Controlling the control valve 38 of the driving turbine 42, which is the operating end, via the computing unit 92 and the proportional integral computing 696;
Increase the speed to the set rotation speed. Further, the rotational speed change rate setter 68B and the low value selector 94 are used to limit the rate of change when there is a deviation between the actual rotational speed and the target rotational speed at the initial stage of acceleration. Rotation speed setting l[
The feature is that 84 is variable. In addition, 52 and 5
As explained in FIG. 2, 4 indicates the water supply pressure at the outlet of the turbine-driven water supply pump, the water supply pressure detector at the discharge side confluence section, and the subtractor 74, which indicates the differential pressure (ΔP) between the pressure signals 70 and 71.
76, and the deviation 80 between this and the signal of the signal generator 68A which has set the target differential pressure to 0 is passed through the proportional-integral calculator 82 to find the rotation speed setting position 84 at which the differential pressure becomes 0. can.

According to this embodiment, the rotation is such that the difference pressure O between the water supply pressure of the water supply pump 12 or 14 (signal detected by the pressure detector 52) and the water supply pressure at the discharge side junction (signal detected by the pressure detector 56) is obtained. It is possible to automatically increase the speed of the turbine-driven water supply pump 12 to the number (84), that is, the rotation speed corresponding to the water supply starting point. Note that the water supply pump 14 is also configured with a control circuit in the same manner.

According to this implementation, the rotation speed of the water supply pumps 12 and 14 can be increased to the equivalent of the water supply starting point regardless of changes in the system head of the water supply system, and the subsequent transition to water supply control becomes smooth. Enjoy the benefits.

As described above, according to the present invention, stable and smooth water supply control can be achieved regardless of changes in the system head of the water supply system.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram showing the relationship between the discharge pressure and flow rate of the water supply system, Fig. 2 is a system diagram showing the schematic configuration of a power generation plant to which an embodiment of the present invention is applied, and Fig. 3 is a diagram showing the schematic configuration of a power generation plant to which an embodiment of the present invention is applied. FIG. 4 is a block diagram showing the configuration of a control circuit according to an embodiment of the present invention. 12.14... Turbine-driven water pump, 16...
Electric motor driven water supply pump, 38.40...Adjustment valve. 42.44...Turbine, 52.54...Pressure detector. 56... Pressure detector at the confluence section, 66... Control circuit,
68...command, 74.78.88...=subtractor, 82
゜1st mouth 5 disclaimer O zo 2 figure

Claims (1)

[Claims] L A water supply pump control device comprising a plurality of water supply pumps that supply water to a steam generator and a control circuit that controls the operation of the water supply pumps based on a predetermined operation command. A first pressure detector provided on each discharge side, a second pressure detector provided at the discharge side confluence of the plurality of pumps, and a second pressure detector provided on each water supply pump, and a second pressure detector provided on each of the water supply pumps, and a second pressure detector provided on each of the water supply pumps, and a second pressure detector provided on the discharge side of each of the plurality of pumps, and a second pressure detector provided on each of the water supply pumps. Equipped with a rotation speed detector to detect
The control circuit is configured to form a target rotational speed command based on pressure signals from both positive force detectors, and to supply water based on the rotational speed signal from the rotational speed detector and the target rotational speed command. A water supply pump control device characterized by being configured to control the rotation speed of a pump.