JPS6093104A - Control apparatus for steam turbine - Google Patents

Abstract

PURPOSE:To prevent the output variation in valve test by providing a reference load setter in individual one of a plurality of steam turbines and changing the reference loads of the turbine subjected to the valve test and other ones to send a certain amount of electric power to a main system. CONSTITUTION:In a control unit for steam turbines 4, 104 which drive a plurality of generators 5, 8 for supplying electric power to a main system 10, the signals of a charging amount setter 144 and a charging amount detector 161 are sent to the input of a comparator 143. The signal from a load rate bias circuit 142 is added to and subtracted from the deviation signal of the comparator by adders 202a, 202b to generate the reference load setting signal of each turbine. When a switch 140 is turned off in the valve test to set any load rate by a bias circuit 142, a valve for one turbine is closed. And the valve opening of the other turbine is increased, and an adding and subtracting valve can be tested without varying electric amount sent to the main system 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a steam turbine control device for a plurality of steam turbines. In particular, the present invention provides a steam turbine control device for Pu-erh mode operation in a geothermal power plant, in which steam valves such as steam control valves and intercept valves that adjust the amount of steam supplied to the steam turbine can be opened and closed without any trouble during turbine operation. The present invention relates to a steam turbine control device suitable for conducting tests.

[Technical background of the invention]

Steam turbine load control is typically performed by controlling the amount of steam supplied via a steam control valve, and therefore, load control of a steam turbine ultimately involves achieving a predetermined amount of steam supplied. This results from controlling the opening degree of the steam control valve so that the FIG. 1 shows such a conventional steam turbine control device together with a steam system. boiler/
In the illustrated case, the main steam generated in supplied to The steam supplied to the steam turbine 1 drives the steam turbine 1 and a generator j connected thereto. The exhaust gas from the steam turbine ≠ is condensed in the condenser 6 and returned to the boiler 1 by the feed water pump 7 to become steam, and the above-mentioned cycle is repeated thereafter. Steam turbine 104 similar to steam tarping and generator j
t and a generator t are also provided, but details of the latter steam system are omitted. The output ends of the generators J-X♂ are connected to the main system 10 via the switch circuits B and the common switch circuit C, respectively.

There is a speed detection gear on the rotor shaft 7 of the steam tarping.
2 are directly connected to each other, and a non-contact electromagnetic pickup 13 is fixedly arranged opposite to this gear 7.2. The gear 2 and the electromagnetic pickup 3 constitute a speed detector, and the electromagnetic pickup 3 outputs a frequency signal with a number of pulses proportional to the turbine rotation speed. This frequency signal is converted by a frequency-voltage converter /l into an analog quantity proportional to the turbine rotational speed, and is input to an adder lS and a differentiator /7, respectively. In the adder IS, the speed signal from the frequency-to-voltage converter /Q is compared with the setting signal from the speed setter It, and the deviation signal is sent to the low value priority circuit: 1. Added to /. The differentiator 17 outputs a differential value of the manually input speed signal, that is, an acceleration signal. This acceleration signal is compared with the setting signal from the acceleration setter /q by an adder 15, and the deviation signal thereof is integrated by an integrator 2θ, and is used as a speed error signal to be sent to a low value priority circuit: 1. second to l
It is human-powered as a human-powered signal.

In the low value priority circuit No. 2, the one with the lowest value of both human power signals is selectively output, and this becomes the speed deviation signal of the speed control system. This speed deviation signal is compared with the setting signal from the load setting device force by an adder n, and a speed deviation signal is output as the deviation. This speed deviation signal is made into a steam control valve control signal commensurate with the speed regulation rate by the speed control circuit J.
It is compared with the limit value from the load limiter 33 in the low value priority circuit 2J.

During normal operation, the load limiter 33 is generally set to 100%, and the output of the low value priority circuit Δ is
This is the steam control valve control signal from.

The output signal of the low value priority circuit is the first steam control valve 3.
The adder unit 6a compares the bias signal from the valve test bias circuit 30m for performing the test of m to produce a valve test signal. During normal operation other than the valve test period,
The bias signal from the valve test bias circuit 30a is zero, and the output of the low value priority circuit 2J is output as is. The output signal of the adder core Am is power amplified by a power amplifier core a, and is input to an electro-hydraulic converter 3m. The electro-hydraulic converter Mm converts the input signal into a proportional mechanical position amount, and depending on this deviation amount, the steam control valve oil cylinder, 2qa
is activated to control the opening of the steam control valve 3&.

The steam control valve control signal from the low value priority circuit 3 is sent to the adder 31.
B, 3/c, and 3/d are also manually operated. In adders 31b, J/c, 3/d, steam regulating valve opening start bias circuits 3.2b, 3:l are provided for steam regulating valves Jb1Ja, Jd other than steam regulating valve 31.
The bias signal from c, 3.2 d and the steam regulator control signal from the low value priority circuit Δ are compared, and the steam regulator valve 38 is tested first, followed by the steam regulators 38 to 3.2. The valve tests of the valves 3b to 3d are arranged to be performed in sequence to enable nozzle governing. The subsequent flow of signals is similar to the steam control valve 38 described above, and the amount of steam supplied to the steam tarping is controlled via the steam control valves 3b to 3d. Incidentally, :16b-, ud are adders, adders similar to 2Aa, 3θb~30
d is steam control valve test bias circuit, near b-, 27d
is a power amplifier, CO&B-UGD is an electro-hydraulic converter, and CO9B-COQD is a steam control valve oil cylinder.

[Problems with background technology]

In the apparatus shown in FIG. 1 having such a configuration, the generator output supplied to the main system 10 via the switch C may be controlled to be constant, and therefore the turbine load may be controlled to be constant. . For example, this is the case when a contract is concluded with a fixed amount of charging, with the amount of power supplied to the main system 10 being the amount of charging. In such a case, the valve stems of the steam control valves 31 to 3d shown in the figure are held at a constant valve opening position 11, and the so-called valve stem sticking phenomenon occurs. There is a risk. One way to prevent this is to test the steam control valve at bias times u, 3°a~30
d to perform an opening/closing test of the steam control valves 3a to 3d. However, as a matter of course, this valve test causes the inconvenience that the steam amount in the main steam system of the steam control valve that is opened or closed increases or decreases, and the turbine output or generator output also increases or decreases accordingly. be.

[Purpose of the invention]

The present invention was made in consideration of the above circumstances, and a plurality of steam turbine generators installed in the same power plant are each connected to the main system via a switch, so that the amount of power transmitted to the main system is constantly controlled. Provided is a steam turbine control device that is capable of preventing fluctuations such as decreases in the amount of electricity transmitted by a power plant even if a valve test of the steam control valve is carried out when the control is controlled to be constant. The purpose is to provide

[Summary of the invention]

In order to achieve this object, the present invention includes a plurality of load setters that individually set reference loads for each of a plurality of steam turbines whose loads are controlled via steam valves, and Means for changing the reference load of at least the steam turbine controlled by the test steam valve and other steam turbines while keeping the total load of the plurality of steam turbines constant, and the changed reference for each individual steam turbine. This steam turbine control device is configured to include a plurality of sets of turbine control devices that control the load of the nuclear steam turbine using the load as a target value via the steam valve.

[Embodiments of the invention]

FIG. 2 shows one embodiment of the present invention, and the present invention will be described in detail below based on this figure.

The present invention can be applied to any number of steam turbines, but here, the case of two steam turbines will be described. In other words, the apparatus shown in FIG. 2 is provided with a steam tarping driven by a generator and a steam turbine/I4t which drives a generator r. Both steam turbines If, 1011 are operated in delal mode operation (one unit low pressure operation/
/machine high pressure operation) method. It is assumed that the machine is operated with a considerable margin against the full load, such as when two machines are operated at low pressure. The control device for the first steam tarping is shown as a block/jcrc;
It is the same as the control device shown in the figure. However, although the adder n and the load setting device are included in the control device/10, for convenience of explanation, they are extracted therefrom and shown. The control device for the No. 1 steam turbine 10μ is designated by block /j/, and its internal configuration is the same as the control device IO. Again, the adder /, 2.2 corresponding to the adder n and the load setter 7.23 corresponding to the load setter are shown outside the block. Steam control valve 31 ~ that adjusts the amount of steam to the first steam turbine ≠
3d, a steam control valve 103a = ~1 for adjusting the amount of steam to the second steam turbine 10hiro.
03 d is provided on the steam turbine IO≠ side.

The steam control valves 38 to 3d and 10311 to 103d are designed so that the steam flow rate (vertical axis) of the group of steam control valves as a whole is almost proportional to the control signal (horizontal axis) as shown in FIG. The control ranges are overlapped little by little and shifted from each other. Individually, the characteristic line 300m represents the steam flow rate of the seventh steam control valve 3a, 103a, the characteristic line 300b represents the steam flow rate of the second steam control valve 3b, 103b, and the characteristic line 300c represents the steam flow rate of the third steam control valve 3b, 103b. Steam control valve 3c, 10
Characteristic line 3ooa shows the steam flow rate of μth steam control valve 3d1/θ3d, respectively. In order to achieve the steam flow rate of such individual steam control valves, the first to
As shown in Fig. μ, the steam control valve No.
.

As shown at 1100 c and 4100 d, valve opening degree (vertical axis) characteristics are given that overlap slightly and deviate from each other. In addition, AXB in Figure 3 and Figure ≠.

C and D represent arbitrary control signal points that correspond to each other.

In the device shown in FIG. 2, the portion denoted by /≠0-203 is a circuit portion added according to the present invention. Charge amount setting device/
The charge amount setting value set by 4tllt and the charge amount actual value detected by the charge amount detector /1/ are compared by the adder /113, and a charge amount deviation signal representing the deviation is outputted, and both are added. The vessels 202g and 202b are manually powered. One adder θ2a adds the load ratio signal from the load ratio bias circuit/4', 2 and the charge amount deviation signal, and the other adder 20.2b adds the charge amount deviation signal and the above load ratio. The sum signal of the former is sent to the load change rate control circuit 20/a, and the difference signal of the latter is sent to the load change rate control circuit 201b. It is derived as a setting signal and adjusted here to achieve the optimum load change rate. The load setting signal output from the load change rate control circuit 20/h1.201b is output from the generator output detector /AOa, /A
Each generator output detected by Ob and adder/Hiroshi/a
, /4'/b, and the deviation signals are sent to the load setter, )J, /23 via the pulse generator circuit, 2007hX200b and pulse motor: 13MX/23M, respectively.
Change the setting value.

On the other hand, each generator output detected by the generator output detectors /AOa, /AOb is also led to an adder 203, where the difference between the two human power is calculated, and the output is sent to the load ratio bias circuit via the switch /≠O. /≠2, it is manually input as a feedback signal during automatic control operation.

The switch/μO is turned off in the valve test state and turned on during normal operation. The load ratio bias circuit/Kuco is always at the intermediate position during normal operation, and the generated bias value at this time is zero, so the signal from the adder 203 is the same as the 11 adder 202g.

20.2b is manually operated. Therefore, during normal operation,
Both steam turbines≠,' 1011 are controlled so that they bear equal loads. The load ratio bias circuit/112 is configured such that the width A between its upper limit and lower limit is limited according to the setting value of the charge amount setter l≠≠, and the valve test is performed within this limited width.

Now, in the apparatus shown in FIG. 2, the steam control valves 3m to 3d are operated without changing the charge amount, that is, the total output (total output) of both steam turbines ≠, /III.

The operations for performing the valve tests 103a to 103d are performed as follows.

Normally, use the charge amount setting device /4 (≠ to set the desired charge amount,
Load ratio bias circuit/Hiroko and both steam generators≠, IO
Since the load ratio of ≠ is set to the intermediate position, that is, so - SO (%), the steam flow rate characteristics and valve opening characteristics of the steam control valves 3a to 3d and the steam control valves 103 & to 103d are as shown in FIGS. ≠For example, it is located on line B in the figure. The opening degree of each steam control valve on this line B is as shown in Fig.
m, 10.3b is already fully open, steam control valves 3c and 103c are at intermediate opening, steam control valves 3d and 10.
3d is in a fully closed state. However, in accordance with the present invention, in the embodiment of FIG.
A valve test of the steam control valve is performed by manipulating I/L, 2 and forcibly changing the load ratio of both steam turbines.

When testing the steam control valve, switch 1/4tO.
is turned off, the load on the steam turping side is set to 30 cm, and the load on the other steam turbine is set to 30 cm using the load ratio bias circuit /
When the load on the side of the steam turbine 10 is set to 70%, the steam control valve control signal on the steam turbine μ side moves from line B to line A, and the control signal of the steam control valve on the steam turbine 10≠ side moves from line B to line C. do. As a result, the steam control valve 3 on the steam turbine μ side
In addition to d, the steam control valve 3c is also fully closed, and the steam control valve 3
b is closed at 1 from fully open to intermediate opening. 1, the steam control valve 103c on the steam turbine IO Hiro side becomes fully open from an intermediate opening, and the steam control valve 103d opens from fully closed to an intermediate opening at 1. By operating the load ratio bias circuit l in this way and changing the load ratio from the above-mentioned 3o -7o (%) to, for example, yotat (%),
Subsequently, the steam control valve 3b is fully closed, and the steam control valve Ja? +'
It can be closed at a minute opening of 1. Conversely, when operating the steam control valve on the steam turbine IOμ side in the closing direction, the load ratio bias circuit lμ2 is operated in the opposite direction to change the load ratio to 7o-s, for example.
o (%) etc.

In this way, in the embodiment shown in Fig. 2, the load ratio of the two steam turbines can be arbitrarily set using seven load ratio bias circuits, and the valve test of the steam control valve can be performed through the process of realizing the set value. However, the steam control valves on each side of the two steam turbines are linked and simultaneously open and close in opposite directions, allowing the desired steam control valve to be opened and closed without changing the amount of power transmitted to the main system 10. Able to carry out tests.

Figure 1 shows a second embodiment of the present invention. Second
The embodiment shown in the figure performs a relatively large-scale valve test of the steam control valve for each steam turbine, whereas the embodiment shown in Fig. 5 performs a valve test for each individual steam control valve. It is. The first control device /30 and the second control device @/jtl have the same configuration and have the same basic configuration as the control device shown in FIG. Both control devices/! 0. /! / are connected via wiring tot, tot. A speed deviation signal from a low value priority circuit (not shown) is sent to an adder 2 as a setting signal from a load setting device Okara, and from a second control device (described later) via wiring ro&. A new speed deviation signal is generated by comparing it with the deficit signal from the valve test. This speed deviation signal is converted into a steam control valve control signal matching the speed regulation rate by the speed control circuit J, and is compared with the limit value from the load limiter 33 in the low value priority circuit J. Generally, during normal operation, the load limiter 33 is set to 100% load, and the output of the low value priority circuit 25 becomes the steam control valve control signal from the speed control circuit Yuhiro.

The output signal of the low value priority circuit 2J is sent to the valve test bias circuits 308 to 308 in each steam control valve by an adder jOO.
The signal from 30d and the signal from each adder unit 6a-, 2Ad are combined into an adder! 0/a-! It is compared with the valve test surplus signal obtained by adding 0/d, and becomes the steam control valve control signal only during the valve test. The output signal of the adder jθO is compared with the test signal from the valve test bias circuit 30m for performing a valve test of the steam control valve 3a in an adder 26m, and a valve test signal is generated as the deviation. During normal operation other than that, low value priority circuit 2J
The output signal of is 1-! The power is amplified by the power amplifier near a'''C and then output to the electro-hydraulic converter Sgm.

1, the output signal of adder j00 is output from adder 31b to 3/d.
It is also applied to the bias circuit 32 at which the steam regulating valves 3b to 3d other than the steam regulating valve 311 begin to open.
The bias signals from b to 32d are also added,
After the steam control valve 3a that opens first, the steam control valves 3b to 3d
are adjusted so that they open sequentially. The output signal of adder 200 is also applied to comparator 102 where it is compared with a limit value from load limiter 33. Comparator! 0.2 compares the steam control valve control signal from the adder J- (777) with the limit value from the load limiter 33, and closes the contact top inserted in the wiring rot only when the former is greater than or equal to the latter. and sends the former signal to an adder (not shown) in the control device /J-/, 2
:L is manually input as a shortage signal during valve test. wiring ro
The control signal delivered via t is the missing signal during a valve test in the control device lJ'l.

Next, the operation of the apparatus shown in FIG. 5 will be explained with reference to FIG. 11. The explanation will be given by setting the initial condition that the steam control valve control signal is operating at a value corresponding to line B in FIG. In this state, the seventh steam regulating valve 3 Todoroki 00m and the second steam regulating valve opening 4
too b is fully open, but the third steam control valve opening t/
LOOc is the intermediate opening degree, and the Vth steam control valve opening degree≠0
0d is fully closed. Here, the steam control valve 3c with an intermediate opening degree is the only one that controls the amount of steam at the control signal point on the B line, and it constantly moves slightly, so even if it is excluded from the valve test target ρ. Generally, the first and second steam control valves 3a and 3b, which are fully open in this state, are subject to the valve test.

First, if a valve test is to be performed on the first steam control valve 3a, a test signal is generated from the valve test bias circuit 30m and sent to both adders 26a and J'0/a. Adder u8 also receives a steam control valve control signal from adder 200, and the difference between these inputs is input as a valve test signal to power amplifier v1 and adder tO/a. Adder like this! At O/8, the valve test signal and the signals from the valve test bias circuit 30a are compared, and the deviation thereof is sent to the adder as a valve test surplus signal.

In this way, by sending a signal from the valve test bias circuit 30m, the steam control valve 3a gradually operates from fully open to fully closed, and the surplus signal input to the adder 100 is not fully opened. Steam control valves 3c and 3 that are not installed
This acts in the direction of increasing the opening degree of d. The biggest feature of this embodiment is that this linked operation, that is, the phenomenon in which the first three steam control valves are fully closed and the amount of steam flowing into the steam turbine is reduced, can be controlled by other steam control valves that have not yet been fully opened. The point is that the valve is opened according to the opening characteristic shown in Fig. μ. Similarly, the second steam control valve 3b can be implemented using a valve test bias circuit 30b.

Next, a valve test method will be described when all the steam control valves 3 to 3d are fully open and operating at full load (operation on line D in Fig. μ). In this case, the valve test method using the MO valve test bias circuits 30a to 30d is the same as that described above, but the valve test of any steam regulating valve is performed with all steam regulating valves 38 to 3d fully open. If this is carried out, there is no steam control valve that should be opened by the surplus signal from the adder jOO, so a load reduction (turbine output reduction) occurs by the amount of the steam control valve that is undergoing the valve test, which is undesirable. Therefore, the surplus signal obtained by the adder 100 is compared with the signal from the load limiter 33 by the comparator 302, and the set value from the load limiter 33 is also
If the signal output from is large, it is a contact! θ≠ is closed, and the latter signal is sent to an adder 22 (not shown) in the control device /j/.
It is manually operated as a shortage signal during valve testing. This shortage signal does not increase the load setting signal for the second steam turbine 104t, but the steam control valve control signal increases by an amount commensurate with the shortage signal, so the valve opening schedule shown in FIG. Accordingly, the steam control valve is opened, and the insufficient steam amount of the steam terping of M/ can be compensated for by the second steam turbine IO≠. In other words, the load reduction of the steam turbine undergoing the valve test can be compensated for by other steam turbines, and the desired valve test can be performed without causing any change in the total output of all steam turbines. .

In both the embodiments shown in FIG. 2 and FIG. 3, the case where two steam turbines are provided has been described, but there is no limit to the number of turbines, and the present invention is applicable even when three or more steam turbines are provided. can do.

1. In the above embodiment, a steam control valve was exemplified as a test steam valve, but the present invention is also applicable to other steam valves for regulating the amount of steam, such as an intercept valve having a similar function. .

〔Effect of the invention〕

As described above, according to the present invention, it is possible to perform a valve test on any steam valve without changing the total output.
Therefore, for example, even if a power plant with multiple steam turbine generators is operating under a fixed charge amount contract, it is possible to maintain a stable supply of charge amount while controlling the valve of any steam control valve. You will be able to perform the test.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional control device, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a characteristic diagram showing the flow rate characteristics of a steam control valve, and Fig. μ is a steam control valve. FIG. 5 is a block diagram showing a second embodiment of the present invention. 38-3d... Steam control valve, ≠, 1017... Steam turbine, s, r... Generator, IO... Main system, lg2... Load ratio bias circuit, l≠≠・・・Charge amount setting device, /! 0゜l/...control device, 300.
! 0/a~jO/d...Adder, j02...Comparator, SO<t...Comparator operating contact,! ;Ojt. So Otsu,! 07...Wiring. Applicant's agent Kiyoshi Inomata (23)

Claims (1)

[Scope of Claims] A plurality of load setters that individually set reference loads for each of a plurality of steam turbines whose load is controlled via four steam valves, and a plurality of means for changing the reference loads of at least the steam turbine controlled by the test steam valve and other steam turbines while keeping the total load of the turbine constant; and a means for changing the reference loads of the changed reference loads for each individual steam turbine to a target value. A control device for a steam turbine, comprising: a plurality of sets of turbine control devices for controlling the load of the steam turbine through the steam valve. 2. A plurality of steam supply systems each having a steam valve are provided for each steam turbine, and the test steam valve is subjected to a valve test by adding a valve test bias signal to the steam valve control signal. Providing a means to add the signal difference again as a common speed control signal for each steam valve.
Claim 1 characterized in that during the valve test of the test steam valve, the reduced amount of steam flowing into the steam turbine is compensated for by opening other steam valves that are either intermediately opened or fully closed. A control device for the steam turbine described above. 3. By providing means for adding the difference between the valve test bias signal accompanying the valve test of any steam valve and the steam valve control signal of that steam valve as the speed control signal of the steam valve in the control device of another steam turbine. When performing a valve test on any steam valve in a steam turbine that is operated at full open when all the steam valves belonging to a steam turbine consisting of 3. The steam turbine control device according to claim 2, wherein the load reduction is compensated for by opening steam valves of other steam turbines that are at an intermediate opening or fully closed.