JPS59185806A - Turbine control device - Google Patents

Abstract

PURPOSE:To prevent rise of the turbine exhaust temperature and minimize generator output within a range witout hindrance to controlling steam extraction by controlling an adjustment valve for the last stage steam extraction at the minimum definite opening at the time of generating minimum operation of a steam extraction turbine. CONSTITUTION:In a control device of a two-stage steam extraction turbine, a signal sD, obtained by letting a speed deviation signal es pass through a speed controller 13, is added to a load setting signal lL by means of an adder 15, and the sum is inputted to a distribution ratio operation part 25 as a signal cL. Further, deviation signals cp1, cp2 for the difference between the first extraction pressure and the second extraction pressure are also inputted to the operation part 25, and openings of a steam adjustment valve and the first, the second steam extraction adjustment valves are controlled by means of controllers 26-28. At the time of the generating minimum operation, a switch 22 is put in ON state and a load setting signal lL, corresponding to a deviation of a minimum opening setting signal dR2ECV for the second steam extraction adjustment valve from an actual opening signal b2ECV, is sent out to maintain the the second steam extraction adjustment valve at the minimum opening all the time, therefore, the extraction pressure is constant and the minimum generator output can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a turbine control device suitable for load control without affecting the extraction pressure of an extraction turbine.

[Technical background of the invention and its problems]

Generally, extraction turbines are employed in industrial private power generation equipment that requires two types of energy: electric power and steam. The primary operational requirements when operating this bleed turbine include speed control control and bleed control. In other words, the importance of speed governor control goes without saying, but controlling the bleed pressure to a constant level plays an important role in maintaining factory production activities. On the other hand, there is load control as a secondary operation requirement. This means that during times when electricity prices are high, power generation is maximized, which in turn reduces electricity costs.

The main control is to minimize power generation and purchase electricity during times when money is cheap.

In order to perform this minimum power generation operation, lower the load setting and
It is necessary to reduce the flow rate of steam input to the turbine. However, if the steam flow rate is reduced too much, the turbine exhaust flow rate decreases too much, resulting in poor cooling and a rise in exhaust gas temperature, leading to overheating of the final stage turbine. Furthermore, if this overheating continues, it will cause fatal damage to the turbine.

For this reason, operators must restrict the exhaust flow rate so that it does not fall below a certain flow rate, and monitor and operate the bleed air pressure so that it does not fluctuate in response to changes in the bleed air flow rate. There were problems that required effort.

[Purpose of the invention]

The present invention maintains the turbine exhaust flow rate constant, prevents overheating of the final stage turbine, and maintains the extraction pressure constant regardless of the extraction flow rate used in the factory.
1. It is an object of the present invention to provide a turbine control device that can obtain the minimum load that can be handled, that is, the power generation output, depending on the flow rate of extracted air at that time.
purpose.

[Summary of the invention]

Therefore, the present invention prevents the turbine exhaust temperature from rising by controlling the opening of the final stage bleed control valve to a minimum constant opening during the minimum power generation operation, and maintains the temperature within a range that does not interfere with the bleed control C'-]. The feature is that the generator output is the minimum possible.

[Embodiments of the invention]

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows a configuration diagram of a two-stage bleed air turbine control system according to an embodiment of the present invention, in which 1 is a turbine control device, 2 is a steam control valve, 3 is a first bleed air control valve, and 4 is a second bleed air control system. The extraction control valve 1.5 is a high pressure turbine, 6 is an intermediate pressure turbine, 7 is a low pressure turbine, 8 is a generator, 9 is a speed sensor, and 10.11 is a pressure sensor.

The turbine control device 1 includes a speed sensor 9, a pressure sensor 10.
11, respectively, a speed signal S, a first bleed pressure signal pl,
The second bleed pressure signal p2 is input, and the steam control valve drive signal aCV, the first bleed control valve drive signal algcy, and the The second bleed control valve drive signal a2ECV is output to the steam control valve 2, first bleed control valve 3, and second bleed control valve 4, respectively.

At this time, the following relationship is established between the flow rate of each control valve and each bleed air flow rate.

'c ''=f, E +f, zc ''−・−・−
(1) fl. . = f2゜10'2IIC...
・・・・・・・・・・・・ (2) f2 Oh. ”fCON
・・・・・・・・・・・・・・・・・・・・・
(3) However, fo is the main steam flow rate, fIB is the first bleed air flow rate, fiEC is the first bleed air control valve flow rate, f2° is the second bleed air flow rate, f2EC is the second bleed air control valve flow rate, and fcoN is the exhaust flow rate. .

Further, the output or load of the generator 8 driven by the high pressure turbine 5, intermediate pressure turbine 6, and low pressure turbine 7 is expressed by the following equation.

L=ηhf. +ηlf, one. 1ηtf2□,...
(4) However, η5 is the high pressure turbine flow rate output ratio, η1 is the intermediate pressure turbine flow rate output ratio, and η is the low pressure turbine flow rate output ratio.

Therefore, from equations (1) to (4) above, it can be seen that the extraction turbine control when the minimum power generation operation is not performed can be performed as follows.

For example, in order to increase only the load without causing fluctuations in the extraction pressure, open the steam control valve 2 and open the main steam flow rate f.
c and at the same time, the first bleed air flow rate f1. , the first bleed air control valve 3 and the second bleed air control valve 4 may be controlled to be opened so that the second bleed air flow rate f2K does not increase.

Next, in order to increase only the first bleed pressure pl without changing the load and the second bleed pressure p2, first open the steam control valve 2, close the first bleed control valve 3, and then increase the first bleed air flow rate f.
Increase lE. At this time, the first bleed air control valve 3 is closed to reduce the load, so the first bleed air control valve flow rate fl. . decreases, and the second bleed air flow rate f2E decreases, so the second bleed air control valve 4 is controlled to be closed.

On the other hand, in the case of performing the minimum amount of power generation during a time period when the electric power rate is low, the bleed air turbine control in this embodiment controls the second bleed air control valve 4 to the minimum opening degree. In this state, the bleed air flow rate 'I
E, f2 has bleed air pressure P11 according to factory use.
Steam control valve 2 and first bleed air control valve 3 so that P2 is constant.
Control by opening and closing. As a result, the minimum possible output of the generator can be obtained depending on the amount of extracted air at that time.

Figure 2 shows a turbine control device 1 for performing the above control.
This shows the specific configuration diagram of 12゜17.20.2
3 is a deviation calculator, 13 is a speed control unit, 14 is a load setting device, 15 is an adder, 16 is a first bleed pressure setting device, 18 is a first bleed air control portion, 19 is a second bleed pressure setting device, 21 22 is a power generation minimum mode selection switch; 24 is a power generation minimum control unit; 25 is a distribution ratio calculation unit; 26, 27
, 28 is a valve controller consisting of a four-way controller.

In the configuration shown in the figure, the minimum power generation mode selection switch 22 is turned off during times when electricity rates are high. At this time, the deviation calculator 12 calculates the deviation between the speed setting signal 8R and the speed signal B, and outputs the speed deviation signal es.
inputs the speed deviation signal e8, multiplies it by a proportionality constant, and outputs the speed control command signal BD. The load setting device 14 outputs a load setting signal tL, and the adder 15 inputs and adds this load setting signal tL and the speed control command 8p, and outputs a load control command signal CL.

Next, the deviation calculator 17 outputs the first bleed pressure setting signal PIB output from the first bleed pressure setting device 16 and the first bleed pressure signal pl.
The first bleed air control unit 18 inputs this first bleed pressure deviation signal e p 1, performs lead/lag compensation and proportionally multiplies it, and outputs a first bleed air control command signal cpi.

Regarding the second air bleed control, the second air bleed control section 21 outputs the second air bleed control command signal CP2 through the same process as the first air bleed control described above. Here, p2R is a second extraction pressure setting signal, p2 is a second extraction pressure signal, and eP2 is a second extraction pressure deviation signal.

The distribution ratio calculation unit 25 inputs the load control command signal CI, the first bleed control command signal CPl, and the second bleed control command signals e and p□, and increases or decreases the load as described in the explanation of FIG. For example, the following (5 ) calculation of the distribution ratio shown in the formula is performed to obtain the steam control valve opening commands d,,v.

A first bleed control valve opening command dIKCV and a second bleed control valve opening command d2ECV are output.

(However, α and j indicate calculation constants.) The valve controller 26 receives a steam control valve opening command signal dc.
Input v and steam control valve drive signal a. V is the steam control valve 2
Output to. The valve controller 27 inputs the first bleed control valve opening command signal dIECV, and outputs the first bleed control valve drive signal "ECV" to the first bleed control valve 3.
The valve controller 28 inputs the second bleed control valve opening command signal d2ECV, and receives the second bleed control valve drive signal a2Ec.
V' is the second bleed air control valve.

Output to.

This makes it possible to maintain the first bleed pressure signal P1% and the second bleed pressure signal p2 constant, and to supply the required first bleed air flow rate fl2 and second bleed air flow rate f28 to the factory.

Next, during the minimum power generation operation, the minimum power generation mode selection switch 22 is turned ON and L to select the minimum power generation mode. Then, the adder 15 outputs the second bleed control valve minimum opening setting signal d.
The load setting signal LL corresponding to the opening deviation signal e between R2cv and the second bleed control valve actual opening signal b2□cv and the speed control command signal are added and output to the distribution ratio calculation unit 25. .

In fact, during the minimum power generation operation, the second bleed air control valve 4 is always controlled to a constant minimum opening degree. Therefore, at this time, the minimum steam flow determined by the bleed flow rates fIE and f2□ flows through the second bleed air control valve 4, and the minimum steam output is obtained within a range that does not affect the bleed pressure signal p1+p2. .

The second bleed air control valve minimum opening degree setting signal dR2EC'V is set to a value slightly larger than the required minimum value of the second bleed air control valve opening degree, taking into account the variation in the bleed air flow rate.

Although the above embodiment describes an example in which the present invention is applied to a two-stage bleed turbine, it goes without saying that the present invention is not limited to this and can be similarly applied to a single-stage bleed turbine and a multi-stage bleed turbine of three or more stages. .

〔Effect of the invention〕

As described above, according to the present invention, when performing minimum power generation,
It is possible to prevent a rise in exhaust temperature and protect the final stage turbine from overheating. Furthermore, by making the control loop that minimizes power generation an integral characteristic, and by appropriately selecting the time constant, pressure and speed control are prioritized. Minimum power generation operation is possible while keeping the extraction pressure constant.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a two-stage extraction turbine control system according to an embodiment of the present invention, and FIG. 2 is a block diagram of the turbine control device of FIG. 1. 1... Turbine control device, 2... Steam control valve, 3...
...First bleed air control valve, 4...Second air bleed control valve, 5...
- High pressure turbine, 6... Intermediate pressure turbine, 7... Low pressure turbine, 8... Generator, 9... Speed sensor, 10
, 11...pressure sensor, 12, 17, 20.23...
- Deviation calculator, 13... Speed control section, 14... Load setting device, 15... Adder, 16... First bleed pressure setting device, 18... First bleed air control section, 19 ...Second bleed pressure setting device, 21...Second bleed air control section, 22...Minimum power generation mode selection switch, 24...Minimum power generation control section, 2
5...Distribution ratio calculation unit, 26.27.28...Pulp controller. Figure 1 Figure 2 Rotation

Claims (1)

[Claims] (1) In a turbine control device that performs speed load control and control without interfering with each other, means for outputting a speed control command signal according to a deviation between a speed setting signal and an actual speed signal, and a speed control command signal means for outputting a load control command signal by adding a load setting signal to the bleed air; means for outputting a bleed air control command signal according to a deviation between the bleed air pressure setting signal and the actual bleed air pressure signal; A means for calculating the distribution ratio of the control command signal and outputting a steam control valve opening command signal and a bleed control valve opening command signal, and a means for actually controlling the steam control valve opening and the bleed control valve opening according to these command signals. and means for outputting a load setting signal according to the deviation between the opening degree setting signal and the actual opening degree signal of the final stage bleed air control valve during minimum power generation operation. . (2. The turbine control device according to claim 1, wherein the extraction turbine is equipped with one or more extraction control valves.