JPH01267305A - Control method for compound power plant - Google Patents

Abstract

PURPOSE:To aim at improvement in plant thermal efficiency and prevention against erosion due to wetness by measuring pressure and temperature in a mid-step end at a steam turbine for their arithmetic processing, and performing control and performance monitoring over the plant thermal efficiency, the wetness of steam turbine exhaust or the like. CONSTITUTION:A fuel flow signal 11, a gas turbine load signal 13 and a gas turbine exhaust gas temperature signal 12 are operated each by a gas turbine controller 14. On the basis of these signals 11-13, a gas turbine fuel flow control valve 5 and an inlet guide vane 2 are controlled. On the other hand, on the basis of each detection signal out of a temperature gage 42 and a pressure gage 43, high pressure main steam pressure 45, temperature 46 and low pressure main steam pressure or the like are operated by a steam turbine computing element 48, and this operated result is inputted into the gas turbine controller 14. In addition, at this gas turbine controller 14, a control signal between the inlet guide vane 2 and each of high-low pressure main steam pressure control valves 23, 24 is operated according to a deviation with a signal out of the steam turbine computing element 48.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a combined power generation plant consisting of a gas turbine, an exhaust heat recovery boiler, and a steam turbine. -Relates to a control method for a combined power generation plant that uses temperature for operation control and operation management.

[Conventional technology]

In conventional single-shaft combined cycle power plants, the main steam pressure and temperature at the steam turbine inlet are measured.

It was only used for monitoring and was not controlled.

The main steam pressure and temperature are determined by the exhaust gas characteristics of the gas turbine, which is the heating source of the waste heat recovery boiler, and the main steam pressure and temperature are not controlled in consideration of optimal efficiency.

・As an example similar to the present invention, an example of correcting the gas turbine exhaust gas temperature using a main steam temperature signal when the main steam temperature rises rapidly or excessively is disclosed in Japanese Patent Application Laid-Open No. 58-107805. However, control was not performed in consideration of the optimum operating conditions of the steam turbine.

[Problem to be solved by the invention]

Thermal power plants, which consist of a boiler and a steam turbine, use steam to heat the feed water in the feed water heater.
Steam is extracted from a steam turbine and used. Therefore, it was possible to install a pressure gauge and a thermometer in the bleed air pipe, measure the pressure and temperature of the bleed air, and estimate the pressure and temperature in the middle of the steam turbine stage from this pressure and temperature.

On the other hand, in combined cycle power plants, no feedwater heaters are installed, and therefore there is no oil from the steam turbine, so pressure and temperature in the middle of the steam turbine stage are not measured. Therefore, there was a problem in that the i-s line of the steam turbine could not be confirmed by actual measurement.

The steam flowing inside the steam turbine is superheated steam at the steam turbine inlet, but it expands and does work, and also increases pressure and
The temperature decreases and becomes wet steam in the low pressure stage. Since wet steam may cause erosion in the blades of the steam turbine, the wetness of the steam in the final stage of the steam turbine is generally limited to around 13%. When selecting the steam conditions for the steam turbine, it is planned that the steam humidity at the final stage of the steam turbine will be within the humidity limit value in all operating ranges from rated load to partial load. However, since it is not possible to confirm the humidity of the final stage of the steam turbine by actual measurement of 1-Sa, and it is not possible to control the humidity, when selecting the steam conditions, it is necessary to make sure that the humidity is below the limit value. It is selected to have a margin of . In terms of plant thermal efficiency, steam conditions with high humidity at the final stage of the steam turbine are better; therefore, if a large humidity margin is taken, the plant thermal efficiency decreases.

A mixed-pressure steam turbine is a type of steam turbine that mixes low-pressure steam in addition to main steam into a stage in the middle of the steam turbine, but there is a certain limit on the temperature difference between the steam flowing in the steam turbine stage and the low-pressure steam mixed. It is necessary to keep the temperature within this value.If the temperature difference of the steam at this point of entry increases,
There is a problem of deformation and vibration of the casing and rotor of the steam turbine.

For this reason, steam conditions are selected so that the temperature difference at the mixing point does not exceed the limit value, but since the temperature difference at the mixing point is not conventionally controlled, when selecting steam conditions, the temperature difference at the mixing point is There was a problem in that a large margin was required, resulting in a decrease in plant thermal efficiency.

The purpose of the present invention is to provide a method for controlling operation so that plant thermal efficiency is optimized within the limits of steam turbines (exhaust humidity, temperature difference at mixing point, etc.) and a method for managing operation such as aging deterioration. It's about doing.

[Means to solve the problem]

The above purpose is to measure the pressure and temperature in the middle stage of the steam turbine, calculate the i-s line, and calculate the main steam pressure, main steam temperature, and low pressure steam so that the plant thermal efficiency is optimized within the steam turbine limit range. This is achieved by controlling the pressure.

[Effect]

In single-pressure steam turbines, pressure gauges and temperature gauges are installed in the low-pressure stage and in the stage where the steam does not become wet. In a mixed pressure steam turbine, a pressure gauge/temperature gauge 1 is installed in the upstream stage immediately before the location where low pressure steam is mixed.

In addition to the pressure and temperature in the turbine stage, main steam pressure, main steam temperature, and low pressure steam pressure are measured, and these data are processed by an electronic meter to determine the steam turbine Meas line, exhaust humidity, and low pressure. Calculate the steam heating point temperature difference, etc. These processed data and the optimal i-
S-line, optimum steam pressure, temperature, and exhaust humidity limit value,
The optimum main steam pressure, main steam temperature, and low-pressure steam pressure are set from the mixing point temperature difference limit value, and the gas turbine inlet guide vane (IGV), main steam pressure regulating valve, and low-pressure steam are adjusted to approach these set conditions. Control the pressure regulating valve.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 11 shows a schematic system of a combined power generation plant mainly consisting of a gas turbine device, an exhaust heat recovery boiler device, and a steam turbine device.

Air 3 whose flow rate is controlled by a gas turbine inlet guide vane 2 installed at the inlet of the gas turbine compressor 1 is compressed by the gas turbine compressor 1 to become high-pressure air, and is sent to the combustor 4. The high-pressure air sent to the combustor 4 mixes with fuel 6 whose flow rate is controlled by a fuel flow rate regulating valve 5, and is combusted in the combustor 4 to become a high-temperature, high-pressure gas.

The high-temperature, high-pressure combustion gas expands in the gas turbine 7 and performs work. Further, the gas turbine 7 drives a gas turbine generator 8 to obtain electrical output.

Gas turbine exhaust gas 9 after finishing work with gas turbine 7
is sent to the exhaust heat recovery boiler 20 installed on the downstream side, where it undergoes heat exchange with water and steam in order to recover the thermal energy (sensible heat) possessed by the gas turbine exhaust gas 9, and the low-temperature exhaust gas 10 and is finally released into the atmosphere.

On the other hand, the feed water 19 supplied to the exhaust recovery boiler 20 recovers the sensible heat of the gas turbine exhaust gas 9 and produces high temperature and high pressure high pressure main steam (superheated steam), relatively low temperature and low pressure low pressure main steam (saturated steam) ) and is sent to the steam turbine.

A steam turbine is composed of a high pressure steam turbine and a low pressure steam turbine and is called a mixed pressure steam turbine.

The high-pressure main steam 21 generated from the exhaust heat recovery boiler 2o first flows into the high-pressure steam turbine 23, and sequentially performs work toward the low-pressure steam turbine 24 side, becoming a relatively low-temperature and low-pressure state. be led to.

The other low-pressure main steam 22 generated from the exhaust heat recovery boiler 20 flows into the low-pressure steam turbine 24 and joins with the exhaust gas of the high-pressure steam turbine.

The combined steam sequentially performs work in the low-pressure steam turbine 24, and finally becomes low-temperature, low-pressure steam 25 and flows into the condenser 2.
Sent to 7.

The high pressure steam turbine 23 and the low pressure steam turbine 24 further drive a steam turbine generator 26 for electrical output.

The steam 25 that has completed its work in the low-pressure steam turbine 24 exchanges heat with seawater 28 in the condenser 27, condenses and becomes condensed water.
It is stored in the condenser 27. Furthermore, the condensate is pumped out by a water supply pump 30 installed at the outlet of the condenser 27,
The pressure is increased and the water is sent as water supply 19 to the exhaust heat recovery boiler 20 .

Next, a method for managing the performance of a steam turbine, which is a first embodiment of the present invention, will be explained with reference to FIGS. 11 and 12.

FIG. 12 shows in detail the internal structures of the high pressure steam turbine 23 and the low pressure steam turbine 24 in FIG. 11.

High-pressure main steam 21 generated from the exhaust heat recovery boiler 2o passes through a high-pressure steam control valve 31 provided at the inlet of the high-pressure steam turbine 23 and is guided to the high-pressure steam turbine bowl portion 33.

There, the steam diffused in a similar manner expands repeatedly in each stage (rotor blade section) 35 around the entire circumference of the high-pressure steam turbine to perform work and obtain driving force. The flow of steam is shown by dashed line 37.

One low-pressure main steam 22 passes through a low-pressure steam control valve 32 provided at the inlet of the low-pressure steam turbine 24 and is introduced into the low-pressure steam turbine bowl section 34, where it finishes its work in the high-pressure steam turbine 23. The low-pressure steam 38 is mixed with steam and diffused in a negative manner, and the low-pressure steam 38 repeatedly expands in each stage (rotor blade section) 36 around the entire circumference of the low-pressure steam turbine, performs work, and obtains driving force.

The high-pressure steam 37 is introduced into the high-pressure steam turbine 23 in a superheated state of high temperature and high pressure, but in the low-pressure steam turbine bowl portion 34 it becomes superheated steam of relatively low temperature and low pressure. Further, in the low pressure steam turbine bowl portion 34, the steam is mixed with low pressure main steam 22, which is saturated steam at a slightly different temperature level from the high pressure steam, and introduced into the low pressure steam turbine 24. The steam at this time is in the superheated region.

By the way, as the low-pressure steam 38 sequentially performs work in the low-pressure steam turbine 24, the pressure gradually decreases and the steam shifts to a wet state where it becomes drain.

The low-pressure steam 38 that has completed its work is finally recovered as exhaust gas 25 to the condenser 27 in a vacuum state. In order to manage the performance of the steam turbine, which is an embodiment of the present invention, the above-mentioned steps are necessary. It is necessary to monitor the state of steam inside the steam turbine. Therefore, the instrument position for measuring the representative steam state is determined at the rotor blade final stage position 41 of the high-pressure steam turbine, where the steam state changes at a constant rate and is near the end point.

Generally, in a thermal power plant consisting of a boiler and a steam turbine, a large number of feed water heaters are installed and steam extracted from the steam turbine is used to heat the feed water.

For this reason, the thermometer 42 and the thermometer 43 are
was installed, measured the oil temperature and pressure, determined the heat capacity, etc. from this temperature and pressure, and was able to estimate the temperature and pressure in the middle of the steam turbine stage.

In contrast, combined cycle power plants do not have feedwater heaters installed, so there is no oil from the steam turbine. Therefore, the measurement points are limited directly to the middle of the steam turbine stage.

The main measurement position 41 is preferably such that the steam in the middle of expansion of the steam turbine is in a superheated region under all operating conditions, and is as close as possible to the end point of expansion. The reason for being in the overheating area is
Its state is limited by temperature and pressure, and other saturated steam tends to become wet steam if the conditions change slightly.As for wet steam, the temperature is determined by its pressure, but the state quantity is precisely the humidity (%). It cannot be determined unless it can be measured. Furthermore, it is currently very difficult to accurately measure the humidity.

The installation positions of the thermometer and pressure gauge in a mixed-pressure steam turbine have been limited above, but as mentioned above, installation in a general car-pressure steam turbine also needs to be in the overheating region over the entire operating range. .

Next, the changes in the steam state inside the steam turbine shown in FIG. 12 are specifically shown in FIGS. 13 and 14 using i-s diagrams.

FIG. 13 shows changes in the state of steam inside the steam turbine when the combined power plant is at rated load, with the horizontal axis showing entropy and the vertical axis showing enthalpy.

Expansion starting point of high air steam 37 is 50 Yin, high temperature and high pressure is 57 at
a, the temperature is 480° C., and is located at the high pressure steam turbine bowl portion 33 in FIG. Generally, work is performed from here until the expansion end point 56 of the low pressure steam turbine exhaust 25 (0,052 ata in the vacuum section in this state).

However, in a double-pressure mixed-pressure steam turbine, during expansion, saturated low-pressure main steam 53 mixes with high-pressure steam 52 at the same pressure in the low-pressure steam turbine bowl portion 34 of FIG. 12. The temperature of the low pressure main steam 53 is about 160°C, which is about 50°C lower than that of the high pressure steam 52.

Therefore, the low pressure steam turbine expansion start point in the low pressure steam turbine bowl portion 34 in FIG. 12 shifts to 53, which is about 8° C. lower in temperature than the state of the high pressure steam 52.

The low pressure steam expands uniformly from 54 and 1. Expansion end point 55 of low pressure steam turbine exhaust 25 (vacuum part 0, 052at
Perform work up to a).

The state of the steam on the downstream side of the low-pressure steam turbine rotor blades 36 is in a humid region, and the humidity is severest in the final stage rotor blade portion, which is the most downstream side. In other words, some of the steam turns into water droplets, and the two lotions on the wings become sad.

As a countermeasure for these two lotions, a regulation value of about 13% humidity is currently set.

In Figure 13, the i-5 line (
50-52-56) and the i-s line (
As can be seen by comparing 50 to 52 to 54 to 55), the humidity in the mixed pressure steam turbine is severe, and it is considered necessary to take countermeasures.

In addition, the performance (efficiency) of a steam turbine increases as the humidity increases.
This is better because the turbine has a large heat drop.

Thus, the performance of the turbine is determined in part by the wetting bilotion limit.

FIG. 14 shows changes in the state of steam inside the steam turbine during partial load of the combined power plant, and like FIG. 13, the horizontal axis shows entropy and the vertical axis shows enthalpy.

The expansion starting point 70 of the high pressure steam 37 is approximately 20 ata, 33
The temperature is 0°C, which is lower than that of the rated load. During expansion, saturated low-pressure main steam 73 mixes with high-pressure steam 72 at the same pressure to form low-pressure steam, but this state 74 is about 2.5 ata, 133°C, which is lower than that at rated load, and is saturated steam. It is in a state close to that of

Further, the temperature difference between the high pressure steam 72 and the low pressure main steam 73 here is as small as about 6°C.

Furthermore, the low pressure steam expands uniformly in the low pressure turbine from the low pressure steam expansion start point 74, and the expansion end point 76 of the low pressure steam turbine exhaust 25
Work is done until (vacuum part 0, 052ata). The humidity is also 12% to 13%, which is higher than the i-sg (70 to 72-75) of a typical steam turbine.

Next, FIG. 1 shows an optimal control method for plant efficiency, which is part of a method for managing plant performance.

This will be explained with reference to FIG.

FIG. 1 shows a system diagram of a combined power generation plan which is an embodiment of the present invention, and FIG. 2 shows a control block diagram corresponding to FIG.

Load setting is performed in response to the power supply command, the deviation from the gas turbine actual load signal 13 is taken, and the gas turbine control device 1
4 is used as a load change signal with respect to the target load.

Further, a combustion temperature signal is obtained from the gas turbine exhaust gas temperature signal 12 by the function generator, and the gas turbine exhaust gas temperature 1
Take the deviation from the actual measured signal of 2. And fuel flow signal 1
1, a gas turbine load signal 13, and a gas turbine exhaust gas temperature signal 12 are calculated, and the opening degree of the gas turbine fuel flow control valve 5 is controlled based on the fuel flow rate opening signal to control the gas turbine inlet fuel amount and further the gas turbine inlet fuel amount. Control the turbine load and ultimately the plant load.

On the other hand, the control of the inlet guide vane 2 is performed by calculating the actual measurement signal of the gas turbine exhaust gas temperature 12 and the fuel flow rate 12 as a representative, and controlling the gas turbine inlet air flow rate using the opening signal of the inner blade 2. Finally, gas turbine load control is performed. next.

Control around the steam turbine will be explained. In order to grasp the steam condition inside the steam turbine, the actual measurement signals from the thermometer 42 and the pressure gauge 43 are sent to the steam turbine computing unit 48 to determine the conventionally installed high-pressure main steam pressure 45, temperature 46, and low pressure. An actual measurement signal of the main steam pressure 46 (this steam is saturated steam, so temperature and other conditions can be determined from pressure alone) is calculated and sent to the gas turbine control device 14.

The gas turbine controller 14 obtains a control signal for the inlet guide vanes 2 from the deviation from the signal from the steam turbine controller 48, and further controls the high-pressure main steam pressure control valve 23 and the low-pressure main steam pressure control valve 23 in order to adjust the steam turbine efficiency. This is fed back to the opening signal of the steam pressure control valve 24.

Here, the steam turbine control device 48 has optimal efficiency characteristics shown in FIGS.
(i-s line shown in FIG. 4) is stored, and the deviation of each signal is converged in order to approximate this characteristic.

Note that the performance of steam turbines deteriorates over time and gradually deviates from the optimum efficiency characteristics as the operating time passes, but in this control method, the pressure and temperature in the middle of the steam turbine step are measured and calculated, and the actual Since the i-s line and the steam turbine efficiency are calculated, it is possible to correct and control deviations from the optimum efficiency characteristics due to aging.

Next, measures to deal with the humidity of steam turbine exhaust will be explained.

FIG. 9 shows the gas turbine exhaust gas temperature 15. High pressure main steam temperature 62 and pressure 631 are shown,
and shows the moisture characteristics 64 of the steam turbine exhaust.

Here, the exhaust gas temperature 15 means that the gas turbine load is 100
As the load decreases from % to approximately 80%, due to the operation control characteristics,
- Increases over time. This is due to the fact that the opening degree of the inlet guide vanes is controlled in order to raise the exhaust gas temperature in order to improve the performance of the steam turbine cycle on the downstream side of the gas turbine.

Further, since the high-pressure main steam temperature 62 is dependent on the characteristics of the exhaust gas temperature 15, the temperature tends to be similar with a certain temperature difference.

As explained in FIGS. 13 and 14, the humidity 64 of the steam turbine exhaust is mainly determined by the conditions of the high-pressure main steam, the internal efficiency of the steam turbine, and the conditions of the low-pressure main steam (mixing point). It is.

At around 80% gas turbine load, the gas turbine exhaust gas temperature 15, that is, the high pressure main steam temperature 62 is at its highest.
It has the characteristics that reduce moisture the most.

The rotor blades of a steam turbine, especially the final stage blades, are safe from erosion.

Overall, there is a characteristic that moisture becomes severe at high loads and at low loads.

FIG. 2 shows a first system for reducing moisture in the steam turbine exhaust, and FIG. 5 shows a control block diagram corresponding to FIG. 2.

In this embodiment, in order to reduce moisture, the temperature of the gas turbine exhaust gas is controlled by the inlet guide vane, as explained in FIG. 9.

First, high pressure main steam flow rate 65. Pressure 45. The I-S line of the steam turbine is simulated by introducing the measured signals of temperature 44, low pressure main steam flow rate 66, and pressure 46, as well as the measured signals of pressure 43 and temperature 44 before the pressure mixture inside the steam turbine into a computing unit. and predict the humidity of the actual exhaust.

The humidity signal is further calculated for deviation from a limit value of exhaust humidity. The signal obtained by the steam turbine control device 48 is sent to the gas turbine control device 14, where it is repeatedly calculated with the actual value of the exhaust gas temperature 12, and is finally used to calculate the actual opening degree signal of the inlet guide vane 2, which can influence the exhaust gas temperature. The deviation is taken and the opening degree of the inlet guide vane is controlled within the exhaust gas temperature control value.

Specifically, when the steam turbine exhaust becomes extremely humid, the gas turbine inlet guide vanes are operated in the closing direction.

Then, the gas turbine inlet air flow rate decreases and the combustion temperature increases within the limit value. As the combustion temperature rises, the gas turbine exhaust gas temperature and further the high pressure main steam temperature rise as explained in FIG. 9.

Steam turbine exhaust humidity tends to decrease as the high-pressure main steam temperature increases. As a second method of reducing exhaust humidity, a method of controlling the low-pressure main steam pressure is shown in FIGS. 3 and 6.

Figure 3 shows a system for reducing steam turbine exhaust paint.
FIG. 6 shows a control block diagram corresponding to FIG. 3.

First, high pressure main steam flow rate 65. The I-S line of the steam turbine is simulated by introducing the measured signals of the temperature 44, the low-pressure main steam pressure 66, and the pressure 46, and the measured signals of the pressure 43 and temperature 44 before the pressure mixture inside the steam turbine into a computing unit. To,
Predict the humidity of the actual exhaust.

The humidity signal is selected to be a low value relative to the limit value of the exhaust humidity, and the deviation between this signal and the actual measured opening of the low pressure steam control valve is taken to generate an opening signal for the low pressure steam control valve and the water valve is activated. 32.

Specifically, the first example deals with the case where the exhaust humidity becomes severe.
This will be explained using Figure 3.

First, the low pressure steam control valve 24 is throttled down. Then, the low-pressure main steam pressure increases. The main steam moves from 53 to 53' along the saturation line 61 from the saturated steam. The saturated steam temperature tends to increase. On the other hand, the steam flow rate tends to decrease due to the heat exchange characteristics of the exhaust heat recovery boiler 20.

Here, the position of the mixing point 54 is further changed to 54' where the temperature is higher due to the mixing of the high pressure steam and the low pressure steam under this condition.
transition to.

Eventually, the end point 55 of the low pressure steam turbine exhaust will move to a position 55' where the moisture is reduced.

Next, a method of controlling the steam temperature difference at the mixed pressure point, which is a fourth embodiment of the present invention, will be explained with reference to FIG.

In a mixed pressure steam turbine, steam at the high pressure steam turbine outlet and low pressure main steam mix with a temperature difference.

If this temperature difference is large, the thermal stress of the turbine becomes large, causing vibrations during operation, and furthermore, there are concerns that the life of the turbine will be shortened.

Generally, it is desirable to provide a margin and reduce this temperature difference, but as explained in FIG. 13, this is contrary to improving the performance of the steam turbine.

In Fig. 7, the deviation between the measured signals of pre-mixing pressure steam temperature 42 and low-pressure main steam pressure 46 (temperature is expected from the pressure of saturated steam) is taken, and compared with the temperature difference limit value at the mixing pressure point, a low value is selected. do. Furthermore, the pressure-controlled low-pressure main steam that reflects the deviation between this signal and the measured opening signal of the low-pressure steam control valve in the opening control of the water valve 32 is not in a saturated state, but if the temperature difference at the point of entry is too large. , the saturation temperature increases by increasing the pressure. The process moves from 53 shown in FIG. 13 to 53'. Then, the mixing point 54 moves to 54' and acts in the direction of reducing the temperature difference.

Finally, the fifth embodiment, which deals with aging deterioration of a steam turbine, will be explained with reference to FIGS. 10 and 8.

When the turbine deteriorates over time, as shown in Figure 10, the turbine Mie S line (50~52~54~5
5) deviates from 50 to 52' to 67 to 68. Although the situation is on the safe side with respect to the humidity of the turbine exhaust, the turbine performance (efficiency) decreases.

High pressure main steam pressure 45. Temperature 44 and mixed pressure pre-pressure 43.
The actual measurement signal of the temperature 42 is taken into a computing unit, and the internal efficiency characteristics at the time of design and the internal efficiency characteristics during deterioration over time are compared using 1-5 g of the turbine, and the results are displayed or stored on the monitoring device on a daily basis.

In this way, it is possible to quickly and accurately notify operators of aging deterioration or turbine abnormalities, which can be an extremely effective means for turbine maintenance management.

〔Effect of the invention〕

According to the present invention, it is possible to improve plant thermal efficiency, prevent double lotion due to moisture in the final stage of the steam turbine, and prevent deformation and vibration of the steam turbine rotor casing due to temperature difference at the mixing point.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are system diagrams of an embodiment of the present invention,
Figure 4, Figure S, Figure 6, Figure 7, and Figure 8 are control block diagrams showing embodiments of the present invention, Figure 9 is a temperature pressure and humidity characteristic diagram, and Figure 10 is a diagram of aging. IS diagram, Fig. 11 is a system diagram of a combined power generation facility, Fig. 12 is an explanatory diagram of the internal examination structure of a steam turbine, Fig. 13 is an IS diagram at rated load,
FIG. 14 is an IS diagram at partial load. DESCRIPTION OF SYMBOLS 1... Gas turbine compressor, 2... Inlet guide vane, 4... Combustor, 5... Fuel flow control valve,
7... Gas turbine, 8... Gas turbine generator. Figure 1 Figure 2! +Sound-------Things---Bones--・+-+--+-
Figure 3 Figure 4 Section 5 Figure 6 Figure 7 Figure 8 Figure 9 ρ 2D# ω r Belly gas 7
- Pishi load (S) Figure 1 O 2 Trophies Figure 11 Figure 12 Figure 1 2 Trohi 0

Claims (1)

[Scope of Claims] 1. A combined power generation plant comprising a gas turbine, an exhaust heat recovery boiler of the gas turbine, and a steam turbine driven by steam generated by the exhaust heat recovery boiler, comprising: A complex system characterized by measuring and calculating the pressure and temperature in the middle paragraph, and controlling and monitoring performance of plant thermal efficiency, humidity of steam turbine exhaust, temperature difference at the point where low-pressure steam is mixed, aging deterioration, etc. How to control a power plant. 2. In claim 1, the pressure/temperature measurement position in the intermediate stage of the steam turbine is a low-pressure stage in a single-pressure steam turbine and a stage in which the steam condition does not become wet; A method for controlling a combined power generation plant, characterized in that the turbine is placed in the upstream stage immediately before the position where low-pressure steam is mixed. 3. In claim 1, the main steam pressure, main steam temperature, low pressure steam pressure, steam, and I-S line in the turbine stage are simulated in advance so that the thermal efficiency of the plant is optimized according to the plant load. The i-s line in the steam turbine stage is calculated by a computer from the actually measured main steam pressure, the main steam temperature, the low-pressure steam pressure, and the steam pressure and temperature in the turbine stage. to bring it closer to the optimal setting value,
A method for controlling a combined power generation plant, comprising controlling the main steam pressure, the main steam temperature, and the low pressure steam pressure. 4. In claim 1, the steam turbine exhaust humidity is calculated from the actually measured main steam pressure and main steam temperature and the steam pressure and temperature in the turbine stage, and the steam turbine exhaust humidity does not exceed a limit value. A method for controlling a combined power generation plant, the method comprising controlling the main steam temperature in such a manner as to control the main steam temperature. 5. In claim 1, the steam turbine exhaust humidity is calculated from the actually measured main steam pressure, main steam temperature, low pressure steam pressure, and steam pressure and temperature in the turbine stage, and the steam turbine exhaust humidity is limited. A method for controlling a combined power generation plant, characterized in that the low pressure steam pressure is controlled so as not to exceed a value. 6. In claim 1, so that the difference between the temperature of the low-pressure steam and the steam temperature in the turbine stage upstream of the mixing point of the low-pressure steam does not exceed a limit value,
A method for controlling a combined power generation plant, comprising controlling the pressure of the low-pressure steam. 7. Claim 1, characterized in that the main steam pressure is controlled so that the difference between the low pressure steam temperature and the steam temperature in the turbine stage upstream of the mixing point of the low pressure steam does not exceed a limit value. A control method for a combined cycle power plant. 8. In claim 1, the internal efficiency of the turbine is calculated by calculating the internal efficiency of the turbine by measuring the main steam pressure, the main steam temperature, and the pressure and temperature of a stage in the middle of the steam turbine, and calculating the internal efficiency of the steam turbine through arithmetic processing. 1. A method for controlling a combined power generation plant, comprising: storing information in a computer, and monitoring aging deterioration of the steam turbine based on aging changes in the internal efficiency of the steam turbine.