JPH04179835A - Fuel gas pressure control method - Google Patents

Abstract

PURPOSE:To restore the fuel gas pressure to a normal level without stopping the operation of a gas turbine or releasing to the atmosphere from a vent stack, by increasing or decreasing the fuel consumption of each gas turbine until the deviation in gas pressure between the fuel and a reference is zeroed. CONSTITUTION:A load control apparatus for combined power generation facilities composed of 12 units is constituted by a unit load control means 17 for controlling the loads of individual power generation facilities Nos. 1 to 6, and a successive load control apparatus for making general control of the loads of the unit power generation facilities. A fuel gas pressure deviation signal 36 representing the deviation between a fuel gas pressure and a reference gas pressure is equally distributed with respect to each of the unit load control means 17. And the fuel gas pressure is determined, while being adjusted, by increasing or decreasing the gas turbine fuel consumption quantity until the deviation is zeroed. This enables restoring the fuel gas pressure to a normal level without stopping the turbine operation, or causing air release to the atmosphere from the vent stack.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to fuel control, and particularly to a fuel gas pressure control system suitable for combined power generation equipment directly connected to fuel gas supply equipment.

[Conventional technology]

In the conventional fuel gas pressure control method of combined power generation equipment, if the supply capacity of the fuel gas supply equipment side is insufficient and the fuel gas pressure decreases as described in JP-A-62-58022, the combined power generation equipment The fuel gas pressure is stabilized by sequentially stopping the side gas turbines. Conversely, when the fuel gas pressure rose, the vent stack was opened to release the gas to the atmosphere.

[Problem to be solved by the invention] In the conventional fuel gas pressure control system, when the fuel gas pressure decreases, the gas turbines are sequentially stopped in order to stabilize the fuel gas pressure. Even if the gas turbine is stopped, the gas turbine is restarted and generates electricity.
There was also the problem that it took a long time to restore the original output. There was a problem in that when the fuel gas pressure rose, it had to be released into the atmosphere.

An object of the present invention is to directly control the fuel consumption of a combined power generation facility using a fuel gas pressure deviation signal, and to bring the fuel gas pressure to a normal value without stopping the gas turbine or releasing it into the atmosphere from the vent stack. 6 [Means for Solving Problem 111] To provide a fuel gas pressure control method that can restore fuel gas pressure to the fuel gas supply equipment. and a combined power generation facility consisting of multiple gas turbine/steam turbine power generation facilities are equipped with a load control device, and each load control device controls the fuel gas pressure of the fuel gas supply facility. In the control method, a fuel gas pressure deviation signal resulting from the deviation between the fuel gas pressure and the reference gas pressure is equally distributed to each load control device, and the fuel consumption amount of each gas turbine is increased or decreased until the deviation disappears. The gas pressure is configured to settle.

The load control device then equally distributes the fuel gas pressure deviation signal to each combined power generation equipment under load operation in either automatic load control or manual load control operation mode, and simultaneously increases or decreases the fuel consumption of each gas turbine. By doing so, the fuel gas pressure is stabilized.

In addition, the load control device suppresses load control by automatic load control or manual load control by detecting the fuel gas pressure deviation signal, and evenly distributes the fuel gas pressure deviation signal to the plurality of power generation facilities under load operation. A configuration may also be adopted in which the control is switched to fuel gas pressure control and the fuel gas pressure is stabilized.

Furthermore, when a fuel gas pressure deviation signal is detected as a positive deviation signal on the fuel increasing side, the gas turbine is prevented from proceeding to stop during the process of stopping the combined power generation equipment, and a plurality of gas turbines are controlled by fuel gas pressure control. do.

When the fuel gas supply equipment experiences pressure fluctuations in which the fuel gas pressure deviates from the pressure adjustment range and detects a pressure deviation of the pressure fluctuations, the fuel gas pressure is adjusted by increasing or decreasing the fuel consumption of the combined power generation equipment. When a failure occurs in the pressure control of the gas supply equipment and the fuel gas pressure is not stabilized, the fuel consumption amount of the combined power generation equipment is maintained at the reference gas pressure by increasing or decreasing it.

[Effect]

According to the fuel gas pressure control method of the present invention, when the fuel gas supply capacity is insufficient and the fuel gas pressure decreases, the fuel consumption of all gas turbines operating in parallel is simultaneously suppressed. The fuel gas pressure is restored without sequentially stopping the gas turbines. Therefore, by returning the fuel gas pressure on the fuel gas supply equipment side to normal, the pressure on the combined power generation equipment side is also restored in a short time. On the other hand, if the fuel gas supply capacity becomes excessive and the fuel gas pressure increases, the fuel of all the gas turbines operating in parallel will increase and the fuel consumption will increase, without releasing into the atmosphere by opening the vent stack. Fuel gas supply pressure is returned to normal.

〔Example〕

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

As shown in Fig. 1, the combined power generation facility consists of a total of 12 units, 6 units in Group 1 and 6 units in Group 2, and these load control devices.

It consists of a unit load control device 17 that controls the loads of individual combined power generation facilities from &1 to Na6, and a series load control device M1 that collectively controls the loads of these unit power generation facilities. The configuration of the series load control device M1 is such that the power supply command 2 is a signal switching l! ! 3, and a signal from a series load manual setting device 4 is connected to the signal switch 3 via an analog memory 5.

The 8-power side of the signal switch 3 is connected to a series load control subtracter 9 via a series MW tracking mode switch 7. The series actual MW obtained by adding the total output ° of the combined power generation equipment from NQ 1 to Nα6 to the series load control subtracter 9
The signal No. 8 is also connected and subtracted from the target value of series load control. The deviation signal after this subtraction is the gain corrector 10
The automatic mode of the combined power generation equipment from NAL to NQ6 is selected through each unit load control system! 17 via each wiring.

In the unit load control device 17, the load command 11 from the series load control device 1 is connected to the unit switch 18.

A signal from a unit load manual setting device 19 is connected to the unit switching device 18 via an analog memory 20. The output side of the unit switch 18 is connected to a unit load control subtracter 26 via a unit MW tracking mode switch 22, a unit load change rate limiter 23, and a unit load control upper/lower limit l#24. The actual MW 25 of the unit output is also connected to the unit load control subtracter 26, and a subtraction operation is performed with the target value of the unit load control.

The deviation signal after this subtraction is connected to a signal reduction comparator 29 and a signal increase comparator 30 via a low value selector 27 and a high value selector 28. The output signals from the increase and decrease signal comparators are connected to the governor circuit 31 of the gas turbine fuel control circuit. On the other hand, the fuel gas pressure signal 32 on the fuel gas supply equipment side of the combined power generation equipment is connected to a fuel gas pressure control reference signal generator 34 and a fuel gas pressure control subtractor 33 . The result of subtracting these two signals is transmitted as a fuel gas pressure deviation signal 36 to the No. 1 train 6 of the power plant via the fuel gas pressure control dead zone 35.
It is equally distributed to a total of 12 units, including the unit and 6 units of the No. 2 series, via their respective wirings.゛The fuel gas pressure deviation signal 36 received on the unit side is sent to the zero level signal generator 38 as well as the fuel gas pressure control use exclusion switch 3.
Connected to 7. A switching signal from this switch is connected to a fuel gas pressure control plus bias adder 39 and a fuel gas pressure control minus bias adder 40. The other signal, either the fuel gas pressure control plus bias signal 41 or the zero level signal generator 42, is connected to the fuel gas pressure control plus bias adder 39 via the fuel gas pressure control plus bias switch 43. be done. The sum signal of these two signals is then connected to the low value selector 27.

Further, as the other signal of the fuel gas pressure control minus bias adder 40, either the fuel gas pressure control minus bias signal 44 or the zero level signal generator 45 is sent via the fuel gas pressure control minus bias switch 46. Connected. The addition signal from this fuel gas pressure control minus bias adder 40 is connected to the high value selector 28. The above is the overall configuration of the load control system of the Humbind cycle power generation facility.

Next, the operation of fuel gas pressure control in the load control system of the combined power generation facility will be explained.

Series load control when the fuel gas pressure on the fuel gas supply equipment side is in a normal state is performed using the power supply command 2 or the series load manual setting device 4.
The signal switch 3 can arbitrarily select any one of the load command signals from the load command, and the selected signal becomes the target value 6 of the series load control. This target value 6 is the series actual M of the signal obtained by adding the total output during load operation as a group of combined power generation equipment
W8 is subtracted, and if the target value is larger than the series actual MW, it is equally distributed to each unit (combined power generation equipment) as a positive deviation. This distribution signal from the series load control device is received and becomes the target value 21 for unit load control when the signal switch 18 on the unit side is in the automatic load control operation mode position. When the signal switch 18 is in the manual load control operation mode position, the signal from the unit load manual setting device 19 becomes the target value 21 of the unit load control. The unit in the automatic mode (operation mode of automatic load control) receives the unit load control target value signal from the series load control device 1 and subtracts it from the actual MW 25 of the unit output. A positive deviation is output. At this time, the fuel gas pressure is normal, so the fuel gas pressure deviation signal 3 connected to the unit
6 is ±O, and the signal from the fuel gas pressure control plus bias signal generator 41 and the signal from the minus bias signal generator 44 are added to this signal, respectively, and the fuel gas pressure control plus bias addition signal is selected as a low value. To vessel 27,
The fuel gas pressure control minus bias addition signal is connected to the high value selector 28.

Here, the positive deviation signal from the previous unit load control subtractor 26 and the fuel gas pressure control plus bias addition signal are as follows: The positive deviation signal from the load side # side is passed by the low value selector 27, and the next gate is The passed load control side positive deviation signal and the fuel gas pressure control minus bias addition signal are compared, the high value selector 28 passes the load control side positive deviation signal, and the signal increase comparator 30 controls the gas turbine fuel. The circuit governor 31 is moved in the increasing direction to increase fuel (fuel consumption). This increase in fuel continues until there is no deviation between the target value for train load control and the train actual MW8.

Next, on the contrary, if the target value of the series load control is smaller than the series actual MW, it is equally distributed to each unit as a negative deviation, and the operation is opposite to the case explained with a positive deviation. . That is, a negative deviation signal is output from the unit load control subtractor 26, compared with the fuel gas pressure control plus bias addition signal, and the low value selector 27 outputs a negative deviation signal.
The negative deviation signal on the load control side passes through. At the next gate, this signal is compared with the fuel gas pressure control minus bias addition signal, the high value selector 28 passes the minus deviation signal on the load control side, and the reduction signal comparator passes the minus deviation signal to the governor 31 of the gas turbine fuel control circuit.
to decrease the fuel consumption.

Next, a case where a pressure fluctuation occurs on the fuel gas supply equipment side such that the fuel gas pressure on the fuel gas supply equipment side deviates from the pressure adjustment range will be described.

When the load control of the unit is in automatic mode as described above,
It follows the target value of unit load control from the upper series load control device 1, and when in manual mode (operation mode of manual load control), load control that targets the set value by unit load manual setting device 19. However, if the fuel gas pressure fluctuates outside the pressure adjustment range, a fuel gas pressure deviation signal 36 is generated between the fuel gas pressure signal 32 and the fuel gas pressure control reference signal generator 34. When the fuel gas pressure rises above a reference value (reference gas pressure), a positive deviation occurs, and conversely, when it falls below the reference value, a negative deviation occurs. When this deviation value reaches a value equal to or greater than a specified value set by the fuel gas pressure control dead band device 35, the deviation signal is equally distributed to the 12 unit load control devices 17. This equal distribution is equally distributed to all units operating in parallel, regardless of whether it is the No. 1 or No. 2 train in the power plant, and regardless of the automatic mode or manual mode load control mode within the train. This distributed fuel gas pressure control deviation signal determines the value of the fuel gas pressure control plus bias signal generator 41 or fuel gas pressure control minus bias signal generator 44 that determines the start of fuel gas pressure control in the unit load control device. When it exceeds the unit actual MW)-racking switch 22, the unit load control shifts to actual MW tracking using the unit output, and the output of the unit load control subtractor 26 becomes zero deviation. Under such circumstances, when the fuel gas pressure deviation signal is taken in as a positive deviation, this signal receives a signal from the fuel gas pressure control plus bias signal generator 41 and a signal from the fuel gas pressure control minus minus signal generator 44, respectively. The signals are added and compared with the zero value of the deviation signal from the load control side. In the low value selector 27, a signal obtained by adding a positive bias to the positive deviation signal of the fuel gas pressure is compared with the zero value of the deviation signal on the load control side, and the low value zero value of the deviation signal on the load control side is passed. At the next gate, when the positive deviation amount is greater than the positive deviation of the fuel gas pressure minus the negative bias signal at the fuel gas pressure starting point, the deviation signal on the load control side exceeds the zero value and the high value selector 28 selects the fuel gas pressure. A positive deviation signal on the gas pressure control side is passed, and the increase signal comparator 30 moves the governor 31 of the gas turbine fuel control circuit in the increase direction to increase the amount of fuel. This behavior is performed simultaneously for all units during load operation, and continues until the pressure falls below the fuel gas pressure control start point. When the fuel gas pressure settles within the specified value, the actual MW tracking is excluded, and the signal passing through the low value selector 27 and the high value selector 28 becomes a deviation on the load control side and returns to the original unit load control. Conversely, when the fuel gas pressure deviation signal is input as a negative deviation, the operation is opposite to that described for the positive deviation, and the signal from the fuel gas pressure control plus bias signal generator 41 and the fuel gas The signal from the pressure control minus bias signal generator 44 is added and compared with the zero value of the deviation signal from the load control side. In the low value selector 27, when the negative deviation amount is equal to or greater than the sum of the positive bias and the negative deviation signal of the fuel gas pressure, the negative deviation of the fuel gas pressure control is changed from the time when the deviation signal on the load control side exceeds the zero value. The signal passes. The high value selector 28 of the next gate compares the negative deviation signal of the fuel gas pressure control with a signal in which a negative bias is further added. The deviation signal passes when a high value is selected, and the reduction signal comparator moves the governor 31 for gas turbine fuel control in the direction of reduction, thereby reducing the amount of fuel, thereby suppressing the fuel consumption of the entire power plant. This suppression is performed until the fuel gas pressure is stabilized.

Next, if a situation occurs in which the fuel gas pressure cannot be controlled to a fixed value due to a malfunction in the gas pressure adjustment device, etc. on the fuel gas supply equipment side, the combined power generation equipment side will increase or decrease the fuel consumption in response to a signal that the trouble has occurred. The function of controlling the planting of fuel gas pressure by performing the following will be explained.

When a trouble occurs in the gas pressure adjustment device or the like on the fuel gas supply equipment side, each unit of the combined power generation equipment receives this trouble signal and uses the unit MW tracking switch 22.

Switch to actual MW tracking mode using unit output, and shift to fuel gas pressure control mode.

Simultaneously fuel gas pressure control plus bias signal switch 43
, and fuel gas pressure control minus bias signal switch 4
6, the bias for fuel gas pressure control is switched to zero value bias on both the plus and minus sides. When the fuel gas pressure is above the reference value and becomes a positive deviation of the fuel gas pressure control dead band device 35 or more, the positive deviation amount goes straight into the low value selector 27 and high value selector 28,
It is compared with the zero value of the deviation signal on the load control side, and the high value selector 28
As a result, the positive deviation signal on the fuel gas pressure control side is passed, and the amount of fuel is increased. Conversely, when the deviation is negative, the negative deviation signal on the fuel gas pressure control side is passed by the low value selector 27, and the fuel reduction operation is performed. By setting the bias for fuel gas pressure control to zero in this way, it is possible to control the increase/decrease in fuel consumption on the combined power generation equipment side and to control the fuel gas pressure to be constant. Selection of whether or not to perform these fuel gas pressure control and fuel gas pressure constant value control is made using the fuel gas pressure control use/exclusion switch 37.
When the gas turbine is in the process of starting up, increasing the load, or stopping, the switch 37 switches the signal to the zero level signal side and excludes it from the units subject to fuel gas pressure control. In this use/exclusion, if the fuel gas pressure deviation signal is a positive deviation and it is necessary to act on the fuel increasing side, the progress of the stop process is inhibited,
The load drop during the stop process is interrupted, and the fuel gas deviation signal is switched to the receiving/accepting side by the fuel gas pressure control use/exclusion switch 37, so that the unit in the stop process is also incorporated into the fuel gas pressure control target unit. There is.

According to the embodiment described above, adjustment of pressure fluctuations that deviate from the pressure control range on the fuel gas supply equipment side or gas pressure adjustment when pressure adjustment is malfunctioning on the fuel gas supply equipment side can be performed by stopping the gas turbine or venting. It is possible to stabilize the increase or decrease in fuel consumption on the gas turbine side by adjusting and controlling a plurality of gas turbines simultaneously without taking steps to release fuel by opening the stack. This has the effect of quickly recovering the output of the combined power generation equipment after fluctuations in fuel gas pressure have stabilized, and solving the problem of fuel gas being released into the atmosphere.

〔Effect of the invention〕

According to the fuel gas pressure control method of the present invention, the fuel gas pressure can be controlled without stopping the gas turbine. Since the gas turbine system does not stop, it also has the effect of significantly shortening the time it takes to restore the original output of the combined power generation equipment after the fuel gas pressure is restored.

Furthermore, it is possible to eliminate the release of fuel gas into the atmosphere due to opening of the vent stack for adjusting the fuel gas pressure, and there is an effect that the amount of fuel equivalent to the release into the atmosphere can be taken out in the form of electrical pressure.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of load control of a combined power generation facility showing an embodiment of the present invention. 1... Series load control device, 2... Power supply command, 3...
・Signal switch, 4... Series load manual setting device, 5...
Analog memory, 6... target value for series load control, 7 series MW tracking mode switch, 8... series actual M
W. 9... Series load control subtractor, 10... Gain corrector, 11... Load command from series, 17... Unit load control device, 18... Signal switch, 19... Unit load Manual setting device, 20...Analog memory, 21.
...Target value of unit load control, 22...Unit M
W tracking switch, 23...Unit load change rate limiter, 24...Unit load control upper/lower limiter, 2
5... Unit actual MW, 26... Unit load control subtractor, 27... Low value selector, 28... High value selector, 24... Comparator for reduced signal, 30... Increased signal comparator, 31... governor of gas turbine fuel control circuit, 32... fuel gas supply pressure signal, 33...
-Fuel gas pressure control subtractor, 34...Fuel gas pressure control reference signal generator, 35...Fuel gas pressure control dead band device, 36...Fuel gas pressure deviation signal, 37...Fuel gas pressure control Use/exclusion switcher, 38... Zero level signal generator, 39... Fuel gas pressure control plus bias signal adder, 40... Fuel gas pressure control minus bias signal adder, 41... Fuel gas Pressure control plus bias signal generator, 42...Zero level signal generator, 4
3...Fuel gas pressure control plus bias signal switch,
44...Fuel gas pressure control minus bias signal generator, 45...Zero level signal generator, 46...Fuel gas control minus bias signal switch. Agent Tatsuyuki Unuma

Claims (1)

[Claims] 1. A load control device is provided in a thermal power generation facility that directly connects a fuel gas supply facility and a combined power generation facility consisting of a plurality of gas turbine/steam turbine power generation facilities, and each load control device controls the fuel In a fuel gas pressure control method for controlling the fuel gas pressure of gas supply equipment, a fuel gas pressure deviation signal based on the deviation between the fuel gas pressure and a reference gas pressure is equally distributed to each load control device, and the deviation is A fuel gas pressure control method characterized in that the fuel gas pressure is stabilized by increasing or decreasing the fuel consumption of each gas turbine until the fuel gas pressure is exhausted. 2. The load control device equally distributes the fuel gas pressure deviation signal to each combined power generation equipment under load operation in either automatic load control or manual load control operation mode,
2. The fuel gas pressure control method according to claim 1, wherein the fuel gas pressure is stabilized by simultaneously increasing and decreasing the fuel consumption of each gas turbine. 3. The load control device suppresses load control by automatic load control or manual load control by detecting the fuel gas pressure deviation signal, and evenly distributes the fuel gas pressure deviation signal to the multiple combined power generation equipment under load operation, thereby controlling the load. 2. The fuel gas pressure control method according to claim 1, wherein the control is switched to fuel gas pressure control to stabilize the fuel gas pressure. 4. When a fuel gas pressure deviation signal is detected as a positive deviation signal on the fuel increasing side, the progress of stopping the gas turbine in the process of stopping the combined power generation equipment is suppressed, and a plurality of gas turbines are controlled by fuel gas pressure control. The fuel gas pressure control method according to claim 1, characterized in that: 5. When a pressure fluctuation occurs in the fuel gas supply equipment in which the fuel gas pressure deviates from the pressure adjustment range and a pressure deviation of the pressure fluctuation is detected, the fuel gas pressure is set by increasing or decreasing the fuel consumption of the combined power generation equipment. The fuel gas pressure control is characterized in that when a failure occurs in the pressure control of the fuel gas supply equipment and the fuel gas pressure is not stabilized, the fuel consumption of the combined power generation equipment is increased or decreased to maintain it at a reference gas pressure. method.