JPH02185604A - Generator output control method - Google Patents

Abstract

PURPOSE:To make the output deflection of a generator extremely small by correcting the opening of an intermediate control valve on the basis of a differential pressure between the exit pressure of a primary superheater and the entrance pressure of a turbine and an output deflection between the output and the output command of the generator. CONSTITUTION:A differential pressure (a) between the exit pressure of a primary superheater 3 and the entrance pressure of a turbine 1 is found and divided by a standard differential pressure value (b), and in accordance with the obtained value a flow correction value (c) is found by rooter 22. Also, the output and the output command of a generator 15 are comparison-computer to find an output deflection (d), and a corrected opening (e) for this output deflection (d) is corrected with the flow correction value (c) fro the rooter 22 to find an openings signal (f) for correction. Then, by adding an opening signal from a basic opening program in accordance with the output command to the opening signal (f) for correction, an intermediate control valve 12 is adjusted. In this way, the opening of the intermediate control valve 12 can be always adjusted corresponding to the differential pressure (a) and the output deflection (d) to control flow rate, so that the output deflection can be made extremely small.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a generator output control method for controlling the output of a generator by controlling a superheater intermediate valve used in a steam line of a constant pressure boiler. It is related to.

[Prior Art] In equipment in which steam is guided from the furnace of a boiler to a turbine to drive the turbine, and the turbine is driven to operate a generator, normally, as shown in FIG. A steam line 2 that leads steam to the steam line 1 is arranged, and from the upstream side to the downstream side of the steam line 2, a next week heater 3, a plate superheater 4, and a final superheater 5 are installed. - A bypass line 6 is provided between the outlet side of the heating device 3 and the inlet side of the plate superheater 4, and the bypass line 6 is connected to a flash tank 7 and a flash tank inlet valve ( A check valve (N valve) 9 on the outlet side of the flash tank is provided, and an on-off valve (■ valve) 11 as a superheater intermediate valve 10 and an intermediate control valve (■ valve small valve) are provided. 12, and the V-valve small valve 12 is provided with an opening program setting section 14 that sets a basic opening program based on the output command from the output command section 13. It is designed to be controlled based on the opening program. 15 is a generator, and 16 is a condenser recovery line that returns from the flash tank 7 to the condenser.

When controlling the generator output using the above-mentioned conventional method, first, at startup, the P valve 8 is opened and the steam/water mixture that has exited the primary superheater 3 is sent to the flash tank 7, where it is separated from the steam and water to the turbine. The necessary amount of steam requested by
5 will be activated and the rest will be returned to the condenser. When switching from starting circulating operation to true current operation (during ramping),
The P valve 8 is closed and the V valve 11 is opened to direct the steam from the primary superheater 3 to the plate superheater 4 via the valve 11. Since it is difficult to maintain balance, the opening degree is adjusted by opening and closing the small valve 12. In this case, the adjustment of the small valve 12 is based on the basic opening based on the output command from the output command section It was supposed to be done only by opening according to the degree program.

[Problems to be Solved by the Invention] However, in the conventional system described above, when entering the operating state from startup, the V valve 11 is opened and the P valve 8 is closed forcibly, so the inlet pressure of the turbine 1 fluctuates. However, the generator output deviation occurs. Therefore, the above output deviation is corrected by adjusting the opening degree of the small valve 12.
■Valve The small valve 12, which should originally be quantitatively adjusted by the control valve, is adjusted only by the programmed opening degree, so even when an output deviation occurs, it cannot be dealt with.

Therefore, the present invention not only controls the small V-valve as a superheater intermediate control valve by an opening program based on an output command, but also calculates the differential pressure between the primary superheater outlet pressure and the turbine inlet pressure. The purpose is to correct the differential pressure based on the pressure difference and minimize the output deviation.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a structure in which a small V-valve as an intermediate control valve is adjusted by a basic opening program based on an output command. Determine the differential pressure between the pressure at the outlet of the heater and the pressure at the turbine inlet, divide it by the standard differential pressure value, use that value to determine the standard flow rate using the router, and calculate the comparison between the generator output and the output command. to find the output deviation,
The corrected opening degree for the determined output deviation is determined by a bias opening program based on the reference differential pressure value, and the corrected opening degree is corrected with the flow rate reference value from the router to obtain a correction opening signal. , the opening signal from the basic opening program based on the output command and the correction opening signal are added to obtain V.
The method is to adjust the small valve.

[Function] At the start of switching from startup circulation operation to once-through operation (ramping), the differential pressure between the primary superheater outlet pressure and the turbine inlet pressure is large, and after ramping starts, the turbine inlet pressure gradually increases and the differential pressure gradually increases. It's getting less. When this differential pressure decreases, ■ the amount of steam flowing through the small valve decreases,
It is necessary to increase the opening degree of the valve, and when the differential pressure is large, the flow of steam increases accordingly, so the opening degree of the valve only needs to be small.

In the present invention, the control signal to the small V-valve is corrected based on the value obtained by dividing the above-mentioned differential pressure by the reference differential pressure value, and the corrected opening value obtained from the generator output and the output deviation due to the output command. Therefore, the valve opening degree is always adjusted according to the differential pressure and output deviation, making it possible to control the flow rate and minimize output deviation.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a primary superheater 3, a plate superheater 4, and a final superheater 5 are provided in the middle of a steam line 2 that leads steam from a boiler furnace to a turbine 1. - Next week, between the heater 3 and the plate superheater 4, an on-off valve (V valve) 11 and an intermediate control valve (V valve small valve) 12 as the heater intermediate valve 10 are installed, and also flushed on the bypass line 6. Tank 7, flush tank inlet valve (P valve) 8 and check valve 9,
Both are provided in the same manner as shown in FIG.
In a configuration in which a reference opening degree program setting unit 14 based on an output command from an output command unit 13 is connected to the outlet side of the -next week heating unit 3, there is a primary superheater outlet for detecting the outlet pressure of the next week heating unit 3. A pressure gauge 17 is installed, and a turbine inlet pressure gauge 18 for detecting the inlet pressure of the turbine 1 is installed on the inlet side of the turbine 1, and the pressure gauges 17 and 18 are connected to the calculator 19. The outlet pressure and the turbine inlet pressure are compared and calculated by the calculator 19 to obtain the differential pressure a before and after the intermediate valve, and this differential pressure a and the output deviation d, which will be described later, are calculated.
Based on this, the adjustment of the small V-valve 12 is corrected to increase or decrease the flow rate, thereby modifying the generator output. 20 is a divider that divides the differential pressure a between the primary superheater outlet pressure and the turbine inlet pressure determined by the calculator 19 by the reference differential pressure value from the reference differential pressure setting device 21; 22 is a divider; 23 is a generator output signal, and 24 is a router (square square device) that calculates a correction value C for the flow rate from the value from the device 19; 24 is a generator output signal and an output command from the output command unit 13; 25 is a reference bias opening program setting unit that sets the reference bias correction opening e @ for the output deviation d from the calculator 24 based on the reference differential pressure setting device 21; 26 is the bias opening A UI device that calculates a correction opening signal f by correcting the reference bias correction opening e from the degree program setting section 25 using the flow rate correction value C from the router 22;
7 is a controller, and 28 is an adder.

During start-up circulation operation, only the P valve 8 is opened, as in the conventional method, and the flow is transferred from the primary superheater 3 to the flash tank 7 and the plate superheater 4.
, steam is sent to the turbine 1 via the final superheater 5, and the operation of the generator 15 is started.

After the start of ramping and until once-through operation begins, the V valve 11 is opened and the P valve 8 is closed. At this time, it is difficult to maintain steam balance, and when the output of the turbine 1 fluctuates, the output of the generator also fluctuates, so the turbine output deviation is kept small by adjusting the opening of the small valve 12. In this case, the next week's heater outlet pressure and turbine inlet pressure are always detected and the computing unit 19
The differential pressure is determined by inputting the pressure to the generator, and the flow rate is controlled by correcting the opening of the V-valve small valve 12 by capturing this differential pressure fluctuation and the generator output deviation, so the turbine output, that is,
It is possible to smoothly reach the generator output to the state during normal operation. In other words, the differential pressure calculated by the calculator 19 indicates that the upstream pressure is 200 KI at the start of ramping.
lcti, which is the largest at the turbine inlet as it is around 6ONg/cm. Therefore, the fluid flow is good, so the valve opening can be small, but as time passes, the differential pressure becomes smaller. The fluid becomes difficult to flow, and the valve must be opened to a large degree. Therefore, the differential pressure a obtained by the calculator 19 is divided by the standard differential pressure value by the divider 20 and sent to the router 22, where the correction value C for the flow rate differential pressure is determined. It is used to correct the opening degree.

Now, the differential pressure a calculated by the calculator 19 is 1ooKy/cd
Assuming that, the reference differential pressure value of the reference differential pressure setting device 21 is 70.
Assuming that KI/ctA, in the router 22, a correction value C of the flow rate is determined by assuming that f is a bath.

On the other hand, the output signal 23 of the generator and the output command suitable for the load from the output command unit 13 are compared and calculated in the calculator 24 to obtain the output deviation d, and further, the reference differential pressure of the reference differential pressure setting device 21 is calculated. The standard bias opening degree program setter 25 based on the output deviation d determines the standard bias correction opening degree e as a percentage of the opening degree, and the multiplier 26 uses this standard bias correction opening degree e to calculate the standard bias opening degree e from the output deviation d. Flow rate correction value C from
to obtain a correction opening signal f, and send this correction opening signal f from the output command section 13 to the opening program setting section 14.
to the opening signal sent via the As a result, the flow rate is controlled via the V-valve small valve 12 based on the differential pressure before and after the intermediate valve and the actual generator output, so even if a deviation in the output of the turbine 1 (generator output) occurs, the small valve Valve 1
2 is controlled, fluctuations in turbine output can be suppressed, and generator output deviations can be minimized.

FIG. 2 shows the relationship in which the above-mentioned turbine output fluctuation is corrected by the V-valve small valve 12. The solid line indicates the normal control state, and the turbine output changes from startup circulation operation to once-through operation. P valve 8 so that it rises between
, open the small valve 12, and open the V-valve 11. However, if an output deviation occurs in the turbine output as shown by the broken line, the small V-valve 12 is adjusted according to this output deviation. Adjustments are made as shown by the broken line based on the differential pressure from the unit 19 and the output deviation from the calculator 24. In this case, if the turbine output falls below the state shown by the solid line, the small valve 12 should be opened wide as shown by the broken line to increase the flow rate, and the turbine output should be If the temperature rises above the solid line, reduce the opening of the small valve 12 as shown by the broken line.
The turbine output is controlled to be close to the reference curve shown by the solid line, and the generator output deviation is reduced.

In this way, in the present invention, when there is a turbine output deviation,
The opening degree of the small V-valve 12 is adjusted in accordance with the output deviation obtained by substantially calculating the differential pressure, and the output deviation is minimized by increasing or decreasing the flow rate.

[Effects of the Invention] As described above, according to the generator output control method of the present invention,
A superheater intermediate valve is installed in the middle of the steam line leading from the boiler furnace to the turbine, and when switching to close the flash tank inlet valve (P valve) and open the intermediate valve (V valve) when starting circulation operation, When adjusting the intermediate control valve (V valve small valve), calculate the differential pressure between the next week's heater outlet pressure and the turbine inlet pressure, calculate the output deviation from the generator output and output command, and use these as a base. Since the opening degree of the small V-valve is corrected, even if a generator output deviation occurs, it can be automatically corrected and the output deviation can be minimized, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the method of the present invention, FIG. 2 is a diagram showing a state of output deviation correction according to the present invention, and FIG. 3 is a diagram showing a conventional example. 1...Turbine, 2...Steam line, 3...Next week's heater, 4...Plate superheater, 5...Final superheater, 7
...Flash tank, 8...Flash tank inlet valve (P valve), 10...Superheater intermediate valve, 11...Opening/closing valve (V valve), 12...Intermediate control valve (V valve small valve), 1
3... Output command unit, 15... Generator, 17... Primary superheater outlet pressure cutter, 18... Turbine inlet pressure gauge,
19... Arithmetic unit, 20... Divider, 21... Reference differential pressure setting device, 22... Router, 23... Generator output signal, 24... Arithmetic unit, 25... - Reference bias opening program setting section, 26... Multiplier, 28... Adder, a... Differential pressure, b... Reference differential pressure value, C... Flow rate correction value, d... - Output deviation, e... Reference bias correction opening degree, f... Correction opening signal. Figure 1 Figure 3

Claims (1)

[Claims] (1) When switching from the flash tank inlet valve to the superheater intermediate valve after startup in order to drive the turbine and operate the generator to increase the generator output, it is used as an intermediate control valve in the superheater intermediate valve. When adjusting the V-valve small valve, find the differential pressure between the primary superheater outlet pressure and the turbine inlet pressure, divide this differential pressure by the reference differential pressure value to find the flow rate reference value with the router, and also calculate the generator output After determining the output deviation from the above reference differential pressure value and the output command, the corrected opening degree for the output deviation is calculated based on the above reference differential pressure value, and then the corrected opening degree is corrected with the flow rate reference value from the above router for correction. Find the opening signal and use this signal to set the above V.
A generator output control method characterized by correcting the opening degree of a small valve.