JPH02238103A - Turbine controller - Google Patents

Abstract

PURPOSE:To improve the controllability by once closing a reducing valve and an intercepting valve in the turbine speed run back control mode and setting the opening degree of the reducing valve to a memorized run back opening degree on the reopening and carrying out the turbine speed control with the intercepting valve. CONSTITUTION:When the turbine speed is increased, the difference between the aimed accelerating speed 105 and the aimed speed 101 is PI-calculated by a calculator 106, and the output is inputted into an integrator 109, and a control signal 130 is obtained. A reducing valve 3 is opened by the output which is obtained by adding the bias 112 on the start of opening of the reducing valve onto the control signal 130 by an adder 113, and the turbine speed increase is started. In run back, a switch 103 is turned OFF, and a switch 104 is turned ON, and the aimed speed is switched to the aimed run-back speed 102, and the difference from the turbine speed 128 is PI-calculated in the calculation part 106. A switch 121 is turned ON by the output of a comparator 115, and an intercepting valve control signal 150 as the output of a subtraction calculator 114 is added onto the reducing valve control signal by an adder 117, and the reducing valve 3 is perfectly closed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steam turbine having a turbine bypass system, and particularly to speed control of the steam turbine.

[Conventional technology]

Conventional equipment opens the regulator valve when starting the turbine, maintains a constant opening, and then opens the intercept valve to increase the speed to the rated speed.

Setting the regulating valve to a constant opening degree when starting the turbine is a necessary means for warming up the high-pressure turbine.

[Problem to be solved by the invention]

In the above conventional technology, no consideration is given to the runback control of the turbine speed, and the intercept bypass valve closes during the runback control of the turbine speed.
There was a problem that the control valve did not close and the Yuichi bin speed did not run back. An object of the present invention is to promptly run back the turbine speed at the time of turbine speed runback and improve controllability.

[Means to solve the problem]

The above purpose is to fully open the intercept bypass valve and the control valve at the same time at the time of turbine speed runback, runback the turbine speed, and improve the stability of the turbine speed and the high pressure turbine when the turbine speed reaches the target runback speed. To warm up, the intercept bypass valve and control valve are opened again.

[Effect]

A method for starting an intermediate pressure turbine is to start the turbine by opening a control valve to a certain degree to warm up the high pressure turbine, and opening an intercept valve and bus pass valve to allow steam to flow into the intermediate pressure turbine. The fastest way to reduce the speed of the turbine is to cut off the steam flowing into the turbine. Therefore, during turbine speed runback, the regulator valve and intercept bypass valve that control the amount of steam flowing into the high-pressure turbine and intermediate-pressure turbine are fully closed in order to quickly pass through the critical turbine speed range.

〔Example〕

FIG. 2 shows a turbine system diagram having a turbine bypass system. Turbine bypass refers to steam generated in the boiler heater being passed through the boiler reheater, without passing through the steam turbine.
The purpose of this system is to circulate the water with the condenser to shorten the boiler startup time and continue independent operation within the plant. Referring to FIG. 2, the flow of steam during operation of the turbine bypass system will be explained.

Steam generated from the heater 18 of the boiler 1 flows from the main steam system 21 into the turbine bypass system 23, passes through the high pressure bypass valve (HPBV) 14 of the turbine bypass system, bypasses the high pressure turbine 4, and is supplied to the boiler 1. It flows into the reheater 6.

The steam reheated through the reheater 6 is passed through the low pressure bypass valve 15.
It flows into the condenser 12 from the steam system 24 through the steam line 24. Therefore, the intermediate pressure turbine 10 and the low pressure turbine 11 are also bypassed. As described above, the steam generated in the boiler 1 flows into the condenser 12 through the main steam system 21, the turbine bypass system 23, the reheat system 22, and the steam system 24, and bypasses the steam turbine.

The check valve 5 is for preventing backflow of steam from the turbine bypass system 23 to the high pressure turbine 4. The main steam system 21 from the heater 18 of the boiler 1 to the high-pressure turbine 4 is provided with a main steam stop valve (MSV) 2 and a control valve (CV) 3 that controls the steam flow rate. The reheat system 22 extending from the steam turbine 6 to the intermediate pressure turbine 10 is provided with a reheat steam stop valve (RSV) 7, an intercept bypass valve (engineering cV) 8, and an intercept bypass valve (ICBV) 9 that control the steam flow rate. . The condensate of the condenser 12 is supplied to a condensate system 25 equipped with a pump device 19.
The water is supplied to the heater 18 of the boiler 1 by the following. In addition, the generator 13 takes the load from the steam turbine. When starting a steam turbine with a turbine bypass system, first reset the steam turbine, fully open the main steam stop valve 2 and the reheat steam stop valve 7, and keep the control valve 3 at a constant level to warm up the high-pressure turbine. The intercept valve bypass valve 9 is gradually opened to allow steam to flow into the steam turbine and speed up the turbine.

After the merging, the intercept bypass valve 9 and the intercept valve 8 are opened, and after the intercept valve 8 is fully opened, the control valve 3 is engaged, allowing even more steam to flow into the turbine. As the amount of steam flowing into the steam turbine increases, the high-pressure bypass valve 14 and the low-pressure bypass valve 15 close, and finally, they are fully closed and enter a normal operating state.

A conventional example of speed control for this steam turbine will be explained with reference to FIG. When the turbine speed is increased, by setting the target acceleration 105 and target speed 101, the calculating section 106 calculates the PI of the deviation and inputs the output to the integrator 109.

The control signal 130 output from the integrator is input to the adder 13 through the holding circuit 110. The adder 113 further receives a regulating valve opening start bias 112 as input.

The output of this adder 113 opens the control valve, and the speed-up of the Yuichi bin begins. The relationship between the intercept valve and the addition valve is determined by the function generators 118 and 119 so that the intercept valve opens first in response to the control signal 130, and after the intercept valve is fully opened, the control valve opens. .

When the comparator 111 that detects the turbine speed of 50 Orpm or more operates, the holding circuit 110 and the switching SW 120 that store the opening of the regulating valve corresponding to the turbine speed at that time are turned on, and the regulating valve 3 is kept open at a constant level. Maintain degree.

After this, as the turbine speed further increases, the integrator 10
The control signal 130 which is the output of adder 11 becomes large.
The output of No. 4 increases from 0, the intercept bypass valve 9 opens, and the output speed increases to the rated speed.

At this time, the adjustment valve 3 maintains a constant opening degree until the joint is entered.

? - When vibration occurs in the turbine during the speed-up process, it is necessary to run back the turbine speed, but even if only the intercept bypass valve 9 is fully opened, the regulator valve 3 is open for warming, so the turbine speed will not run back. It takes a long time to descend to the target back speed, which is unfavorable for the turbine body.

The present invention aims to solve the above-mentioned problems without impairing the warming function of the high-pressure turbine. FIG. 1 is a control system diagram showing the control contents of the present invention.

The turbine speed increases with the target speed 101 as the target, but for example, the turbine speed 30 at time to in FIG.
If the turbine vibration becomes large at 00 rpm, change the target speed to SW.
Turn off 103. Switch SW104 to ONL, runback target speed 102 (1000 rpm). With this operation, ■ Runback target speed 102 and turbine speed 12
The deviation (minus) from 8 is calculated by the calculation unit 106, and
The output is input to an integrator 109.

Control signal 130 (EL) Adjustment valve control signal 140 (CVEL) Intercept valve control signal 1 at current time To
Assume that the value of 50 (IVE!L) is as follows, as shown in FIG.

CVIEL = CV opening start position + turbine speed 500r
pm equivalent position = 10 + 5 = 15 EL = 10 IVE;, = turbine speed 3000 rpm equivalent position = 5
(EL-Turbine speed 500rpJ current position) Control signal 1
30 is 10 in to as described above, but since it is negative in the calculation unit 106 during speed runback (to=tt), the control signal 130 decreases and changes from a positive region to a negative region. Therefore, the output of subtractor 114 (IVEL)
becomes negative, the comparator 115 operates, turns on the SWI 21, and adds the intercept valve control signal 150 (IVε), which is the output of the subtractor 114, to the regulator valve control signal, so that the regulator valve control signal 140 decreases from 15. The opening point of the adjustment valve becomes 10 or less, and the adjustment valve 3 goes from 20% opening to 0.
% opening (fully open).

This causes the turbine speed to drop quickly and settle at the runback speed.

In addition, as a means for closing the adjustment valve, in addition to the above, (1) the opening bias is set to O during speed runback.

(2) Input the switch SW 120 to the FFL control signal 130 to the adder 113.

is possible.

〔Effect of the invention〕

At the time of speed runback, the output of the integrator 109 becomes a large negative value. Considering the controllability at restart after the runback, a lower limiter of about -10, for example, is provided, so that the output of the integrator 109 at the time of restart is reduced. The output quickly reaches the positive range, and since the SWI 21 is turned off at this time, it quickly reaches the position equivalent to 500 rpm at startup, which improves speed controllability at restart.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a system diagram, Fig. 3 is a control system diagram of the prior art, Fig. 4 is a diagram showing the operation of the present invention, and Fig. 5 is a diagram of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Boiler, 4... High pressure turbine, 10... Intermediate pressure turbine, 11... Low pressure turbine, 13... Generator, 101... Target speed setting, 102... Runback target Speed setting, 103, 104, 120, 121-・
-SW, 105... Target acceleration setting, 106... Arithmetic unit, 109... Integrator, 110... Holding circuit, 11
1,115...Comparator, 112...Adjustment valve opening start bias, 113,114,117...Adder, 11
8,119...Function M2 diagram

Claims (1)

[Claims] 1. A power generation facility in which steam from a boiler flows into a high-pressure turbine through a control valve, and further flows into an intermediate-pressure turbine through a reheater and a tantercept valve. In a control device that is equipped with a bypass valve for bypassing, and has means for controlling the turbine speed using an intercept valve when starting the turbine and at the same time opening the regulating valve to warm up the high-pressure turbine, a regulating valve opening degree storage means is provided, In the turbine speed runback control mode when vibration occurs, the regulator valve and intercept valve are closed simultaneously during turbine warm-up control, and when restarting, the regulator valve opening is set to the memorized runback opening, and the turbine is A turbine control device characterized by speed control using an intercept valve. 2. The turbine control device according to claim 1, further comprising a lower limiter provided for the speed control PI calculation output.