JPS62267503A - Pressure control device of feed water pump driving turbine - Google Patents

Abstract

PURPOSE:To supply a proper quantity of steam to an auxiliary steam main immediately after FCB (First Cut Back) so as to plane stability of the turbine in the caption by controlling the pressure regulating valve in the auxiliary steam main pipe of a feed water driving turbine for a constant period immediately after FCB and according to the load just before FCB. CONSTITUTION:Two pressure regulating valves 9 and 10 are provided in an auxiliary steam pipe 3 on the boiler side connected to an auxiliary steam main pipe 1 for supplying steam to a feed water pump driving turbine. The valve 10 receives a control signal from a pressure regulating valve control circuit 40 and is fully opened immediately after FCB occurs. The valve 9 also receives a deviation between pressure set value of a set value circuit 14 and detected value of a pressure detector 13 through a proportional integral circuit 15. Further, a signal g is supplied according to a load signal f from a plant automatic control device 16 for a constant period just after FCB occurs, and said valve 9 is controlled. Accordingly, a proper quantity of steam can be supplied to an auxiliary steam main pipe just after FCB.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention provides a steam generator, a main turbine, and a generator.
In the power generation equipment that supplies 1J of water to the steam generator, the water pump drive turbine pressure control device controls the pressure of the auxiliary steam D1 pipe that supplies driving steam to the feed water pump drive turbine that drives the water pump that drives the water pump that supplies 1 J of water to the steam generator. About

(Prior art) Auxiliary steam is used for various purposes in the city construction cooperative, which is equipped with a steam light unit, a main turbine, and a starter, but the one that requires the most 7fi is , water pump drive! This is the supply of driving steam to the FII turbine (hereinafter referred to as 8PPT).

Below, as an example of the power generation membrane width, the configuration of a steam system of a thermal power plant facility will be explained using FIG. 2.

The main steam system consists of 1, boiler 2, which has a economizer, evaporator, superheater, superheater, and reheater that make up the k-air generator.
The main steam control valve 8△ installed on the output side of the superheater ■
, a reheat steam control valve 8B provided on the output side of the reheater, and a high-pressure turbine (+-I P) 23, intermediate pressure turbine (IP) 24, J3 and low pressure turbine (LP 25)
a condenser 31 that collects the exhaust gas of the turbine 3o as condensate, a condensate pump 27,
Low pressure water supply heating! 32, a water supply pump 28 driven by the BFPT 5, a high-pressure water supply heater 33, and piping connecting these devices.

On the other hand, the auxiliary steam system generates steam from the oil air of the high-pressure turbine 23 during normal operation, and supplies steam whose pressure has been adjusted by the pressure regulating valve 7 to the auxiliary steam main pipe 1.
For emergency backup, hot air is pumped from an appropriate part of the steam condition in the middle stage of the superheater of the boiler 29, and the pressure is increased through the pressure regulating valves 9 J5 and 10. A boiler-side auxiliary steam pipe 3 is provided for supplying the regulated steam to the auxiliary steam ffi pipe 1. Steam is supplied from the auxiliary steam main pipe 1 to the BFPT 5 via the control valve 4. In order to stably supply water to the boiler 29, it is necessary that the pressure in the auxiliary steam main pipe 1 be controlled within a certain range. During the shore operation, the pressure of the auxiliary steam main pipe 1 is controlled by adjusting the amount of steam flowing in from the turbine side auxiliary steam pipe 2 with the turbine side pressure regulating valve 7 using a signal from the pressure regulator 6. Ru.

However, due to an accident in the power transmission system, FCB (first cut back) control is entered, load is cut off, and the amount of steam flowing into the turbine 30 is reduced to the main steam control valve 8.
It seems that J: was rapidly narrowed down to A.
The steam f line from the targon side auxiliary air pipe 2 also rapidly decreases. In order to cope with this situation, a pressure regulating valve 9 is also installed in the auxiliary steam pipe 3 on the boiler side. Supply is being carried out.

FIG. 3 is a block diagram of a pressure control (2II device) according to the prior art. 22 output signals: a pressure regulating valve control circuit 40 that quickly fully opens the pressure regulating valve 10; a set value circuit 14 that outputs an upper air signal according to the set pressure of the auxiliary steam main pipe 1; , this setting (IC
The pressure setting value A;) C which is the output of the 1 circuit 14 is compared with the pressure signal of the auxiliary steam 1 pipe 1 detected by the pressure detector 13, and the auxiliary steam main pipe 1 is set based on the deviation.
A proportional integral circuit (denoted as PI) 15 is provided, which outputs a valve opening command signal e to the pressure regulating valve 9 so that the pressure of the pressure becomes a set value.

As shown in Fig. 3, in the conventional pressure control device, the amount of steam required at PT is approximately constant in the settling state after FCB, but immediately after FCB,
Since C can take a fairly wide range of values depending on the plant operating state before I', if the pressure regulating valve 10 follows poorly, F
Immediately after CB, there are many problems such as insufficient supply of water due to insufficient supply of auxiliary steam, or conversely, too much attention is paid to the initial supply at a rapid breath rate, resulting in abnormal pipe pressure and back pressure. In the worst case, it may lead to FCB failure.

(Problems to be Solved by the Invention) The present invention solves the following problems:
Immediately after the FCB, steam of appropriate speed is supplied from the boiler side to the auxiliary steam main pipe to ensure a stable supply of steam for driving the feed water pump, thereby reducing the pressure of the water pump driving turbine to reduce the failure factors of FC [3]. [Structure of the Invention] (Means for Solving the Problems) The present invention provides a main steam system that drives a main turbine with steam from a steam generator. a water supply pump drive turbine that drives a water supply pump that supplies water to the water supply pump; an auxiliary steam main pipe that supplies driving steam to the water supply pump drive turbine; and a steam extractor that guides steam extracted from the main turbine to the auxiliary steam main pipe. First pressure adjustment block? a turbine-side auxiliary steam pipe that supplies steam whose pressure has been adjusted by the steam generator; and a turbine-side auxiliary steam pipe that supplies steam whose pressure has been adjusted by
A power generation facility comprising an auxiliary steam system that connects a second pressure regulating valve and a third pressure regulating valve to a steam generator side auxiliary steam pipe that supplies pressure-regulated steam to the auxiliary steam main pipe. The auxiliary steam system includes a pressure regulating valve control circuit capable of fully opening the third pressure regulating valve during normal operation and fully opening it immediately after an FCB occurs; A set value circuit that outputs an electrical signal according to the set pressure, a pressure set value signal that is the output of this set value circuit, and a pressure signal that indicates the pressure of the auxiliary steam main pipe are compared, and based on the deviation, Said auxiliary steam F! J
In the pressure control device for a water supply pump drive turbine, the pressure control device includes a proportional-integral circuit that outputs a valve opening command signal to the second pressure regulating valve so that the pressure in the pipe becomes a set value. Enter the indicated value and press F at 2 o'clock.
a hold circuit that holds a signal of the load state immediately before reaching the CB state; and a hold circuit that holds a signal of the load state immediately before reaching the CB state, and generates an opening setting signal for the second pressure regulating valve according to the load immediately before reaching the P CB state, which is held in this hold circuit. L-1 is characterized by comprising a function generator and a switching logic circuit for setting the output of the function generator as the opening command value of the second pressure regulating valve for a certain period of time after the occurrence of FOB. be.

(Function) According to the above pressure control device, immediately after FCB, steam with an appropriate ω is supplied from the steam generator side to the auxiliary steam main pipe and sent to the feed water pump drive turbine, depending on the load operating state immediately before FCB occurs. The supply steam pressure can be stabilized.

(Example) Fig. 2 is a steam system diagram of a thermal power plant in which the pressure control device according to the present invention is applied to thermal power generation equipment. The description is omitted because it has already been explained in the technology section.In this embodiment, the pressure control 211 neck 12 is equipped with a plant automatic control device (
Hereinafter, it will be referred to as Δ1]0) The load state of the photoelectric equipment is received from 16, and the 0 point number f is input. As this load signal 1', it is also possible to use a power generation plant output signal, a turbine first stage steam ΣF force signal, or the like.

FIG. 1 is a diagram of one embodiment of a pressure control device 12 according to the present invention. The pressure control device 12 includes an OR circuit 38, a pressure regulating valve control circuit 40, an on-delay timer (hereinafter referred to as a timer) 19, a sign inversion circuit 20, an AND circuit 21, three switching circuits, and a proportional integral It includes a circuit 15, a set value circuit 14, a hold circuit 17, and a function generator 18.

The FCB status signal a, which is the output of the protection-in 9099 circuit 11, and the start signal i, which is the output of the auxiliary steam start circuit 22, are sent to the pressure regulating valve control circuit 40 via the OR circuit 38.
is input, and the pressure regulating valve 10 is rapidly fully opened. Further, the FCB status signal @a, which is the output of the protection interlock circuit 11, is sent to the timer 19, the sign inverting circuit 20, and the AND
The circuit 21 generates a signal that remains ON for a certain period of time t (timer setting time) after FCB, and this signal 1) becomes 1,
7J u circuit 39 and hold circuit 17. The hold circuit 17 receives a load signal f from the APC 16 indicating the 9-hold state of the power generating equipment, and also receives a load signal f from the FCB.
When a signal that remains ON for a certain period of time t is input, F
The load signal f immediately before CB is held for a time t and output to the function generator 18.

Function generation: Tomoe 1B is a pressure regulating valve opening command signal (
q (hereinafter referred to as an opening command signal) is generated and output to the three I and IHJ circuits. On the other hand, the three switching circuits select the opening command signal Q which is the output of the opening number generator 18 for a while when a signal that is ON for a certain time t after FC [3] is input, During this time, a degree command signal @q is output to the pressure regulating valve 9. As a result, the opening degree of the regulating valve 9 is maintained at the necessary opening degree to obtain the required auxiliary steam flow at the time of load immediately before FCB until the timer 19 operates, and the pressure is adjusted. Since the pressure regulating valve 10 is controlled by the valve υ control circuit 40, the temporary low F of the pressure in the auxiliary steam main pipe 1 can be suppressed to a minimum. Timer 19 is +: When the CB power generation is activated for a predetermined time, the signal turns OFF, and the three switching circuits output the output signal of the pressure detector 13 of the auxiliary steam main pipe 1, which is the output of the setting circuit. Pressure set value signal C
The pressure regulating valve opening command signal e, which is the output of the proportional-integral circuit 15 based on the deviation from the pressure regulating valve 9, is selected and output to the pressure regulating valve 9. The pressure regulating valve 9 adjusts the valve opening based on the pressure regulating valve opening command signal e, and the pressure of the auxiliary steam Ffi pipe 1 becomes the set pressure.

In the above embodiments, a boiler of a thermal power generation facility is used as an example of the steam generator, but this can be replaced with a steam generating means of a nuclear power generation facility.

〔Effect of the invention〕

The pressure υ1611 shield according to the present invention supplies an appropriate amount of steam from the hot air generator side to the feedwater pump-driven turbine immediately after the FCB via the auxiliary steam main pipe, depending on the load operating state immediately before the FCB occurs. This allows for a stable supply of steam for driving the water pump, thereby reducing the FCB
This reduces the failure factors.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the pressure control device according to the present invention, Fig. 2 is a steam system diagram of thermal power generation equipment when the pressure control device according to the present invention is used, and Fig. 3 is a conventional pressure control device. It is a 10-step diagram of a control device. 1... Auxiliary steam main pipe, 9... Pressure regulating valve, 10...
・Pressure regulating valve, 12...Pressure control device, 14...Set value circuit, 15...Proportional integral circuit, 17...Bold circuit, 18...Function generator, 1...Timer ,2
0... Sign inversion circuit, 21... AND) circuit, 29
...Boiler, 30...Turbine, 38...OR circuit, 39...1 old circuit, 40...Pressure regulating valve l
112f1 circuit. One person who submitted the application: Sato-Wai Figure 1

Claims (1)

[Claims] A main steam system that drives a main turbine with steam from a steam generator includes a water pump drive turbine that drives a water pump that supplies water to the steam generator, and an auxiliary steam generator that supplies driving steam to the water pump drive turbine. a turbine-side auxiliary steam pipe that guides steam extracted from the main turbine and supplies steam whose pressure is regulated by a first pressure regulating valve to the auxiliary steam main pipe; An auxiliary steam system having a steam generator side auxiliary steam pipe that guides steam from the generator and supplies steam whose pressure has been adjusted by a second pressure regulating valve and a third pressure regulating valve to the auxiliary steam main pipe. For the auxiliary steam system in a power generation facility consisting of a A set value circuit that outputs an electric signal according to the set pressure of the auxiliary steam main pipe, a pressure set value signal that is the output of this set value circuit,
A pressure signal indicating the pressure of the auxiliary steam main pipe is compared with a pressure signal indicating the pressure of the auxiliary steam main pipe, and based on the deviation, a valve opening command signal is output to the second pressure regulating valve so that the pressure of the auxiliary steam main pipe becomes a set value. A pressure control device for a feed water pump drive turbine comprising a proportional integral circuit that inputs a signal indicating a load state of the power generating equipment and holds a signal of a load state immediately before reaching an FCB state during FCB; , a function generator that generates an opening setting signal for the second pressure regulating valve according to the load held in the hold circuit immediately before reaching the FCB state; A pressure control device for a water supply pump driving turbine, comprising a switching logic circuit for setting an opening degree command value of the second pressure regulating valve.