JPS6098110A - Turbine bypass device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a turbine bypass device in thermal and nuclear power plants.

[Technical background of the invention]

FIG. 1 shows part of a typical nuclear power plant system with a turbine bypass system. In the same area, steam supplied from a steam generator (not shown) is inserted into a main steam pipe 1 and this main steam head 1, and is passed through a main steam stop valve 2 that cuts off the supply of steam to the turbine, and further controls the steam flow rate. It passes through the high air control valve 3 and reaches the high pressure turbine 442. The steam that has done work in the 11-pressure turbine 4 is further sent to each low-pressure turbine 5 arranged in parallel (unisystem), and after doing work in the low-pressure turbine 5, it is condensed in the condenser 6. The turbine bypass pipe 7 branched from the steam 'Ft 1 branches into three systems, each of which is connected to a pressure converter 9 consisting of a multi-stage orifice provided with a turbine bypass valve 8 and connected to the condenser 6. Cooling water is supplied to this pressure reducer 9 from an external cooling water tank or the like through a cooling water pipe IO and a cooling water spray valve 11 provided in this cooling water pipe 10. When the turbine bypass valve 8 is opened, the cooling water spray valve 11 is fully opened at the same time, and the main steam passing through the turbine bypass pipe 7 is cooled and sprayed into the condenser 6 so as to bypass the turbine.
(It is designed to lead to two.

Such turbine bypass systems are used in thermal and nuclear power plants, and their purpose is to reduce the system load during plant startup and turbine operation.
The second purpose is to recover part or all of the steam generated by the steam generator into the condenser so that the steam generator can continue to operate properly. The operation of this turbine bypass system will be explained below as an example at the time of plant startup and at the time of system load cutoff.

(1) At plant start-up At plant start-up, at least the minimum required amount of steam is generated in the steam generator, and overheating of the steam generator itself is prevented and stability is ensured. Among the steam generated at this time, the main steam other than the amount of steam necessary for starting the turbine is recovered to the condenser 6 via the turbine bypass pipe 7. As the load on the turbine increases, the opening degree of the steam control valve 3 gradually increases.As the amount of air supplied to the turbine increases, the turbine bypass valve 8 gradually closes and the bypass steam Normally, the turbine bypass valve is fully closed when the turbine is running.

■ When the load is cut off when the turbine is normally operated, and when the load is cut off due to an accident in the electric power system, the steam control valve 3 is rapidly turned m1 to cut off the live steam that should flow into the turbine.

At the same time, the output of the steam generator is controlled to decrease, but the pressure of the steam generator rises rapidly due to the sudden closing of the steam regulating valve 3. Therefore, in conjunction with the sudden opening of the steam regulating valve 3, the turbine bypass is The live steam that has also passed through the turbine bypass 7 is depressurized by the pressure reducer 9, further reduced in temperature by the cooling water, and recovered in the condenser 6. Note that the cooling water supplying the cooling water The spray valve 11 is the turbine bypass valve 8
It is designed to open in conjunction with. In this way, it is possible to prevent sweat buildup in the steam generator, thereby avoiding an emergency shutdown of the plant such as a nuclear reactor scram.

In addition, the turbine bypass valve that suddenly opened at this time is closed as the output of the steam generator decreases (-), and when the output of the steam generator reaches about 30 to 50% of the rated value, the turbine stops generating electricity. A steam turbine plant that is operated according to the internal load and bypasses excess live steam to the condenser as described above (in some cases, the main steam under high temperature surface pressure is directly supplied to the steam turbine) Since the main steam is introduced into the condenser at the same time, it is possible to prevent the main steam from being damaged in the condenser by introducing it into the condenser.
I try to increase /+ and decrease /+1 item. Conventionally, in order to generate one vortex of steam on the shaft, 4.・I was trying to supply cooling water from the water sprayer 1o by opening the hydraulic sprayer pH, but in the unlikely event that the turbine bypass valve 8
If only the cooling water spray valve 11 were to open and the cooling water spray valve 11 did not operate, the temperature of the condenser 6 (2 bW) would not have been reduced.Needless to say, such an unexpected situation would have occurred. In this case, it would be a good idea to close the turbine bypass valve 8, but then the steam generator would have to be stopped, and it would be difficult to ensure continuous operation of the steam generator.・The original purpose of the bypass system will not be fulfilled.

[Object of the Invention] The present invention has been made with the above point C1 in mind: Therefore, its purpose is to reduce the amount of cooling water spray "11110 -14- When the #i temperature of the steam was tr and tc (in the second case, one water vessel was retained and the safety was 416
The present invention is to provide a turbine bypass device i'lL that can maintain the engine speed and avoid a shutdown of the plant or steam generator.

[Summary of the Invention] The present invention includes a turbine bypass valve provided in a line path that branches off from a main steam pipe and connects to a condenser (two condensers), and a turbine bypass valve provided in a line path that branches from the main steam pipe to a condenser (two separate lines). When the turbine bypass Jr reaches f, 11.10, the cooling water spray valve is opened and the cooling water spray valve is opened. This turbine bypass device includes a control device that detects the operation of the cooling water spray valve and fully closes the turbine bypass valve in which the cooling water spray 5F has not opened normally after a certain period of time has elapsed.

That is, in the past, C-, which opens the cooling water spray valve, detects the opening of the turbine bypass valve and operates in conjunction with the opening of the turbine bypass valve, but in the present invention C-2, the operation of the cooling water spray valve is detected, and if the cooling water spray valve is not opened, the turbine bypass valve is fully closed after a certain period of time has elapsed. The bypass steam is not supplied with enough cooling water and is incomplete.
This ff1r (bypassing the AM bypass steam) will cause the rise in the internal temperature of the condenser to be within the measurement range. It is preferable that the steam generated until the output decreases (can be treated in two ways).

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. In addition, when the following [31 page (2) and the same part as shown in FIG.

FIG. 2 shows the present embodiment (- related turbine bypass device t't
This shows the system of a steam turbine plant equipped with
A control device 20 is installed which connects the turbine bypass valves 8a, 8b, 8c and the cooling water spray valves 11a, 11b, llc i, and each of the valves is connected to the control device 2.
C2 is controlled by 0(2).

The internal configuration of the control device 20 is shown in FIG. In FIG. 3, a turbine speed 4M 30 detected from the turbine is manually input to a steam amount calculator 33 together with a setting value 32 set in a load setting device 31.

This steam amount calculator 331- calculates the amount of steam required for turbine operation using two parameters: the size of the dog and the difference between the actual turbine speed and the rated speed. The thus obtained required steam amount signal 34 is converted into a control valve flow rate signal 36 by a limiter 35, which takes into account load restrictions based on various factors or restrictions such as the maximum steam flow rate of the reactor H1. On the other hand, the main steam pressure signal 37 indicating the steam pressure in the reactor (2) is input manually to the main steam amount calculator 38, and the R & main air pressure h1 calculator 38 ("The amount of steam generated in the reactor is ↓?" is output). Then, in the bypass steam calculator 39, the amount of steam discharged from the reactor 11 and the valve flow rate □ are reduced from this reactor generated natural air 1jI,
The difference is the turbine bypass valve am! No. 48 40
I get criticized. This turbine bypass valve flow 114's No. 4
0 is three (-branched, each turbine bypass valve 8a, 8b
, 8cl are transmitted to control systems provided independently, of which only the system of the turbine bypass valve 8C is illustrated here.

Now, the turbine bypass valve +51t k 48 40 is input to the turbine bypass valve control device fPi41.

This turbine bypass valve control %r, 41 controls the servo valve of the turbine bypass valve 8C to the turbine bypass valve i! d
E in 4D No. 40, and as a result, the opening degree of the turbine bypass valve 8C is controlled. For this purpose, a turbine bypass valve control signal 42 is output to the turbine bypass valve 8C. Further, the turbine bypass valve control device 41 detects the signal status of the turbine bypass valve flow signal 40 or the turbine bypass valve control signal 42 that the turbine bypass valve is in a state of being opened, and opens the cooling water spray valve 11C. A cooling water spray valve open signal 43 is output. Reference numeral 44 is a contact point for detecting the operation of the cooling water spray valve 110, and a contact point for energizing or de-energizing the delayed activation relay 46 via an operation detection contact 45 installed in the same manner as that of the two turbine bypass valves 8C1. It has become. The turbine bypass valve 8c is connected to one end of the contact 47 driven by the delay activation relay 46, and the turbine bypass valve control device 41 and the full close signal transmitter 48 are connected to the other end. (2) Therefore, the turbine bypass valve 8C is connected to either the turbine bypass valve control device 41 or the fully closed signal transmitter 48.

The above turbine bypass valve 8C and cooling water spray valve 1
Paulownia shows the 1C control circuit in more detail.

This is Figure 4. Figure 4 (2) Turbine bypass valve r amount signal 40 transmitted from bypass steam generator
is input to the valve position control circuit 50. This valve position control circuit 50 includes each turbine bypass valve 8 a .

Different valve opening start biases 51 are applied depending on 8b and sc, and at the same time, a valve opening degree signal 52 which gives a valve opening degree corresponding to the steam flow rate is inputted. Therefore, in the valve position control circuit 5o, the turbine bypass valve flow rate signal 40 is generated according to the valve opening degree 46 and the valve opening start bias 51. do.

On the other hand, the first position control circuit 50 is provided with a bypass valve open signal detector 53 that detects that the turbine bypass valve control signal 42 is in the state of "valve 5 open".This bypass valve open signal detector When 53 detects that the turbine bypass valve control signal 42 is in the valve "open" state, it conducts to the contact 55 connected to the cooling water spray valve solenoid 54 in the i-point series C. When the contact 55 is conductive, the control bus P is applied to the cooling water spray valve solenoid 54.

Via Pl? tplt is supplied, and the cooling water spray valve solenoid 54 is energized. That is, when the turbine bypass valve control signal 42 is in the valve "open" state, the cooling water spray valve solenoid 54 is energized to open the cooling water spray valve IIC. The above contact point 55
A contact 56 that becomes non-conductive when the relay 57 is energized is connected in parallel with the relay 57 . The relay 5711-J and the control bus P
0. P1+2 are connected, so when the turbine bypass valve 8c becomes 1)110, the bypass valve open detection switch 45 becomes non-conductive, the relay 57 becomes de-energized, and the contact 56 becomes conductive. In this way, the cooling water spray valve 11
The thread path for energizing C to the wrong lead 54 is the contact 55 and the contact 5.
Two systems, 6, are provided, and these contact points are both electrically connected when the turbine bypass valve 8C is opened.

On the other hand, a contact 58 that becomes non-conductive when the relay 57 is energized, like the contact 56, has a cooling water spray valve 11
A delayed activation relay 46 is connected via a contact 44 that becomes conductive when C is not activated.This delayed activation relay 46 is energized after a certain period of time U/R after being energized to close its contact. 47. One end of the contact 47 of the slow-actuation relay 46 is connected to the turbine bypass valve 59, and the other end (the second end is connected to the valve position control circuit 50'd and the fully closed signal transmitter 48). The contact 47 is connected to the delay activation relay 46 (Tanekoma? 1H'j l2 is the servo valve 59 and the valve position sub-circuit 50, and the delay activation relay 46 is energized. When the valve is opened, the valve 59 and the valve 48 are respectively connected.

Next, Honji h1. ! To explain the operation of the example, the Coupin bypass system starts ll'I and;! ii) The system mainly operates during the 4th period when the system load is interrupted.Here, we will explain the case where the system load interruption occurs during the latter turbine operation as Example 1.

During the turbine operation of 7G, the bypass power supply I-4 unit 3
The turbine bypass suppression group signal 40 output from 9 is O
or a negative value, and therefore the turbine bypass valve control signal 42 is rejected from the valve position control circuit 50.
Also, the bypass valve is in the “closed” state (there are two types).

However, due to these Iro, the turbine bypass valve 8C
Since the bypass valve open detection switch 45 is fully closed, the bypass valve open detection switch 45 is in a conductive state (there are two, and the relay 57 connected to the bypass valve ill 4r'j = output switch 45 is activated, and the contacts 56 and 58 are non-conducting. As mentioned above, when the turbine bypass valve 1 and the other No. 42 is in the state of ``closed bypass valve 1'', the turbine bypass valve open signal detector 53 establishes conduction when the bypass valve 1 is closed. Contact 5
5 is also non-conducting and 7. [It's on.

Therefore, both points 55 and 56 are non-conductive, and the cooling water spray valve solenoid 54 is energized, so that the opening length of the cooling water spray valve 11C) does not increase.

Furthermore, since the contact 58 is connected to the position 8, the delay activation relay 4
6 is not activated, and the scoring 47 driven by this delayed activation relay is connected to the servo valve 59 and the valve position control circuit 5.
To maintain continuity of 0 (2).

In this state, the system load is cut off (= When the main steam stop valve is fully closed and the steam control valve flow rate signal 36 is O (2, the turbine bypass valve 1f + E N 4F4 output from the bypass steam calculator 39 is reached) 40 suddenly increases. In response to this sudden increase in the turbine bypass valve flow rate signal 40, the valve position control circuit &'650 increases the turbine bypass valve control signal 42, operates the servo valve 59, and suddenly opens the turbine bypass valve 8C.

Simultaneously C2, the turbine bypass valve control (No. 9 42 increases) is detected by opening the turbine bypass valve (No. G detector 53
is detected and the contact 55 is made conductive. The bypass valve open detection switch 45 detects that the turbine bypass valve 8C has opened due to external force.
When detected, the relay 57 is energized and the contacts 56 and 58 are made conductive. The play valve 11C then opens. At this time, if the cooling water spray valve 11C operates normally and opens, the turbine bypass steam is transferred to the cooling water spray valve 11C.
The temperature of the water is reduced by the cooling water supplied through C, and the water is collected in the condenser. [The opening state of this cooling water spray valve 11C is as long as the turbine bypass valve 8C is open.
In other words, the contact point 55 or the contact point 56 is maintained as long as it is conductive.On the other hand, if the cooling water spray valve 11C does not open to the positive U even though the turbine bypass valve 8C is open, the main In the embodiment, C2 operates as follows. That is, when the turbine bypass valve 8c opens, the turbine bypass valve open detection switch 45 is turned on, the relay 57 is energized, and the contacts 56 and 58 are brought into conduction. Excitation current flows through the cooling water spray valve solenoid 54 due to the fragrance oil at the contact point 56, but if the cooling water spray valve 110 does not open normally due to a failure of the valve body or the FMr line of the solenoid, etc.
The contact 44 for detecting malfunction of the cooling water spray valve 11C becomes conductive. At this time, since the contact 58 is also conductive due to the excitation of the relay 57, the delay activation relay 46 starts operating at the same time as the contact 44 is conductive. This delayed action IQ relay 46 is configured to drive the attached contact 47 after a certain period of time has elapsed after being energized like Ail + (it is shown as D), but the activation of this JK point 47 causes the servo of the turbine bypass valve 8C to be activated. Valve 59 and valve position control circuit 50
The servo valve 59 is now connected to the fully closed signal generator 48 (C:). By being connected to this fully closed signal transmitter 48, a turbine bypass valve fully closed signal is input to the servo valve 59.
The turbine bypass valve 8C is immediately fully closed.

In this case, even though the turbine bypass valve 8C has opened, the cooling water spray valve 11C has not opened normally. The turbine bypass valve 8C is fully closed after a period of time has elapsed from when the relay 46 is energized to when the contact 47 is driven.

In the above explanation C2, only one system of Tahif 144F 1F 8C is used as an example (as mentioned above, regarding the remaining two of the three systems of turbine bypass valves 8a r 8b shown in Fig. 2) The opening biases 51 shown in FIG. 4 provided for each of these three turbine bypass valves 8a + 8b-80 are set to different values as bias values, respectively. Three valves are arranged in the passage 7 to open sequentially.

A curve 71 shown in FIG. 5 shows the time change of the turbine bypass steam flow t>l after the system load is cut off, and the vertical axis represents the ratio of the bypass steam flow rate to the rated main steam flow rate. As is clear from the figure, the amount of bypass steam increases rapidly immediately after the load is cut off, and eventually reaches its maximum value. At this time, the entire amount of main steam generated in the reactor is bypassed (-However, since the reactor output is immediately reduced, the amount of bypass steam gradually decreases accordingly. Also, one point shown in the figure Chain @ lines 72a, 72b, and 72c represent the bypass t'1 when only one turbine bypass valve is open, when only two valves are open, and when all three turbine bypass valves are open, respectively.
- Indicates volumetric vapor content. These figures show that, as in this embodiment, cooling water is not supplied to one of the three turbine bypass valve systems even though the bypass valve opens, and after a certain period of time, the turbine bypass valve closes. It can be seen that even if the button is closed, the remaining two presses are enough to process the C bypass steam.

Further, FIG. 6 is a diagram showing the relationship between the elapsed time after the load is cut off and the temperature inside the condenser increased by +1 U. A curve 81 in the figure indicates a case where the cooling water spray valve is normally opened, and indicates that the temperature of the natural air is reduced by the cooling water and the temperature rise inside the condenser is small. The external force curve 82 shows the temperature change when the turbine bypass device according to this embodiment is operated, and the turbine bypass valve is opened with no cooling water being supplied for a certain period of time after the load is cut off, and during this period, the steam is not cooled and the steam is condensed. This shows that even if the condenser is introduced into the condenser, the temperature inside the condenser will rise only to a level that is within the design limit value and has a sufficient margin. Curve 83 shown by a broken line shows the case where the turbine bypass valve continues to be opened even though cooling water is not supplied. reach.

Note that the delay time of the delayed activation relay 46 in this embodiment, that is, the time from energization until the attached reactor 47 is activated, is determined as appropriate depending on the amount of bypass steam, the strength of the condenser, etc. It is something. In this case, this delay time may be set to the formula 21 so as to correlate with the bypass steam +5tf MT. In addition, it does not matter whether the switches and contacts that detect the operating status of the turbine bypass valve and cooling water spray valve are of a type that is directly spread on the valve body or of another type. Needless to say. Furthermore, this embodiment can be suitably implemented even in a system in which cooling water is introduced into the condenser itself rather than into the desuperheater.

〔Effect of the invention〕

As described above, the present invention opens the cooling water spray valve when the turbine bypass valve opens (2) detects the operation of the cooling water spray valve, and detects the operation of the cooling water spray valve when the cooling water spray valve does not open normally. - Since the turbine bypass valve is opened for a certain period of time and the bypass steam is introduced into the condenser (two), the steam can be processed until the output of the steam generator decreases, and the steam generator It has the effect of being able to avoid situations such as stopping the operation of the equipment and releasing steam into the atmosphere.In addition, as a result, there is a possibility of damaging the condenser, so it is considered to be an extremely useful device in practice. I can say it.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a turbine bypass system, Figs. 2 to 6 are explanatory diagrams of an embodiment of the present invention, Fig. 2 is a system diagram showing an overview of the turbine bypass surface arrangement, and Fig. A block diagram showing the internal configuration of the control device f (Fig. 4 shows the control device f)
A circuit diagram showing a part of the device in detail, Figure 5 is a diagram showing the relationship between the elapsed time after load cutoff and the bypass fish flow crucible, and Figure 6 shows the elapsed time after load cutoff and the inside of the condenser. rj
It is a line diagram showing a sacrificial relationship. 1... Main steam pipe 6... Ascites 7... Turbine bypass pipe 8a, 8b18G... Turbine bypass valve 10...
Cooling water pipes 11a, 11b, 11C=-cooling water spray valve 20...
・Control device agent Patent attorney Yu Chikabe (and 1 other person) Fig. 4 Fig. 5 Sadakajuku-Gekisu support Noru's condolence 6 plans Sun Kazen 0 Sakakura special public disclosure

Claims (1)

[Claims] A turbine bypass valve is installed in the line that branches from the main steam pipe and connects to the condenser, and a turbine bypass valve is installed in the line that supplies cooling water to cool the steam flowing from the line to the condenser. When the cooling water spray valve and the turbine bypass valve open, the cooling water spray valve is opened and the operation of the cooling water spray valve is detected, and when the cooling water spray valve does not open normally, Turbine bypass system-0 consisting of a control device that fully closes the turbine bypass valve after a certain period of time has elapsed.