JPS6299602A - Steam turbine control device - Google Patents

Abstract

PURPOSE:To prevent a control hydraulic pressure self-supplying type steam turbine device from abruptly overspeeding during starting of the turbine device, by providing an electrically-operated valve and a bypass valve bypassing the electrically-operated valve upstream of a steam shut-off valve of the turbine device. CONSTITUTION:In a control hydraulic pressure self-supplying type steam turbine device in which hydraulic pressure from an oil pump 12 driven by a turbine 9 is fed as control hydraulic pressure, an electrically operated valve 6, a bypass passage 25 and a bypass valve 26 are provided upstream of an adjusting valve 8 and a steam shut-off valve 26. Further, during starting of the turbine device the adjusting valve 8 and the steam shut-off valve 7 are fully opened, but the electrically operated valve 6 is closed while the bypass valve 26 is gradually opened. Thereby, it is possible to prevent the turbine 9 from overspeeding abruptly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a self-supply steam turbine that supplies control hydraulic pressure to the driving force of a turbine, and particularly relates to a steam turbine with a self-supplying control hydraulic pressure for supplying control hydraulic pressure to the driving force of a turbine. The present invention relates to a steam turbine control device that requires quick start-up, such as in a turbine pump system.

(Technical Background of the Invention and Problems thereof) In general, J3 steam turbine plants are geothermal power generation plants that have only enough DC power to be used for a short period of time, such as for drive signals, and Such as the turbine for backup power supply and the turbine pump system of the reactor isolation system 741, which is one of the reactor auxiliary systems for emergency backup in nuclear power plants, etc. Although it has a steam source, it does not have any other hydraulic power source or auxiliary power source for turbine control or a+rj, and the turbine itself functions to supply oil by driving an oil pump. There is something I did.

For example, Figure 3 shows that when the reactor is isolated from the turbine condenser, cold water is supplied from the condensate storage tank to the reactor to maintain the reactor water level and cool the reactor core. I have shown the system diagram of the reactor isolation cooling IJI system.
A coolant is supplied to a nuclear reactor 2 disposed within the nuclear reactor 2 through a water supply line 3, and steam generated therein is supplied to a main steam turbine (not shown) through a main steam line 4. on the other hand,
A reactor isolation tube cooling system steam line 5 is branched from the main steam line 4, and a part of the main steam is transferred to the electric valve 6 installed in the reactor isolation tube cooling system steam line 5, and the steam It is introduced into a reactor isolation cooling system turbine (RCIG turbine) 9 via a stop valve 7 and a steam control valve 8, and is returned to a pressure suppression ft. 1 boule 11 via its steam turbine waste line 10. Further, the RCIC turbine 9 is directly connected to an oil pump 12 that sends r8 oil to the turbine control device and a reactor isolation cooling system water supply pump 13 that feeds cooling water in the condensate storage tank to the reactor 2. has been done.

In the reactor power generation system, when the reactor 2 is isolated in an emergency such as when the reactor water supply is stopped, and the reactor water level drops and a reactor isolation cooling system activation signal is output,
The motor-operated valve 6 begins to open, and the main steam reaches the RCI via the steam stop valve 7 and the steam control valve 8, which are waiting in the fully open state.
The cooling water is supplied to the C turbine 9, the RCIG turbine 9 is driven, and the reactor isolation cooling system water supply pump 13 supplies cooling water from the condensate storage tank to the reactor 2 to cool the reactor core.
JI will be conducted.

FIG. 4 shows the details of the steam turbine control device for the reactor isolation cooling system. When the reactor isolation cooling system start signal a /J When the electric valve 6 passes through the steam stop valve 7 and the steam control valve 8, the RC
IG turbine 9 starts up.

An oil pump 12 directly connected to the turbine 9 generates control oil that drives the steam control valve 8 in response to startup of the turbine 9.

When the electric valve 6 operates 1711 times, the position detector 14 detects the slightly open state of the electric valve 6 and generates a turbine start signal. This turbine starting signal b1 is applied to the ramp signal calculator 15, and the ramp signal f''3C is output from the ramp signal calculator 15 and applied to the speed control signal disturber 16, which is a low value priority circuit.・On the discharge side of the cold lJ system water supply pump 13 at the reactor interval 211 (Y, flow M
The detector 17 is connected to the ramp signal C, and its flow rate signal d is applied to the flow rate generator 18 and inputted as the flow rate request signal e to the speed request signal calculator 16, where it is compared with the ramp signal C. The value signal is applied to the speed control calculator 19 as a speed request signal f.

The rotation speed detection gear 20 and electromagnetic pickup 21 provided on the turbine shaft detect the actual rotation speed of the RCIC turbine 9, and the rotation speed calculator 22 generates a turbine actual measurement signal Q from the output signal of the electromagnetic pickup 21. It is sent to one of the speed control calculators mentioned above. One of these speed control calculators is
A deviation signal between the speed request signal f from the speed request signal calculator 16 and the actual speed signal q from the rotation speed calculator 22 is sent to the electro-hydraulic converter 23 as a speed control signal. This electro-hydraulic conversion′
Jj23 controls the oil pump 12 based on the speed control signal.
Control oil is controlled and supplied to the oil cylinder 24, and the opening degree of the steam control valve 8 is controlled. Specifically, in the initial stage of startup of the RCIG turbine 9, the ramp signal C is passed through the speed request signal device 16 to become the speed request signal f, and is then sent through the speed control calculator 19 to keep the speed increase rate of the turbine constant. It is added to the electro-hydraulic converter 23, thereby controlling the opening degree of the steam control valve 8. In this way, when the RCIC turbine 9 starts up and the amount of water supplied from the reactor isolation cooling system water supply pump 13 increases, and the flow m request signal d reaches a predetermined value, this flow m request signal e becomes the speed request signal f. As speed request signal calculator 16
The opening of the steam control valve 8 is controlled based on the signal.

However, in such a 5A installation, although it is necessary to always start up quickly, because the oil pump 12 is directly connected to the turbine shaft, the number of revolutions of the RCIC turbine 9 reaches a certain number of revolutions. It takes time to establish the necessary oil pressure to operate the oil cylinder 24.
Therefore, there is a problem that the rotation speed of the RCIC turbine 9 may reach an abnormal initial peak rotation speed that exceeds the rated rotation speed.

That is, FIG. 5 is a diagram showing each state of the reactor isolation cooling system in one shift at the time of starting and renovating.As mentioned above, the RCIC turbine is operated by opening the steam control valve in order to obtain a large starting torque. It is started with the power fully open. In addition, the electric valve 6, steam stop valve 7, and steam control valve 8 are designed to be able to pass steam two to three times the flow rate of steam required during steady operation in order to obtain this starting torque. Therefore, when the electric valve 6 starts to open, a large amount of steam flows into the turbine almost at the same time, so that the turbine rotational speed rapidly increases as shown in FIG. Then, the steam control valve is operated in the fully open direction only when the turbine rotation speed exceeds the ramp signal and the control oil pressure is established as the turbine rotation speed increases. In other words, since there is a time delay before the steam control valve operates, the turbine rotation speed rapidly increases during this time, generating an abnormal initial peak rotation speed n that exceeds the rated rotation speed. There is a risk that a rock formation would activate and cause an emergency shutdown, and the reactor would become even more dangerous.

The above example uses a conventional controlled hydraulic pressure self-supplied steam turbine in the reactor isolation cooling system as an example, but sudden overspeed of the turbine at the time of steam turbine startup also occurs in Haku's controlled hydraulic self-supplied steam turbine. A similar problem arises.

[Purpose of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a steam turbine control device that prevents a sudden overspeed at the time of startup of a controlled oil pressure self-supply steam turbine.

[Summary of the invention]

In order to achieve this object, the present invention includes a steam stop valve, a steam control valve, and an electrically operated valve located upstream of these, and the steam stop valve and the steam control valve are set in advance when the targon is started. In a control hydraulic self-supply type steam turbine that starts the turbine by opening the electric valve and supplies control oil by the driving force of this turbine, there is a bypass path that bypasses the electric valve. The present invention is characterized by comprising a bypass valve installed in the bypass passage, and a control means for opening the bypass valve prior to the molded J valve in response to an activation signal.

[Embodiments of the invention]

Hereinafter, an embodiment of a steam turbine control system according to the present invention will be described with reference to FIGS. 1 and 2, in which the same parts as in FIGS. 3 to 5 are denoted by the same reference numerals.

FIG. 1 shows an embodiment in which the steam turbine control III device according to the present invention is applied to a reactor isolation cooling system. 25 is connected. This bypass passage 25 is provided with an electric bypass valve 26 and an orifice 27 downstream thereof. The diameter of this bypass valve 26 is selected to be approximately 173 to 174 times the diameter of the electric valve 6. In addition, the orifice 27 is configured to allow the flow of the bypass passage 26 so that even when the bypass valve 26 is fully open, the rotational speed of the RC■C turbine 9 is around the minimum field required to establish a control oil stagnation from the oil pump 12. limit. The bypass valve 26 is provided with a bypass valve timer 28. When the bypass valve timer 28 receives the reactor isolation cooling system activation signal a, it fully opens the bypass valve 26 for a predetermined period of time from the time of reception, and then , close again. Further, a delay timer 29 is attached to the electric valve 6, and when the d-delay timer 29 receives the cooling system signal a, the 'Fi valve 6 is opened after a predetermined time delay from the time of reception. This delay time is set shorter than the predetermined time of the bypass valve timer 28. The other configurations are exactly the same as those in FIGS. 3 and 4.

Next, the operation of the device according to the present invention will be explained.

Reactor isolation cooling system start signal J? When ia occurs at time to shown in FIG. 2, bypass valve timer 28 and R delay timer 29 start operating,
8 is a predetermined time from this point 10 (t to t, 2)
/Sends a valve opening signal to the moss bypass valve 26. In response to this valve opening signal, the bypass valve 26 is operated for a certain period of time, for example, from 3 to 7 days.
It is fully opened for only a second. This allows steam to pass through the bypass valve 25.
through which it flows into the RCIC turbine 9 and starts it. Since the flow rate of this bypass passage 25 is restricted by the orifice 27, the turbine rotational speed does not increase excessively and is kept to a low rotational speed necessary for establishing oil pressure by the oil pump 12, as shown in FIG. It is being

On the other hand, the time t when the cooling system activation signal a is generated. , when a predetermined delay time, for example 2 to 5 seconds, reaches time t1,
The delay timer 29 causes the electric valve 6 to open. When the electric valve 9 begins to open, a large amount of steam flows into the turbine 9. The position detector 14 detects the electric valve 6 at 17i1 degrees and generates a turbine start signal. The above delay time (1-1,) is
Since the electric valve 6 is selected to be opened after the control oil pressure to the oil cylinder 24 is established by opening the bypass valve 26, the opening of the electric valve 6 allows a large amount of steam to flow into the turbine 9. , the steam control valve 8 can already be controlled. Therefore, the turbine 9 has a speed of [1!R,
The rotational speed is increased smoothly following the speed control signal from the lJ tit calculator 19. In this way, the bypass valve 26 is
After opening the valve to supply steam with a limited flow rate to the turbine 9 and establishing a control oil pressure, the electric valve 6 is opened and the steam flow m to the turbine 9 is adjusted based on the speed control signal.

It should be noted that the full opening time of the bypass valve 26 determined by the bypass valve timer 28 and the delay time determined by the delay timer 29 are such that the turbine rotational speed exceeds the 4j value required to establish the control oil pressure during the entire opening time of the bypass valve 26. However, it is desirable to set the electric valve 6 to open immediately after the control oil pressure is established. This allows the rapid start-up time to be shortened without overspeeding the turbine.

Further, the driving method of the bypass valve 26 can be appropriately selected depending on the conditions of use, such as a motor drive method or an air operation method.

In this embodiment, the bypass passage 25 is provided with a bypass valve 26 and an orifice 27, but if the flow rate of the bypass passage 25 can be set to an appropriate value simply by appropriately selecting the diameter of the bypass valve 2G, the orifice 27 may be Unnecessary yelling.

In addition, in the above embodiment, a control device for an RCIG turbine in a cooling system for a nuclear reactor isolation section has been described. Moreover, although it has a so-called steam source, such as a geothermal power generation system that it does not have, and a turbine that can supply 43 on-site backup power supplies in case of an emergency, it does not have any other hydraulic power source or auxiliary power source for turbine control and lubrication. It can also be applied to a steam turbine system that functions to supply oil by self-driving, bypassing the rotation of an oil pump.

(Effects of the Invention) As is clear from the above description, the present invention provides a bypass valve in a bypass path that bypasses an electric valve, and opens the bypass valve before the electric valve when starting the turbine. By restricting the flow of steam, it is possible to prevent sudden overspeed at the time of turbine startup and the occurrence of expansion.In addition, the bypass passage equipped with a bypass valve can be easily integrated into the existing steam turbine control system. It can be additionally attached.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a control device for a reactor isolation cooling system equipped with a steam turbine control device according to the present invention, and FIG. 2 shows the state of each part of FIG. Figure 3 is a system diagram showing the conventional reactor interval cooling system, Figure 4 is a system diagram showing the control device in Figure 3, and Figure 5 is a system diagram showing the control device in Figure 4. It is a graph diagram showing the state of the part. 6... Electric valve, 7... Steam stop valve, 8... Steam control valve, 9... Turbine, 25... Bypass path, 26
... Bypass valve, 28 ... Bypass valve timer, 2
9...Delay timer. Applicant's agent Sato-Omo 1 Kuchimura 4 Zuma 5 Figure

Claims (1)

[Scope of Claims] 1. It has a steam stop valve, a steam control valve, and an electric valve located upstream of these, and when the turbine is started, the steam stop valve and the steam control valve are fully opened in advance, and the electric In a control oil pressure self-supply steam turbine that starts the turbine by opening a valve and supplies control oil pressure using the driving force of the turbine, a bypass path that bypasses the electric valve and a bypass provided in this bypass path are provided. A steam turbine control device comprising: a valve; and control means for opening the bypass valve prior to the electric valve in response to a start signal. 2. The control means includes a bypass valve timer that opens the bypass valve for a first predetermined time in response to the start signal, and a bypass valve timer that opens the bypass valve for a second predetermined time in response to the start signal. The steam turbine control device according to claim 1, further comprising a delay timer for opening the valve. 3. The first and second predetermined times are set such that the electric valve is opened while the bypass valve is open. steam turbine controller. 4. The steam turbine control device according to claim 1, wherein the amount of steam flowing through the bypass path is selected to such an extent that the turbine rotational speed can establish a control oil pressure. 5. The steam turbine control device according to claim 4, wherein the bypass passage has an orifice for restricting the flow rate flowing therethrough.