JPS5951106A - Oil pressure generator for steam turbine - Google Patents

Abstract

PURPOSE:To prevent the seizure of a bearing and the stoppage of a generating plant by detecting the bearing temperature of a booster oil pump driven by an oil turbine of a steam turbine and stopping the oil turbine and operating an auxiliary oil pump when the temperature is at a predetermined value or higher. CONSTITUTION:Oil is fed to a main oil pump 7 directly coupled with the shaft of a high/medium pressure steam turbine 10 from a booster oil pump 4 driven by an oil turbine 3. A temperature detector 30 is provided on the bearing of the booster oil pump 4, and when a temperature signal of a predetermined value or higher is sent to a bearing temperature detection device 31, it transmits an abnormarity detection signal 33, which starts a motor auxiliary oil pump 6 through a starter device 32, and a power operation valve 34 is closed by a valve operation signal 45, then the oil turbine 3 and booster oil pump 4 are stopped. Accordingly, the seizure of the bearing of the pump 4 can be prevented and lubricating oil is continually fed, thereby a generating plant can be prevented from being unnecessarily stopped and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a hydraulic pressure generator for a steam turbine provided for supplying oil to a steam turbine control system and a turbine bearing lubrication system in a turbine power generation plant.

[Technical background of the invention and its problems]

This type of turbine power generation plant has a built-in steam turbine, and by applying work to the steam turbine, a generator is driven to generate electricity. A steam turbine has a system that controls the rotation speed of its turbine rotor.
A speed governor that adjusts the turbine load 81 and a safety device that protects the turbine when the turbine is in an abnormal operating state are provided. Control oil is used as a transmission medium in the speed governor and safety device mentioned above, and on the other hand, lubricating oil is supplied to the turbine bearing lubrication system such as the turbine bearing. teeth,
The hydraulic pressure generator shown in FIG. 1 provides the necessary hydraulic pressure.

Fig. 1 is a piping system diagram of a hydraulic pressure generating device for a steam turbine.
．． Drive booster oil pump 4, AC electric bearing oil pump 5
The booster oil and the control oil discharged from the I pump 4 are sucked into the main oil pump 4, and are made to have high pressure by the main oil pump 4. The signal is then supplied to the control device 9. The main oil pump and control device 9 are connected to the turbine rotor of the high and intermediate pressure steam turbine 10.

On the other hand, the high-pressure control oil discharged from the main oil pump 7 is also sent to the oil turbine 3 provided coaxially with the booster oil pump 4, and drives the oil turbine 3 to turn the booster oil pump 4 into yI? Activate the pump.

The control fill oil that has worked in the oil turbine 3 is depressurized and sent to the oil cooler 2, where it is cooled and then passed through the bearing oil supply pipe 11 to the high and intermediate pressure turbine 10. It is supplied to each bearing I5 and thrust bearing 16 of the low pressure turbine 12, generator M13, and exciter 14, and lubricates each rotary bearing part 15, 16. The oil that has lubricated each bearing portion is returned to the oil tank 1 through the return oil pipe 17, and the cycle as control oil and lubricating oil is completed. The AC electric bearing oil pump 5 supplies lubricating oil to the rotating bearings 15 and 16 during the operation of the steam turbines 12 and 12, and its discharge side is connected to the oil cooler 2. Inside the oil tank 1 is a DC that supplies bearing oil when AC power is lost.
A motor-driven pump (not shown) is also installed.

In addition, the main oil pump 7 connected to the rotor shaft of the steam turbine can sufficiently exert its pumping action during rated operation, but satisfactory pump performance cannot be obtained during startup or at low rotational speeds. . For this reason, in the range below the limit rotation speed of the steam turbine, the assistance of another oil pump is required, and for this reason an auxiliary oil pump is installed. The auxiliary oil pump 6 is driven by an AC motor and is designed to supply control oil and lubricating oil over an operating range from the stopped state of the steam turbine to the limit rotation speed.

The above-mentioned auxiliary oil pump is not only produced when the speed of the steam turbine is below the limit rotation speed, but also increases the oil pressure of the control oil when the steam turbine is continuously operated.

When the oil pressure of the control oil in the main oil pump 7 etc. drops below a predetermined pressure, this oil pressure is detected and the auxiliary oil pump 6 is automatically started to obtain a predetermined value of control oil pressure. , to ensure the safety of the control device 9.

Incidentally, the booster oil pump 4 for driving the oil turbine 3 installed in the oil tank 1 is integrally constructed as shown in FIG. 2, and is directly connected to the main shaft 19. The main shaft 19 is rotatably supported by a self-lubricating oil turbine bearing 20 and a booster oil pump bearing 21 . Each bearing portion 21 is supplied with oil and lubricated through oil supply holes 23 a and 23 b opening into the discharge pipe 22 of the booster oil pump 4 .

However, in this type of oil turbine 3 and booster oil pump 4 having a pole-and-line structure, during normal operation of the oil turbine 3, the booster oil 1? There is a possibility that fine foreign matter may enter the pump bearing 21 for some reason.

When fine foreign matter enters the ZOOSTAR oil pump bearing 21, it damages the bearing surface (white metal), causing the white metal bearing surface to heat and expand due to frictional heat, and the temperature of the main shaft 19 to rise. Since the main shaft 19 expands due to the rise in temperature, the clearance between the bearing surfaces decreases, and the minimum required thickness of the oil film may not be ensured in some cases.

If the minimum required oil film thickness cannot be secured on the bearing, the temperature of the bearing will rise further, causing seizure and burnout, and the bearing surface of the booster oil pump bearing 21 will directly hug the main shaft 19, resulting in white Metal (booster oil pump bearing 21
) wiping phenomenon occurs,
The operation of the pump is temporarily restricted, causing a drop in the discharge pressure of the main oil pump 7, resulting in an unfavorable situation for the steam turbine power plant.

[Purpose of the invention]

In consideration of the above-mentioned points, this invention effectively prevents burnout and seizure of the booster oil pump bearing, and also reliably prevents a drop in discharge pressure from the main oil pump to avoid turbine tripping 1-1 It is an object of the present invention to provide a hydraulic pressure generator for a steam turbine, which allows a steam turbine to operate safely and continuously.

[Summary of the invention]

In order to achieve the above-mentioned object, a hydraulic pressure generator for a steam turbine according to the present invention includes: an oil turbine-driven booster oil pump that connects the suction pressure necessary for a main oil pump connected to a turbine rotor of a steam turbine; The main oil pump and an auxiliary oil pump that supplies oil to the oil turbine and booster oil pump system as needed are provided in the oil tank, and the main shaft that integrally connects the oil turbine and booster oil pump is mounted on a bearing. In a rotatably supported steam turbine oil pressure generator, there is a bearing temperature detection device connected to a bearing surface temperature detection device embedded in the bearing, and an abnormal bearing temperature increase signal from this bearing temperature detection device. and a starting device for inputting a signal, and the starting device is set to start the auxiliary oil pump in response to a bearing temperature abnormal rise signal and close a power operation valve provided in an inlet pipe of the oil turbine. This is what I did.

[Embodiments of the invention]

Embodiments of the invention will be described with reference to the accompanying drawings.

FIG. 3 is a system diagram showing an embodiment of the steam turbine hydraulic pressure generator according to the present invention. In this hydraulic pressure generator, the same members as the conventional steam turbine hydraulic pressure generator shown in FIG. The same reference numerals will be given and the explanation will be omitted.

A booster oil pump 4 driven by an oil turbine 3 installed in the oil tank 1 has a coushing structure as shown in FIG. 2 as in the prior art. This casing U is constructed by integrally assembling an oil turbine discharge pipe casing 5, an oil turbine casing 26, a body casing 27, and a Zusta oil ponzo casing 4, which can be divided into four parts.

An oil turbine 3 is installed in the upper part of the casing, and a booster oil pump 4 is installed in the lower part of the casing, and both are connected by a main shaft 19. The top and middle portions of the main shaft 19 are rotatably supported on the oil turbine bearing side by ZOOSTAR oil ΔP bearings 21 . When the control oil from the main oil pump 7 is supplied to the oil turbine 3, the oil turbine 3 is rotationally driven by the oil pressure, and the booster oil pump 4 is operated.

A detection device 3o, such as a thermocouple, for detecting the temperature of the bearing surface is embedded in the booster oil pump bearing 21 that pivotally supports the main shaft 19, in order to detect the temperature near the surface of the bearing.

This detection instrument 3o is connected to a ZOOSTER oil pump bearing temperature detection device 31, as shown in FIG. This detection device 31 is connected to the activation device 32, and the detection device'
In response to the detection signal from 30, a booster oil pump bearing temperature abnormality detection signal 33 is output to the starting device 32. The starting device 32 is connected to the AC electric auxiliary oil pump 6, the power operated valve 34, and the power operated pressure reducing valve 35, respectively, and receives the booster oil pump bearing temperature abnormality detection signal 33 and starts the auxiliary oil pump 6 and both power operated valves 34. , 35
It is designed to control the operation of the

On the other hand, the power operation valve 34 is connected to the inlet pipe 3 of the oil turbine 3.
7, and a check valve 39 is interposed between the outlet pipes. The discharge pipe 40 of the AC electric auxiliary oil pump 6 and the downstream side of the check valve 42 of the discharge pipe 41 of the AC electric bearing oil pump 5 are connected by a communication pipe 43, and the above-mentioned power-operated pressure reducing valve is connected to this communication pipe 43. A valve 35 is provided.

By the way, FIG. 4 qualitatively shows an example of measurement of temperature changes on the bearing surface of the booster oil pump bearing in the oil turbine 3 and the booster oil pump 4. As can be understood from this figure, when the oil supply to the booster oil pump bearing 21 is completely stopped, the bearing surface temperature T after the oil supply is stopped is
gradually rises, and when time t2 elapses, the temperature rises rapidly, leading to burnout and damage.

From this, booster oil pump bearing temperature detection device 31
constantly monitors the bearing surface temperature of the booster oil pump bearing 21 during operation of the steam turbine. Then, the bearing surface temperature T gradually begins to rise, and in FIG. 4, for example, at the time t when the bearing surface temperature reaches T
3 is output and inputted to the activation device 32. In response to the activation bone 33, a power operation valve operation signal 45 that closes the power operation valve 34, an auxiliary oil pump start signal 46 that starts the AC electric auxiliary oil pump 6, and discharge from the AC electric auxiliary oil pump 6. It is configured to issue a power-operated pressure-reducing valve operation signal 47 for operating the power-operated pressure-reducing valve 35 so as to reduce the oil pressure of the lubricating oil to the required bearing oil exact size.

Next, the operation of this invention will be explained.

During normal operation of the steam turbine, the steam turbine hydraulic pressure generator according to the present invention operates in the same manner as the conventional steam turbine hydraulic pressure generator shown in FIG. 1, and lubricates the control system and turbine bearing system of the Ta Hin power plant. It is shown to provide the necessary oil pressure and oil volume for the necessary control oil and lubricating oil.

In addition, the Zostar oil front pump 4 for driving the oil turbine 3 is
A desired suction pressure is applied to the main oil pump 7. This suction pressure corresponds to the head difference between the oil tank 1 and the turbine shaft of the steam turbine, and a pressure corresponding to the head difference is applied to the discharge side of the booster oil pump 4 in advance.

As a result, the bearing surface temperature of the booster oil pump bearing 21 of the booster oil pump 4 gradually increases for some reason, and there is a possibility that the pump bearing may burn out or seize. When the temperature reaches To, this temperature T□ is detected between the bearing surface temperature detection instruments and inputted to the booster oil pump bearing temperature detection device 3, which generates the booster oil pump bearing temperature abnormality detection signal 33. This bearing temperature abnormality detection signal 33 is input to the starting device 32, and this starting device 32 is started. By starting the starting device 32,
Start the AC electric auxiliary oil Ponzoro to generate control hydraulic pressure.

On the other hand, the power operation valve 34 is closed by the power operation valve operation signal 45 from the starting device 7 to prevent control oil from flowing into the oil turbine 3. By closing the ηυ1 force operation valve 34, the rotation of the oil turbine 30 gradually decreases. At this time, the oil pressure of the control oil discharged from the oil turbine 3 is reduced in accordance with the drive of the oil turbine 3, but in this case, the control oil pressure discharged from the oil pump 5 is The oil that is
and the AC electric bearing oil pump 5 discharge pipe 41.
3, the oil pressure is reduced to the required bearing oil pressure by a power-operated pressure reducing valve 35, and the oil cooler 2 is supplied with oil. Therefore, even if the oil turbine 3 stops, sufficient lubricating oil necessary for lubrication of the turbine bearing system is ensured.

Therefore, a series of accidents such as complete burnout or seizing of the booster oil pump bearing 21, adverse effects due to temporary stoppage of the booster oil pump 4, and drop in the discharge pressure of the main oil pump 7 can lead to a serious accident such as a turbine trip. Possibilities are prevented and a stable supply of control oil and lubricating oil is ensured.

In the description of one embodiment of the present invention, an example was explained in which only the AC electric auxiliary oil Bonzoro is started by a signal from the starting device, but in order to secure lubricating oil, the AC electric bearing oil pump 5 The lubricating oil may be supplied to the oil cooler by directly starting the lubricating oil. In this case, the connecting pipe 43 and the power-operated pressure reducing valve 35 are not necessarily required.

〔Effect of the invention〕

As described above, in the steam turbine hydraulic pressure generator according to the present invention, when there is a possibility of seizure or burnout due to some reason due to the lubrication of the oil turbine-driven booster oil pump, the bearing surface temperature The detection device detects the temperature, and the bearing temperature detection device issues a bearing temperature abnormality detection signal. This detection signal activates the starting device, stops the oil turbine, and activates the auxiliary oil pump. It is possible to secure the oil pressure and amount of control oil and lubricating oil necessary for the control system and turbine bearing system, and it is also possible to reliably prevent burnout and seizure of the booster oil pump bearing, reducing burnout accidents. Turbine trip accidents that occur are completely prevented, and even if the booster oil pump stops pumping, the auxiliary oil pump provides sufficient oil pressure and oil volume, allowing the turbine power generation plant to continue operating. This makes it possible to operate the power plant, which has the effect of improving the reliability and safety of the power plant.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional hydraulic pressure generator for a steam turbine, FIG. 2 is a structural diagram showing an oil turbine-driven booster oil pump incorporated in the hydraulic pressure generator, and FIG. 3 is a steam turbine according to the present invention. FIG. 4 is a system diagram illustrating an embodiment of a hydraulic pressure generating device for use in oil turbines. 1'...Oil tank, 2...Oil cooler, 3...
Oil turbine, 4... Booster oil pump, 5...
AC electric bearing oil? pump, 6... Auxiliary oil pump, 7...
・Main oil pump, lO...High pressure and intermediate pressure steam turbine, 12
...Low pressure turbine, 13... Generator, 15... Bearing, 16... Thrust bearing, 19... Main shaft, addition...
・Oil turbine bearing, 21... Booster oil pump bearing, 22... Discharge pipe, U... Casing, 6...
Oil turbine discharge pipe casing, 26...Oil turbine casing, n...Body surface casing, Road...
Booster oil 2 pump casing, 3o... Detection device for detecting bearing surface temperature, 31... Booster oil 2 pump bearing temperature change detection device, 32... Starting device, 34... Power operation valve,
Ah... Power operated pressure reducing valve, 37... Oil turbine inlet pipe, μs... Oil turbine outlet pipe, 43... Communication pipe. Applicant's agent Hisashi Hatano Figure 1

Claims (1)

[Scope of Claims] 1. An oil turbine-driven booster oil pump that provides the necessary suction pressure to the main oil pump connected to the turbine rotor of the steam turbine, and a booster oil pump that is necessary for the main oil pump system. In the hydraulic pressure generator for a steam turbine, an auxiliary oil pump is provided in the oil tank to supply oil according to the oil pressure, and a main shaft that integrally connects the oil turbine and the booster oil pump is rotatably supported by a bearing. A bearing temperature detection device connected to a detection device for detecting the bearing surface temperature embedded in the bearing, and a starting device for inputting a bearing temperature abnormality detection signal from the bearing temperature detecting device are provided, and the starting device is configured to input a bearing temperature abnormality detection signal from the bearing temperature detection device. A hydraulic pressure generating device for a steam turbine, characterized in that the auxiliary oil pump is activated in response to an abnormality detection signal, and a power operation valve provided in an inlet pipe of the oil turbine is closed. 2. A bearing that supports the main shaft that connects the oil turbine and the booster oil pump, an oil turbine bearing and a booster oil pump bearing, and a thermocouple or other sensor for detecting the bearing surface temperature is installed on the booster oil pump bearing. A hydraulic pressure generating device for a steam turbine according to claim 1, in which a device is embedded. 3. A patent claim in which the outlet pipe of an auxiliary oil pump and the discharge pipe of an AC electric bearing oil pump that supplies lubricating oil to the bearing system of a steam turbine are connected by a connecting pipe, and a power-operated pressure reducing valve is provided in this connecting pipe. A hydraulic pressure generator for a steam turbine according to item 1. 4. The hydraulic pressure generator for a steam turbine according to claim 3, wherein the power operated pressure reducing valve receives a signal from the starting device and reduces the hydraulic pressure generated by the auxiliary pump to a required bearing hydraulic pressure.