JPS60237102A - Bearing lubricating oil temperature control method in steam turbine plant - Google Patents

Abstract

PURPOSE:To make the temperature of lubricating oil of a steam turbine rapidly correspond to the change of the cooling water temperature by raising or lowering the oil temperature once to an intermediate temperature at the start or stop of the plant, and after maintaining the intermediate temperature for a predetermined period, raising or lowering the oil temperature to a final temperature. CONSTITUTION:In the control of bearing lubricating oil temperature in a steam plant, the oil temperature is constant-controlled to 29 deg.C during the start preparation period, and is raised once to an intermediate temperature (39 deg.C) with the rise of the rotational speed in an acceleration period up to the rated speed. With the increase of the load, the lubricating oil temperature is raised up to a final temperature (46 deg.C). At the time of stopping the turbine, when the load is decreased to b%, from which the turbine is to be paralleled off after about 15min by calculating back from the decreasing rate of the load, the lubricating oil temperature is made to begin lowering and at the paralleled off point of time the oil temperature is made to an intermediate temperature and after once constant-controlled, the oil temperature is lowered to a final temperature with the decrease of the rotational speed from the turbine trip.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a bearing oil supply temperature control method for a steam turbine plant, and particularly to a method for controlling the bearing oil temperature in a steam turbine plant, and in particular, it is possible to operate the plant extremely efficiently and stably by varying the temperature in stages. The present invention relates to a bearing oil supply temperature control method for a steam turbine plant.

[Technical background of the invention]

As shown in Fig. 1, in a steam turbine plant used in a power plant or the like, a steam turbine 1 is often coaxially connected to a generator λ, and a rotating shaft 3 is supported by a plurality of bearings. be done.

Each of the bearings is supplied with lubricating oil from an oil tank 3, and the returned oil passes through an oil cooler 6 and is cooled to a predetermined temperature before returning to the oil tank S. . Further, cooling water is supplied to the oil cooler 6 by a cooling water pump 7, and the amount of water is regulated by opening and closing a flow rate regulating valve g.

The opening degree of this flow rate regulating valve is adjusted by a valve opening/closing control signal S output from the oil supply temperature regulator 9 based on the oil supply temperature detection signal S1, and the oil supply temperature is always maintained at a predetermined temperature. It looks like this. Further, the cooling water is normally heat exchanged with seawater in a cooling water cooler // to prevent the temperature of the cooling water from rising. In this system, a valve opening/closing control signal S4 is output from the cooling water temperature regulator 12 to the cooling water temperature control valve/3 based on the cooling water temperature signal S.
Cooling water temperature is maintained at a predetermined value.

In addition, as shown in the second diagram ■, the oil supply temperature T (vertical axis)
The temperature is adjusted over time (horizontal axis) to suit each operating state of the steam turbine. In Figure 2,
Diagram ■ and diagram 1 represent the upper and lower limits of the oil supply temperature in each operating state, respectively. In the example shown in this figure, the temperature is controlled at a constant temperature of 29°C during startup preparations until turning is removed, and then the temperature is increased to 6°C before entering rated operation, and the temperature is controlled at 29°C again from turbine trip to turning engagement. I am trying to lower the temperature to ℃.

[Problems with background technology]

However, when the seawater temperature rises in the summer, the cooling water temperature rises and it takes a long time to control the oil supply temperature to fall, which sometimes impedes smooth operation.

In particular, the oil supply temperature may not drop sufficiently between the time of turbine trip and the time of turbine stop, making turning operation impossible.

Additionally, in winter, the temperature of the cooling water would drop too much during backwashing, and the turbine rotation would have to be increased very slowly until the oil supply temperature rose sufficiently, which could become uneconomical.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a bearing oil supply temperature control method for a steam turbine that allows the steam turbine to operate extremely smoothly regardless of temperature fluctuations of cooling water.

[Summary of the invention]

In order to achieve the above object, a bearing oil supply temperature control method for a steam turbine plant according to the present invention temporarily raises and lowers the oil supply temperature to an intermediate temperature when starting and stopping a steam turbine plant, and then maintains the intermediate temperature for a predetermined period of time. After that, the temperature rises to the final temperature.

The temperature is controlled to be lowered in stages, and the temperature is raised and lowered to the minimum intermediate temperature initially required before reaching the final value of the refueling temperature.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 represents an apparatus for carrying out the invention,
The same components as in FIG. 1 are represented by the same symbols. The flow rate control valve S receives the valve opening/closing control signal 81 from the valve opening/closing control device -〇
For opening/closing control by 0, the rotation speed detection signal 811 from the steam turbine 1 rotation speed detector, 2/, the oil supply temperature detection signal S12 from the oil supply temperature detector -, and the load signal from the generator load detector 3 are used. 5ill are applied to each signal, and calculations are performed based on these signals.

As shown in Figure 1, the oil supply temperature (line diagram I) is always between the oil supply temperature upper limit value (line diagram h) and the oil supply temperature lower limit value (line diagram 1).
) is controlled to be set between.

First, to explain in chronological order, during the startup preparation period when the steam turbine is in a turning state, the oil supply temperature is controlled to a constant value of 9°C. Next, during the speed increase period from turning to the rated speed, the rotation speed detection signal 811
As the temperature increases, the oil supply temperature is temporarily raised to an intermediate temperature of 39°C. Since this temperature is only slightly higher than the lower limit of 3t° C. for the oil supply temperature at the rated speed, the temperature rises very quickly. Furthermore, as the load signal SSS rises due to the addition of the generator, the oil supply temperature is increased to the final temperature of Wabi Celsius. In this case, the temperature increase is completed before reaching the load value a% when the load is increased for about 1 seconds, which is calculated backward from the load increase rate.

Furthermore, when the turbine is stopped, when the load reaches b%, which will cause train disconnection in about 75 minutes, calculated backward from the load drop rate, the oil supply temperature is lowered to reach an intermediate temperature of 39° C. at the time of train disconnection. This constant value control of 39° C. is performed until the turbine trips, and the oil supply temperature is lowered to the final temperature of 29° C. in accordance with the decrease in the rotation speed detection signal 81B from the turbine IJ knob. In this case as well, since the range of temperature decrease is small, the temperature decreases very quickly. and,
Turning coupling operation is started when the oil supply temperature reaches 29°C.

〔Effect of the invention〕

As described above, the bearing temperature control method for a steam turbine plant according to the present invention temporarily raises and lowers the supply oil temperature to the minimum necessary intermediate temperature at the time of starting and stopping the steam turbine plant, and then maintains the intermediate temperature at a predetermined level. Since the oil supply temperature is controlled step by step in rows 5 and 5 by raising and lowering the temperature to the final temperature after maintaining it for a certain period of time, the oil supply temperature can be raised and lowered extremely rapidly to the minimum required temperature at startup and stop. This makes it possible to immediately obtain the required oil supply temperature regardless of changes in the temperature of the oil cooling water. Therefore, according to the present invention, a steam turbine plant can be operated very efficiently, stably, and economically.

[Brief explanation of drawings]

Fig. 1 is a system explanatory diagram showing an oil supply system for a general steam turbine plant, Fig. 2 is a diagram showing a conventional oil supply temperature control method, and Fig. 3 is a diagram showing an oil supply system for carrying out the method according to the present invention. FIG. 1 is a diagram illustrating a control method according to an embodiment of the present invention. l...steam turbine, co...generator, da...bearing, S...oil tank, 6...oil cooler, g...flow control valve, 9...oil supply temperature control //...Cooling water cooler, l...Cooling water temperature regulator, 13...Cooling water temperature control valve, 〃...Valve opening/closing control device, 2/...Rotation speed detection n... Oil supply temperature detector, 3... Generator load detector. Applicant's agent Kiyoshi Inomata

Claims (1)

[Scope of Claims] l) A bearing oil supply temperature control method for a steam turbine plant in which the temperature of oil supply supplied to a bearing part of a steam turbine plant is adjusted in accordance with the operating conditions of the steam turbine; The oil supply temperature is controlled in stages by raising and lowering the oil supply temperature to an intermediate temperature when starting and stopping the engine, and after maintaining that intermediate temperature for a predetermined period of time, raising and lowering the oil supply temperature to the final temperature. Features: Bearing oil supply temperature control method for steam turbine plants. h) The intermediate temperature is set to be slightly higher than the lower limit of the oil supply temperature.
A bearing oil supply temperature control method for a steam turbine plant as described in . 3) A bearing oil supply temperature control method for a steam turbine plant according to claim 1, wherein the intermediate temperature is maintained for a period of time until the load of the steam turbine reaches a predetermined value.