JPH0714265B2 - Power plant cooling water system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cooling device for cooling a generator hydrogen cooler, a stator cooler, a turbine oil cooler, and bearings of pumps of a power plant, and more particularly to a cooling device. The present invention relates to a center cooling device suitable for a power plant that operates a generator at peak power consumption overload with a rated output or higher.

[Prior art]

As described in Japanese Patent Laid-Open No. 48-13935, a conventional device relating to the cooling facility for a power plant of this type is designed to control the temperature of the turbine oil cooling water system and the facility cooling water system depending on the turbine operating state (turning off, etc.). I was trying to adjust the temperature setting of the vessel. However, the generator hydrogen temperature and the stator cooling water temperature are adjusted to be constant regardless of the generator output and power factor, and the point where the temperature set value of this temperature controller is adjusted during overload output operation He was not considered.

[Problems to be solved by the invention]

It is known that it is possible to improve the power factor when operating the generator with an overload output that is higher than the rated output. However, in areas where the power grid is large and well developed, it is possible to reduce reactive power and improve power factor.
In areas where the power grid is small and underdeveloped, it is not possible to operate with improved power factor during heavy load hours during the day when the electric motor load in factories is large and a large amount of reactive power is consumed. Therefore, in these areas, when determining the generator capacity, set the rated power factor.
It is set as low as 80% to 85%, and the generator capacity is increased so that overload output can be obtained at this rated power factor. An object of the present invention is to utilize the characteristic that the capacity of the generator changes depending on the cooling medium temperature, and enable overload output operation without increasing the capacity of the generator even in an undeveloped area where the power grid has a small capacity. To provide a device. In addition, since the power factor correction operation decreases the generator terminal voltage (reduction of reactive power), it is necessary to operate in cooperation with other power generation equipment.However, the purpose of the present invention is to operate independently in each power generation equipment. An object is to provide a device capable of performing load output operation.

[Means for Solving Problems] The above object is to provide a cooling water cooler other than in the summer, when the cooling water temperature (seawater temperature) is low, when the generator is operated with overload output, the generator hydrogen temperature and the stator cooling This can be achieved by lowering the water temperature.

The cooling water cooler is designed so that the hydrogen cooler, the stator cooler, the turbine oil cooler, etc. can supply the cooling water of the required water temperature in the rated load state even when the seawater temperature is the highest in the summer. The temperature settings of the on-site cooling water temperature controller, hydrogen cooler hydrogen temperature controller, and stator cooling water temperature controller are also set so that the seawater temperature can be adjusted to a constant value at the maximum water temperature. Therefore, except during summer (when the seawater temperature is low), the set temperature of the temperature controller can be lowered, which can lower the cooling water temperature and hydrogen temperature for the hydrogen cooler and the stator cooling water. it can.

[Action]

FIG. 3 shows an example of the relationship diagram between the generator hydrogen cooler cooling water temperature and the generator capacity. The same characteristics are obtained in the case of the stator cooler.

Fig. 4 shows the relationship between the maximum output power and the cooling water temperature of the generator designed under the conditions of generator rated output 350 MW, rated power factor 0.85, hydrogen cooler design cooling water temperature 33 ° C.

The generator capacity is Becomes Hydrogen cooler The lower the cooling water temperature, the lower the hydrogen temperature can be. Therefore, as shown in this figure, the operable power generation capacity of the same generator is increased. That is, the maximum possible output of the generator can be increased. Since the output of the generator is limited by the temperature limitation of the rotor and stator, if the cooling effect is increased,
That is, if the cooling water temperature and the hydrogen temperature are lowered, the maximum possible output will increase. The present invention utilizes this characteristic that changes depending on the temperature of the cooling medium, and during overload output operation, the temperature setting of the internal cooling water temperature controller, the hydrogen cooling device hydrogen temperature controller, the stator cooling device, and the cooling water temperature controller. The value is switched to the low temperature side.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which the temperature control device according to the present invention is applied to a cooling water system in a general power plant.

The on-site cooling water system of this embodiment is constituted by the following members.

(A) Cooling water pump 1 for circulating the in-house cooling water, (b) Cooling water cooler 2 for cooling the in-house cooling water with seawater, and (c) Outlet water of the cooling water cooler 2 with low temperature and high temperature. Internal cooling water temperature control valve 3 for adjusting the cooling water temperature after the merging with the cooling water bypassing the cooling water cooler 2 and controlling the mixing ratio thereof to a constant temperature. Generator hydrogen cooler 4 that cools hydrogen with the adjusted cooling water, (e) Stator cooler that cools stator cooling water (although not shown, the same structure as the generator hydrogen cooler 4 described above). Is).

(F) A turbine oil cooler 5 that cools turbine lubricating oil, (g) a bearing cooler 6 that cools the bearings of each pump, and (h) a cooling water pipe 7 that connects each cooler described above.

The on-site cooling water temperature control valve 3 includes a temperature detecting element 21 for detecting the cooling water temperature, a temperature controller 22 for issuing a control signal to adjust the cooling water temperature to a constant value, and an electropneumatic converter 23 for converting an electric signal into an air signal. It is adjusted by. Further, in the generator hydrogen cooler 4, the stator cooler (not shown), and the turbine oil cooler 5, in order to adjust the hydrogen, the stator cooling water, and the oil temperature to be constant, the temperature detection elements 24, 27, and the temperature are detected. Controllers 25 and 28, electropneumatic converters 26 and 29, and temperature control valves 8 and 9 are installed. Further, the cooling water cooler 2 is cooled by the discharge water of the seawater pump 10 installed at the intake 9, and is discharged to the water outlet 12 via the seawater pipe 11. Further, a cooling water head tank 8 is installed in the pipe 7 for circulating the cooling water in order to secure the pushing pressure of the cooling water pump 1. The above configuration is the same as that of the conventional general cooling water system.

The present invention, in the above-described cooling water system, when the generator output is an overload output of the rated output or more, the on-site cooling water temperature controller 22
Of the hydrogen temperature controller 25 and the temperature setting value of the stator cooling water temperature controller (not shown) can be switched to lower the set temperature. When the generator output is not higher than the rated output, the high temperature side (33 ° C and
However, if the generator output exceeds the rated output, the low temperature side (2
8 ° C and 42 ° C) can be switched by switches 38 and 39. The primary delay devices 33 and 37 are provided to alleviate control disturbance (abrupt change of hydrogen temperature and cooling water temperature) due to temperature setting switching. As shown in the figure, in this embodiment, the set temperature when the generator rated output is less than or equal to is set to 33 ° C. for the center cooling water and 42 ° C. for hydrogen and the stator cooling water, and the set temperature when the generator rated output or more is set. When the internal cooling water is set to 28 ° C and the hydrogen and stator cooling water are set to 42 ° C, when the seawater temperature is 23 ° C or less (the difference between the internal cooling water and the seawater temperature is generally designed to be 5 ° C),
From Fig. 4, the overload output operation of the generator output 363MN becomes possible. (Generally, the overload output can be up to about 105% of the rated output.) FIG. 2 shows a cooling water system of an embodiment different from the above. Since FIG. 1 and FIG. 2 are almost the same, differences will be described. In FIG. 2, the hydrogen cooler 5 and the stator cooler (not shown) are directly cooled by the outlet water of the cooling water cooler 2, and are adjusted to a constant temperature by the on-site cooling water temperature control valve 3. Cooling water having a temperature lower than that of the cooled cooling water is obtained. Therefore, when the seawater temperature is low except in summer, the overload output can be obtained by switching the temperature setting of the hydrogen cooler hydrogen temperature controller 25 and the stator cooler cooling water temperature controller (not shown) to the low temperature side. It becomes possible to drive. It should be noted that, in FIGS. 1 and 2, the primary delay device 33, 37 is provided in order to mitigate control disturbance (abrupt change of hydrogen temperature and cooling water temperature) by switching the temperature set value.
However, it is also possible to do this by using a ramp function converter.

In addition, the explanation of FIGS. 1 and 2 is based on the signal transmitters 31, 32,
The method of switching to the temperature set to a constant temperature in 35, 36 was explained, but input the generator output, generator power factor and cooling water temperature diagram shown in Fig. 4 to the signal transmitters 32, 36. It is also possible to adjust the cooling water temperature and hydrogen temperature at which overload output operation is possible.

Fig. 5 is a block diagram showing the protection device during overload output operation. If the generator power factor is above the specified value and the generator hydrogen temperature and the stator cooling water temperature are below the specified values, the generator is overloaded. During load output operation, the temperature of the rotor and stator will exceed the limit value, and the coil life will be reduced. For this reason, a protection device for limiting the generator output to the specified value or less is provided by an AND circuit which is equal to or higher than the specified value of the generator power factor and equal to or lower than the specified values of the generator hydrogen temperature and the stator cooling water temperature.

〔The invention's effect〕

As described above, according to the present invention, even in an area where the power grid is underdeveloped and power factor correction operation is not possible, overload operation can be performed by changing the internal cooling water temperature, the generator hydrogen temperature, and the stator cooling water temperature. The effect is that overload output operation can be performed without increasing the capacity. Further, since the operation is not only for improving the power factor, there is an effect that each power generation facility can perform overload output operation independently of other power generation facilities. As a result of these effects, the generator capacity can be reduced by about 5% by applying the present invention.

[Brief description of drawings]

FIG. 1 is a control system of a temperature adjusting device for a cooling water facility in a plant in one embodiment of the present invention, FIG. 2 is a control system diagram of a temperature adjusting device of a cooling water facility in a plant showing another embodiment, and FIG. Chart showing the relationship between generator hydrogen cooler cooling water temperature and generator capacity, Fig. 4 is a chart showing the relationship between generator hydrogen cooler cooling water temperature, generator power factor and generator maximum possible output, FIG. 5 is a block diagram showing a protection device during overload output operation. 1 ... Cooling water pump, 2 ... Cooling water cooler, 3 ... In-house cooling water temperature control valve, 4 ... Generator hydrogen cooler, 5 ... Turbine oil cooler, 6 ... Bearing cooler, 8 , 9 …… Temperature control valve, 22,25,28 …… Temperature controller, 31,32,35,36 …… Signal transmitter.

Claims (1)

[Claims] 1. A generator hydrogen cooler, a stator cooler, a cooling water cooler for cooling cooling water supplied to the generator hydrogen cooler and the stator cooler, and the cooling water cooler. In a cooling device of a power plant comprising cooling water temperature adjusting means for adjusting the temperature of cooling water to be cooled to a predetermined set temperature, the cooling water temperature adjusting means is provided when the generator output is at a rated value and at a rated value. When the value is less than the value, the temperature of the cooling water is adjusted using the first set temperature, and when the generator output is the rated value or more, the second set temperature lower than the first set temperature is used. A cooling device for a power plant, comprising means for adjusting the temperature of the cooling water so that the temperature of the rotor and the temperature of the stator do not exceed specified values.