JPS5826518A - Method of forcibly cooling power cable - 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 The present invention relates to a method for forcedly cooling an electric power cable, and more particularly to a cooling method of a type in which a refrigerant is forcibly circulated and cooled using a refrigerator. Figure 1 schematically shows the forced cooling cable of the above method. 10 is a cable S12 is a refrigerant, 14 is a pump, 2
0 is a heat exchanger, and 22 is a refrigerator.

In the case of internal refrigerant cooling, the temperature of the refrigerant at the cable outlet 102 can reach, for example, 600C (or more).

Conventionally, the refrigerant exiting the cable 10 was cooled only by the refrigerator 22, lowered to a constant temperature change (for example, 20° O), and then pumped through the cable port 101 by the pump 14. .

As a result, the capacity of the refrigerator 22 becomes large, resulting in an increase in equipment costs and operating costs.

Therefore, a method using a pre-cooler 24 as shown in FIG. 2 may be considered. That is, the refrigerant that was at, for example, 60°C at the cable outlet 102 is precooled to about 40°C by the precooler 24, and then cooled to about 2°C by the refrigerator 22.
However, in the conventional cooling system, the refrigerant temperature at the cable inlet 101 is kept constant (for example, 20'O), thereby reducing the load on the refrigerator 22.
). However, if such a method is used to keep the refrigerant temperature constant in the cable population 101, even if the precooler 24 is provided, the time period in which it can be used will be limited as described below.

The situation is explained in "Figure 3".

The refrigerant temperature in the cable population 101 is kept constant (for example, 20° C.) as shown in A. The load in table 10 changes depending on the time (or season) like D-. Therefore, the refrigerant temperature at the cable outlet 102 changes as shown by B.

Since the temperature is lowered to, for example, 20% by the refrigerator 22 and the precooler 24, and the temperature is then input from the cable inlet 101, the cooling load for both the refrigerator 22 and the precooler 24 is a curve like C. draw

However, the precooler 24 can only lower the temperature to about 40°C in the water-cooled type and to about 45°C in the air-cooled type. Therefore, the precooler 24 can be used only in the portions of the three curves that are equal to or greater than, for example, 4 oocJ (hatched portions).

That is, of the C curve showing the overall cooling load, only the shaded portion is the load on the precooler 24, and the remaining portions 0 and 7 are the load on the refrigerator 22.

Therefore, the usage efficiency of the pre-cooler 24 is poor, and the
A significant reduction in the refrigerating capacity of No. 2 cannot be expected.

The present invention aims to solve the above-mentioned problems and enables the load on the refrigerator 22 to be reduced by allowing the precooler 24 to operate at all times.

Configuration of the invention 1) As shown in Figure I"01", the refrigerant temperature at the cable outlet 102 is always maintained at a constant value (for example, 60°a) regardless of the fluctuations in the load of the cape/I/10, 2) The value should be as high as possible within the range of waiting customers. 3) The refrigerant that has reached a high temperature and exits the cable 10 is first cooled down in the pre-cooler 24, and then, if necessary, is lowered to a predetermined temperature in the refrigerator 22 and then transferred to the cable 10. It is characterized by the fact that it can be put into.

More detailed explanation The refrigerant temperature at the cable outlet 102 is defined as "B" in Figure 1.
In order to keep it constant (for example, 6 ooc) (assuming that the circulating flow rate of the refrigerant 12 is kept constant), as the load on the cable 10 fluctuates in a curved manner, the refrigerant in the cable population 101 must be It is necessary to change the temperature like the A curve, but for this purpose, the heat exchange rate of the heat exchanger 20 can be controlled (the cable 10
predict and control load fluctuation patterns).

In this case as well, the total cooling load of both the refrigerator 22 and the precooler 24 is the same as in the conventional case (FIG. 1), as shown by curve C. However, since the temperature of the refrigerant entering the pre-cooler 24 is always high (for example, 6000 ℃), it is possible to utilize the function of the pre-cooler 24 at all times, and its load is as shown in the shaded area in "Figure q".

In other words, the refrigerator 22 should be used to assist only when the load is high≦
(Dot part) When the load is low, only the precooler 24 needs to be operated.

Embodiment (Fig. 16.7) The same parts as in Fig. 1 are designated by the same reference numerals. 62 is a heat storage tank,
Cold heat is stored by the refrigerator 22 and the pump 28. The cold water from the cold water tank 36 is sent to the heat exchanger 20 by a pump 38 for heat exchange, and then returns to the hot water tank 34. This part has a conventionally known configuration; 24 is a precooler, which is of a direct cooling type using an air-cooled heat exchanger; and 26 is a fan for air cooling. This precooler 24 is constantly operating, and the cable 1
The refrigerant 12 that comes out of the outlet 102 is cooled to a constant temperature by the precooler 24 as described above. If it is necessary to further cool the refrigerant 12 depending on the load condition, the refrigerator 22 is operated to cool the refrigerant 12 to the required humidity.

In this case, depending on the load condition, the entrance 101 of the cable 1o
For example, it is necessary to change the heat exchange efficiency of the heat exchanger 20 in order to consider the fullness of the heat exchanger, but this can be done by controlling the amount of cold water circulated from the heat storage tank 32. Note that, in practice, the load fluctuation pattern of the cable 10 is predicted in advance based on experience, and control is performed accordingly.

"Figure 6" is another example of a precooler, showing a direct cooling type using a closed cooling tower.
2, and can cool to a lower temperature than an air-cooled pre-cooler.

"Figure 7" shows a system in which water 29 cooled in a closed cooling tower 24 is used to pre-cool a heat exchanger 60.
Although the heat exchange efficiency is slightly lower, highly reliable cooling can be achieved. In this case, it is possible to share the closed type cooling tower 24 with the cooling tower of the refrigerator 22, and there is also the advantage that the structure can be made into a compact structure. , the pre-cooler function can be utilized at all times. Therefore, it is possible to use only the pre-cooler during times when the cable load is low, and to use the refrigerator for assistance during high load times.

The efficiency of the entire cooling equipment has been improved, and the capacity of the refrigerator is also small□
Anything is fine.

[Brief explanation of the drawing]

Fig. 1 is a general explanatory diagram of a forced cooling cable, Fig. 2 is an explanatory diagram when a pre-cooler is used in combination, Fig. 3 is an explanatory diagram when controlling the amount of refrigerant at the cable inlet at a constant level, and Fig. 1I. are diagrams for explaining the control method of the present invention, and FIGS. 5, 6, and 7 are diagrams for explaining the embodiments of the present invention 10 = cable 12; cable refrigerant 20: heat exchanger 22: refrigerator 24; precooler Patent applicant: Fujikura Electric Cable Co., Ltd. Agent: Keiji Kunite

Claims (1)

[Claims] Forcibly circulating the refrigerant in the cable, and setting the refrigerant temperature at the cable outlet to a constant and extremely high value within an allowable range regardless of fluctuations in the cable load; An electric cable cable characterized in that the refrigerant coming out of the cable is constantly cooled by a pre-cooler that does not use a refrigerator, and then, if necessary, is cooled by a refrigerator to a predetermined temperature and sent to the table again. forced cooling method.