JPS5842611B2 - oil-immersed current transformer - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in oil-filled current transformers.

As is well known, as power demand increases, current transformers with high voltage and high current ratings are required.

In order to deal with the heat problem of current transformers that accompanies large currents, a structure as shown in FIG. 1 is adopted.

A hollow coil 3 is formed into a ring shape at the chain part with the secondary coil 2 wound around the outer periphery of the annular iron core 1, and one end of the hollow conductor 3 is electrically connected to the hollow outer cylindrical conductor 4. The ends are electrically connected to the hollow inner cylindrical conductor 5, and the hollow outer cylindrical conductor 4 and the hollow inner cylindrical conductor 5 are arranged concentrically to form a primary coil.

The outer part of the primary coil is provided with main insulation 6 to withstand high voltage.

The hollow outer cylindrical conductor 4 is connected at its upper end to an opening 8 via a connecting line T.

Similarly, the hollow inner cylinder conductor 5 is connected to the outlet 1 through the connecting wire 9 at the upper end.
Connected to 0.

A tank 11, a main insulator pipe 12, and a cap 13 are hermetically connected to the exterior, and insulating oil 14 is sealed inside from the upper end of the hollow inner cylindrical conductor 5 to form an oil-immersed current transformer.

The cooling effect of a current transformer configured in this way is that the heat generated in the primary coil is transferred to the insulating oil that is close to the primary coil, and the heated insulating oil expands, its specific weight decreases, and moves upward. do.

Here, by changing the calorific value per unit length of the hollow outer cylinder conductor 4 and the hollow inner cylinder conductor 5 (generally speaking, the force of the hollow inner cylinder conductor 5 generates a larger amount of heat than the hollow outer cylinder conductor 4). ) The insulating oil flows into the hollow inner cylinder conductor 5 from between the hollow outer cylinder conductor 4 and the hollow inner cylinder conductor 5 through the hollow conductor 3, is discharged from the upper end of the hollow inner cylinder conductor 5, and heat is radiated to the atmosphere from the side wall of the cap 13. The cooled insulating oil flows between the hollow outer cylindrical conductor 4 and the hollow inner cylindrical conductor 5, and the insulating oil circulates. Since a concentric pipe is used and a hollow conductor is also used for the ring, it takes a long time to bend the hollow conductor and electrically connect it to the concentric pipe, and it is difficult to maintain concentricity during handling during manufacturing. There were some undesirable points, such as the need for jigs and tools.

The object of the present invention is to obtain an oil-immersed current transformer which has a cooling effect similar to or better than that of the conventional transformer, has a simplified secondary coil structure, and eliminates the above-mentioned drawbacks.

An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 2 and 3, a plurality of solid conductors 103 are formed into a ring shape at the outer circle of the annular core 101 (the interlocking part with the wound secondary coil 102). Two solid round bar conductors (shown) A gap is provided between the annular solid conductors 103 to form a circulation path for insulating oil.
One end is electrically connected to the lower end of the flat conductor 104a, and the other end of the ring-shaped solid conductor is electrically connected to the lower end of the flat conductor 104b, and the flat conductors 104a and 104b are arranged to face each other to form a primary conductor.

The outer circular surfaces of the flat conductors 104a and 104b are coated with an insulator 105 that can withstand the mechanical force at the time of a short circuit and is a heat insulator, such as PG tape. Prevent heat radiation to.

Further, a shield tube 106 for relieving electrical stress is installed outside the flat conductors 104a and 104b, and a main insulation 107 is applied to the outer periphery of the shield tube 106 and the outer circle of the solid conductor 103.
A primary coil portion is formed.

In addition, as shown in FIG. 3, a notch 104b' is formed at the lower end of the flat conductor 104b so that insulating oil can circulate, and a notch 104b' is formed between the ring-shaped solid conductors 103 to withstand mechanical force in the event of a short circuit. In addition, several stoppers 103' are arranged at equal intervals so as not to prevent the circulation path of the insulating oil.

These primary coil portions and secondary coil portions are placed in an air insulating tube 108, a tank 109 attached to the bottom of the air insulating tube 108, and a cap 110 attached to the top of the air insulating tube 108. Store each air insulator pipe 1
A sealing gas get (not shown) is interposed between the 08 tank 109 and the cap 110 to provide an airtight structure.

Further, insulating oil 111 and nitrogen gas 112 are sealed inside them to constitute an oil-immersed current transformer.

In the oil-immersed current transformer configured as described above, the insulating oil interposed between the flat conductors 104a and 104b is warmed by the amount of heat generated by the flat conductors 104a and 104b and rises; 103 enters from the notch 104b' of the flat conductor 104b, and the shielded pipe 10
6 and the flat conductors 104a, 104b and flows into the annular solid conductor 103, so the insulating oil 111 circulates.

Then, the flat conductor 104a is heated. The insulating oil 111 rising from the cap 104b is heated to the atmosphere through the cap 110 and cooled. 104a.

104b, there is no need to bend the hollow conductor or electrically connect the concentric pipes; all that is required is the bending of the solid conductor and the electrical connection between the solid conductor and the flat conductor, which can be completed in a short time. It has the effect of being manufacturable.

Furthermore, the circulation of insulating oil is not impaired, and the cooling effect is equal to or greater than that of the conventional method.

Incidentally, in the above embodiment, several ring-shaped conductors 103 are replaced with the flat conductor 1.
04a and 104b are connected in parallel, and the interlinking part is a one-turn coil. However, it is also possible to make a loop with one solid conductor multiple times, and between the rings there is a circulation path for insulating oil as described above. By providing a gap, it is also possible to connect one end of the ring-shaped solid conductor to the flat conductor 104a (and the other end to the flat conductor 104b) to provide a primary coil with a plurality of turns at the interlinking portion.

As described above, according to the present invention, while having a cooling effect similar to or better than that of conventional oil-immersed current transformers,
It is possible to obtain an oil-immersed current transformer that reduces machining time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of an oil-filled current transformer according to the conventional structure O, FIG. 2 is a cross-sectional view showing a schematic structure of an oil-filled current transformer according to the present invention, and FIG. FIG. 2 is an enlarged partial perspective view of the main part of the figure, the joint between the flat coil and the ring-shaped solid conductor. 101... Annular iron core, 102... Secondary coil, 103... Annular solid conductor, 103'.
...stoppers 104a, 104b--
Flat conductor, 104 b'...notch, 105
...Insulation, 106...Shield tube, 1
07...Main insulation, 108...Pipe tube,
109...Tank, 110...Cap, 111...Insulating oil, 112...Nitrogen gas.

Claims (1)

[Claims] 1. A plurality of ring-shaped solid conductors arranged in parallel interlinking with a secondary coil wound around a ring-shaped core, and a lower end connected to both ends of the solid conductor and facing each other. A primary coil part is constituted by a pair of arranged flat conductors and a shield tube provided on the outer surface of this flat conductor, and between the pair of flat conductors of this primary coil part, An oil-immersed current transformer characterized in that an insulating oil circulation path is formed between a plurality of solid conductors and between a flat conductor and a seal half tube. 2. The oil-filled current transformer according to claim 1, wherein both ends of a plurality of ring-shaped solid conductors arranged in parallel are connected in parallel to a pair of flat conductors. 3. Claim 1, which is characterized in that a plurality of ring-shaped solid conductors arranged in parallel are connected in series so as to form several turns, and both ends thereof are connected to a pair of flat conductors. Oil-immersed current transformer as described in section.