JPH1066212A - Three-phase phase separation bus line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a V-phase terminal adapter from having harmful heat and provide easy installation and higher reliability, by setting the thickness of the middle phase of a three-phase isolation plate, which is inserted between the terminal adapter and a three-phase short-circuit plate and isolates both of them, thicker than those of end phases. SOLUTION: The thickness of insulation plate 12b at V-phase of its middle phase is set at about twice as large as those of isolation plates 12a, 12c at Uphase and W-phase of their end phases out of isolation plates 12a, 12b, 12c inserted between a three-phase short-circuit plate 5 and the flange 15 of a terminal adapter 10, and a difference in thickness between them is larger than the thickness of the flange 15. The electric current flowing into the three-phase short-circuit plate 5 from respective phase bus line housing 4 concentrates near the middle of the three-phase short- circuit plate 5, and electric current around V-phase increases. However, the insulation plate 12b at V-phase is thicker than the insulation plates 12a, 12c at other phases, therefore, a distance between the three-phase short-circuit plate 5 to the flange 15 of the terminal adapter 10 at V-phase increases, and a proximity effect from the electric current of the three-phase short-circuit plate 5 decreases. It is thus possible to restrain heat generation around the flange 15 at V-phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase phase-separated bus connected to electric equipment such as a three-phase generator.

[0002]

2. Description of the Related Art FIG. 3 shows, for example, JP-B-53-26663.
FIG. 1 is a perspective view of a conventional three-phase phase-separated bus shown in Japanese Unexamined Patent Application Publication No. 2-46110 and the like, and has a structure called a mini-flux structure. In the figure, 1 is a three-phase generator terminal, 2 is a three-phase main transformer, 3 is a three-phase bus conductor connecting the generator terminal 1 and the main transformer 2, and 4 is 3
A three-phase bus jacket 5 surrounding each of the phase bus conductors is a three-phase short-circuiting plate connecting the three phases to each other at both ends of the bus sheath 4.

FIG. 4 is a side view showing the portion E of FIG. 3 in detail. In FIG. 4, only one phase is shown, but the same applies to all three phases. In the figure, 7 is a terminal conductor of the generator, 8 is a flexible joint for connecting the terminal conductor 7 and the busbar conductor 3,
Reference numeral 9 denotes a seal cover that covers the terminal conductor 7 of each phase, and a terminal adapter that covers the end of the bus conductor 3 of each phase, and an elastic rubber cover 11 that absorbs installation errors and the like. Cover 9 and terminal adapter 1 through
0 is connected. Reference numeral 12 denotes an insulating plate inserted between the three-phase short-circuit plate 5 and the terminal adapter 10, and the three-phase short-circuit plate 5 and the terminal adapter 10 are mechanically connected via the insulating plate 12. However, they are electrically insulated from each other by the insulating plate 12.

Next, the operation will be described. Since the three phases are connected to each other by the three-phase short-circuiting plate 5 at both ends of the busbar jacket 4, when a current flows through each phase bus conductor 3, a current of the same magnitude and in the opposite direction is applied to each phase busbar. It flows to the jacket 4. In each phase, the current flowing through the bus conductor 3 and the current flowing through the bus jacket 4 cancel each other, so that almost no magnetic flux leaks outside the bus jacket 4. Therefore, heat generation due to leakage magnetic flux hardly occurs. The above description is for the portion of the mini-flux structure (the portion between the two three-phase short-circuit plates 5) indicated by the arrow Y in FIG. 4, and the connection portion with another device (here, the generator) indicated by the arrow X. Has a non-mini-flux structure.

[0005] The effect of the leakage flux in the non-mini-flux portion and the structure to cope with it will be described with reference to FIG. In the range indicated by X in FIG. 4, the leakage flux 13 from the current flowing through each phase bus conductor 3 and the magnetic flux 14 from the current of the three-phase short-circuit plate 5 are superimposed, and the terminal adapter is compared with the mini-flux structure. The magnetic flux entering 10 is more than ten times as large (the magnetic fluxes 13 and 14 are shown only for the V phase). Such magnetic fluxes 13 and 14 cause an eddy current loss and a hysteresis loss in the terminal adapter 10 and generate heat. In order to suppress the temperature rise due to this heat generation to a certain value or less, in addition to measures for preventing hysteresis loss by using a non-magnetic material (for example, stainless steel or aluminum) for the terminal adapter 10, the terminal adapter 10 is divided by an insulator. There is a measure to reduce heat generation by reducing the eddy current by reducing the area of each conductor plate receiving the magnetic fluxes 13 and 14.

[0006] In addition to these measures, the following measures are taken. Referring to FIG. 6, a flange 15 is provided at an end of the terminal adapter 10, and at a connection portion between the terminal adapter 10 and the three-phase short-circuit plate 5,
Both are connected using bolts 16. A loop (closed circuit connected by conductors) through which the eddy current flows via these bolts 16 is formed, and between the three-phase short-circuit plate 5 and the terminal adapter 10 to prevent local overheating. The insulating plate 12 is inserted into the base plate, and the bolt 16 is insulated. In this manner, the electrical connection between the terminal adapter 10 and the three-phase short-circuit plate 5 is cut off, and no eddy current loop is formed.

The inter-phase distance (inter-phase pitch) in the generator terminal 1 is determined by the generator capacity, while the outer diameters of the busbar jacket 4 and the terminal adapter 10 are determined by the current flowing through the busbar conductor 3. The clearance between adjacent phases of the bus bar jacket 4 and the terminal adapter 10 is determined by the generator capacity. Usually, it is difficult to make this clearance large, and in many cases, it becomes a small value.

[0008]

Since the conventional phase-separated bus is constructed as described above, the current flowing through the bus sheath 4 flows into the three-phase short-circuit plate 5. At this time, current gathers near the center of the three-phase short-circuit plate 5, that is, near the V-phase (middle phase).
Due to the proximity effect from the current flowing through the three-phase short-circuit plate 5, the flange 15 of the terminal adapter 10 having a non-mini-flux structure is formed.
In the vicinity, a current in the opposite direction to the current of the three-phase short-circuit plate 5 flows,
This current is also greater in the V-phase than in the U-phase and W-phase, and there is a problem that the temperature rise near the V-phase flange 15 is large. In the case of a large current such as an energizing current of 10 to 40 KA, the temperature rise becomes a problem.

Furthermore, depending on the current range of the electric device (generator), the clearance between the phases of the terminal adapter 10 becomes very narrow due to the relationship between the phase pitch and the jacket diameter. In consideration of the manufacturing error and the installation error of the terminal adapter 10, this clearance is required, for example, about 20 to 30 mm. However, in some cases, only a few mm can be taken due to design, and it may be difficult to secure the clearance after installation. . If the jackets make electrical contact between the phases, they generate heat due to the current flowing through the loop formed by the contact, so that the contact portions are melted, the coating film of the terminal adapter 10 is damaged, and the terminals of the electrical equipment are damaged. There were problems such as burning.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, suppresses harmful heat generation in a thermally severe V-phase terminal adapter, and is easy to install and highly reliable. The purpose is to obtain a three-phase phase-separated bus.

[0011]

The three-phase phase-separated bus according to the present invention is inserted between the terminal adapter and the three-phase short-circuiting plate to form a middle-phase three-phase insulating plate. The plate thickness is larger than the plate thickness of the terminal phase. Further, the difference in plate thickness between the middle phase and the end phase of the insulating plate is made larger than the thickness of the flange of the terminal adapter.

[0012]

FIG. 1 is a front view partially showing a three-phase phase separation bus according to an embodiment of the present invention.
4 shows a connection portion with a generator which is a phase electric device. Portions other than those shown are the same as those in the conventional example shown in FIG. FIG. 2 is a front view showing the portion F of FIG. 1 in detail. In these figures, 1 is a three-phase generator terminal, 7 is a three-phase generator terminal conductor, 3 is a three-phase bus conductor, and 8 is a flexible connection between the terminal conductor 7 and the bus conductor 3. The joint 9 is the generator terminal 1
And a seal cover as a three-phase terminal covering that surrounds the terminal conductors 7 of each phase, a three-phase bus covering that surrounds the bus conductors 3 of each phase, and a part 5 that is not illustrated. Bus bar jacket 4
A three-phase short-circuit plate 10 for connecting the three phases to each other at both ends is provided between the seal cover 9 for each phase and the busbar jacket 4 and is a terminal adapter that covers the end of the busbar conductor 3. Seal cover 9 via elastic rubber cover 11 that absorbs
And the terminal unit adapter 10 are connected. The terminal part adapter 10 is provided with a flange 15 at the end on the busbar jacket 4 side.

Reference numerals 12a, 12b, and 12c denote insulating plates inserted between the three-phase short-circuit plate 5 and the flange 15 of the terminal adapter 10, and the U-phase and W-phase insulating plates 12a,
The thickness of the middle phase V-phase insulating plate 12b is about twice as thick as that of the middle phase 12c, and the difference in the thickness is larger than the thickness of the flange 15. The flange 15 of the terminal adapter 10 and the three-phase short-circuit plate 5
They are connected by bolts 16 via a, 12b and 12c. Here, the bolt 16 is insulated and attached (for example, the bolt 16 is covered with an insulating sleeve (not shown), and the bolt head and nut are tightened via an insulating washer (not shown)). Also, the insulating plates 12a, 12b, 12c
The length of the terminal adapter 10 is U-phase,
The V phase is shorter than the W phase. The positional relationship between the three-phase flanges 15 is such that the lower surface of the V-phase flange 15 is higher (ie, closer to the generator side) than the upper surfaces of the U-phase and W-phase flanges 15 in the figure.

Next, the operation will be described. The current flowing into the three-phase short-circuit plate 5 from each phase bus sheath 4 is
, Ie, the current concentrated near the V-phase, that is, the current near the V-phase increases. However, since the V-phase insulating plate 12b is thicker than the other-phase insulating plates 12a and 12c,
The distance from the three-phase short-circuit plate 5 to the flange 15 of the V-phase terminal adapter 10 is large, so that the proximity effect from the current of the three-phase short-circuit plate 5 is reduced, and heat generation near the V-phase flange 15 is suppressed. .

If the clearance between the flanges 15 of each phase is very small in design, adjacent phases may abut each other depending on manufacturing errors or installation errors. Even in such a case, the U-phase and W-phase flanges 15
Are in contact with the V-phase insulating plate 12b, and the flanges 15 are not in contact with each other. Therefore, since there is no electrical connection, no eddy current loop is formed.

[0016]

As described above, according to the present invention, the thickness of the medium phase of the three-phase insulating plate inserted between the terminal adapter and the three-phase short-circuiting plate to insulate them from each other is reduced. The thickness of the three-phase short-circuit plate is reduced so that the proximity effect from the vicinity of the middle phase where the current of the three-phase short-circuit plate is concentrated is reduced, and the heat generated by the eddy current in the middle phase of the terminal adapter is suppressed. Further, by configuring the thickness difference between the middle phase and the end phase of the insulating plate to be larger than the thickness of the flange of the terminal part adapter, when the clearance between the respective phases is very small, it is manufactured. Even if adjacent phases come into contact with each other due to an error or an installation error, the flanges do not come into contact with each other, so that an eddy current loop which causes overheating is not formed, so that installation is easy and reliability is improved.

[Brief description of the drawings]

FIG. 1 is a front view partially showing a three-phase phase separation bus according to an embodiment of the present invention.

FIG. 2 is a front view of a portion F shown in FIG.

FIG. 3 is a perspective view showing a conventional three-phase phase separation bus.

FIG. 4 is a side view of a portion E shown in FIG.

FIG. 5 is a front view partially showing a conventional three-phase phase separation bus.

6 is a front view showing the periphery of the insulating plate 12 shown in FIG.

[Description of Signs] 3 bus conductors, 4 bus sheaths, 5 three-phase short circuit board, 7 terminal conductors, 9 seal cover, 10 terminal adapter,
12a, 12b, 12c Insulating plate, 15 flange.

Claims (2)

[Claims] 1. A three-phase bus conductor connected to a three-phase terminal conductor of a three-phase electrical device, a three-phase bus jacket surrounding each of the three-phase bus conductors, and both ends of the bus sheath. A three-phase short-circuiting plate for connecting the three phases to each other, provided between the three-phase terminal part jacket surrounding the three-phase terminal part conductors of the three-phase electrical device and the three-phase bus bar jacket, respectively; A three-phase terminal adapter having a flange at an end on the busbar jacket side, and a three-phase insulating plate inserted between the terminal adapter and the three-phase short-circuit plate to electrically insulate the two. 3. The three-phase phase separation bus according to claim 1, wherein the thickness of the three-phase middle phase of the insulating plate is greater than the thickness of the end phase. 2. The three-phase phase separation bus according to claim 1, wherein a difference in plate thickness between the middle phase and the end phase of the insulating plate is larger than the thickness of the flange of the terminal adapter.