JPS6011527B2 - Phase separation busbar connection box - Google Patents

Description

Detailed Description of the Invention This invention relates to a phase-separated bus connection box installed in a mini-flux-type phase-separated bus generator or transformer that is used as a power transmission line between a generator and a transformer in a power plant. The present invention relates to an improvement, and more specifically, to provide a phase-separated bus-bar connection box whose purpose is to suppress eddy currents due to interlinkage magnetic flux in the y-direction of the phase-separated bus-bar connection box and to suppress local temperature rises.

To explain with the figures, Fig. 1 is a front view of the transformer side terminal section of the mini-flux type phase separation bus bar installed between the generator and the transformer in a subordinate power plant, and Fig. 2 is a side view thereof. 3 shows each of the AA cross-sectional views of FIG. 2.

In the figure, the same reference numerals indicate the same members; 1 is the phase separation bus of the mini-flux section; 2 is the phase separation bus of the part outside the mini-flux section; 3 is a cylindrical IPB cover coaxial with the phase separation bus; 4 is a good conductor cover 5 is a rubber bellows, 6 is a flexible conductor, 7 is a bushing, 8 is a bushing mounting tube, 9 is a transformer, 10 is a phase separation bus connection box, 11 is a wind tunnel, 12 is a wind tunnel An arrow indicates the direction of flowing cooling air, 13 indicates an inspection manhole flange, 14 indicates a wind tunnel mounting flange, and 15 indicates a lid of the inspection manhole flange. In Figures 1 and 2, x, y
, z each represent the direction of the assumed orthogonal coordinate system.
The phase separation bus connection box 10 is electrically short-circuited to the bushing mounting tube 8 at one point in order to maintain the box body at ground potential. However, these conventional phase separation bus connection boxes 10 are attached to the end of the phase separation bus 2 in a portion away from the mini-flux section as described above, and as shown in FIG. 16, 17, and 18 are supplied to the transformer 9 via the phase separation bus 1 of the mini-flux part and the phase separation bus of the part outside the mini-flux part, via the flexible conductor 6 and the conductor of the bushing 7. In Although,
The length of the power transmission line between the generator and the transformer is generally several dozen, and the IPB cover 3 is a good conductor in the form of a cylinder coaxial with the phase separation bus 1 of the mini-flux section, and both ends are short-circuited. The phase separation busbars 1 and m of the mini-flux part from
The electromagnetic coupling of B cover 3 is very good, and bus currents 16, 17, 1 are applied to mB cover 3 due to electromagnetic transfer.
Currents 19, 20, which are approximately equal in magnitude and in opposite phase to 8,
21 flows.

Figure 4 shows this relationship in a vector diagram, where iu,,lv,,iw are the bus currents 16, 17 in Figure 3.
, 18, and i, lv2, and i represent mB cover currents 9, 20, and 21, respectively, and heart, lv
2, iw2 is the corresponding bus current iu,,lv,,lw,
, the magnitude is almost equal (and the phase is delayed). Originally, this IPB cover current 19, 20, 21
As a result, leakage magnetic flux in the power transmission line became extremely small, preventing damage to steel structures in buildings and communication lines, and this was the most important feature of the mini-flux type phase-separated busbar.

However, as is clear from FIGS. 1 to 3, at the transformer terminals outside the mini-flux section, the three-phase short circuit plate current 19 , 21 are superimposed and a strong magnetic field is formed in the phase separation bus connection box 101 in this part.This magnetic field causes eddy currents to be generated, resulting in a local temperature rise. FIG. 5 is an explanatory diagram showing the magnetic field near the phase separation bus connection box 10, and A in the figure is u, v.
, W phase each phase separation busbar connection box is shown in front view, and the opening is the fifth one.
In the C-C cross-sectional view of Figure A, C shows the interlinkage magnetic flux density due to the bus current outside the mini-flux section and the three-phase short longitudinal plate current, which was obtained at a certain moment under a typical bus current. This shows the magnetic flux entering and exiting in the direction of the paper (pine direction) perpendicular to the straight line DEFGHID at the opening of the figure, and the slight difference in the phase of the magnetic flux density can be classified as "outgoing" or "incoming" with respect to the box. It represents the maximum value of the vertical component of the interlinkage magnetic flux density of each part, and BMAX indicates the maximum value in the graph. As is clear from Figure C, the magnetic flux that intersects with the phase separation bus connection box is in the y direction (perpendicular to the plane formed by the phase bus at the connection).
The reason why the component becomes large is because the bus bar currents 16, 17, and 18 in the portions outside the mini-flux are due to the bus bar arrangement (Figure 3).
The magnetic field is superimposed by the three-phase short circuit plate current 19,2
1 (FIG. 3) is superimposed. Considering this for the transformer terminals, the region where the magnetic field in the y direction is strong is located below (
In other words, it is a region outside the mini-flux portion) and between the centers of the U-phase and W-phase generatrix lines. FIG. 6 is a perspective view of a phase separation bus connection box showing the flow of eddy current due to the conventional y-direction magnetic linkage. The phase separation bus connection box 10 has an interlinkage magnetic flux 22 in the y direction.
An electrical closed circuit is formed in the circuit, and an eddy current 23 flows in the circuit due to the electromotive force caused by the magnetic flux. This y
The eddy current 23 due to the interlinkage magnetic flux in the direction was the largest among the eddy currents flowing through the phase separation junction box. The present invention provides a phase-separated bus connection box for the purpose of effectively suppressing the above-mentioned eddy current caused by the largest interlinkage magnetic flux in the y direction and preventing a local temperature rise due to this. This is what I did.

FIG. 7 is a perspective view and a partial view of the phase-separated bus connection box of the present invention, showing an example in which the entire X-Z plane (i.e., manhole and wind tunnel mounting surface) of the phase-separated bus connection box is made of an insulator, FIG. 8 is a front view of a transformer side terminal portion of a phase separation bus bar showing an embodiment to which the present invention is applied.

The same reference numerals in the drawings indicate the same members, and the directions of the orthogonal coordinate system indicated by x, y, and z also indicate the same directions. 24, 27
Inspection manhole and wind tunnel 1 made of insulating material
1 side plate, 25 is the manhole cover, 26 is the flange part of the manhole, 28 is the flange part on the wind tunnel side, and these 25
, 26, and 28 are all made of an insulator.

29 is a metal side plate, and the side plates 24, 27, this metal side plate 29, the manhole cover 25, and the flange portion 26 are attached by bolting.

Further, the side plate 24 and the flange portion 26 as well as the side plate 27 and the flange portion 28 are fixed with adhesive. In the phase separation bus connection box 10 configured in this way, the electrical circuit of the eddy current for the interlinkage magnetic flux in the y direction is cut by insulators 24 to 28, as shown in the cross-sectional view taken along the line C-C in Figure 5. F-
Although the eddy current due to the magnetic flux in the portion corresponding to G, 1-D remains, it is much smaller than the eddy current 23 as shown in FIG.
It is a value.

That is, by cutting off large eddy currents, it is possible to easily and effectively suppress the local temperature rise in the phase separation bus connection box. FIG. 9 is a cutaway perspective view of another phase-separated busbar connection box, in which the same reference numerals represent the same members, and the directions of the orthogonal coordinate system indicated by x, y, and z also indicate the same directions.

In this embodiment, the electrical circuit for the magnetic flux in the y direction can be cut off even if the insulator 30 is inserted between the manhole or the window for the wind tunnel on the opposite side of the figure from this part to the rubber bellow mounting flange. This shows that the amount of eddy current can be reduced. FIG. 10 is a perspective view of another embodiment of the cylindrical phase-separated busbar connection box, in which the same reference numerals represent the same members, and the directions of the orthogonal coordinate system indicated by x, y, and z also indicate the same directions. There is.

The electrical circuit for the magnetic flux in the y direction is cut using curved electrical insulators 24 and 27, and the main eddy current can be cut off using the same principle as shown in FIG. In the present invention, by using, for example, an epoxy resin molded product as the insulator, a phase-separated busbar connection box with sufficient strength and durability can be obtained.

Further, the present invention may be used in a power transmission line between a generator and a transformer having two bushings for each phase in a power plant. In this way, when this invention is used, the electric circuit viewed from the y direction is cut by an insulator, so the eddy current in the y direction component, which is a large part of the interlinkage magnetic flux, can be suppressed, and local temperature rises can be prevented. It is possible to demonstrate a certain effect.

[Brief explanation of the drawing]

Figure 1 is a front view of the transformer side terminal of a mini-flux type phase separation bus between the generator and the generator in a conventional power plant;
The figure is a side view of Figure 1, Figure 3 is a sectional view along A-A of Figure 2,
Figure 4 is a vector diagram of current, Figure 5 is a distribution diagram of the vertical component of magnetic flux density interlinking with the V-phase separation bus junction box and its C-C cross section, and Figure 6 is a diagram of eddy current due to magnetic flux linkage in the y direction. FIG. 7 is a perspective view of the phase separation bus connection box and its constituent parts; FIG. 8 is a front view showing an embodiment of the present invention using FIG. 7; FIG. 9 is a cutaway perspective view showing another example of the invention, and FIG. 10 is a perspective view showing another example of the invention. The x, y, and z arrows in FIGS. 1 to 10, excluding FIG. 4, indicate the direction of each component of the assumed orthogonal coordinate system, and are the same in each figure. 9 is a transformer, 1 river phase separation bus connection box, 24 ~
28 and 3 rivers insulators. Mizo 1 Kyou 2 Fig. 3 Kyo 4 Fig. 5 Fig. 6 K7 4 Huan 8 Fig. 9 Fig. 10

Claims (1)

[Scope of Claims] 1. In a phase-separated bus connection box at the end of a generator or transformer in which the three-phase busbars of a power transmission line between a generator and a transformer in a power plant are arranged so as to form a plane, All or one of the side plates facing the y-direction of the phase-separated bus-bar junction box are so arranged as to block the flow path of eddy current due to interlinkage magnetic flux in the y-direction of the phase-separated bus-bar junction box (direction perpendicular to the plane formed by the busbars). 1. A phase-separated bus connection box characterized in that a portion thereof is made of an electrical insulator. 2. The phase-separated busbar connection box according to claim 1, which is used in a power transmission line between a generator and a transformer having two bushings for each phase in a power plant.