JPH0311534B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to electromagnetic induction equipment,
In particular, the present invention relates to electromagnetic induction devices such as transformers and reactors that have improved insulation performance of electrostatic shielding plates used in electromagnetic induction devices such as transformers and reactors.

Electromagnetic induction equipment connected to the power transmission system is subject to abnormal voltages that change sharply due to lightning strikes, etc.
At this time, the windings of electromagnetic induction equipment generate complex potential oscillations determined by the applied voltage waveform, the inductance of the windings, and the stray capacitance between turns, between coils, and to the ground. insulation is threatened. The magnitude of this potential oscillation can be improved by increasing the series capacitance between turns of the winding or between coils, creating a so-called vibration-free winding that has a more uniform potential distribution over the entire length of the winding. can be formed. Therefore, in order to increase the series capacitance between windings at the line ends and neutral ends of the windings of electromagnetic induction equipment, metal foil tape is layered with insulating tape on a core made of insulating material. A winding electrostatic shielding plate is often provided.

Figure 1 is a perspective view showing the main body of a transformer, which is a conventional electromagnetic induction device, and Figure 2 is a line drawn from Figure 1.
FIG. In FIGS. 1 and 2, iron cores 1a and 1b have windows 101a and 101a, respectively.
01b. The low-voltage windings 2a to 2c and the high-voltage windings 3a and 3b are each formed in a ring shape, and are arranged alternately to form the windows 10 of the iron cores 1a and 1b.
1a and 101b. Each of the high voltage windings 3a and 3b is constructed as shown in FIG. 2, and is a line constructed by connecting a plurality of insulated rectangular copper wires in parallel and winding them in a ring shape multiple times, with one end connected to a line lead 4. It is composed of a first coil 301 which is a coil, one end of which is connected to the other end of the first coil 301, and a plurality of insulated rectangular copper wires, etc. are connected in parallel and wound multiple times in a stadium shape (mortar shape). A second coil 302, one end of which is connected to the other end of the second coil 302, and a third coil 303 configured in a ring shape, and one end of which is connected to the other end of the third coil 303, forming a stadium shape. A fourth coil 304 configured, one end connected to the other end of the fourth coil 304 and a fifth coil 305 configured in a ring shape, and one end connected to the other end of the fifth coil 305 and the other end. and a sixth coil 306 which is grounded and configured in an annular shape. Note that the number of coils is not limited to six, but can be any value. The electrostatic shielding plate 5 is formed into an annular shape, is provided on the windows 101a and 101b of the iron cores 1a and 1b, and is connected to the line lead 4 by a connecting lead 6. In addition,
The high voltage windings 3a and 3b are stage insulated windings, and the closer they are to the first coil 301, which is a line coin, the greater the insulation distance, so the first to fifth coils 301 to 305
As shown in FIG. 2, the overall cross-sectional shape of the first coil 301 is short and has a large space for the iron core 1a, and the sixth coil 306 has a long winding width for the iron core 1a.
The space between them is narrow and trapezoidal. Further, the low voltage windings 2a to 2c are composed of a coil group similar to the high voltage windings 3a and 3b.

3 is a plan view of the electrostatic shielding plate shown in FIG. 2, and FIG. 4 is a partial side sectional view taken along the line - in FIG. 3. In FIGS. 3 and 4, the core material 7 is formed of, for example, a press board made of an insulating material in an annular shape. A metal foil tape 8 made of aluminum or nickel silver, etc. and an insulating tape 9 are overlapped and wound around the core material 7 in a lap manner, and the metal foil tape 8 is connected to the connection lead 6.

Conventional electromagnetic induction equipment is configured as described above.
Since the metal foil tape 8 is thin, when the insulation class of the electromagnetic induction device increases, the electric field at the side edges of the metal foil tape 8 becomes high, and partial discharge occurs when an abnormal voltage occurs.
The drawback was that the dielectric strength of electromagnetic induction equipment decreased.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 is a partial side sectional view showing an embodiment of an electrostatic shielding plate used in an electromagnetic induction device according to the present invention. In the figure, the same parts as in FIG. 4 are given the same reference numerals. In FIG. 5, conductive tape 1
0 is a material such as carbon paper, which has a sheet resistivity (corresponding to the resistance between two opposing sides of a square member) that is larger than the sheet resistivity of the metal foil tape 8, and is a conventional insulating tape. It was used in place of 9. The area resistivity of the conductive tape 10 is determined by the magnitude of the eddy current in the metal foil tape 8 generated by the leakage magnetic flux shown by the dotted lines in FIG. Therefore, it is best to choose a value as small as possible without causing any obvious changes.

That is, the side edge of the metal foil tape 8 is connected to the adjacent metal foil tape 8 by the conductive tape 10.
The metal foil tape 8 is electrostatically short-circuited and eddy current insulated, thereby preventing partial discharge from occurring from the side edges of the metal foil tape 8. Note that the thickness of each tape is exaggerated compared to the actual thickness.

FIG. 6 is a partial side sectional view showing another embodiment of the electrostatic shielding plate used in the electromagnetic induction device according to the present invention. That is, in the embodiment shown in FIG. 6, the width of the conductive tape 10 is made wider than the width of the metal foil tape 8, and the conductive tape 10 is wound so as to protrude from one or both sides of the metal foil tape 8. This completely covers the side edges of the metal foil tape 8. With this configuration, the side edges of the metal foil tape 8 can be completely covered with the conductive tape 10, preventing concentration of the electric field and further increasing the effect of mitigating the electric field.

This invention is constructed as described above, and the conductive tape 10 having a higher area resistivity than the metal foil tape 8 is overlapped with the metal foil tape 8 and wound around the core material 7 in a lap manner, thereby preventing leakage of electromagnetic induction equipment. Low voltage windings 2a to 2c and high voltage windings 3a, 3 which are magnetic flux
Without changing the eddy current distribution of the metal foil tape 8 due to the wetting magnetic flux in b, the electric field concentration at the side edge of the metal foil tape 8 is alleviated, suppressing the occurrence of partial discharge when abnormal voltage attacks, and improving the performance of electromagnetic induction equipment. Insulator strength can be improved.

As described above, the present invention has the effect of suppressing the occurrence of partial discharge when an abnormal voltage occurs and improving the insulator strength.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the main body of a transformer, which is a conventional electromagnetic induction device, and Figure 2 is a line drawn from Figure 1.
3 is a plan view of the electrostatic shielding plate shown in FIG. 2, FIG. 4 is a partial side sectional view taken along the line - in FIG. 3, and FIG. 5 is an electromagnetic induction device according to the present invention. FIG. 6 is a partial side sectional view showing another embodiment of the electrostatic shielding plate used in the electromagnetic induction device according to the present invention. It is a diagram. In the figure, 1a and 1b are iron cores, 2a to 2c are low voltage windings, 3a and 3b are high voltage windings, 4 is a line lead, 5 is an electrostatic shielding plate, 6 is a connection lead, and 7
8 is a core material, 8 is a metal foil tape, and 10 is a conductive tape. Note that the same parts in each figure are given the same reference numerals.

Claims (1)

[Scope of Claims] 1. A coil formed by winding a conductor, and a static coil formed by wrapping a metal foil tape and a conductive tape over a core material made of an insulating material, which is placed in parallel with the coil, and winding the same in a lap manner. 1. An electromagnetic induction device comprising an electric conductor plate, wherein the conductive tape has a sheet resistivity greater than the sheet resistivity of the metal foil tape. 2. The electromagnetic induction device according to claim 1, wherein the conductive tape is made of carbon paper. 3. The width of the conductive tape is configured to be wider than the width of the metal foil tape, and the conductive tape is superimposed on the outside of the metal foil tape and protrudes from one side edge or both side edges of the metal foil tape, An electromagnetic induction device according to claim 1 or 2, which is wound around a core material.