KR100915653B1 - Current measuring device of high voltage instrument insulated using electromagnetic induction - Google Patents

Abstract

The present invention relates to a current transformer (Current Transformer) for measuring the conduction current in the air-insulated high voltage equipment (breaker, switchgear) installed on the high-voltage distribution line, applying the electromagnetic induction phenomenon to the current transformer (CT) and the conduction line (booth bar) The present invention relates to a fixed non-contact current measuring device capable of measuring the energized current by separating the current. In general, the current measurement of the air insulated high voltage equipment is performed by inserting a conducting wire (enclosed) in the U shape inside the epoxy support insulator (insulation support) installed on the upper part of the high voltage equipment frame, and winding the winding around the stratified core on the U-shaped line. The current transformer system used and the current transformer insulated by the other epoxy which an electricity supply line penetrates on the epoxy support insulator are performed. This conventional method has a weak point of partial discharge due to the insulation distance between the high-voltage current transformer and the current transformer and the minute click of the epoxy material, and may cause a grounding accident due to the partial discharge destruction of the epoxy material for a long time. According to the present invention devised to solve these disadvantages, it is possible to separate and install the current transformer and the current-carrying wire, so that sufficient insulation interval and partial discharge separation distance can be secured to secure the safety of the high-voltage device, and the transformer can be configured only by the coil without the core. Therefore, it is possible to expect the safe and efficient operation of the air insulated high voltage equipment by securing the precision and economics of the current characteristic curve and preventing the enlargement of support insulators.

Description

Current measuring device of high voltage instrument insulated using electromagnetic induction}

The present invention relates to a fixed contactless current measuring device capable of measuring the current carrying current by separating the current transformer (CT) and the conducting wire (booth bar) by applying the electromagnetic induction phenomenon.

Compact high voltage equipment installed on the high voltage distribution line. Insulation current measurement and insulation method of airborne high voltage equipment (breaker, switchgear) in the situation of moving from high voltage equipment adopting the air insulation method to the insulation oil insulation method under the tendency of light weight and gathering in the distribution room, not on the roof or outdoors. The technology is required to be equipped with safety, precision, and economic feasibility in various factories and consumers using high voltage equipment, and the technology of high voltage equipment and precise conduction current measuring device of the device with high insulation is required to secure it. .

Figure 1 shows the insulation and current measurement device between the phase and the ground of the conventional air-insulated high voltage equipment.

The current measurement of the conventional general air insulation high voltage equipment, as shown in Figs. 1a and 1b, the conduction wire (enclosed) 12 inside the epoxy support insulator (insulation support) 11 installed on the high voltage equipment frame (10) After inserting in a U-shape, a current-carrying current transformer 13 wound around a stratified core in the center of the U-shaped line, and a conductive line 22 penetrates the epoxy support insulator 21 as shown in FIG. 1C. The method of constructing and performing the current transformer 23 insulated by the other epoxy used is used.

This conventional method has a weak point of partial discharge due to the insulation distance between the high-voltage current transformer and the current transformer and the minute click of the epoxy material, and may cause a grounding accident due to the partial discharge destruction of the epoxy material for a long time.

Epoxy support insulators (11) and (21) with current transformers are enlarged in volume to secure an insulation distance and a partial discharge safety distance, and the striae core (core) of the striae core in the heat treatment process of the support insulators (11) (21). Due to material modification, the current characteristic curves of the current transformers 13 and 23 may change. In addition, in consideration of the hypertrophy of the support insulators 11 and 21, the partial discharge may be vulnerable due to the distance limit between the conducting line 12, the straight conducting line 22, and the current transformers 13 and 23.

When a current transformer impregnated with a separate epoxy is installed in the place where the conductive lines 12 and 22 penetrate the epoxy support insulators 11 and 21, the current lines 12 and 22 and the current transformers 13 and 23 ), It may be vulnerable to partial discharge of the support insulator (11, 21) and the current transformer (13, 23). In addition, the current characteristic curves of the current transformers 13 and 23 may change due to the material modification of the core in the heat treatment process after the epoxy current impregnation of the current transformers 13 and 23.

Even if the current error due to the deformation of the current transformer curve is compensated for in the controller, each current transformer error may err in precision.

Partial discharge destruction can cause noise and grounding accidents, and grounding accidents can cause fatal damage to high-voltage equipment, which makes it difficult to maintain stability and maintain reliability.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, to ensure the safety of the high-voltage equipment by separating the current transformer and the support insulator to ensure sufficient insulation distance and partial discharge separation distance, Insulation to support energized wire (boost bar) by constructing transformer with only coil without core to secure precision and economic efficiency of current characteristic curve, and to secure economic efficiency by preventing bloat of supporting insulator by applying electromagnetic induction phenomenon Maintain sufficient insulation distance in the support insulator to create an independent space insulated by air, and when it is separated and installed in the space, when current is applied to the electricity supply line, the magnetic field caused by the conduction current passes through the support insulator which is nonmagnetic and induces electromagnetic induction to the coil. If a phenomenon occurs and a secondary current proportional to the conduction current flows out, the flowed current is amplified and the conduction current flows. It is an object of the present invention to provide a fixed non-contact current measuring device for measuring.

The present invention is applied to the electromagnetic induction phenomenon to separate the current transformer and the conducting wire to ensure the safety secured insulation, and to manufacture the current transformer with only a coil without a core to secure the precision by eliminating the deformation of the core material and the simplicity of the current transformer and the support insulator The economy was also secured.

The present invention for achieving the above object, the insulating support insulator is formed on the frame to form an insulated independent space; A conducting wire (bus bar) inserted into the insulating support insulator; A current transformer configured in the busbar to measure current; A bobbin shield for shielding an electric field due to the high voltage of the busbar; Current transformer external magnetic field shielding device to reduce the indirect induction electromotive force and shield the magnetic field, such as the peripheral transformer; And a current transformer noise filter for excluding effects other than current components.

The busbar 301 of the present invention is characterized by having a straight line shape.

The bobbin of the current transformer of the present invention is characterized by consisting of only a coil without a core.

The bobbin and the magnetic field shield of the current transformer of the present invention are characterized in that they are integrated.

In the fixed non-contact current measuring device of the present invention, an alternating magnetic field proportional to the current when the current is applied to the high voltage equipment conducting line is formed in accordance with the law of the Enpern-Thread screw, and the magnetic field is an insulating support insulator supporting the conducting line. The induction electromotive force due to electromagnetic induction phenomenon is formed in accordance with the law of Lenz, i.e., Lentz's law. The output will be converted to.

As described above, according to the current measurement device of the air insulated high voltage device applying the electromagnetic induction phenomenon of the present invention, since the current transformer and the conducting line can be separated and installed, sufficient insulation interval and partial discharge separation distance can be secured to improve the safety of the high voltage device. As it is possible to construct a current transformer with only a coil without a core, it is possible to secure precision and economics of the current characteristic curve, and to secure economical efficiency by preventing bloat of support insulators, so that safe and efficient operation of the air insulated high voltage equipment can be expected.

Although the present invention has described a technique of using a current transformer as a current measuring device composed of only a coil without a core in a specific embodiment, the present invention is not limited thereto, and modifications and variations may be made within the scope of the technical idea of the present invention. Of course it is possible. In addition, the technology of the present invention can be applied to low pressure equipment as well as high pressure equipment.

1 is a device for measuring insulation and current between a phase and a ground of a conventional air insulation high voltage device.

Figure 1a is an external view of the current transformer installation for the epoxy insulation support insulator,

Figure 1b is a detailed view of the internal installation of Figure 1a.

Figure 1c is a detailed view of the current transformer installation for the powder-type epoxy insulation support insulator.

2 is a view to help understand the current measuring device using the electromagnetic induction phenomenon according to an embodiment of the present invention,

2a is an external view;

2b is an installation diagram,

Figure 2c is a detailed structural diagram of the portion A of Figure 2b,

3 is a block diagram of a current measuring device using the electromagnetic induction phenomenon according to an embodiment of the present invention.

Figure 4 is a triangular view for explaining the principle of the electromagnetic induction phenomenon according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

101: busbar (electric wire) 111: insulation support insulator

304,305,306: Current transformer 307: Noise filter

308: bobbin shield 309: magnetic field shield

310: shielded wire

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view to help understand the current measuring device using the electromagnetic induction phenomenon according to an embodiment of the present invention, FIG. 3 is a block diagram of a current measuring device using the electromagnetic induction phenomenon according to an embodiment of the present invention.

As shown in FIGS. 2 and 3, when a current I1 is energized in a straight bus bar 301 inside the support insulator (insulation support) 111 installed on the frame 100, a magnetic field proportional to the size of I1 The magnetic field is formed around the busbar 301 according to Fernner's law, and the magnetic field generates the main induced electromotive force in the current transformer 304 based on the electromagnetic induction phenomenon, and induces the indirect induced electromotive force in the peripheral current transformers 305 and 306. Let's do it.

In the same principle, when the current I2 is energized in the busbar 302, a magnetic field proportional to the size of I2 is formed around the busbar 302, and the magnetic field generates a main induced electromotive force in the current transformer 305, and the peripheral current transformer (304) (306) also induces indirect electromotive force.

In the same principle, when the current I3 is energized in the busbar 303, a magnetic field proportional to the size of I3 is formed around the busbar 303, and the magnetic field generates a main induced electromotive force in the current transformer 306. Indirect induced electromotive force is also generated in the current transformers 305 and 304.

When the three-phase currents I1, I2, and I3 are simultaneously energized while maintaining a phase angle of 120 °, the current transformer 305 is only affected by the current I2 since the effects of the preceding current I1 and the following current I3 cancel each other out.

Since the difference between the main induced electromotive force and the indirect induced electromotive force is large according to the following equation, each main induced electromotive force can be taken as the basis of the current conversion value within the tolerance range.

In FIG. 4, the magnitude of induced electromotive force by the current I is proportional to the rate of change of the magnetic flux over time, and the magnetic flux (magnetic flux) passing through the coil wound N times is the time. While Induced electromotive force E generated when changed by is equal to Equation 1 below based on Faraday's law.

(Unit: V)

In Equation 1, the number of turns N is a fixed variable and a magnetic flux that is a variable variable. Is based on the Ampere's law.

In Equation 2, the coil cross-sectional area A is a fixed variable, and the variable B , the magnetic field B, is expressed by Equation 3 below based on the Enfer law.

( Is a constant, Silver street)

Thus, the induced electromotive force E is of the coil energization current I, number of turns N, the cross-sectional area A, A Proportional to the distance between the live line and the current transformer It is inversely proportional to.

In the case where the current I is energized in FIG. 4, the main induced electromotive force E induced in the current transformer “ga” having the number of turns N , the coil cross-sectional area A, and the right-angle distance h becomes as follows.

(120: 60Hz full wave rectification T = 1 / f * 2)

Also each , The indirect induced electromotive force e induced in the current transformer "b" having a distance r is expressed by Equation 5 below.

Where h and r are largely different and also Since the value of is small, the value of e is calculated within the tolerance of the E value in Equations 4 and 5, and the influence of the indirect induced electromotive force can be ignored.

Based on the principle of the above equations, when the three-phase currents I1, I2, and I3 are simultaneously energized while maintaining a phase angle of 120 °, current transformers 304, 305, 306 having a winding number N and a coil cross-sectional area A are shown. Induced electromotive force induced at is formed by the current transformer 304 at I1, the current transformer 305 at I2, and the current transformer 306 at I3, amplifying the value of the current transformer 304 by the amplifier 311, and converting the value. The current of I1 may be measured by converting the current into a calculator 312, and the current of each phase may be measured in the same manner.

The electric field due to the high voltage of the busbars 301, 302, and 303 is grounded and shielded by the bobbin shield 308, and the indirect induction electromotive force and the magnetic field such as a peripheral transformer are shielded by the external magnetic field shield 309. The noise filter 307 is installed in each of the current transformers 304, 305, and 306 so as to exclude an influence other than the current component in the current transformer, and the shield wire 310 is used to increase the precision to measure the precise current. A device capable of doing so can be provided.

At this time, the current transformer 304, 305, 306 bobbin and the magnetic field shield 309 is manufactured integrally.

In FIG. 2C, reference numeral 112 denotes an insertion hole into which an insulating support bolt 114 used to fix the current transformers 304, 305 and 306 to the insulating support insulator 111 is inserted. It represents.

Claims (4)

An insulation support insulator 111 installed on the frame 100 to form an insulated independent space; A conducting wire (bus bar) 301 disposed on the insulation support insulator 111; Is installed inside the insulating support insulator 111 supporting the bus bar 301, the magnetic field formed around the bus bar 301 generates an induced electromotive force by the electromagnetic induction phenomenon to measure the current accordingly Current transformers 304, 305, 306 installed in a lower portion spaced apart from the busbars 301; A bobbin shield 308 for shielding an electric field due to the high voltage of the bus bar 301; A current transformer external magnetic field shield device 309 for reducing indirect induction electromotive force and shielding a magnetic field such as a peripheral transformer; And Air current insulated high voltage equipment current measuring device applied to the electromagnetic induction phenomenon characterized in that it comprises a current transformer noise filter (307) for excluding effects other than the current component. 2. The apparatus of claim 1, wherein the bus bar 301 has a linear shape. The apparatus of claim 1, wherein the bobbin of the current transformer (304, 305, 306) is composed of only a coil without a core. The apparatus of claim 1, wherein the bobbins of the current transformer and the magnetic field shielding device are integrally formed.