KR101555233B1 - Broadband sensor for detecting partial discharge of pole transformer - Google Patents

Abstract

The present invention relates to a broadband sensor for detecting partial discharge of a pole transformer. The broadband sensor for detecting partial discharge of a pole transformer, which detects a radiation electromagnetic wave caused by partial discharged of the pole transformer, comprises: an upper cone having a section becoming narrower toward the upper part; a lower cone having an upper surface in contact with a lower surface of the upper cone and having a section becoming narrower toward the lower part thereof; a grounding plate arranged on a lower part of the lower cone and having a through-hole; a plurality of conductive plates connected in a vertical direction between a part of the external surface of the lower cone and an upper surface of the grounding plate and arranged in a circumferential direction of the lower cone; and a coaxial cable forming a coaxial track on a lower part of the grounding plate, allowing an interior conductor to be connected to a vertex of the lower cone through the through-hole, and allowing an exterior conductor to be connected to the grounding plate. According to the present invention, the radiation electromagnetic wave radiated to the exterior of the pole transformer by a partial discharge of the interior of the pole transformer can be detected with highly sensitive broadband characteristics, thereby increasing reliability in diagnosing a fault.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a broadband sensor for detecting a partial discharge of a pillar-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadband sensor for detecting partial discharge of a pillar transformer, and more particularly, to a broadband sensor for detecting partial discharge of a pillar transformer for detecting radiated electromagnetic waves due to partial discharge of a pillar transformer.

Conventionally, there is a technique using an ultra high frequency (UHF) sensor in a gas insulated switchgear (GIS) as an insulation diagnosis using radiation electromagnetic waves. This UHF technique can predict the insulation diagnosis inside the GIS by detecting electromagnetic waves and ultrasonic waves due to the micro discharge generated by the conductive particles introduced in the foreign matter, repair and assembly inside the gas insulated switchgear. However, when the UHF sensor is mounted inside the GIS, a reflection loss of about -4 dB occurs. Therefore, there is a limit in locating the partial discharge and grasping the cause of the failure in detail.

In general, the failure of a power plant to which a high voltage is applied is closely related to insulation. In general, the pillar transformer operates in a high voltage environment of 22.9 kV, and the insulation diagnosis of the device is essential.

Since insulation failure and dielectric breakdown go through partial discharge, one of the effective methods for insulation diagnosis is to detect partial discharge. Partial discharge due to insulation degradation is accompanied by the generation of heat, light, sound, chemical reaction, and electromagnetic wave as well as its generation. Therefore, the current insulation transformer insulator deterioration and insulation diagnosis techniques use heat, sound, and chemical reaction.

However, the reliability of fault diagnosis is lowered and it takes a long time to judge the fault diagnosis as compared with the diagnosis technique using radiating electromagnetic wave, such as infrared camera, ultrasonic wave, and gas analysis method.

Up to now, a method of detecting a partial discharge of a pillar transformer using a radiated electromagnetic wave has not been used. This is because the external structure of the pillar transformer is composed of a closed conductor, so that the electromagnetic wave is not emitted to the outside and the installation position (about 10 m) is relatively high.

However, since the pillar transformer can radiate electromagnetic waves through some parts connected to a cylindrical type outer conductor, it is necessary to develop an antenna which is a high-sensitivity broadband sensor capable of measuring radiated electromagnetic waves from the outside of the pillar transformer, There is a need to increase the reliability of the apparatus.

The technology that becomes the background of the present invention is disclosed in Korean Patent Laid-Open Publication No. 2013-0052832 (published on May 23, 2013).

An object of the present invention is to provide a broadband sensor for detecting a partial discharge of a pillar transformer capable of detecting radiated electromagnetic waves radiated to the outside of a pillar transformer due to partial discharge inside a pillar transformer with high sensitivity and a wide band characteristic.

The present invention relates to a broadband sensor for detecting partial discharge of a pneumatic transformer for detecting radiated electromagnetic waves caused by partial discharge of a pillar transformer, comprising: an upper cone having a section narrowed toward the upper part; And a grounding plate disposed at a lower portion of the lower cone and having a through hole, wherein the grounding plate is vertically connected between a part of an outer surface of the lower cone and an upper surface of the grounding plate, And a coaxial line is formed at a lower portion of the ground plate and an inner conductor is connected to a vertex of the lower cone through the through hole and an outer conductor is connected to the ground plate A broadband sensor for partial discharge detection of a pillar transformer including a coaxial cable is provided.

Here, the conductive plate has a triangular shape, and a portion corresponding to the first side of the triangle is in contact with a part of the outer surface of the lower cone along the direction of the busbars, wherein the first side is shorter than the length of the busbars , The first vertex portion facing the first side may be in contact with the upper surface of the ground plate.

The conductor plate may be formed such that the first side is formed to have a predetermined length along the direction of the busbars starting from the upper edge of the lower cone and connects the second vertex corresponding to the upper edge to the first vertex And the second side may be perpendicular to the ground plate.

In addition, the conductive plates may be arranged in a pair facing each other with respect to the circumferential direction of the lower cone.

The wide-band sensor for detecting the partial discharge of the pillar-shaped transformer may further include: a cylindrical ferrite disposed to surround the outside of the coaxial cable; and a ferrite including the coaxial cable and the ferrite, And a connector which is connected to the other end of the coaxial cable through a central portion of the cap portion and is connectable to an external measuring instrument, may further comprise a housing coupled to the lower surface of the housing, a cap portion covering the other end of the housing, .

According to the broadband sensor for detecting the partial discharge of the pillar transformer according to the present invention, the radiated electromagnetic wave radiated to the outside of the pillar transformer due to the partial discharge inside the pillar transformer can be detected with high sensitivity and wide band characteristics, have. In addition, the reflection loss characteristic is greatly improved compared to the conventional UHF sensor, so that it can be utilized not only for the partial discharge detection of the pillar transformer, but also as a sensor for fault diagnosis of power distribution and power facilities.

1 is a sectional view of a broadband sensor for detecting partial discharge of a pillar transformer according to an embodiment of the present invention.
FIG. 2 is a perspective view of a wide band sensor when a = 0 in FIG.
Fig. 3 shows an example of the configuration of the conductive plate shown in Fig.
FIG. 4 shows the frequency characteristics of the reflection loss when the triangular conductor plate does not exist in FIG.
FIG. 5 shows the frequency characteristics of the return loss when the number of triangular conductor plates is taken as a parameter in FIG.
Fig. 6 shows the frequency characteristics of the return loss when a, which is related to the position of the triangular conductor plate in Fig. 2, is used as a parameter.
Fig. 7 shows the frequency characteristics of the reflection loss when w, which is related to the width of the triangular conductor plate in Fig. 2, is used as a parameter.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

The present invention relates to a broadband sensor for detecting a partial discharge of a pillar transformer, and provides an antenna sensor of high sensitivity and wide band characteristics capable of detecting and measuring electromagnetic waves radiated to the outside of a pillar transformer when a partial discharge occurs in a pillar transformer.

In order to measure the electromagnetic wave generated inside the pillar transformer from the outside of the pillar transformer, a condition of high sensitivity and wide band is essential. The wide band sensor according to the embodiment of the present invention exhibits a high sensitivity with a reflection loss characteristic of less than -10 dB and has a wide band characteristic in the range of 1 to 7 GHz.

Hereinafter, a wideband sensor according to an embodiment of the present invention will be described in detail. 1 is a sectional view of a broadband sensor for detecting partial discharge of a pillar transformer according to an embodiment of the present invention.

1, a broadband sensor 100 for detecting partial discharge of a pillar transformer according to an embodiment of the present invention includes an upper cone 110, a lower cone 120, a conductive plate 130, a ground plate 140, Includes a coaxial cable 150, a ferrite 160, a housing 170, a cap portion 180, and a connector 190.

The upper cone 110, the lower cone 120, the conductive plate 130 and the ground plate 140 positioned at the upper end of the sensor 100 serve as radiators in the broadband sensor 100. A lower cone 120 and an upper cone 110 are connected to an upper portion of the ground plate 140 and a plurality of conductive plates 130 are connected between the ground plate 140 and the lower cone 120.

The upper cone 110 has a shape in which the section becomes narrower toward the upper part, and the lower cone 120 has a shape in which the section becomes narrower toward the lower part. The upper surface of the lower cone 120 is in contact with the lower surface of the upper cone 110.

In this way, the upper cone 110 and the lower cone 120 are connected to each other to meet the wideband characteristic and have a double conical configuration. It is apparent that the upper cone 110 and the lower cone 120 are formed of a conductive metal because they serve as radiators. The upper cone 110 and the lower cone 120 may be coupled to each other after their manufacture, or may be manufactured as a single body in the manufacturing process.

The ground plate 140 is disposed below the lower cone 120 and has a through hole 141 formed at the center thereof. The ground plate 140 serves as a ground in the broadband sensor 100 and stably supports the conical radiator structure through the upper conductive plate 130.

The conductor plate 130 is vertically connected between a part of the outer surface of the lower cone 120 and the upper surface of the ground plate 140. The upper end is connected to the outer surface of the lower cone 120 and the lower end is connected to the upper surface of the ground plate 140.

The conductive plates 130 may be arranged in a plurality of positions with respect to the circumferential direction of the lower cone 120. In the case of FIG. 1, the conductive plates 130 are arranged in a pair facing each other with respect to the circumferential direction. Of course, the present invention is not necessarily limited to this.

In the embodiment of the present invention, the conductive plate 130 maintains the robust structure of the sensor between the lower cone 120 and the ground plate 140 and improves the reflection loss characteristic of the sensor. In particular, the a value associated with the mounting location of the conductor plate 130 and the w value associated with the width of the conductor plate 130 are used to improve and control the characteristics of the return loss.

2 is a perspective view of a wideband sensor when a = 0 in FIG. In this embodiment, as the conductive plate 130 is positioned at the edge of the lower cone 120 as shown in FIG. 2, the reflection loss characteristic is improved.

The embodiment of the present invention can adjust the reflection loss characteristic of the antenna by adjusting the variable a corresponding to the mounting position of the triangular conductor plate 130 and the variable w corresponding to the width of the triangular conductor plate 130 . This will be explained later through simulation results.

Fig. 3 shows an example of the configuration of the conductive plate shown in Fig. 3 (a) is an example in which the conductive plate 130 is connected at a point inward from the upper edge of the lower cone 120 by an inner point, and FIG. 3 (b) And the conductive plate 130 is connected to the upper edge of the lower cone 120 as shown in FIG.

The construction of the conductive plate 130 will be described in more detail as follows. First, the conductor plate 130 has a triangular shape, and a portion corresponding to the first side of the triangle (a portion corresponding to the w-length) is tangent to the direction of the busbar at a portion of the outer surface of the lower cone 120 .

Here, the length w of the first side is shorter than the length L of the bus bar (w <L), and the portion of the first vertex p1 at the lower end opposite to the first side is in contact with the upper surface of the ground plate 140 . The second side connecting the first vertex p 1 and the second vertex p 2 is perpendicular to the ground plate 140. The other third side is formed to have a slope from the surface of the ground plate 140, and a space apart from the horizontal direction is present between the lower cone 120 and the conductive plate 130 of the triangle.

FIG. 3B shows a case where a = 0, where the first side is formed with a predetermined length w along the direction of the busbars starting from the upper edge of the lower cone 120. Here, a second side connecting the second vertex p2 corresponding to the upper edge and the first vertex p1 is perpendicular to the ground plate 140.

The bandwidth of the sensor can be determined by adjusting the distance a between the upper edge of the lower cone 120 and the second apex p2 and the length w of the first side. The performance of the triangular conductive plate 130 according to the setting of the conductive plate 130, the number of the conductive plates 130, and the parameters a and w will be described later in detail through experimental data.

Meanwhile, a coaxial cable 150 forming a coaxial line exists under the ground plate 140. The coaxial cable 150 has an inner conductor, an outer conductor, and a dielectric that maintains a gap between the two conductors.

The inner conductor of the coaxial cable 150 is electrically connected to the vertex portion of the lower cone 120 through the through hole 141 of the ground plate 140 and is not connected to the ground plate 140. At this time, a separate connection line may be used for ease of connection. The outer conductor of the coaxial cable 150 is directly connected to the ground plate 140 and may be connected to the inner wall of the ground plate 140 or the through hole 141 of the ground plate 140, for example.

According to this configuration, the current path is formed in the order of the internal conductor of the coaxial cable 150, the double cones 120 and 110, the conductor plate 130, the ground plate 140, and the external conductor in this order.

The ferrite 160 has a hollow cylindrical shape at the center and is disposed so as to surround the outside of the coaxial cable 150. The ferrite 160 prevents a current from being induced on the external conductor of the coaxial cable 150 due to external electromagnetic waves, and prevents the induction field induced in the coaxial cable 150 from being generated.

The housing 170 includes the coaxial cable 150 and the ferrite 160 and is made of a dielectric material having a small dielectric constant. One end of the dielectric 170 is coupled to the lower surface of the ground plate 140. The cap portion 180 covers the other end of the housing 170 and has a central opening.

The connector 190 is connected to the other end of the coaxial cable 150 through a central portion of the cap portion 180 and is connectable to external measuring equipment. Such a connector may correspond to the SMA connector in consideration of the frequency band of the radiated electromagnetic wave of the pillar-form transformer.

1, the radiator is connected to a measuring instrument (spectrum analyzer or receiver) through a coaxial cable and can measure electromagnetic waves radiated from the inside of the pillar-shaped transformer to the outside. This enables early detection and diagnosis of the occurrence of partial discharge of the pillar transformer, the failure type and faulty fault, thereby securing the power supply reliability of the power distribution system.

Hereinafter, simulation data on the effect of improving the reflection loss due to use of the conductive plate and its effectiveness will be described.

FIG. 4 shows the frequency characteristics of the reflection loss when the triangular conductor plate does not exist in FIG. In the broadening of the antenna, although the broadening of the high frequency band can be easily realized, the broadening of the low frequency band is left as a difficult problem. As shown in FIG. 4, in the low frequency band of 1.6 GHz or less without the conductive plate, the reflection loss is less than -10 dB and the reflection is large. Therefore, it is required to improve the reflection loss characteristic.

In the embodiment of the present invention, a triangular conductor plate 130 is added as described below in order to improve a return loss characteristic in a low frequency band. In the present embodiment, the triangular conductor plate 130 serves to disperse the current magnitude in the sensor during power supply and to vary the current path to adjust the ratio of the current flowing in the lower cone 120.

FIG. 5 shows the frequency characteristics of the return loss when the number of triangular conductor plates is taken as a parameter in FIG. FIG. 5 shows a change in the number of conductive plates with a fixed at a = 0 mm and w = 34.94 mm. As shown in FIG. 2, when the pair of triangular conductor plates are connected to each other at symmetrical positions, that is, when two conductor plates are used (2-plate), the return loss characteristic is improved in the low frequency band (1.6 GHz or less) .

Here, when the number of the conductive plates is two, the reflection loss characteristic is also the best. If the number of the triangular conductor plates 130 is increased infinitely, they are connected to each other to have a cylindrical structure, so that the broadband characteristic is lost. However, when two triangular conductor plates 130 are used as shown in FIG. 2, the current ratio of the lower cone 120 and the triangular conductor plate 130 is adjusted to improve the return loss characteristic in the low frequency band.

Fig. 6 shows the frequency characteristics of the return loss when a, which is related to the position of the triangular conductor plate in Fig. 2, is used as a parameter. 6 shows a case where the position a of the triangular conductor plate 130 is changed in the structure using the two triangular conductor plates 130 and the structure where w is set to 34.94 mm by using the two triangular conductor plates 130 to be.

Based on FIG. 6, it can be seen that the reflection loss characteristics of the low frequency band are improved as the triangular conductor plate 130 is positioned at the edges of the upper and lower cones (closer to a = 0). This is because the current path becomes longer as the conductor plate 130 is positioned at the edge of the upper and lower cones.

Fig. 7 shows the frequency characteristics of the reflection loss when w, which is related to the width of the triangular conductor plate in Fig. 2, is used as a parameter. Fig. 7 shows a case in which the width w of the triangular conductor plate 130 is changed in a structure in which two triangular conductor plates 130 are used and fixed at a = 0 mm.

When the width of the triangular conductor plate is generated, the current distribution is diffused and dispersed, and the reflection loss characteristic in the low frequency band is improved. However, it can be seen that the reflection loss characteristics of -10 dB or less in the band of 1 to 7 GHz are satisfied when w = 6.82, 17.93, 26.98, and 34.94 mm, respectively, as compared with the case where the triangular conductor plate is absent.

Of course, the degree of improvement of the magnitude of w and the reflection loss characteristic is not always proportional. For example, when a value of a is almost equal to the length L of the bus line in a state of a = 0, as shown in FIG. 3 (b), shorting from the base of the triangular conductor plate 130 connected to the ground plate 140 to the vertex P1 The current path is formed, so that the characteristics of the low frequency band are not improved. The width w of the triangular conductor plate 130 can be adjusted through simulations within the length of the bus bar so as to form a long current path while maintaining the current ratio with the lower cone 120.

The reflection loss and the band characteristics are determined in consideration of the installation height of the pillar transformer and the frequency band of the radiated electromagnetic wave. Since the type of pillar transformer failure can be confirmed by detecting the frequency band of the radiated electromagnetic wave, the sensor of the present invention having the broadband characteristic can diagnose various failure types.

Also, the structure of the sensor according to the embodiment of the present invention can be utilized for detection of radiated electromagnetic waves of other bands through the modification of dimensions and design, and it is possible to use a sensor for other distribution equipment (insulator, switch, cable) It can also be mass-produced as an integrated product.

The wide-band sensor of this embodiment can be used as a sensor for constructing a power distribution system fault diagnosis system, thereby contributing to prevention of power outage in the power distribution system and securing reliability of electric power supply. Furthermore, it is possible to quickly and clearly diagnose fault diagnosis of power distribution facilities, and it is expected to create a power utility diagnostic service business.

According to the above-described broadband sensor for detecting the partial discharge of the pillar transformer according to the present invention, the radiated electromagnetic wave radiated to the outside of the pillar transformer due to the partial discharge inside the pillar transformer can be detected with high sensitivity and wide band characteristics, .

In addition, the reflection loss characteristic is greatly improved compared with the conventional UHF sensor, so that it is advantageous not only for the partial discharge detection of the pillar type transformer but also as a sensor for prevention of power outage of the power distribution system and fault diagnosis of the power distribution facility.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: broadband sensor 110: upper cone
120: lower cone 130: conductor plate
140: ground plate 150: coaxial cable
160: ferrite 170: housing
180: cap part 190: connector

Claims (5)

1. A broadband sensor for detecting partial discharge of a pillar-type transformer for detecting radiated electromagnetic waves due to partial discharge of a pillar-type transformer,
An upper cone having a narrower section toward the upper part;
A lower cone having an upper surface contacting the lower surface of the upper cone and a lower surface tapering downward;
A ground plate disposed at a lower portion of the lower cone and having a through hole;
A conductive plate connected in a vertical direction between a part of the outer surface of the lower cone and the upper surface of the ground plate and disposed in a plurality of positions in the circumferential direction of the lower cone; And
And a coaxial cable forming a coaxial line at a lower portion of the ground plate, wherein an inner conductor is connected to a vertex of the lower cone through the through hole and an outer conductor is connected to the ground plate,
The conductive plate may include:
Wherein a portion corresponding to a first side of the triangle is in contact with a portion of an outer surface of the lower cone along a direction of a busbar, the first side being shorter than the length of the busbar, Wherein a first vertex portion of the ground contact plate is in contact with an upper surface of the ground plate. delete The method according to claim 1,
The conductive plate may include:
Wherein the first side is formed to have a predetermined length along the direction of the bus bar from the upper edge of the lower cone,
And a second side connecting the second vertex corresponding to the upper edge and the first vertex is perpendicular to the ground plate. The method according to claim 1 or 3,
The conductive plate may include:
And a pair of opposed upper and lower cones facing each other with respect to a circumferential direction of the lower cone. The method according to claim 1,
A cylindrical ferrite disposed so as to surround the outside of the coaxial cable;
A housing including the coaxial cable and the ferrite, the housing being formed of a dielectric and having one end coupled to a lower surface of the ground plate;
A cap portion covering the other end of the housing and having a central portion opened; And
And a connector connected to the other end of the coaxial cable through a center portion of the cap portion and capable of connecting an external measurement device.

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