JP2014082292A - Transformer for vacuum capacitor instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance voltage measurement accuracy of a vacuum VT.SOLUTION: A transformer 1 for vacuum capacitor instrument (vacuum VT) comprises: an outer casing 5 formed by a primary insulation tube 2, a cylindrical part 3 and a ground cylindrical part 4; and a primary capacitor 6 provided in the outer casing 5. The primary capacitor 6 is formed by causing the side face of an internal primary electrode 8a provided on a primary end plate 8 to face the side faces of internal secondary electrodes 11a, 11b provided on a secondary end plate 11 each other. A molded portion 14 is formed by covering the primary insulation tube 2 with an insulation mold. Outer periphery of the molded portion 14 is covered with a metallic film 15. The ratio of lengths of the primary insulation tube 2 and the outer casing 5 is 1:2-1:10.

Description

  The present invention relates to a capacitor-type instrument transformer, and more particularly to a vacuum capacitor-type instrument transformer using a vacuum capacitor as a main capacitor provided between a primary side terminal and a voltage dividing point.

  Instrument transformers (VT: Voltage Transformers) are devices used to convert a high voltage into a safe voltage by a voltage dividing circuit and input it to a measuring instrument such as a voltmeter or a protective relay. There are several types of instrument transformers: winding type, capacitor type, and resistance type.

  As a voltage transformer, there is a vacuum capacitor type voltage transformer using a vacuum capacitor (VC) (for example, Patent Document 1). Hereinafter, the vacuum capacitor type instrument transformer is referred to as a vacuum VT. The vacuum VT has a high dielectric strength due to the structure of the vacuum capacitor, and is a highly reliable instrument transformer that does not cause a burnout accident due to aging.

JP 2011-54796 A

  However, in the vacuum VT, the capacitance of the primary-side vacuum capacitor may change due to the influence of the surrounding environment. The change in capacitance may cause a decrease in voltage measurement accuracy of the vacuum VT.

  Therefore, an object of the present invention is to provide a technique that contributes to the improvement of the voltage measurement accuracy of the vacuum VT.

  One aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object is a cylindrical outer casing, a primary end plate provided by closing an open end of the outer casing, and the primary side An internal primary electrode erected in the outer casing from the end plate surface, and a secondary side end plate provided in the outer casing facing the surface on which the internal primary electrode of the primary side end plate is provided And an internal secondary electrode erected from the secondary side end plate surface in the direction of the primary side end plate, and the internal primary electrode and the internal secondary electrode are arranged opposite to each other to form a main capacitor A vacuum capacitor type instrument transformer in which a space in which the main capacitor is formed is evacuated, wherein at least a part of the outer casing is an insulating cylinder, and the primary side end plate and the insulating cylinder A mold part in which the outer peripheral part of the mold is covered with an insulating mold, and the outer periphery of the mold part is covered with a metal film. It is a symptom.

  Further, another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above-described object is that in the vacuum-capacitor-type instrument transformer, the insulating tube is provided biased toward the primary side end plate. It is characterized by.

  According to another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object, in the vacuum capacitor-type instrument transformer, the ratio of the length of the insulating cylinder to the length of the outer casing is 1 : 2 to 1:10.

  Another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object is that the vacuum capacitor-type instrument transformer has an open end that is not closed by the primary side end plate of the outer casing. A ground-side end plate provided; and a cylindrical secondary-side insulating cylinder provided between the ground-side end plate and the secondary-side end plate; and an inner circumference of the secondary-side insulating cylinder A space formed by the surface and the secondary side end plate is evacuated, and a secondary capacitor is provided in the space.

  Another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object is that the vacuum capacitor-type instrument transformer has an open end that is not closed by the primary side end plate of the outer casing. A ground-side end plate provided; and a cylindrical secondary-side insulating cylinder provided between the ground-side end plate and the secondary-side end plate; and an inner circumference of the secondary-side insulating cylinder An inert gas or dry air is enclosed in a space formed by the surface and the secondary end plate, and a secondary capacitor is provided in the space.

  Further, another aspect of the vacuum capacitor instrument transformer of the present invention that achieves the above object is the vacuum capacitor instrument transformer, wherein the outer casing is formed by joining a conductor cylinder to the insulating cylinder, The conductor cylinder is formed of a material constituting the primary side end plate or the ground side end plate.

  According to another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object, in the vacuum capacitor-type instrument transformer, a part of the mold part is fitted to a joint part to be measured. The fitting part is not covered with a metal film.

  Another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object is the vacuum capacitor-type instrument transformer according to the present invention, wherein the contact portion between the joint portion to be measured and the fitting portion of the mold portion is contacted. It is characterized by closely contacting the surfaces.

  Another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above object is characterized in that the metal film is grounded in the vacuum capacitor-type instrument transformer.

  Another aspect of the vacuum capacitor-type instrument transformer of the present invention that achieves the above-described object is that in the vacuum capacitor-type instrument transformer, the primary side end plate and the secondary side end plate have a diameter. A cylindrical internal primary electrode plate and an internal secondary electrode plate having different sizes are provided concentrically, and the maximum value of the diameter of the internal secondary electrode is greater than the maximum value of the diameter of the internal primary electrode. It is also characterized by making it larger.

  According to the above invention, it can contribute to the improvement of the voltage measurement precision of vacuum VT.

It is sectional drawing of the transformer for vacuum capacitor type instruments which concerns on embodiment of this invention. It is explanatory drawing explaining the example which connected the transformer for vacuum capacitor type instruments which concerns on embodiment of this invention to C-GIS. It is explanatory drawing (principal part expanded cross section) explaining the state which connected the transformer for vacuum capacitor type instruments which concerns on embodiment of this invention to the connection part of C-GIS.

  A vacuum capacitor type instrument transformer (vacuum VT) according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of a vacuum VT1 according to an embodiment of the present invention. The vacuum VT 1 according to the embodiment includes an outer casing 5 formed by the primary insulating cylinder 2, the cylindrical portion 3, and the grounded cylindrical portion 4, and a primary side capacitor 6 provided in the outer casing 5. Note that a secondary side capacitor (not shown) for sharing the output voltage to the protective relay and the measuring instrument is provided in the secondary side case 7 formed in the outer casing 5.

  The primary insulating cylinder 2 is a member formed of an inorganic insulating material such as a ceramic material in a cylindrical shape. A cylindrical portion 3 that is a cylindrical conductive member is provided at one open end of the primary side insulating cylinder 2, and a grounded cylindrical portion that is a cylindrical conductive member is provided at the other open end of the primary side insulating cylinder 2. 4 is provided.

  A primary end plate 8 that is a conductive member is provided at the open end of the cylindrical portion 3. On the other hand, a ground side end plate 9 which is a conductive member is provided at the open end of the ground cylindrical portion 4. A ground wire (not shown) is connected to the ground-side end plate 9, and the outer casing 5 (ground cylindrical portion 4) of the vacuum VT1 is grounded. The ground side end plate 9 is formed with a circular hole centered on the axis of the outer casing 5, and is formed of an inorganic insulating material so as to stand from the outer periphery of the hole toward the primary side end plate 8. A cylindrical secondary insulating cylinder 10 is provided. The open end of the secondary side insulating cylinder 10 on the primary side end plate 8 side is sealed by a secondary side end plate 11 which is a conductive member. In this way, the open end of the cylindrical portion 3 is sealed with the primary side end plate 8, and the open end of the ground cylindrical portion 4 is sealed with the ground side end plate 9, the secondary side insulating cylinder 10, and the secondary side end plate 11. As a result, a vacuum portion 12 is formed in which the inside of the outer casing 5 is evacuated. In addition, the primary side end plate 8 may be provided directly on the primary side insulating cylinder 2 to seal the open end of the primary side insulating cylinder 2. Further, the ground side end plate 9 may be provided directly at the other open end of the primary side insulating cylinder 2. The secondary insulating cylinder 10 and the ground end plate 9 are connected directly or via a cylindrical portion 13a which is a conductive member. Similarly, the secondary side insulating cylinder 10 and the secondary side end plate 11 are connected directly or via a cylindrical portion 13b which is a conductive member.

  The primary side capacitor 6 is formed between the primary side end plate 8 and the secondary side end plate 11. An inner primary electrode 8 a is provided on the main surface of the primary side end plate 8 and on the inner peripheral surface of the outer casing 5. The internal primary electrode 8a is, for example, a cylindrical electrode and extends in the direction of the secondary side end plate 11. In the case where a plurality of internal primary electrodes 8a are provided, a plurality of internal primary electrodes 8a whose diameters are sequentially reduced are arranged concentrically. On the other hand, on the surface of the secondary side end plate 11 facing the primary side end plate 8, internal secondary electrodes 11a and 11b are provided. The internal secondary electrodes 11a and 11b are, for example, cylindrical electrodes having a diameter different from that of the internal primary electrode 8a, and extend in the direction of the primary side end plate 8. That is, the internal primary electrode 8a and the internal secondary electrodes 11a and 11b are alternately arranged so that the side surfaces thereof face each other in a non-contact manner, and the primary side capacitor 6 is formed.

  Further, the diameter of the inner secondary electrode 11a having the largest diameter is larger than the diameter of the inner primary electrode 8a having the largest diameter, and the side surface of the inner secondary electrode 11a is the inner peripheral surface of the outer casing 5 (grounding cylinder). (Inner peripheral surface of the part 4). Thus, a capacitor is formed between the internal secondary electrode 11a and the ground cylindrical portion 4 by making the internal secondary electrode 11a and the inner peripheral surface of the ground cylindrical portion 4 face each other. As a result, when a secondary capacitor (not shown) is connected to the secondary end plate 11, the capacitance of the voltage dividing capacitor is formed between the internal secondary electrode 11 a and the ground cylindrical portion 4. This is the combined capacity of the capacitor and secondary capacitor. Therefore, the capacitance of the voltage dividing capacitor is increased.

  A connection conductor 8b connected to the measurement target device (high voltage side) is provided on the surface of the primary side end plate 8 opposite to the surface on which the internal primary electrode 8a is provided. The connecting conductor 8b (primary side end plate 8) and the primary side insulating cylinder 2 are covered with an insulating mold to form a molded portion. Furthermore, the outer periphery of the mold part 14 is covered with a metal film 15. The metal film 15 is not particularly limited as long as it is a metal. Further, the metal film 15 is grounded directly or via the grounding cylindrical portion 4. By covering the mold part 14 with the metal film 15 in this way, the influence of the electric field around the vacuum VT1 and the influence of atmospheric humidity, atmospheric pressure, and fouling are reduced.

The secondary case 7 is formed by the inner peripheral surface of the secondary insulating cylinder 10 and the secondary end plate 11. A secondary capacitor (not shown) is provided in the secondary case 7. By vacuuming the inside of the secondary side case 7 or filling with inert gas (He, N ₂ , Ar, SF _6, etc.) or dry air, the influence of atmospheric humidity or atmospheric pressure on the secondary side capacitor 2 The effect of contamination of the secondary capacitor is reduced. As a result, the leakage current flowing from the secondary side end plate 11 through the surface of the secondary side insulating cylinder 10 and the secondary side capacitor through the ground side end plate 9 is reduced, the output of the vacuum VT1 is stabilized and the vacuum VT1 Voltage measurement accuracy is improved.

  The secondary side capacitor is electrically connected to the secondary side end plate 11 and the ground side end plate 9. As the secondary capacitor, a known capacitor may be used as appropriate. For example, a film capacitor is used. Alternatively, the inside of the secondary side case 7 may be evacuated, electrodes may be disposed therein, and the secondary side capacitor may be a vacuum capacitor.

  The vacuum VT1 of the present invention will be described in more detail with reference to FIGS. FIG. 2 illustrates an example in which a plug-in type vacuum VT1 is connected to a gas-insulated switchgear (C-GIS) 16 (C-GIS). In addition to the C-GIS 16, there is a solid-insulated switchgear (SIS) as an apparatus to be measured to which the vacuum VT1 is connected.

As shown in FIG. 2, the C-GIS 16 is provided with a bushing mold 17 to which the mold part 14 of the vacuum VT 1 can be attached and detached. Insulation with the part 19 is performed. The bushing mold 17 (and the bushing conductor 20 and the joint 20a shown in FIG. 3) is provided in a state in which the hermeticity of the exterior 18 is ensured. The exterior 18 is filled with an insulating gas such as SF ₆ gas. The outer casing 18 and the outer casing 5 of the vacuum VT1 are grounded, and the outer casing 18 and the outer casing 5 (metal coating 15) of the vacuum VT1 are electrically connected. Thus, by providing two grounding portions, the safety of the vacuum VT1 is further improved.

  As shown in FIG. 3, the mold part 14 of the vacuum VT1 is fitted into the bushing mold 17 of the C-GIS 16, and the bushing conductor 20 of the C-GIS 16 and the connection conductor 8b of the vacuum VT1 are electrically connected. Specifically, by fitting the mold part 14 to the bushing mold 17, the connection conductor 8 b and the joint part 20 a (such as multi-contact) provided at the end of the bushing conductor 20 are joined, and the vacuum VT 1 and the measured object The unit 19 is connected.

  When the mold part 14 of the vacuum VT 1 is fitted to the bushing mold 17, the exterior 18 provided on the outer surface of the bushing mold 17 and the metal film 15 of the vacuum VT 1 come into contact with each other. The C-GIS 16 is provided by directly grounding the exterior 18 (or connecting a ground wire (not shown) to the exterior 18). On the other hand, the metal film 15 is also grounded directly or via the grounding cylindrical portion 4. That is, by bringing the exterior 18 and the metal film 15 into contact, the C-GIS 16 and the vacuum VT <b> 1 have two ground portions, that is, the ground at the exterior 18 and the ground at the metal film 15.

  The mold part 14 is provided in the bushing mold 17 so that the contact surface (indicated by A in the drawing) of the mold part 14 and the bushing mold 17 is in close contact. For example, the mold part 14 is fitted into the bushing mold 17 via grease or a silicon cover. By eliminating the gap between the mold part 14 and the bushing mold 17 in this way, a flash from the bushing conductor 20 is prevented. Further, in order to prevent the flashing from the bushing conductor 20 (and the joint 20a) to the metal film 15, the metal film 15 is not provided at the fitting portion of the mold part 14 to the bushing mold 17. In addition, if the shape of the mold part 14 is a shape which can be fitted in the bushing mold 17, the shape will not be specifically limited.

  As described above, according to the vacuum VT of the present invention, the insulation of the outer casing can be ensured by covering the primary side insulating cylinder with the insulating mold. In addition, by covering the outer periphery of the mold part covering the primary insulating cylinder with a metal film, the influence of noise from the external environment on the main capacitor can be reduced, and the voltage measurement accuracy of the vacuum VT can be improved.

  In addition, according to the vacuum VT of the present invention, the primary side insulating cylinder constituting the outer casing is provided on the primary side end plate side, so that the influence of noise from the external environment on the main capacitor is reduced. The voltage measurement accuracy can be improved. That is, the length of the primary insulating cylinder in the outer casing is shortened, and the side where the ground side end plate of the outer casing is provided is a grounding cylindrical portion which is a conductive member, thereby increasing the grounding portion of the vacuum VT. be able to. As a result, the influence of the surrounding electric field on the vacuum VT is reduced, and the voltage measurement accuracy of the vacuum VT is improved.

  Further, by arranging the primary side insulating cylinder in the vicinity of the primary side end plate, the mold part formed on the outer periphery of the primary side end plate and the primary side insulating cylinder can be made small, and the vacuum VT can be reduced in size. Can be

  As the length of the primary insulating cylinder is shortened, the size of the vacuum VT can be reduced. This is because the thickness of the cylindrical portion formed of a metal such as stainless steel or the grounded cylindrical portion can be made thinner than the primary insulating tube formed of ceramic or the like, and the lateral width of the vacuum VT1 can be reduced. Because. On the other hand, the insulation of the outer casing can be secured by setting the length of the primary insulating cylinder to 1/10 or more of the length of the outer casing. Therefore, the insulation ratio of the outer casing is maintained by setting the ratio of the length of the primary insulating cylinder to the length of the outer casing to 1: 1 to 1:10, more preferably 1: 2 to 1:10. Thus, the vacuum VT can be reduced in size.

  Further, in the vacuum VT of the present invention, the grounding cylindrical portion is formed of a conductive member, and the internal secondary electrode is provided so as to face the inner peripheral surface of the grounding cylindrical portion, whereby the internal secondary electrode, the grounding cylindrical portion, A capacitor is formed between the two. As a result, the capacitance of the voltage dividing capacitor is the combined capacitance of the capacitor formed between the internal secondary electrode and the grounded cylindrical portion and the secondary side capacitor, and increases the capacitance of the voltage dividing capacitor. Can do.

  In addition, each conductive member to be joined, such as a primary side end plate and an internal primary electrode, a secondary side end plate and an internal secondary electrode, a ground cylindrical portion and a ground side end plate, or a cylindrical portion and a primary side end plate, By forming with the same material, the discharge voltage, workability, thermal deformability and strength of the vacuum VT are improved. As a material constituting each conductive member, for example, stainless steel (SUS) is preferable from the viewpoint of workability and availability. In addition, when a vacuum VT is formed by forming the primary side end plate and the internal primary electrode, the grounding cylindrical portion and the grounding side end plate with different types of conductive members, the structure and combination thereof stabilize the discharge part and voltage. You may have to consider sex.

  In addition, when the vacuum VT is provided in a device to be measured by grounding the outer casing (metal film or ground cylindrical portion) of the vacuum VT, the grounding in the vacuum VT and the grounding in the exterior of the device to be measured Grounding will be performed at two places. That is, the grounding of the vacuum VT and the ground of the measurement target device are provided in two places, so that the grounding of the vacuum VT and the ground of the measurement target device can be more reliably performed, thereby improving safety.

  In addition, in the case of a plug-in type in which the vacuum VT is fitted to the joint portion of the measurement target device, the bushing conductor and the other are brought into close contact with the contact surface between the joint portion of the measurement target device and the fitting portion of the vacuum VT It is possible to prevent a flash between the two members. In addition, by covering the outer periphery of the insulating mold with a metal film, a flash between the bushing conductor and another member can be further prevented.

  Although the vacuum VT of the present invention has been described in detail with specific examples, the vacuum VT of the present invention is not limited to the above-described embodiment, and the design is appropriately changed within a range not impairing the features of the present invention. Such a modified form also belongs to the scope of the vacuum VT of the present invention.

  For example, the internal structure of the vacuum VT described in Patent Document 1 may be applied as the internal structure of the vacuum VT of the present invention. Specifically, the vacuum VT insulating cylinder described in Patent Document 1 is reduced and provided on the primary line side flange side, thereby reducing the size of the vacuum VT and improving the voltage measurement accuracy of the vacuum VT. be able to. Also, by forming a vacuum capacitor between the secondary side end plate and the ground side end plate, the capacitance of the voltage dividing capacitor is reduced by the vacuum capacitor and the secondary side capacitor (and the outer casing and the internal secondary electrode). And the capacitance of the voltage dividing capacitor can be increased.

  Moreover, when not considering the miniaturization of the shape of the vacuum VT, the insulation of the vacuum VT can be further improved by increasing the insulating cylinder length or covering the entire vacuum VT with an insulating mold.

  In addition, the primary capacitor may be configured by only a minimum configuration in which the internal primary electrode and the internal secondary electrode are arranged to face each other.

1… Vacuum capacitor type instrument transformer (vacuum VT)
2 ... Primary side insulation cylinder (insulation cylinder)
3, 13a, 13b ... cylindrical part 4 ... grounding cylindrical part (conductor cylinder)
5 ... Outer casing 6 ... Primary side capacitor (main capacitor)
7 ... Secondary side case 8 ... Primary side end plate 8a ... Internal primary electrode, 8b ... Connection conductor 9 ... Ground side end plate 10 ... Secondary side insulating cylinder 11 ... Secondary side end plates 11a, 11b ... Internal 2 Next electrode 12 ... Vacuum part 14 ... Mold part 15 ... Metal film 16 ... Gas insulation switchgear (C-GIS)
17 ... Bushing mold 18 ... Exterior 19 ... Measured part 20 ... Bushing conductor 20a ... Joint part

Claims (10)

A cylindrical outer casing,
A primary side end plate provided by closing an open end of the outer casing;
An internal primary electrode standing in the outer casing from the primary side end plate surface;
A secondary side end plate provided in the outer casing facing a surface on which the internal primary electrode of the primary side end plate is provided;
An internal secondary electrode erected from the secondary side end plate surface toward the primary side end plate;
A vacuum capacitor type instrument transformer in which a main capacitor is formed by disposing the internal primary electrode and the internal secondary electrode so as to face each other, and a space in which the main capacitor is formed is vacuumed,
At least a part of the outer casing is an insulating cylinder,
Providing a mold part in which an outer peripheral part of the primary side end plate and the insulating cylinder is covered with an insulating mold;
A vacuum capacitor type instrument transformer characterized in that the outer periphery of the mold part is covered with a metal film. 2. The vacuum capacitor type instrument transformer according to claim 1, wherein the insulating cylinder is provided to be biased toward the primary side end plate. 3. The vacuum capacitor-type instrument transformer according to claim 1, wherein a ratio of a length of the insulating cylinder to a length of the outer casing is 1: 2 to 1:10. 4. A ground-side end plate provided at an open end that is not blocked by the primary-side end plate of the outer casing;
A cylindrical secondary insulating tube provided between the ground side end plate and the secondary side end plate;
Further comprising
4. The space defined by the inner peripheral surface of the secondary insulating cylinder and the secondary end plate is evacuated, and a secondary capacitor is provided in the space. A vacuum capacitor type instrument transformer according to claim 1. A ground-side end plate provided at an open end that is not blocked by the primary-side end plate of the outer casing;
A cylindrical secondary insulating tube provided between the ground side end plate and the secondary side end plate;
Further comprising
2. An inert gas or dry air is enclosed in a space formed by an inner peripheral surface of the secondary insulating cylinder and the secondary end plate, and a secondary capacitor is provided in the space. The vacuum capacitor type instrument transformer according to any one of claims 1 to 3. The outer casing is formed by joining a conductor cylinder to the insulating cylinder,
6. The vacuum capacitor-type instrument transformer according to claim 1, wherein the conductor tube is formed of a material constituting the primary-side end plate or the ground-side end plate. 7. . A part of said mold part is formed so that it may fit in the junction part of a measuring object, and the metal film is not coat | covered to the said fitting part, The any one of Claims 1-6 characterized by the above-mentioned. The vacuum capacitor type instrument transformer as described. The vacuum capacitor-type instrument transformer according to claim 7, wherein a contact surface between the joint portion to be measured and the fitting portion of the mold portion is brought into close contact. The vacuum capacitor type instrument transformer according to any one of claims 1 to 8, wherein the metal film is grounded. The primary side end plate and the secondary side end plate are each provided with a cylindrical inner primary electrode plate and an inner secondary electrode plate having different diameters in a concentric manner,
10. The vacuum capacitor-type meter according to claim 1, wherein the maximum value of the diameter of the internal secondary electrode is made larger than the maximum value of the diameter of the internal primary electrode. Transformer.

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