JP5573447B2 - Gas insulated instrument transformer - Google Patents

Description

  The present invention relates to a transformer for gas insulated instruments. More particularly, the present invention relates to a gas insulated instrument transformer that transforms a high voltage applied to a primary coil to provide a monitoring voltage to a monitoring device connected to the secondary coil.

As one of the components of a gas insulated switch-gear (GIS: Gas Insulated Switch-gear) provided in power equipment such as power receiving / transforming equipment, there is a gas insulated instrument transformer (gas VT: Voltage Transformer). Gas-insulated instrument transformers are placed in a space formed inside a metallic container filled with an insulating gas such as SF ₆ gas, and the high voltage of the primary circuit is monitored, such as instruments and relays. Is transformed to a voltage of the secondary side circuit of about 100 V that can be measured with high accuracy. Further, in the gas insulated instrument transformer, the primary side circuit and the secondary side circuit are electrically insulated. For this reason, the gas insulated instrument transformer insulates the monitoring device connected to the secondary side circuit from the primary side circuit to which a high voltage is applied, and protects these devices.

  With reference to FIG. 6, the structure of the conventional transformer for gas insulation instruments is demonstrated. In FIG. 6, the longitudinal cross section of the conventional transformer 60 for gas insulation instruments is shown. As shown in FIG. 6, the gas insulated instrument transformer 60 has an arrangement in which the secondary coil 2 and the primary coil 4 are arranged concentrically on the iron core 1. The primary coil 4 is connected to a primary circuit such as a power transmission line or a bus of a gas insulated switch connected to a distribution line via a main transformer, and a high voltage is applied. The secondary coil 2 supplies the voltage transformed with the primary coil 4 as a monitoring voltage to a monitoring device connected to the secondary side circuit. In general, an insulating layer or a shield layer is formed between the secondary coil 2 and the primary coil 4 to reinforce the insulation between the secondary coil 2 and the primary coil 4. In the gas insulated instrument transformer 60 shown in FIG. 6, the secondary coil 2 and the primary coil 4 are wound around the secondary winding 3 and the primary winding 5, respectively. A high voltage shield 6 is annularly arranged so as to surround the outer periphery of the primary coil 4. The high voltage shield 6 has a C-shaped curved cross section in order to relax the electric field on the outer surface thereof.

  The lead wire 21b of the secondary coil 2 of the gas insulated instrument transformer 60 is drawn out in the same direction as the lead wire 21a through the outer peripheral surface of the winding portion of the secondary coil 2. For this reason, on the outer peripheral surface of the secondary coil 2, the finished dimension of the portion where the lead wire 21 b is arranged becomes larger by the outer diameter length of the lead wire 21 b than the finished dimensions of the other portions. As the finished dimension of the secondary coil 2 increases in this way, the circumferential length of the insulating layer disposed on the outer peripheral surface of the secondary coil 2 and the primary coil 4 increases. As a result, there is a possibility that the manufacturing cost of the gas-insulated instrument transformer 60 may increase due to an increase in the amount of insulating material and material used such as a conductive wire. It is also conceivable to employ an arrangement (not shown) in which the lead wire 21b of the secondary coil 2 is arranged on the outer peripheral surface of the primary coil 4. However, in such an arrangement, since the lead wire 21b is arranged close to the primary coil 4, there is a high possibility that the lead coil 21b receives an electromagnetic or electrostatic action from the primary coil 4 to which a high voltage is applied.

  As a structure of the secondary coil 2, a structure in which a flat portion is provided on the outer peripheral portion of the secondary coil 2 is proposed (Patent Document 1). FIG. 7 is a perspective view of the secondary coil 2 in which a flat portion is provided on the outer peripheral portion. By adopting the structure shown in FIG. 7, even if the lead wire 21b is pulled out through the outer peripheral surface of the secondary coil 2, the problem that the external dimension of the secondary coil 2 becomes large does not occur. For this reason, size reduction of the transformer 60 for gas insulation instruments and reduction of manufacturing cost can be aimed at.

  However, since the structure shown in FIG. 7 has a flat portion in the secondary coil 2, the tension applied to the conducting wire when the conducting wire is wound around the secondary winding 3 to form the winding of the secondary coil 2. Need to change. For this reason, the manufacturing process of the secondary coil 2 becomes complicated. In order to solve this problem, a structure is adopted in which one lead wire 21b is wired close to the iron core 1 and drawn to the same end surface 23 as the other lead wire 21a. FIG. 8 shows a longitudinal section of a gas insulated instrument transformer 70 in which the lead wire 21b is wired close to the iron core 1. In this structure, since the lead wire 21b is wired close to the iron core 1, the finished dimension of the secondary coil 2 does not change. For this reason, the problem that the external dimension of the secondary coil 2 becomes large does not arise. Furthermore, since the winding of the secondary coil 2 is a cylindrical winding, there is no problem that the process of forming the winding of the secondary coil 2 becomes complicated.

JP 58-153426 A

  However, when one lead wire is wired close to the iron core, the surge voltage generated in the primary coil when the switch is turned on or opened is electromagnetically or electrostatically induced in the secondary coil, There is a risk of damaging the monitoring equipment connected to the secondary coil. That is, when a steep surge occurs in the primary circuit during the operation of the switch, electromagnetic induction generated in the secondary coil based on the mutual inductance between the primary coil and the lead wire of the secondary coil Based on the voltage or electrostatic coupling between the primary coil and the secondary coil, either the electrostatic induction voltage generated in the secondary coil may damage the monitoring equipment connected to the secondary coil. is there.

  Then, an object of this invention is to provide the transformer for gas insulation meters which suppresses the electromagnetic or electrostatic induction | guidance | derivation from a primary coil, and does not have a possibility of damaging the monitoring apparatus.

  A secondary coil and a primary coil are wound around the outer periphery of the iron core, and the secondary coil is formed at one end of a winding part having an odd number of layers and a conducting wire constituting the winding part. The first lead wire led out from one end face of the lead wire and the other end of the conducting wire are drawn out from the same end face as the first lead wire through a gap formed between the iron core and the secondary coil. A gas insulation instrument transformer having a second lead wire.

  The disclosed transformer for gas-insulated instruments has the effect of suppressing the electromagnetic or electrostatic induction from the primary coil and not damaging the monitoring device.

It is a figure which shows roughly the longitudinal cross-section of the transformer for gas insulation instruments which concerns on this invention. It is a perspective view of an example of the secondary coil of the transformer for gas insulation instruments concerning the present invention. It is a figure which shows roughly an example of the AA 'cross section of FIG. It is a figure which shows roughly the other example of the AA 'cross section of FIG. It is a perspective view of the other example of the secondary coil of the transformer for gas insulation instruments which concerns on this invention. It is a figure which shows schematically the longitudinal cross-section of the conventional transformer for gas insulation instruments. It is a perspective view of an example of the secondary coil of the conventional transformer for gas insulation instruments. It is a figure which shows schematically the longitudinal cross-section of the conventional transformer for gas insulation instruments.

  FIG. 1 schematically shows a longitudinal section of a gas insulated instrument transformer according to the present invention. In FIG. 1, a gas insulated instrument transformer 10 includes an iron core 1, a secondary coil 2 formed by winding a conducting wire around a leg portion of the iron core 1, and a secondary coil 2 outside the secondary coil 2. The primary coil 4 is formed by winding a conducting wire concentrically with the secondary coil 2. That is, the gas insulated instrument transformer 10 shown in FIG. 1 is an inner iron type transformer in which cylindrical windings are arranged in a concentric arrangement.

  The conducting wire forming the secondary coil 2 has lead wires 21a and 21b on the respective end faces. One lead wire 21a is disposed on one end face 23a. Further, the other lead wire 21b is formed in the inner diameter of the secondary coil 2 from the other end surface 23b, and the same end surface 23a as the lead wire 21a through a gap between the iron core 1 and the secondary coil 2. Pulled out. Since the secondary coil 2 has a hollow portion in which the iron core 1 is disposed inside the inner diameter, the lead wire 21b is interposed via a gap formed between the winding portion and the iron core 1 disposed in the hollow portion. It is possible to pull out from the end surface 23b to the end surface 23a.

  With reference to FIG. 2, the arrangement of the lead wires 21a and 21b of the secondary coil 2 according to the present invention will be described in more detail. FIG. 2 shows a perspective view of the secondary coil 2 according to the present invention and the secondary winding 3 wound around the secondary coil. In FIG. 2, other components of the gas insulated instrument transformer 10 such as the iron core 1, the primary coil 4, and the primary winding 5 are not shown for the sake of simplicity.

The secondary coil 2 is a coil constituted by a conducting wire wound on the secondary winding 3. The number n of layers of the secondary coil 2 is an odd number. That is, the secondary coil 2 is obtained by winding a conducting wire an odd number of times in the length direction of the cylindrical winding. When the number n of layers of the secondary coil 2 is an even number, the lead wires 21a and 21b of the secondary coil 2 are drawn out to the same end face 23, so there is no need to consider the path of the other lead wire 21b. is there. The number n of layers of the secondary coil 2 is defined by the number of turns N _{2 of} the secondary coil 2 and the length L of the secondary coil 2. Turns N ₂ of the secondary coil 2, the primary voltages V ₁ to a gas insulated voltage transformer 10 is used, the number of turns N ₁ of the primary coil 4, the secondary voltage V _2, are defined. On the other hand, the length L of the secondary coil 2 is defined by the mechanical size of the gas insulated instrument transformer 10, the outer diameter of the conducting wire used, and the like. As described above, the number n of layers of the secondary coil 2 can be obtained by appropriately selecting a predetermined constant. However, in general, in the gas-insulated instrument transformer 10, the priority in designing the number of layers n is not high compared to other factors such as the mechanical size and the outer diameter of the conducting wire used. For this reason, in order to raise the freedom degree of design of the transformer 10 for gas insulation instruments, the number n of layers of the secondary coil 2 is often selected appropriately.

  When the number of layers of the secondary coil 2 is an odd number, one lead wire 21a is arranged on one end surface 23a, and the other lead wire 21b is arranged on the other end surface 23b. For this reason, when pulling out both the lead wires 21a and 21b to the same end surface 23a or 23b, it is necessary to route either one of the lead wires 21a or 21b. In the gas insulated instrument transformer 10 according to the present invention, either the lead wire 21a or 21b is connected to the other lead wire 21b or the other lead wire 21b via a hollow portion formed inside the inner diameter of the secondary coil 2. It is pulled out to the end face 23b or 23a where 21a is arranged. For this reason, the lead wire 21 can reduce the electromagnetic induction voltage or the electrostatic induction voltage generated by the surge voltage applied to the primary coil 4. This is because the lead wire 21 is disposed in a hollow portion formed inside the inner diameter of the secondary coil 2, so that it is not in parallel with the primary coil 4. Moreover, it will be expected that the secondary coil 2 functions as a shield against electromagnetic induction and electrostatic induction. Furthermore, since the lead wire 21 is disposed not inside the outer peripheral surface of the secondary coil 2 but inside the inner diameter, there is no problem that the outer dimension of the secondary coil 2 becomes large. Furthermore, since the shape of the winding part of the secondary coil 2 is a cylindrical shape having no flat part, there is no problem that the process of forming the winding part becomes complicated.

  Referring to FIG. 1 again, other components of the gas insulated instrument transformer 10 according to the present invention will be described in order. The iron core 1 forms a magnetic circuit that magnetically couples the secondary coil 2 and the primary coil 4. Preferably, the iron core 1 is formed of a magnetic material having high permeability and low loss. In order to reduce eddy current loss, the iron core 1 may have a stratified structure of a cold-rolled silicon steel sheet having a thickness of about several hundred microns. Furthermore, the iron core 1 can form an inorganic insulating film on the surface. By using a directional silicon steel strip as the core material, the core 1 having good excitation characteristics can be formed. Moreover, you may use a non-oriented silicon steel strip as an iron core material. Moreover, as shown in FIG. 3, the iron core 1 adapted to the inner diameter of the secondary coil 2 can be formed by combining silicon steel strips having appropriate widths. Also in this case, the lead wire 21 of the secondary coil 2 is led out to the end face 23 where the other lead wire 21 is disposed through a gap formed by the secondary coil 2 and the iron core 1. In some cases, a gap having a cross section through which the lead wire 21 can pass cannot be formed due to the relationship between the inner diameter of the secondary coil 2 and the structure of the iron core. In this case, as shown in FIG. 4, one or two or more silicon steel strips constituting the iron core 1 are replaced with silicon steel strips having an appropriate width to form a gap through which the lead wire 21 can pass. May be. Furthermore, the iron core 1 may be connected to a gas insulating container or the like with a grounding wiring, and the potential of the iron core 1 may be set to the ground potential.

  The primary coil 4 can be wound on a cylindrical primary winding 5 via an insulating layer and an electric field relaxation shield (not shown). When the primary coil 4 has a plurality of layers, each layer is insulated by being wound through an insulating film (not shown) or the like.

  In FIG. 5, the other example of the secondary coil 2 used for the transformer 10 for gas insulation instruments is shown. Similar to the secondary coil 2 shown in FIG. 2, in the secondary coil 2 shown in FIG. 5, the lead wire 21 b is connected to the other lead wire 21 a via a hollow portion formed inside the inner diameter of the secondary coil 2. Is pulled out to the end face 23a where the is disposed. However, the lead wire 21b is disposed on the inner diameter surface of the secondary coil 2 farthest from the lead wire 21a. Thus, in the secondary coil 2 used in the gas insulated instrument transformer 10, the lead wire 21 b can be arranged at an arbitrary position on the inner diameter surface of the secondary coil 2. For this reason, the lead wire 21b can be arrange | positioned in a suitable position based on the structure of the iron core 1, or the arrangement | positioning which draws out a secondary voltage from the transformer 10 for gas insulation instruments.

  The embodiments described above exemplify the embodiments of the present invention, and combinations, modifications, and variations of the components of the embodiments will be apparent to those skilled in the art. It will be apparent to those skilled in the art that various modifications of the above-described embodiments can be made without departing from the principles of the invention and the scope of the invention as set forth in the claims.

  For example, the secondary coil 2 and the primary coil 4 of the gas-insulated instrument transformer 10 described in the present specification are wound around the secondary winding 3 and the primary winding 5, respectively. May be. That is, the secondary coil 2 is formed by winding an insulator around the secondary coil 2 via the insulator around the core leg of the iron core 1 without arranging the secondary winding 3, and further placing the primary winding 5 thereon. The primary coil 4 may be wound without being arranged. Moreover, although the secondary coil 2 and the primary coil 4 of the gas-insulated instrument transformer 10 are arranged in a concentric arrangement, they may be arranged in an alternating arrangement. Further, the gas insulated instrument transformer 10 is an inner iron type transformer, but may be an outer iron type transformer.

1 Iron Core 2 Secondary Coil 3 Secondary Winding 4 Primary Coil 5 Primary Winding 6 High Voltage Shield 10 Gas Insulated Instrument Transformer 21 Lead Wire

Claims (2)

A transformer for a gas insulated instrument configured by winding a secondary coil and a primary coil on the outer periphery of an iron core,
The secondary coil is
A winding portion having an odd number of layers;
A first lead wire formed at one end of a conducting wire constituting the winding portion and drawn out from one end face of the winding portion;
A second lead wire formed on the other end of the conductive wire and drawn from the same end surface as the first lead wire through a gap formed between the iron core and the secondary coil. ,
The iron core is formed by laminating a plurality of silicon steel strips so that their surfaces are in contact with each other ,
The gap formed between the iron core and the secondary coil is formed by disposing a silicon steel strip that is shorter than the width of the silicon steel strip in contact with each of both surfaces, and the width is A gas insulated instrument characterized in that the difference between the width of the silicon steel strip contacting each of both surfaces of the short silicon steel strip and the width of the short silicon steel strip is at least larger than the diameter of the conducting wire Transformer.   The gas insulated instrument transformer according to claim 1, wherein the primary coil is concentrically disposed outside an outer peripheral surface of the secondary coil.

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