JP2016081894A - Polymer bushing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that can improve, in a transformer polymer bushing, reliability of an axis sealing structure of a portion where the central conductor is drawn into the air, and that is applicable also to transformers installed outdoors where a temperature load is large.SOLUTION: A polymer bushing 1 includes a polymer porcelain tube 2 to which flange metal fittings 7 and 8 of a porcelain tube main body 5 are arranged, a central conductor 3 penetrating through the center section of the polymer porcelain tube 2, and a RIP capacitor core 4 for electric field relaxation formed around the central conductor 3, and in the polymer bushing 1, insulation gas is filled in an interior space 9 of the polymer porcelain tube 2. In the polymer bushing 1, a portion where the central conductor 3 is drawn into the air from the polymer porcelain tube 2 is made to be of a static seal structure by an O ring 13, a terminal-integrated lid 10 is arranged over the flange metal fitting 7 arranged in the upper part of the porcelain tube main body 5, and, as electrification means for electrifying the terminal-integrated lid 10 and the central conductor 3, a slidable electrification member 11 is included, and a length (L2) of a portion existing in the RIP capacitor core 4 and in the porcelain tube main body 5 is made to be within a range of 50-70% of the full length (L1) of the porcelain tube main body 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polymer bushing for a transformer.

  As a polymer bushing for transformers, it has a RIP (resin impregnated paper) capacitor core inside the polymer insulator that penetrates the center conductor, and is formed above the RIP (resin impregnated paper) capacitor core inside the polymer insulator. A product in which an insulating gas is filled in a space is commercialized (Non-Patent Document 1).

  In the above products, a structure in which an O-ring is provided at the interface between the center conductor and the polymer soot pipe is adopted as a shaft seal structure where the center conductor is drawn out from the inside of the polymer soot pipe. However, in such a conventional shaft seal structure, there is a risk that the O-ring may be worn due to the conductor expansion and contraction accompanying the temperature change of the conductor. From the viewpoint of the reliability of the shaft seal structure, it is installed outdoors where the temperature load is particularly large. There was a problem that it could not be applied to transformers.

HSP Hochspannungsgerate GmbH homepage (www.hspkoeln.de) product introduction page (HVDC Transformer Bushings: Type GSETF / GSETt)

  The object of the present invention is to solve the above-mentioned problems and to have a RIP (resin impregnated paper) capacitor core inside the polymer soot tube penetrating the central conductor, and within the polymer soot tube, the RIP (resin impregnated paper) capacitor core. In the transformer polymer bushing in which the insulating gas is filled in the space formed above the transformer, the reliability of the shaft seal structure at the location where the center conductor is drawn out into the air is improved, and the transformer is installed outdoors with a large temperature load. Is to provide technology that can be applied.

  The present invention made in order to solve the above-mentioned problems is formed around the center conductor, a polymer core tube in which flange metal fittings are respectively arranged on the top and bottom of the tube body, a central conductor penetrating through the central portion of the polymer core tube, and In a polymer bushing provided with an RIP capacitor core for electric field relaxation and filled with an insulating gas in the interior space of the polymer soot tube, the location where the central conductor is drawn out from the polymer soot tube has a fixed seal structure by an O-ring, and the soot body A terminal integrated lid is arranged on the upper part of the flange fitting disposed above, and a slidable energizing member is provided as an energizing means for energizing the terminal integrated lid and the central conductor. The length (L2) of the portion existing in the soot tube main body is in the range of 50 to 70% of the total length (L1) of the soot tube main body. It is.

  The length L1 is preferably a length required for the insulation performance of the polymer bushing, and L2 is preferably a length required for the discharge performance of the polymer bushing. Here, “the length required for the insulation performance of the polymer bushing” means the minimum effective length of the soot tube that satisfies “JEC-5202-2007, P14 Table 6”.

  Moreover, it is preferable that the center clamp means for pulling up the center conductor is provided at the upper end of the capacitor core.

  In the present invention, a polymer pipe having flange fittings arranged on the upper and lower sides of the pipe main body, a central conductor penetrating through the central portion of the polymer pipe, and an RIP capacitor core for electric field relaxation formed around the central conductor are provided. In the polymer bushing in which the inner space of the polymer soot tube is filled with an insulating gas, the location where the central conductor is pulled out from the polymer soot tube has a fixed seal structure with an O-ring, and the upper part of the flange fitting disposed above the soot tube body Since a structure including a slidable energizing member is employed as an energizing means for energizing the terminal integral lid and the central conductor by arranging a terminal integrated lid on the shaft, conventionally, a shaft seal via an O-ring is used. Problems that occurred when the structure was used (O-ring wears due to conductor expansion / contraction caused by temperature change of the center conductor, and the reliability of the seal decreases. Avoiding problems), the reliability of the shaft sealing structure, it is possible to improve to a level that can be applied to a transformer to be installed outdoors temperature load is large.

  Since heat is generated when a current flows through the central conductor, the polymer bushing is required to have an appropriate structure for radiating this heat in order to avoid a decrease in product life due to this heat. RIP resin has low thermal conductivity and cannot be expected to dissipate heat through RIP resin. However, in the conventional shaft seal structure with an O-ring, the shaft seal portion has high thermal conductivity. The heat dissipation structure is not particularly considered. On the other hand, in the present invention, an energization structure via a slidable energization member is adopted, and in this structure, thermal conductivity is reduced as compared with a structure via an O-ring. It is necessary to secure the heat dissipation capability with another structure. Therefore, in the present invention, the length (L2) of the portion existing in the soot tube in the RIP capacitor core is set to a range of 50 to 70% of the overall length (L1) of the soot tube body (the space filled with the insulating gas ( That is, good heat dissipation characteristics are ensured by sufficiently securing a space in which heat is radiated from the surface of the central conductor not covered with the RIP resin toward the insulating gas.

It is a vertical sectional view of a polymer bushing. It is explanatory drawing of the location which pulls out a conductor in the air from internal space. (A) It is a side view of a slidable electricity supply member. (B) It is a top view of a slidable electricity supply member. It is explanatory drawing of a center clamp means.

  Preferred embodiments of the present invention are shown below.

  As shown in FIG. 1, the polymer bushing 1 of the present embodiment is formed by winding a paper around a polymer soot tube 2, a center conductor 3 penetrating through the inner center of the polymer soot tube 2, and a lower portion of the center conductor 3. RIP (resin impregnated paper) capacitor core 4.

  The RIP capacitor core 4 is formed by winding paper around the central conductor 3 for insulation and impregnating the paper with resin (generally epoxy resin), or winding the paper on which the resin has been applied in advance around the central conductor 3 while heating. It is a manufactured capacitor core.

  The polymer soot tube 2 includes an FRP cylinder 5 constituting the soot body 5, an outer sheath 6 made of, for example, silicone rubber provided around the FRP cylinder 5, an upper flange fitting 7 and a lower flange that are held and fixed at both ends of the FRP cylinder 5 It consists of a metal fitting 8.

  The internal space 9 of the polymer soot tube 2 is filled with SF6 gas as an insulating medium.

  On the upper part of the upper flange metal fitting 7, a terminal integrated lid 10 used for connection between the central conductor 3 and an external device is disposed.

  In the present invention, a slidable energizing member 11 is provided as shown in FIG. 2 in order to energize the current flowing through the center conductor 3 to the terminal integrated lid 10. Moreover, in order to ensure the airtightness of the internal space 9 of the polymer soot tube 2, the fixing O-ring 13 is disposed.

  In the present embodiment, as the slidable energizing member 11, as shown in FIG. 3, a multipoint contact type contact is used. This multipoint contact type contact is a multi-faceted contactor made of beryllium copper or copper (for example, a louver-shaped metal strip known by the trade name of multilam band: manufactured by Multicontact Corporation) In the embodiment, is arranged in an annular shape on the outer periphery of the center conductor 3. Thus, in the present invention, the conventional structure for pulling the center conductor into the air (the shaft seal structure via the O-ring) is abolished, and the center conductor 3 is connected to the terminal integrated lid 10 via the slidable energizing member. Energized, and the seal structure employs a fixed seal structure with an O-ring 13, so the problem that occurred in the past when the shaft seal structure was through an O-ring (contractor expansion / contraction due to temperature changes in the center conductor) The problem that the O-ring wears down and the reliability of the seal is reduced) is avoided, and the reliability of the seal structure is improved to a level that can be applied to transformers installed outdoors with large temperature loads. Can do.

  Since heat is generated when a current flows through the central conductor, the polymer bushing is required to have an appropriate structure for radiating this heat in order to avoid a decrease in product life due to this heat. RIP resin has low thermal conductivity and cannot be expected to dissipate heat through RIP resin. However, in the conventional shaft seal structure with an O-ring, the shaft seal portion has high thermal conductivity. The heat dissipation structure is not particularly considered. On the other hand, in the present invention, a structure through a slidable energizing member is adopted, and in this structure, the thermal conductivity is lower than that of a shaft seal structure through an O-ring. It is necessary to secure the heat dissipation capability of the other structure. Therefore, in the present invention, the length (L2) of the portion existing in the soot tube in the RIP capacitor core is set to 70% or less of the overall length (L1) of the soot tube main body (ie, RIP) Good heat dissipation characteristics are ensured by sufficiently securing a space in which heat is radiated from the surface of the central conductor not covered with resin toward the insulating gas.

  L2 should be short from the viewpoint of heat dissipation characteristics, but on the other hand, it should be long from the viewpoint of electric field characteristics. When "L2 is less than 50% of L1," the absolute value of the creeping electric field by electric field analysis is Since a region exceeding the discharge electric field is generated, it is desirable that “L2 is 50% or more of L1” from the viewpoint of electric field characteristics.

  Here, “L1” is the minimum required length for insulation performance (minimum effective length of the soot tube that satisfies “JEC-5202-2007, P14 Table 6”) (regardless of the contamination level) Since it can be defined uniquely, the “capacitor core designed so that L2 is 70% or less of L1” is also uniquely determined, and when the total length of the tub tube body changes under fouling conditions (for example, for heavy fouling) The capacitor core can be shared even in the case where the total length of the soot tube main body is longer than that for light fouling.

  When “L2 is less than 50% of L1”, there is a region where the absolute value of the creeping electric field by electric field analysis exceeds the discharge electric field. From the viewpoint of electric field characteristics, “L2 is 50% or more of L1”. It is desirable to have L2 in the range of 50 to 70% of L1, so that the inside of the polymer soot pipe has a RIP (resin impregnated paper) capacitor core inside the polymer soot pipe penetrating the center conductor. In the polymer bushing for transformers, where the space formed above the RIP (resin-impregnated paper) capacitor core is filled with insulating gas, the reliability of the shaft seal structure at the location where the center conductor is drawn into the air is improved, and the temperature load is increased. Therefore, it is possible to realize a structure that can be applied to a transformer installed outdoors.

  As described above, the polymer bushing of the present invention is decomposable, and only the soot tube main body portion of the polymer soot tube can be replaced. Since polymer pipes are made of organic insulating materials, they generally have a short life of about 30 years due to deterioration due to discharge at the time of fouling, deterioration of the interface, etc., and transformers with a life expectancy of 40 to 50 years. There is no coordination. For this reason, it is necessary to replace the bushing when the transformer is in use and damage due to aging or handling mistakes during maintenance / maintenance is appropriate, but now it is a non-decomposable polymer bushing (molded with urethane elastomer). The bushing that is directly molded to the RIP resin, etc.) is the mainstream, so it is necessary to replace the entire polymer bushing, and it involves ancillary work such as processing transformer oil. Cost is required. On the other hand, as described above, according to the present invention in which only the soot tube main body portion of the polymer soot tube can be replaced, these disadvantages can be eliminated.

  In the present embodiment, since the center clamp means 12 for pulling up the center conductor 3 is provided at the upper end of the RIP capacitor core 4, the center conductor 3 is placed on the lower oil central portion 14 even during the replacement work of the soot tube main body. It can be held in place without being dropped.

  As shown in FIG. 4, the center clamp means 12 has a configuration in which an appropriate number of compression springs 15 are arranged on the upper part of the RIP capacitor core 4, and the reaction force of the compression springs 15 is centered via a spring retainer 16. By acting in the direction in which the conductor 3 is lifted, the central conductor 3 is held at the above-mentioned fixed position. In the unlikely event that the internal pressure rises, the force of the compression spring 15 acts in a direction to move the center conductor 3 to the lower oil middle portion 14, but in this embodiment, the compression spring 15 is completely short-circuited as shown in FIG. Since the spring retainer 16 is brought into contact with the stopper 17 before the movement, the movement of the center conductor 3 can be prevented. In FIG. 4, 18 is a half screw, 19 is an upper shield cover, 20 is a lock nut, and 21 is a lower shield cover.

  Table 1 below shows the results of electric field analysis and thermal fluid analysis while changing the length of L2 on the premise of a polymer bushing for 154 kV (RIP capacitor core, gas filling in the internal space).

  In Table 1, L1 = 1500 mm is a value determined based on “JEC-5202-2007, P14 Table 6”.

  The electric field analysis is a short-term commercial frequency withstand voltage test voltage (325 kVrms) based on “JEC-5202-2007, P14 Table 6”, evaluated by the presence or absence of discharge in the rubber surface electric field, and “NG” Those that did not occur were designated as “OK”.

The thermal fluid analysis uses a compressible unsteady analysis method, the outside air temperature is 40 ° C., the insulating oil temperature is 95 ° C., the center conductor is an aluminum wrought material, and the heat generation amount is 1.77 × 10 ⁴ W / m ^3. went. As a result of the analysis, the case where the maximum value of the temperature rise of the central conductor exceeds 65K is set as “NG”, and the case where it is less than 65K is set as “OK”.

  As shown in Examples 1 and 2, “the inside of the polymer pipe having the central conductor penetrated has a RIP (resin impregnated paper) capacitor core, and inside the polymer pipe, the RIP (resin impregnated paper) capacitor core The space formed above is filled with insulating gas, and the structure that draws the center conductor into the air (shaft seal structure via the O-ring) is abolished, and the center conductor is connected to the terminal integrated lid via a slidable energizing member. In the transformer polymer bushing in which the seal structure is a fixed seal structure using an O-ring, by setting L2 within the range of 50 to 70% of L1, the temperature load is reduced in both the heat radiation characteristics and the electric field characteristics. It was confirmed that a structure with a level of characteristics applicable to a large transformer installed outdoors could be realized. On the other hand, as shown in Comparative Example 1, when L2 is less than “50% of L1,” it is confirmed that a region where the absolute value of the creeping electric field by electric field analysis exceeds the discharge electric field occurs. It was done. Further, as shown in Comparative Example 2, when L2 exceeds “70% of L1,” “a space where heat is radiated from the surface of the central conductor not covered with the RIP resin toward the insulating gas” is generated. It was confirmed that the above level could not be satisfied from the viewpoint of heat dissipation characteristics, which could not be secured sufficiently.

DESCRIPTION OF SYMBOLS 1 Polymer bushing 2 Polymer soot pipe 3 Center conductor 4 RIP capacitor core 5 FRP cylinder, soot pipe main body 6 Jacket | cover 7 Upper flange metal fitting 8 Lower flange metal fitting 9 Internal space 10 Terminal integrated cover 11 Sliding electricity supply member 12 Center clamp means 13 O ring 14 Oil middle part 15 Compression spring 16 Spring retainer 17 Stopper 18 Counter split screw 19 Upper shield cover 20 Lock nut 21 Lower shield cover

Claims (5)

A polymer pipe having flange metal fittings disposed on the upper and lower sides of the pipe main body, a center conductor penetrating through a central portion of the polymer pipe, and an RIP capacitor core for electric field relaxation formed around the center conductor, the polymer pipe In polymer bushings filled with insulating gas in the interior space of
The location where the center conductor is pulled out from the polymer soot tube has a fixed seal structure with an O-ring,
A terminal integrated lid is arranged on the upper part of the flange fitting disposed above the soot tube main body, and includes a slidable energizing member as an energizing means for energizing the terminal integrated lid and the central conductor,
A polymer bushing characterized in that the length (L2) of the portion of the RIP capacitor core existing in the soot tube body is in the range of 50 to 70% of the overall length (L1) of the soot tube body.   2. The polymer bushing according to claim 1, wherein the length “L1” is a length required for insulation performance of the polymer bushing.   2. The polymer bushing according to claim 1, wherein the “L2” has a length required for discharge performance of the polymer bushing.   The polymer bushing according to claim 1, wherein a center clamp means for pulling up the center conductor is provided at an upper end portion of the capacitor core.   The polymer bushing according to claim 1, wherein the slidable energizing member is a multi-point contact type contact made of a louver-like metal strip.