Power transformer ascending flanged base provided with CT wire outlet pipe barrel
By setting θRed in the transformer lift seat to set the CT outlet pipe horizontally, and setting oil-guiding vias and flared oil-gas induction grooves at the highest point of the end cover of the transformer lift seat, the moisture enrichment and chemical primary battery problems caused by the "arc-shaped triangle dead oil area" are solved, and the sufficient circulation and heat exchange of insulating oil are achieved, avoiding the risk of equipment deflagration.
Patent Information
- Application Number
- CN202510131518.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-06
- Publication Date
- 2025-05-13
AI Technical Summary
When the transformer lift seat is installed inclined, a "arcous triangle dead oil zone" is easily formed in the casing CT outlet tube, resulting in thermal and viscous effects of insulating oil, enrichment of moisture and forming chemical primary cells, which in turn causes vicious accidents of flashover along the casing and equipment explosion.
By setting θRed, when the transformer lifting seat body is installed inclined, the casing CT outlet tube is set horizontally to eliminate the "arcous triangle dead oil area"; at the same time, the oil-guiding via hole is set at the highest point of the end cap of the transformer lifting seat, and an oil-gas induction groove is used to promote the circulation and heat exchange of insulating oil and avoid the formation of the "dead oil area".
The full circulation and heat exchange of insulating oil are achieved, moisture enrichment is reduced, and vicious accidents such as flashover along the casing and equipment explosion.
Smart Images
Figure CN119993688A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power transmission and transformation equipment, and in particular to a power transformer (reactor) riser equipped with a CT outlet tube. Background Art
[0002] The transformer bushing is the main insulating component of the transformer, and the transformer (reactor) riser is a device used to support and fix the transformer bushing. In order to achieve metering and protection, a current transformer (CT) is usually installed in the transformer riser, and a bushing CT outlet tube is set on one side of the transformer riser for the CT cable to be led out. At present, the bushing CT outlet tube is usually set vertically to the transformer riser.
[0003] Due to the size limitation of transformer and the need of line layout, in some cases, the transformer riser needs to be installed at an angle (the angle is usually 15-22°). When the transformer riser is installed at an angle, the direction of the bushing CT outlet tube can be set at a depression angle or an elevation angle. Since the bushing CT outlet tube set at a depression angle is not convenient for the installation and maintenance of the lead-out cable, the elevation angle arrangement is often used in actual projects, that is, the outlet of the bushing CT outlet tube faces upward.
[0004] When the equipment is running at high load, the insulating oil in the transformer riser will form an "arc-shaped triangular dead oil zone" on the inner wall of the bushing CT outlet tube perpendicular to the bushing riser due to the gasification effect of heat evaporation. Considering the blocking effect of the cables in the bushing CT outlet tube, the trace moisture contained in the insulating oil will be enriched and circulated in the "triangular dead oil zone". After the equipment is shut down, the moisture in the oil will condense or even drip here. If the CT outlet terminal adopts the hot-dip galvanizing process, a "chemical primary battery" will be formed due to the potential between the CT lead wires. When the equipment is cold-started after maintenance (in winter), the surface insulation of the bushing oil end, which is gradually damp (or due to the conductive metal ions formed by oxidation), is prone to surface flashover accidents. Summary of the invention
[0005] First, the research and development background and ideas of this application are described as follows: In recent years, the accident rate of explosion of oil-paper (OIP) bushing, dry rubber-impregnated paper (RIP) bushing and rubber-impregnated fiber (RIF) bushing has remained high. The inspection of the explosion bushing and transformer at the accident site is as follows: in many explosion accidents, the main insulation of the bushing was damaged and no through-break of insulation between screens was detected. It was mainly manifested as surface flashover from the edge of the last screen on the oil side of the bushing to the high-voltage end on the oil side; there were traces of transverse cracks from the last screen to the high-voltage end on the oil side.
[0006] The remaining unexploded bushings dismantled from the accident transformer and the oil-side surface of the bushings replaced from the same batch of operating transformers were found to have colored streaks (metallic luster), the range of which has extended to the root of the bushing flange. The meter measured these colored streaks as "high-resistance conductors". After scanning electron microscopy observation and energy spectrum component analysis, it was found that there were metal copper and zinc in the sample chips with metallic luster. This test result shows that there is an atmosphere of metal ions and their oxides in the transformer riser. Considering the existence of the adjacent CT outlet terminal and high field strength, the applicant evaluated whether there is a weak electrolyte in the retained environment on the oil side of the bushing.
[0007] Furthermore, the applicant found that all fault transformer risers were installed at an angle of 15-22°, and the CT outlet tubes of the installed bushings were all set on the elevation side (such as Figure 1 As shown). Therefore, after collecting and analyzing sample data, the applicant confirmed that the following "dead oil areas" where heat exchange is blocked exist in the inclined transformer riser: (1) Since the bushing CT outlet tube is vertically arranged with the transformer riser, when the transformer riser is installed at an angle, an "arc-shaped triangular dead oil area" (such as Figure 1 (A) The net depth of the bushing CT outlet tube is generally about 90-130mm, and the height of the "arc-shaped triangle dead oil zone" is 23.3-33.6mm. Due to the thermal effect and viscosity effect of the insulating oil, the height of the "arc-shaped triangle dead oil zone" can reach 26-38mm; (2) The oil guide holes on the transformer riser are usually set at 0~20mm from the lower edge of the end cover (or flange). A "dead oil zone" may also be formed on the top of the transformer riser (such as Figure 1 (3) If the oil guide hole is not set at the highest point of the transformer riser, a "dead oil zone" will be generated on the top of the transformer riser due to the angular position difference of the oil hole.
[0008] Since there are various forms of gas traps in the design, manufacture and installation of the transformer riser structure, even if the trace moisture in the transformer oil is strictly controlled, when the equipment is running at high load, the insulating oil in the transformer riser located at the highest position of the transformer will accumulate more "water + oil and gas" than under normal temperature conditions due to the effects of heat and evaporation. If there is a corresponding "dead oil zone" where heat exchange is blocked, the moisture will repeatedly gather and exchange in this small area; when there are metals with large electrode potential (metal activity) differences in this area (such as copper and zinc, that is, the copper terminals on the CT outlet terminals and their galvanized layers), a chemical primary cell is formed, and the water-oil-gas mixture in the "dead oil zone" becomes the conductive liquid of the chemical primary cell, and the oxidized and reduced ion-shaped metal compounds will be adsorbed on the surface of the bushing (oil side). When the gradually accumulated conductive oxide covers and crosses the interface between the end screen and the second end screen of the bushing, the thermal effect of its surface conductivity will cause the insulating oil and the nearby resin materials to heat up until they vaporize. These gases cause the field strength around the end screen of the bushing to be seriously distorted, thereby causing a surface flashover fault in the bushing starting from the end of the screen with the maximum field strength distortion.
[0009] In order to eliminate the "dead oil zone" on the transformer riser structure as much as possible, achieve sufficient circulation and heat exchange of insulating oil, and reduce moisture enrichment, the present application provides a power transformer riser equipped with a CT outlet tube.
[0010] The present application provides a power transformer riser equipped with a CT outlet tube, which adopts the following technical solution: A power transformer riser equipped with a CT outlet tube, comprising a transformer riser body and a bushing CT outlet tube fixedly connected to one side of the transformer riser body, wherein the angle between the axis of the transformer riser body and the axis of the bushing CT outlet tube is θ Red , θ Red =90°+ θ ,in θ It is the inclination angle of the transformer riser body when it is installed; when the transformer riser body is installed at an angle, the bushing CT outlet tube is arranged horizontally.
[0011] Furthermore, the inclination angle of the transformer riser body during installation θ It is 15-22°.
[0012] Different from the conventional bushing CT outlet tube being vertically arranged to the transformer riser, the bushing CT outlet tube in the present application is not vertical to the transformer riser, so that when the transformer riser body is installed at an angle, the bushing CT outlet tube is horizontally arranged, which helps to eliminate the "arc-shaped triangular dead oil zone" in the bushing CT outlet tube, realizes full circulation and heat exchange of insulating oil, reduces moisture enrichment, and helps to avoid serious accidents such as bushing surface flashover and equipment explosion caused by moisture on the oil side insulation of the transformer bushing.
[0013] Furthermore, a transformer lift base end cover is provided on the transformer lift base body, and an oil guide hole is opened on the transformer lift base end cover. One end of the oil guide hole is connected to the internal space of the transformer lift base body, and the other end is connected to an oil guide connecting pipe, and the oil guide connecting pipe is connected to the oil pillow.
[0014] Furthermore, when the transformer riser body is installed at an angle, the oil guide hole is located at the highest point of the transformer riser end cover.
[0015] During operation, the insulating oil circulates and heat exchanges between the transformer riser body and the oil pillow; unlike the conventional oil guide through-hole arranged at the lower edge of the transformer riser end cover (or flange), the present application arranges the oil guide through-hole on the transformer riser end cover, and the oil guide through-hole is located at the highest point of the transformer riser end cover, thereby facilitating the insulating oil rich in moisture at the top of the transformer riser body to be discharged through the oil guide through-hole, thereby avoiding the formation of a "dead oil zone" at the top of the transformer riser body.
[0016] Furthermore, a flow guide structure is provided on the end cover of the transformer riser, which is used to guide the insulating oil rich in moisture in the transformer riser body out through the oil guide hole.
[0017] Furthermore, the flow guide structure includes an oil-gas induction groove opened on the inner side of the transformer lift seat end cover, and the oil-gas induction groove is connected to the oil guide hole.
[0018] Furthermore, the oil and gas induction groove is arranged in a flared manner.
[0019] The expanded oil and gas induction groove has a collecting effect on the insulating oil rich in water vapor at the top of the transformer riser body, which is conducive to inducing the insulating oil rich in water vapor to be discharged from the oil guide hole, avoiding the formation of a "dead oil zone" at the top of the transformer riser body.
[0020] Furthermore, the depth of the oil and gas induction groove is not greater than 2 / 3 of the thickness of the transformer riser end cover.
[0021] Furthermore, the width of the oil-gas induction groove is not greater than 1.5 times the diameter of the oil guide hole.
[0022] The oil and gas induction groove adopts appropriate depth and width, which can achieve effective diversion while also ensuring the safe mechanical strength of the transformer riser end cover.
[0023] Furthermore, the oil-conducting joint does not contain metal components with high electrode potential.
[0024] Avoiding the use of components containing metal components with high electrode potential (such as hot-dip galvanized components) is a necessary measure to eliminate "chemical galvanic cells".
[0025] In summary, this application includes the following beneficial technical effects: This application reduces the "dead oil area" on the transformer riser structure, achieves full circulation and heat exchange of insulating oil, reduces water enrichment, and helps avoid the vicious accidents of bushing surface flashover and equipment explosion caused by moisture on the oil side insulation of the transformer bushing. The details are as follows: 1. Through settings θ Red When the transformer riser body in the present application is installed at an angle, the bushing CT outlet tube is arranged horizontally, thereby helping to eliminate the "arc-shaped triangular dead oil zone" in the bushing CT outlet tube; 2. By setting the oil guide hole at the highest point on the end cover of the transformer riser, it is helpful to guide the insulating oil rich in moisture at the top of the transformer riser body through the oil guide hole, thereby avoiding the formation of a "dead oil zone" at the top of the transformer riser body; 3. The expanded oil and gas induction groove has a collecting effect on the insulating oil rich in water vapor at the top of the transformer riser body, which is conducive to inducing the insulating oil rich in water vapor to be discharged through the oil guide hole, avoiding the formation of a "dead oil zone" at the top of the transformer riser body. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a schematic diagram of the installation of the power transformer riser and the bushing CT outlet tube in the prior art; Figure 2 Schematic diagram of a power transformer riser equipped with a CT outlet tube according to an embodiment of the present application, wherein (a) is one embodiment and (b) is a second embodiment; Figure 3 It is a schematic diagram mainly used to show the transformer lift end cover, oil guide holes and oil and gas induction grooves in the embodiment of the present application, wherein (a) is a top view of the transformer lift end cover, and (b) is a cross-sectional view of the transformer lift end cover.
[0027] Figure numerals: 1. Transformer riser body; 2. Bushing CT outlet pipe tube; 3. Transformer riser end cover (flange); 4. Transformer bushing; 5. Oil guide hole; 6. Oil guide connecting pipe; 7. Oil and gas induction groove; 8. Bushing hole; 9. End cover welding line. DETAILED DESCRIPTION
[0028] The following is combined with Figure 2-3 This application is described in further detail.
[0029] The present application embodiment discloses a power transformer riser equipped with a CT outlet tube. Figure 2 The power transformer riser equipped with a CT outlet tube comprises a transformer riser body 1 and a bushing CT outlet tube 2 fixedly connected to one side of the transformer riser body 1. The angle between the axis of the transformer riser body 1 and the axis of the bushing CT outlet tube 2 is θ Red (named "Red Horn"), θ Red =90°+ θ ,in θ is the inclination angle of the transformer riser body 1 during installation, θ When the transformer lifting base body 1 is tilted, the bushing CT outlet tube 2 is horizontally arranged. The outlet flange of the bushing CT outlet tube 2 can be tilted (such as Figure 2 ), or it can be set vertically (as shown in (a) in Figure 2 (as shown in (b) in the figure).
[0030] Different from the conventional bushing CT outlet tube 2 and the transformer riser body 1 are arranged vertically (such as Figure 1 As shown in FIG. 1 ), the bushing CT outlet tube 2 in the present application is not perpendicular to the transformer riser body 1 (as shown in FIG. Figure 2 As shown in the figure, when the transformer riser body 1 is installed tilted, the bushing CT outlet tube 2 is horizontal, thereby eliminating the "arc-shaped triangular dead oil zone" in the bushing CT outlet tube 2, achieving full circulation and heat exchange of the insulating oil, reducing water enrichment, and helping to avoid the vicious accidents of bushing surface flashover and equipment explosion caused by moisture on the oil side insulation of the transformer bushing.
[0031] Reference Figure 2 and Figure 3 The transformer elevating seat body 1 is provided with a transformer elevating seat end cover 3, and a bushing through hole 8 for the transformer bushing 4 to pass through is provided in the center of the transformer elevating seat end cover 3. An oil guide through hole 5 is provided on the transformer elevating seat end cover 3, and one end of the oil guide through hole 5 is connected to the internal space of the transformer elevating seat body 1, and the other end is connected to an oil guide connecting pipe 6, and the oil guide connecting pipe 6 is connected to the oil pillow (not shown in the figure). The edge of the oil guide through hole 5 is tangent to the end cover welding line 9. When the transformer elevating seat body 1 is installed at an angle, the oil guide through hole 5 is located at the highest point of the transformer elevating seat end cover 3.
[0032] When the transformer is working, the insulating oil circulates and heat exchanges between the transformer riser body 1 and the oil pillow. Figure 2 The oil guide pipe 6 in the figure is a pipe for insulating oil to flow from the transformer riser body 1 to the oil pillow. The pipe for insulating oil to flow from the oil pillow to the transformer riser body 1 is not shown in the figure. Different from the conventional oil guide hole 5 arranged at the lower edge of the transformer riser end cover 3 (or flange) (such as Figure 1 As shown in FIG. 1 ), the present application sets the oil guide hole 5 on the transformer lifting seat end cover 3 (as shown in FIG. Figure 2 As shown), the oil guide hole 5 is located at the highest point of the transformer riser end cover 3, thereby facilitating the water vapor-rich insulating oil at the top of the transformer riser body 1 to be discharged through the oil guide hole 5, thereby avoiding the formation of a "dead oil zone" at the top of the transformer riser body 1.
[0033] Furthermore, a flow guiding structure is also provided on the transformer elevating seat end cover 3, which is used to guide the insulating oil rich in moisture in the transformer elevating seat body 1 out through the oil guiding hole 5. Figure 3 The flow guiding structure includes an oil-gas induction groove 7 provided on the inner side of the transformer elevating seat end cover 3, and the oil-gas induction groove 7 is connected to the oil guide hole 5. The oil-gas induction groove 7 is an expanded conical surface, that is, the width of the oil-gas induction groove 7 is gradually set, and the width of the oil-gas induction groove 7 at one end close to the inner side of the transformer elevating seat body 1 is larger, and the width of the oil-gas induction groove 7 at one end close to the outer side of the transformer elevating seat body 1 is smaller.
[0034] The expanded oil and gas induction groove 7 has a collecting effect on the insulating oil rich in water vapor at the top of the transformer riser body 1, which is conducive to inducing the insulating oil rich in water vapor to be discharged from the oil guide hole 5, avoiding the formation of a "dead oil zone" at the top of the transformer riser body 1.
[0035] In order to achieve effective diversion while ensuring the safety and mechanical strength of the transformer lifting seat end cover 3, refer to Figure 3 In (b), the depth h of the oil and gas induction groove 7 is not greater than 2 / 3 of the thickness H of the transformer riser end cover 3, and the width d of the oil and gas induction groove 7 is not greater than 1.5 times the diameter D of the oil guide hole 5.
[0036] In order to eliminate the "chemical primary battery", components containing metal components with high electrode potential (such as hot-dip galvanized components) should be avoided. Therefore, the oil guide pipe 6 is a non-galvanized pipe, and the CT wiring area uses non-galvanized materials, which can also be insulated (coated).
[0037] In addition, the use of the fully sealed internal oil type corrugated oil pillow needs to consider the breathing of the transformer body insulating oil and the oil and gas release. The inclination angle of the oil guide pipe 6 should ensure the release of gas in the oil, and the fully sealed internal oil type corrugated oil pillow should be equipped with a breather.
[0038] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.
Claims
1. A power transformer riser equipped with a CT outlet tube, characterized in that: The invention comprises a transformer elevating seat body and a bushing CT outlet tube fixedly connected to one side of the transformer elevating seat body, wherein the angle between the axis of the transformer elevating seat body and the axis of the bushing CT outlet tube is θ Red , θ Red =90°+ θ ,in θ It is the inclination angle of the transformer riser body when it is installed; when the transformer riser body is installed at an angle, the bushing CT outlet tube is arranged horizontally.
2. The power transformer riser equipped with a CT outlet tube according to claim 1, characterized in that: The inclination angle of the transformer riser body during installation θ It is 15-22°.
3. The power transformer riser equipped with a CT outlet tube according to claim 1, characterized in that: The transformer lift base body is provided with a transformer lift base end cover, and the transformer lift base end cover is provided with an oil guide hole, one end of the oil guide hole is connected to the internal space of the transformer lift base body, and the other end is connected to an oil guide connecting pipe, and the oil guide connecting pipe is connected to the oil pillow.
4. The power transformer riser equipped with a CT outlet tube according to claim 3, characterized in that: When the transformer elevating seat body is installed at an angle, the oil guide hole is located at the highest point of the transformer elevating seat end cover.
5. The power transformer riser equipped with a CT outlet tube according to claim 3, characterized in that: The transformer lift base end cover is provided with a flow guide structure for guiding the insulating oil rich in moisture in the transformer lift base body out through the oil guide hole.
6. The power transformer riser equipped with a CT outlet tube according to claim 5, characterized in that: The flow guide structure includes an oil-gas induction groove opened on the inner side of the transformer lift seat end cover, and the oil-gas induction groove is connected to the oil guide hole.
7. The power transformer riser equipped with a CT outlet tube according to claim 6, characterized in that: The oil and gas induction groove is arranged in a flared manner.
8. The power transformer riser equipped with a CT outlet tube according to claim 7, characterized in that: The depth of the oil and gas induction groove is not greater than 2 / 3 of the thickness of the transformer riser end cover.
9. The power transformer riser equipped with a CT outlet tube according to claim 8, characterized in that: The width of the oil-gas induction groove is not greater than 1.5 times the diameter of the oil-conducting hole.
10. The power transformer riser equipped with a CT outlet tube according to claim 3, characterized in that: The oil-conducting connecting pipe does not contain any metal component with high electrode potential.