Method for searching internal fault of power transformer winding

Abstract

The invention relates to the technical field of power systems, and discloses a method for searching internal faults of power transformer windings, which comprises the following steps of: arranging a plurality of groups of transparent hoses made of polyurethane materials in gaps among three-phase high, middle and low-side windings of a transformer to serve as maintenance observation pipes; when the system has a short-circuit fault, checking the current state of the transformer and checking whether the transformer trips and is powered off; after the transformer is stopped and safety measures are taken, a maintainer climbs up the top end of the transformer, inserts an industrial endoscope into an observation hole reserved in the top of the transformer and observes an internal winding of the transformer; an endoscope is inserted downwards into the transformer along the maintenance observation pipe, whether a fault exists in the transformer or not is judged through the real-time observation function of the endoscope, and the specific position of a fault point is positioned; according to the invention, an endoscope visiting mode is adopted, so that an internal fault point can be quickly positioned without disassembling the transformer, and the workload of maintainers is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of power systems, and in particular to a method for finding internal faults of power transformer windings. Background Art

[0002] The normal operation of the power system is usually dynamically balanced, and the system and equipment will not suffer a large degree of impact. When a short circuit occurs in the system, its instantaneous short-circuit current may reach several times or even dozens of times that of normal operation.

[0003] In addition to impacting the line and causing the line to trip, the short-circuit current will also have an adverse effect on the transformer. A large short-circuit current flowing through the transformer winding will produce a strong thermal effect, causing the insulation between the transformer winding turns to be damaged, the insulation strength to decrease, and cause insulation breakdown and arc discharge (such as Figure 3 ); Short-circuit current flowing through the winding will also generate a huge electric force, squeezing and pulling the winding, causing the transformer winding to deform, resulting in imbalance in the three-phase parameters of the transformer winding, and in severe cases, the entire transformer may be scrapped. If the transformer is out of service for some reason, it is necessary to conduct a comprehensive analysis to determine whether it has the operating conditions; and the transformer windings are mostly enclosed in a casing and filled with transformer oil for heat dissipation and insulation; if the transformer has an internal fault, it is not easy to detect the internal fault by conventional methods such as withstand voltage test and insulation resistance measurement, nor is it easy to accurately locate the internal fault point, which brings great difficulties to the maintenance and further analysis of the transformer.

[0004] Based on the above situation, we propose a method for finding internal faults in power transformer windings. This method is simple to apply and easy to operate. It can quickly and accurately locate the internal fault point of the transformer without disassembling the transformer, improve the accuracy of fault analysis, improve the efficiency of equipment maintenance, and ensure the safe and stable operation of the power system.

[0005] Therefore, the above problem is solved by a method for finding internal faults of power transformer windings. Summary of the invention

[0006] The purpose of the present invention is to provide a method for finding internal faults of power transformer windings to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: comprising the following steps: (1) arranging a plurality of groups of transparent hoses made of polyurethane as inspection and observation tubes in the gaps between the three-phase high, medium and low side windings of the transformer;

[0008] (2) When a short circuit occurs in the system, check the current transformer status to see if the transformer has tripped and cut off power;

[0009] (3) After the transformer is shut down and safety measures are taken, the maintenance personnel climb to the top of the transformer, insert an industrial endoscope through the observation hole reserved on the top of the transformer, and observe the internal windings of the transformer;

[0010] (4) Insert the endoscope down the inspection observation tube into the transformer, and use the real-time observation function of the endoscope to determine whether there is a fault inside the transformer and locate the specific location of the fault point;

[0011] (5) The inspection and observation tubes between the windings on both sides of the high and medium and between the windings on both sides of the medium and low are arranged in a staggered manner, further expanding the observable range.

[0012] Preferably, the maintenance observation tube is arranged from the top to the bottom of the transformer casing, and is arranged between the high and medium voltage side windings and the medium and low voltage side windings.

[0013] Preferably, a sealing opening is provided at the top of the inspection and observation tube.

[0014] Preferably, during the use of the endoscope, the location of the fault point can be further confirmed in combination with common methods such as transformer withstand voltage test and insulation resistance test.

[0015] Preferably, the maintenance observation tubes are distributed in a circular array, and the number of the maintenance observation tubes distributed between the windings on both sides of the high and medium windings and between the windings on both sides of the medium and low windings is 24-36.

[0016] Preferably, the endoscope in step (4) is used to observe whether deformation occurs inside the transformer. When deformation occurs inside the transformer, the inspection and observation tube changes along with the deformation.

[0017] Preferably, the inspection and observation tube is made of polyurethane material.

[0018] Technical effects and advantages of the present invention:

[0019] 1. The present invention is easy to operate: the present invention adopts an endoscopic inspection method, and the internal fault point can be quickly located without disassembling the transformer, which greatly reduces the workload of maintenance personnel.

[0020] Accurate positioning: Through real-time observation through the endoscope, maintenance personnel can intuitively see the condition of the internal windings of the transformer, thereby accurately determining whether there is a fault and the specific location of the fault.

[0021] Improve efficiency: The application of the present invention can significantly improve the efficiency of power grid fault handling and power grid equipment maintenance, and provide a scientific decision-making basis for whether the transformer can continue to operate, thereby ensuring the safe and reliable operation of the power grid.

[0022] Reduced costs: Since there is no need to dismantle the transformer for fault finding, a lot of dismantling and reinstallation costs can be saved.

[0023] 2. The search method of the present invention is simple to apply and easy to operate. It can quickly and accurately locate the internal fault point of the transformer without disassembling the transformer, thereby improving the accuracy of fault analysis, improving the efficiency of equipment maintenance, and ensuring the safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic side view of the transformer of the present invention.

[0025] Figure 2 This is a schematic diagram of the arrangement position of the maintenance observation tube of the present invention.

[0026] Figure 3 It is a schematic diagram of insulation damage of the winding of the present invention.

[0027] Figure 4 This is a schematic diagram of the deformation of the winding of the present invention caused by electric force extrusion. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] The present invention provides Figures 1 to 4 A method for finding internal faults in a power transformer winding is shown in FIG. Figure 1 , 2 Each of them is a three-phase power transformer structure schematic diagram, attached Figure 1 is a side view, with Figure 2 This is a top view. From left to right, there are three-phase windings A, B, and C. From the outside to the inside, each phase winding is the high-voltage side, medium-voltage side, and low-voltage side. The black dots in the figure are the locations where the inspection and observation tubes are arranged.

[0030] As attached Figure 1 As shown in the figure, several groups of transparent polyurethane hoses are arranged on the high, medium and low voltage sides of the three-phase windings of the transformer body as inspection and observation tubes. A sealing port is set at the top to prevent foreign matter and water from entering the transformer during normal operation. The inspection and observation tubes are arranged from the top to the bottom of the transformer shell, and are arranged between the high and medium voltage side windings and the medium and low voltage side windings (see Appendix). Figure 2 There is an observation hole reserved on the top shell of the transformer.

[0031] When a short circuit occurs in the system, its instantaneous short circuit current may reach several times or even dozens of times that of normal operation. In addition to impacting the line and causing the line to trip, the short circuit current will also have an adverse effect on the transformer. After the transformer is shut down and safety measures are taken, the maintenance personnel climb to the top of the transformer, insert an industrial endoscope through the reserved observation hole, and observe the internal winding conditions of the transformer.

[0032] Insert the endoscope downward along the inspection observation tube into the transformer. Use the real-time observation function of the endoscope to determine whether there is a fault inside the transformer and locate the specific position of the fault point. The endoscope observes whether deformation occurs inside the transformer. When deformation occurs inside the transformer, the inspection observation tube changes with the deformation.

[0033] The maintenance observation tubes between the high and medium sides and the medium and low sides are distributed in a circular array. There are 24 maintenance observation tubes distributed between the high and medium sides, and 24 maintenance observation tubes distributed between the medium and low sides. Because the windings are cylindrical, the 24 maintenance observation tubes are distributed in an equal-angle circular distribution, which further expands the observable range. The visualization method can help maintenance personnel quickly determine whether there is a fault inside the transformer and locate the fault position, reducing the workload of maintenance personnel and providing scientific decision-making for whether the transformer can continue to operate, thereby ensuring the safe and reliable operation of the power grid.

[0034] This method can also be combined with common methods such as transformer withstand voltage test and insulation resistance test to further confirm the location of the fault point and improve the accuracy of finding the winding fault point.

[0035] Arrangement of inspection and observation tubes:

[0036] Several groups of polyurethane transparent hoses are arranged in the gaps between the high, medium and low voltage sides of the three-phase windings of the transformer body as inspection and observation tubes. These tubes extend from the top to the bottom of the transformer shell and are arranged between the high and medium voltage windings and the medium and low voltage windings (such as the attached Figure 2 A sealing opening is provided at the top of the inspection and observation tube to prevent foreign matter, water, etc. from entering the transformer.

[0037] Use of endoscope:

[0038] After the transformer is shut down and safety measures are taken, the maintenance personnel climb to the top of the transformer and insert the industrial endoscope through the reserved observation hole. The endoscope is inserted down along the maintenance observation tube into the transformer. Through the real-time observation function of the endoscope, the maintenance personnel can intuitively see the condition of the transformer's internal windings.

[0039] Fault finding and location:

[0040] Through endoscope observation, maintenance personnel can quickly determine whether there is a fault inside the transformer. If there is a fault, the specific location of the fault point can be further located through the endoscope's magnification, rotation and other functions. At the same time, since the maintenance observation tube adopts a staggered layout, the observable range can be further expanded, improving the accuracy of fault finding.

[0041] Combined with other testing methods:

[0042] The method of the present invention can also be combined with common methods such as transformer withstand voltage test, insulation resistance test, etc. to further confirm the location of the fault point. By comprehensively applying multiple test methods, the accuracy of finding the winding fault point can be further improved.

[0043] Implementation effect:

[0044] After adopting the method of the present invention, maintenance personnel can quickly locate the internal fault point of the transformer in a short time, providing strong support for the maintenance and further analysis of the transformer. At the same time, since there is no need to disassemble the transformer for fault finding, a lot of time and cost can be saved. In addition, the application of the present invention can also improve the efficiency of power grid fault handling and power grid equipment maintenance, providing strong guarantee for the safe and stable operation of the power system.

[0045] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for finding internal faults in a power transformer winding, characterized in that: The following steps are involved: (1) Arrange several groups of transparent polyurethane hoses as maintenance observation tubes in the gaps between the three-phase high, medium and low side windings of the transformer; (2) When a short circuit occurs in the system, check the current transformer status to see if the transformer has tripped and cut off power; (3) After the transformer is shut down and safety measures are taken, the maintenance personnel climb to the top of the transformer, insert an industrial endoscope through the observation hole reserved on the top of the transformer, and observe the internal windings of the transformer; (4) Insert the endoscope down the inspection observation tube into the transformer, and use the real-time observation function of the endoscope to determine whether there is a fault inside the transformer and locate the specific location of the fault point; (5) The inspection and observation tubes between the windings on both sides of the high and medium and between the windings on both sides of the medium and low are arranged in a staggered manner, further expanding the observable range.

2. A method for finding internal faults in power transformer windings according to claim 1, characterized in that: The maintenance observation tube is arranged from the top to the bottom of the transformer casing, and is arranged between the high and medium voltage side windings and the medium and low voltage side windings.

3. A method for finding internal faults in a power transformer winding according to claim 2, characterized in that: A sealing opening is arranged at the top end of the inspection and observation tube.

4. The method for finding internal faults of power transformer windings according to claim 1, characterized in that: During the use of the endoscope, the location of the fault point can be further confirmed in combination with common methods such as transformer withstand voltage test and insulation resistance test.

5. The method for finding internal faults of power transformer windings according to claim 1, characterized in that: The maintenance observation tubes are distributed in a circular array, and the number of the maintenance observation tubes distributed between the windings on both sides of the high and medium and between the windings on both sides of the medium and low is 24-36.

6. A method for finding internal faults in power transformer windings according to claim 1, characterized in that: The endoscope in step (4) is used to observe whether deformation occurs inside the transformer. When deformation occurs inside the transformer, the inspection and observation tube changes along with the deformation.

7. A method for finding internal faults in power transformer windings according to claim 6, characterized in that: The inspection and observation tube is made of polyurethane material.

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