Underground power station long vertical bus section overhaul and maintenance tool and method

Abstract

The invention provides a repair and maintenance tool and method for a long vertical bus section of an underground power station. The repair and maintenance tool comprises a fixed supporting structure used for clamping and fixing a bus to be dismantled. The fixed supporting structure comprises a rack main body, the top of the rack main body is fixedly provided with a top fixing frame, and an arc-shaped supporting structure used for supporting a bus is arranged between the rack main bodies; the dustproof baffle structure is used for preventing aluminum skimmings and dust from falling off in the bus bar cutting process, and the dustproof baffle structure is of a split structure. According to the tool and the method, a customized overhaul tool is carried out for the bus where a fault point possibly occurs, a scientific overhaul and maintenance strategy is formulated, an old bus can be conveniently and rapidly transported out of a vertical shaft, and a new bus can be conveniently hoisted to an installation position so as to deal with daily maintenance and emergency repair under an emergency situation.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive evaluation of power systems, and specifically to a tool and method for overhauling and maintaining a vertical bus section of an underground power station. Background Art

[0002] The conventional way to lead the IPB of the underground powerhouse of a hydropower station to the ground booster station is generally to adopt the method of one machine and one shaft. The main circuit closed busbar of the hydropower station generator is arranged horizontally with three phases. The main circuit closed busbar of the generator starts from the pit wall, passes through the downstream wall of the underground powerhouse to the horizontal busbar tunnel. The excitation transformer, PT / lightning arrester cabinet and generator electric brake switch device are arranged at the bottom of the horizontal busbar tunnel. Each machine is equipped with a CT detachable device on the horizontal section of the main circuit IPB located behind the generator electric brake switch device in the horizontal busbar tunnel. The IPB of the underground power station is connected to the ground switch station through the horizontal busbar corridor, the busbar vertical shaft and the ground switch station. The layout method of two machines and one shaft is adopted. The shaft section adopts the form of a long vertical phase-separated closed busbar. The height difference of the long vertical section is about 100 meters. There are many elbows, branch circuits and joints, and the busbar installation environment is complex.

[0003] Since the high-current busbar shell and conductor have large dimensions and are made of pure aluminum, they may experience many operating problems after years of long-term operation, such as local deformation, increased deflection, non-concentricity of the conductor shell, loose soft connections, poor electrical contact, and insulation degradation. However, due to the complex direction of the busbar, the large number of connected devices, and the long length, its status is difficult to monitor effectively, which can easily lead to various insulation degradation faults, endangering the safe and stable operation of the unit. In the event of a fault, it is necessary to use appropriate maintenance methods to carry out maintenance to meet daily maintenance and to respond to emergency repairs in emergencies. Summary of the invention

[0004] Against the above background, the invention provides a tool and method for the inspection and maintenance of the vertical busbar section of an underground power station. This tool and method are customized for the busbar where fault points may occur, and a scientific inspection and maintenance strategy is formulated. The old busbar can be easily and quickly transported out of the shaft, and the new busbar can be conveniently hoisted to the installation location to cope with daily maintenance and emergency repairs in unexpected situations.

[0005] In order to realize the above technical features, the purpose of the invention is achieved as follows: an underground power station long vertical bus section inspection and maintenance tool, including a fixed support structure for clamping and fixing the bus to be removed; The fixed support structure includes a frame body, a top fixing frame is fixed on the top of the frame body, and an arc-shaped support structure for supporting the busbar is arranged between the frame bodies; It also includes a dustproof baffle structure for preventing aluminum chips and dust from falling during the busbar cutting process, and the dustproof baffle structure adopts a split structure.

[0006] The frame body adopts a rectangular frame structure, a reinforcing beam is fixed between the rectangular frame structures, a first triangular reinforcing plate is arranged between the inner top corners of the rectangular frame structure, and a second triangular reinforcing plate is arranged between the reinforcing beam and the inner wall of the rectangular frame structure.

[0007] The arc-shaped support structure adopts an arc-shaped support rod, both ends of which match with the matching holes on the rectangular frame structure through the first mounting hole, and the arc-shaped support structure is selectively mounted on the matching holes of the rectangular frame structure.

[0008] The dust baffle structure includes an annular plate, a center hole is arranged at the center of the annular plate, end face flanges are arranged at two butting ends of the annular plate, flange holes are arranged on the end face flanges, the flange holes are fixedly connected by connecting bolts, and the two matching sets of annular plates are connected by the end face flanges.

[0009] A method for inspecting and maintaining a vertical busbar section of an underground power station, the maintenance method being implemented by using the maintenance tool, comprising the following steps: Step 1: Before cutting the busbar conductor, a dust baffle structure is used to fix it. The dust baffle structure consists of two parts, which are assembled into a whole on site. A fire blanket is inserted in the gap between the inner circle of the dust baffle structure and the busbar conductor to prevent aluminum chips and dust from falling to the lower busbar when cutting the busbar conductor. Step 2: If the fixed support structure at a certain location of the 1# fixed point fails, the corresponding construction plan is adopted to repair and replace the failed busbar at that location; Step 3: If the fixed support structure at a certain location of the 2# fixed point fails, the corresponding construction plan is adopted to repair and replace the failed busbar at that location; Step 4: If the fixed support structure at a certain location of the 3# fixed point fails, the corresponding construction plan shall be adopted to repair and replace the failed busbar at that location; Step 5: If the fixed support structure at any of the 4# and 5# fixing points fails, and so on, the corresponding construction plan will be adopted to repair and replace the failed busbar at that location.

[0010] The step 2 specifically includes: There are a / b / c three-phase busbars at the 1# fixed point. Due to the layout of the transformer, the a / b / c-phase busbars of the 27# machine need to be lifted up 2m and turned after exiting the shaft before they can be connected to the a-phase low-voltage bushing of the transformer. Based on this, the a / b / c-phase busbars at the 1# fixed point are only 2.1m away from the bottom of the cable interlayer. The space is limited. If the a / b / c-phase fixed support at the 1# fixed point fails, the corresponding section number is the 11# busbar. At this time, the 11# busbar needs to be replaced, and the 13# and 14# busbars above this section of the busbar need to be removed to make room for busbar replacement. The outer shell bracket between the #13 and #14 busbars was removed by grinding, and the conductor displacement value was measured. The design value of the gap between the two conductors here is 340mm; Grind and remove the outer shell tiles and conductors between the #14 and #45 busbars, and remove the 14# busbar; grind and remove the outer shell tiles below the unit aluminum corrugated tube at an elevation of 140m, and measure the conductor displacement value at this location. The design value of the gap between the two sections of conductors here is 550mm. The actual displacement of this unit conductor is obtained through the displacement difference and recorded so that the gap between the two sections of busbar conductors can be restored to the original design value when it is restored; add temporary support for the conductor in this unit aluminum corrugated tube at an elevation of 140m to prevent the conductor from moving further downward and affecting the next unit conductor; use a dust baffle structure to seal the conductor and the outer shell here to prevent aluminum chips from falling to the next unit busbar when cutting the outer shell tiles above; cut the #7 section and #1 1. Cut the shell and conductor bushings between busbar sections #13 and #11, dismantle and remove busbar section #13; dismantle and remove busbar section #11, put new busbar #11 in place, adjust the gap between the conductor of new busbar #11 and the conductor of original busbar #7 to the original design value of 550mm, and weld the conductor bushings; put original busbars #13 and #14 in place, weld the conductor bushings of #13 and #14, #14 and 45# busbars; clean the dust and aluminum chips in the busbar, and weld the shell bushings; after the above work is completed, finally complete the welding of shell bushings at elevation 140m; before all busbars are in place, relevant insulation and withstand voltage tests are required, and they can be put in place only after passing the tests.

[0011] The step 3 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 2# fixing point fails, it is necessary to first remove the shell brackets under the aluminum corrugated tubes at the 2# unit and the 3# unit, and measure the conductor displacement value at this location; then remove the shell brackets under the aluminum corrugated tubes at the 2# unit and the 1# unit, and measure the conductor displacement value at this location. Next, perform step 2 to remove the single-phase busbar of a / b / c phase at the 1# fixing point; then remove the conductor fixed support section at the 2# fixing point, and replace the new #2 busbar in the same way as the busbar at the 1# fixing point.

[0012] The step 4 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 3# fixing point fails, it is necessary to first remove the shell brackets under the aluminum bellows at the 3# unit and the 4# unit, and measure the conductor displacement value at this location; then remove the shell brackets under the aluminum bellows at the 3# unit and the 2# unit, and measure the conductor displacement value at this location; next, perform step three to remove the single-phase busbars of a / b / c phase at the 1# and 2# fixing points; then remove the conductor fixed support section at the 3# fixing point, and replace the new #3 busbar in the same way as the busbars at the 1# and 2# fixing points.

[0013] The step 5 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 4# fixed point fails, it is necessary to first remove the shell bracket under the aluminum corrugated pipe at the 4# unit and the 5# unit, and measure the conductor displacement value at this location; then remove the shell bracket under the aluminum corrugated pipe at the 4# unit and the 3# unit, and measure the conductor displacement value at this location; next, perform step 4 to remove the single-phase busbars of a / b / c phase at the 1#, 2#, and 3# fixed points; then remove the conductor fixed support section at the 4# fixed point, and replace the new #4 busbar in the same way as the busbars at the 1# and 2# fixed points; If the single-phase fixed support structure of a / b / c phase at the 5# fixing point fails, it is necessary to first remove the shell bracket under the 5# unit and the last section of the aluminum corrugated pipe, and measure the conductor displacement value at this location; then remove the shell bracket under the aluminum corrugated pipe at the 5# unit and the 4# unit, and measure the conductor displacement value at this location; next, perform step five to remove the a / b / c phase single-phase busbar at the 1#, 2#, 3#, and 4# fixing points; then remove the conductor fixed support section at the 5# fixing point, and replace the new #5 busbar in the same way as the busbars at the 1# and 2# fixing points.

[0014] The invention has the following beneficial effects: 1. The present invention designs maintenance tools tailored to the busbar where the fault point may occur, and formulates a scientific maintenance strategy, which can conveniently and quickly transport the old busbar out of the shaft and conveniently hoist the new busbar to the installation location to cope with daily maintenance and emergency repairs in unexpected situations.

[0015] 2. The present invention uses a dust baffle to fix the busbar conductor before cutting. The dust baffle is designed as two parts, which are assembled into a whole on site. A fire blanket is plugged in the gap between the inner ring and the conductor to prevent aluminum chips and dust from falling to the lower busbar when cutting the busbar conductor.

[0016] 3. The present invention assumes that a fixed support structure at a 1# fixed point fails, and proposes a construction plan for emergency repair and replacement of the failed busbar; assumes that a fixed support structure at a 2# fixed point fails, and proposes a construction plan for emergency repair and replacement of the failed busbar; assumes that a fixed support structure at a 3# fixed point fails, and proposes a construction plan for emergency repair and replacement of the failed busbar; assumes that the single-phase fixed support structure of phase a at the 4# and 5# fixed points fails, and so on, and assumes that the single-phase fixed support structure of phase b at the 1#~5# fixed points fails, and proposes a construction plan for emergency repair and replacement of the failed busbar. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 The present invention is a schematic diagram of the location of the busbar fault section.

[0019] Figure 2 This is a top view of the dust baffle structure of the invention.

[0020] Figure 3 This is the AA view of the dust baffle structure in Invention Question 2.

[0021] Figure 4 This is a top view of the dust baffle structure of the invention.

[0022] Figure 5 This is the AA view of the dust baffle structure in Invention Question 2. DETAILED DESCRIPTION

[0023] The embodiments of the invention will be further described below in conjunction with the accompanying drawings.

[0024] Embodiment 1: See also Figure 1-5 , a tool for repairing and maintaining the vertical busbar section of an underground power station, including a fixed support structure for clamping and fixing the busbar to be removed; the fixed support structure includes a frame body 7, a top fixing frame 6 is fixed on the top of the frame body 7, and an arc support structure 12 for supporting the busbar is arranged between the frame bodies 7; it also includes a dust baffle structure for preventing aluminum chips and dust from falling during the busbar cutting process, and the dust baffle structure adopts a split structure. This tool and method are tailor-made for the busbar where the fault point may occur, and a scientific repair and maintenance strategy is formulated, which can conveniently and quickly transport the old busbar out of the shaft, and facilitate the hoisting of the new busbar to the installation position to cope with daily maintenance and emergency repairs in emergencies.

[0025] Furthermore, the frame body 7 adopts a rectangular frame structure, a reinforcing crossbeam 8 is fixed between the rectangular frame structures, a first triangular reinforcing plate 11 is arranged between the inner corners of the rectangular frame structure, and a second triangular reinforcing plate 13 is arranged between the reinforcing crossbeam 8 and the inner wall of the rectangular frame structure. The frame body 7 of the present invention can be used for Furthermore, the arc support structure 12 adopts an arc support rod, both ends of which cooperate with the matching holes 9 on the rectangular frame structure through the first mounting holes 10, and the arc support structure 12 is selectively installed on the matching holes 9 of the rectangular frame structure.

[0026] Furthermore, the dust baffle structure includes an annular plate 1, a center hole 2 is provided at the central portion of the annular plate 1, end face flanges 4 are provided at two butting ends of the annular plate 1, flange holes 5 are provided on the end face flanges 4, the flange holes 5 are fixedly connected by connecting bolts 3, and the two matching sets of annular plates 1 are connected by the end face flanges 4.

[0027] Embodiment 2: A method for inspecting and maintaining a vertical busbar section of an underground power station, the maintenance method being implemented by using the maintenance tool, comprising the following steps: Step 1: Before cutting the busbar conductor, a dust baffle structure is used to fix it. The dust baffle structure consists of two parts, which are assembled into a whole on site. A fire blanket is inserted in the gap between the inner circle of the dust baffle structure and the busbar conductor to prevent aluminum chips and dust from falling to the lower busbar when cutting the busbar conductor. Step 2: If the fixed support structure at a certain location of the 1# fixed point fails, the corresponding construction plan is adopted to repair and replace the failed busbar at that location; Step 3: If the fixed support structure at a certain location of the 2# fixed point fails, the corresponding construction plan and emergency plan shall be adopted to repair and replace the failed busbar at that location; Step 4: If the fixed support structure at a certain location of the 3# fixed point fails, the corresponding construction plan shall be adopted to repair and replace the failed busbar at that location; Step 5: If the fixed support structure at any of the 4# and 5# fixed points fails, and so on, the corresponding construction plan will be adopted to repair and replace the failed busbar at that location.

[0028] Embodiment 3: The present invention takes the extreme working conditions of the closed busbar of the main circuit of a generator in an underground powerhouse of an existing power station and the failure of the fixed support structure as an example to introduce the implementation of the inspection and maintenance of the long vertical busbar section of the underground power station at different fixed points in the present invention and the tooling method.

[0029] The three-phase closed busbar of the generator main circuit is arranged horizontally with a phase-to-phase distance of 2.0m. The vertical height of the busbar shaft is about 80m, and the cross-sectional size of the shaft is 6600x8000mm. The current of the isolated phase busbar is 26000A. According to relevant calculations and selection, the conductor size is Ф1040×16 / 17mm, the conductor weight is 156.04 kg / m; the shell size is Ф1600×12mm. According to the strength verification of the fixed support of the isolated phase closed busbar, the isolated phase busbar needs to be equipped with a fixed support structure every 18 meters or so. Therefore, the longest busbar segment shell in the shaft is 5.4 meters, including 6.1 meters for the conductor, and the break between sections is 0.6 meters. A telescopic joint is set every 18 meters for the busbar conductor in the shaft, and a total of 5 sets of conductor telescopic joints and 5 sets of shell fixed support structures are set in the vertical section.

[0030] After arranging two IPBs in a shaft of this size, the operating space left for maintenance is very limited. Due to the limitations of on-site conditions, during the construction period, hooks were installed in the workshop at the top of the busbar shaft for secondary transportation, lifting and positioning of IPBs. Therefore, the maintenance and repair of the isolated phase busbars need to use the original hooks.

[0031] Step 1: Before cutting the busbar conductor, a dust baffle structure is used to fix it. The dust baffle structure consists of two parts, which are assembled into a whole on site. A fire blanket is inserted in the gap between the inner circle of the dust baffle structure and the busbar conductor to prevent aluminum chips and dust from falling to the lower busbar when cutting the busbar conductor. Step 2: Assuming that the a / b / c phase fixed support structure fails somewhere at the 1# fixed point, propose a construction plan for emergency repair and replacement of the failed busbar at that location.

[0032] There are a / b / c three-phase busbars at the 1# fixed point. Due to the layout of the transformer, the a / b / c-phase busbars of the 27# machine need to be lifted up 2m and turned after exiting the shaft before they can be connected to the a-phase low-voltage bushing of the transformer. Based on this, the a / b / c-phase busbars at the 1# fixed point are only 2.1m away from the bottom of the cable interlayer. The space is limited. If the a / b / c-phase fixed support at the 1# fixed point fails, the corresponding section number is the 11# busbar. At this time, the 11# busbar needs to be replaced, and the 13# and 14# busbars above this section of the busbar need to be removed to make room for busbar replacement. The outer shell bracket between the #13 and #14 busbars was removed by grinding, and the conductor displacement value was measured. The design value of the gap between the two conductors here is 340mm; Grind and remove the outer shell tiles and conductors between the #14 and #45 busbars, and remove the 14# busbar; grind and remove the outer shell tiles below the unit aluminum corrugated tube at an elevation of 140m, and measure the conductor displacement value at this location. The design value of the gap between the two sections of conductors here is 550mm. The actual displacement of this unit conductor is obtained through the displacement difference and recorded so that the gap between the two sections of busbar conductors can be restored to the original design value when it is restored; add temporary support for the conductor in this unit aluminum corrugated tube at an elevation of 140m to prevent the conductor from moving further downward and affecting the next unit conductor; use a dust baffle structure to seal the conductor and the outer shell here to prevent aluminum chips from falling to the next unit busbar when cutting the outer shell tiles above; cut the #7 section and #1 1. Cut the shell and conductor bushings between busbar sections #13 and #11, dismantle and remove busbar section #13; dismantle and remove busbar section #11, put new busbar #11 in place, adjust the gap between the conductor of new busbar #11 and the conductor of original busbar #7 to the original design value of 550mm, and weld the conductor bushings; put original busbars #13 and #14 in place, weld the conductor bushings of #13 and #14, #14 and 45# busbars; clean the dust and aluminum chips in the busbar, and weld the shell bushings; after the above work is completed, finally complete the welding of shell bushings at elevation 140m; before all busbars are in place, relevant insulation and withstand voltage tests are required, and they can be put in place only after passing the tests.

[0033] Step 3: Assuming that the single-phase fixed support structure of a / b / c phases at the 2# fixed point fails, a construction plan for emergency repair and replacement of the failed busbar is proposed.

[0034] The step 3 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 2# fixing point fails, it is necessary to first remove the shell brackets under the aluminum corrugated tubes at the 2# unit and the 3# unit, and measure the conductor displacement value at this location; then remove the shell brackets under the aluminum corrugated tubes at the 2# unit and the 1# unit, and measure the conductor displacement value at this location. Next, perform step 2 to remove the single-phase busbar of a / b / c phase at the 1# fixing point; then remove the conductor fixed support section at the 2# fixing point, and replace the new #2 busbar in the same way as the busbar at the 1# fixing point.

[0035] Step 4: Assuming that the single-phase fixed support structure of a / b / c phases at the 3# fixed point fails, a construction plan for emergency repair and replacement of the failed busbar is proposed.

[0036] The step 4 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 3# fixing point fails, it is necessary to first remove the shell brackets under the aluminum bellows at the 3# unit and the 4# unit, and measure the conductor displacement value at this location; then remove the shell brackets under the aluminum bellows at the 3# unit and the 2# unit, and measure the conductor displacement value at this location; next, perform step three to remove the single-phase busbars of a / b / c phase at the 1# and 2# fixing points; then remove the conductor fixed support section at the 3# fixing point, and replace the new #3 busbar in the same way as the busbars at the 1# and 2# fixing points.

[0037] Step 5, assuming that the single-phase fixed support structure of a / b / c phases at the 4# and 5# fixed points fails, propose a construction plan for emergency repair and replacement of the failed busbar at that location.

[0038] The step 5 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 4# fixed point fails, it is necessary to first remove the shell bracket under the aluminum corrugated pipe at the 4# unit and the 5# unit, and measure the conductor displacement value at this location; then remove the shell bracket under the aluminum corrugated pipe at the 4# unit and the 3# unit, and measure the conductor displacement value at this location; next, perform step 4 to remove the single-phase busbars of a / b / c phase at the 1#, 2#, and 3# fixed points; then remove the conductor fixed support section at the 4# fixed point, and replace the new #4 busbar in the same way as the busbars at the 1# and 2# fixed points; If the single-phase fixed support structure of a / b / c phase at the 5# fixing point fails, it is necessary to first remove the shell bracket under the 5# unit and the last section of the aluminum corrugated pipe, and measure the conductor displacement value at this location; then remove the shell bracket under the aluminum corrugated pipe at the 5# unit and the 4# unit, and measure the conductor displacement value at this location; next, perform step five to remove the a / b / c phase single-phase busbar at the 1#, 2#, 3#, and 4# fixing points; then remove the conductor fixed support section at the 5# fixing point, and replace the new #5 busbar in the same way as the busbars at the 1# and 2# fixing points.

Claims

1. A tool for inspecting and maintaining the vertical busbar section of an underground power station, characterized in that: It includes a fixed support structure for clamping and fixing the busbar to be removed; The fixed support structure comprises a frame body (7), a top fixing frame (6) is fixed on the top of the frame body (7), and an arc-shaped support structure (12) for supporting the busbar is arranged between the frame bodies (7); It also includes a dustproof baffle structure for preventing aluminum chips and dust from falling during the busbar cutting process, and the dustproof baffle structure adopts a split structure.

2. According to claim 1, a tool for repairing and maintaining a vertical busbar section of an underground power station, characterized in that: The frame body (7) adopts a rectangular frame structure, a reinforcing crossbeam (8) is fixed between the rectangular frame structures, a first triangular reinforcing plate (11) is arranged between the inner top corners of the rectangular frame structure, and a second triangular reinforcing plate (13) is arranged between the reinforcing crossbeam (8) and the inner wall of the rectangular frame structure.

3. According to claim 2, a tool for repairing and maintaining a vertical busbar section of an underground power station, characterized in that: The arc-shaped support structure (12) adopts an arc-shaped support rod, and the two ends of the arc-shaped support rod are matched with the matching holes (9) on the rectangular frame structure through the first mounting holes (10), and the arc-shaped support structure (12) is selectively mounted on the matching holes (9) of the rectangular frame structure.

4. According to claim 1, a tool for repairing and maintaining a vertical bus section of an underground power station, characterized in that: The dust baffle structure comprises an annular plate (1), a central hole (2) is provided at the central portion of the annular plate (1), end face flanges (4) are provided at two butting ends of the annular plate (1), flange holes (5) are provided on the end face flanges (4), the flange holes (5) are fixedly connected by connecting bolts (3), and the two matching sets of annular plates (1) are connected by the end face flanges (4).

5. A method for inspecting and maintaining a vertical busbar section of an underground power station, characterized in that: The maintenance method is implemented by using the maintenance tool according to any one of claims 1 to 4, and comprises the following steps: Step 1: Before cutting the busbar conductor, a dust baffle structure is used to fix it. The dust baffle structure consists of two parts, which are assembled into a whole on site. A fire blanket is inserted in the gap between the inner circle of the dust baffle structure and the busbar conductor to prevent aluminum chips and dust from falling to the lower busbar when cutting the busbar conductor. Step 2: If the fixed support structure at a certain location of the 1# fixed point fails, the corresponding construction plan is adopted to repair and replace the failed busbar at that location; Step 3: If the fixed support structure at a certain location of the 2# fixed point fails, the corresponding construction plan is adopted to repair and replace the failed busbar at that location; Step 4: If the fixed support structure at a certain location of the 3# fixed point fails, the corresponding construction plan shall be adopted to repair and replace the failed busbar at that location; Step 5: If the fixed support structure at any of the 4# and 5# fixing points fails, and so on, the corresponding construction plan will be adopted to repair and replace the failed busbar at that location.

6. A method for inspecting and maintaining a vertical busbar section of an underground power station according to claim 5, characterized in that: The step 2 specifically includes: There are a / b / c three-phase busbars at the 1# fixed point. Due to the layout of the transformer, the a / b / c-phase busbars of the 27# machine need to be lifted up 2m and turned after exiting the shaft before they can be connected to the a-phase low-voltage bushing of the transformer. Based on this, the a / b / c-phase busbars at the 1# fixed point are only 2.1m away from the bottom of the cable interlayer. The space is limited. If the a / b / c-phase fixed support at the 1# fixed point fails, the corresponding section number is the 11# busbar. At this time, the 11# busbar needs to be replaced, and the 13# and 14# busbars above this section of the busbar need to be removed to make room for busbar replacement. The outer shell bracket between #13 and #14 busbars was removed by grinding, and the conductor displacement value was measured. The design value of the gap between the two conductors here is 340mm; Grind and remove the outer shell tiles and conductors between the #14 and #45 busbars, and remove the 14# busbar; grind and remove the outer shell tiles below the unit aluminum corrugated tube at an elevation of 140m, and measure the conductor displacement value at this location. The design value of the gap between the two sections of conductors here is 550mm. The actual displacement of this unit conductor is obtained through the displacement difference and recorded so that the gap between the two sections of busbar conductors can be restored to the original design value when it is restored; add temporary support for the conductor in this unit aluminum corrugated tube at an elevation of 140m to prevent the conductor from moving further downward and affecting the next unit conductor; use a dust baffle structure to seal the conductor and the outer shell here to prevent aluminum chips from falling to the next unit busbar when cutting the outer shell tiles above; cut the #7 section and #1 1. Cut the shell and conductor bushings between busbar sections #13 and #11, dismantle and remove busbar section #13; dismantle and remove busbar section #11, put new busbar #11 in place, adjust the gap between the conductor of new busbar #11 and the conductor of original busbar #7 to the original design value of 550mm, and weld the conductor bushings; put original busbars #13 and #14 in place, weld the conductor bushings of #13 and #14, #14 and 45# busbars; clean the dust and aluminum chips in the busbar, and weld the shell bushings; after the above work is completed, finally complete the welding of shell bushings at elevation 140m; before all busbars are in place, relevant insulation and withstand voltage tests are required, and they can be put in place only after passing the tests.

7. A method for inspecting and maintaining a vertical bus section of an underground power station according to claim 6, characterized in that: The step 3 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 2# fixing point fails, it is necessary to first remove the shell brackets under the aluminum corrugated tubes at the 2# unit and the 3# unit, and measure the conductor displacement value at this location; then remove the shell brackets under the aluminum corrugated tubes at the 2# unit and the 1# unit, and measure the conductor displacement value at this location. Next, perform step 2 to remove the single-phase busbar of a / b / c phase at the 1# fixing point; then remove the conductor fixed support section at the 2# fixing point, and replace the new #2 busbar in the same way as the busbar at the 1# fixing point.

8. A method for inspecting and maintaining a vertical busbar section of an underground power station according to claim 6, characterized in that: The step 4 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 3# fixing point fails, it is necessary to first remove the shell brackets under the aluminum bellows at the 3# unit and the 4# unit, and measure the conductor displacement value at this location; then remove the shell brackets under the aluminum bellows at the 3# unit and the 2# unit, and measure the conductor displacement value at this location; next, perform step three to remove the single-phase busbars of a / b / c phase at the 1# and 2# fixing points; then remove the conductor fixed support section at the 3# fixing point, and replace the new #3 busbar in the same way as the busbars at the 1# and 2# fixing points.

9. A method for inspecting and maintaining a vertical bus section of an underground power station according to claim 6, characterized in that: The step 5 specifically includes: If the single-phase fixed support structure of a / b / c phase at the 4# fixed point fails, it is necessary to first remove the shell bracket under the aluminum corrugated pipe at the 4# unit and the 5# unit, and measure the conductor displacement value at this location; then remove the shell bracket under the aluminum corrugated pipe at the 4# unit and the 3# unit, and measure the conductor displacement value at this location; next, perform step 4 to remove the single-phase busbars of a / b / c phase at the 1#, 2#, and 3# fixed points; then remove the conductor fixed support section at the 4# fixed point, and replace the new #4 busbar in the same way as the busbars at the 1# and 2# fixed points; If the single-phase fixed support structure of a / b / c phase at the 5# fixing point fails, it is necessary to first remove the shell bracket under the 5# unit and the last section of the aluminum corrugated pipe, and measure the conductor displacement value at this location; then remove the shell bracket under the aluminum corrugated pipe at the 5# unit and the 4# unit, and measure the conductor displacement value at this location; next, perform step five to remove the a / b / c phase single-phase busbar at the 1#, 2#, 3#, and 4# fixing points; then remove the conductor fixed support section at the 5# fixing point, and replace the new #5 busbar in the same way as the busbars at the 1# and 2# fixing points.

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