CN111614010B

CN111614010B - 500kV welding type GIL pipeline bus decomposition and maintenance method

Info

Publication number: CN111614010B
Application number: CN202010397751.7A
Authority: CN
Inventors: 孙昕; 肖荣; 王翔; 褚建华; 秦风斌; 刘跃伟; 朱君; 赵雁群; 陈涛; 鲍鹏; 付国宏; 梁绍龙; 王义平; 唐敦浩; 吴穹
Original assignee: China Yangtze Power Co Ltd
Current assignee: China Yangtze Power Co Ltd
Priority date: 2020-05-12
Filing date: 2020-05-12
Publication date: 2021-04-13
Anticipated expiration: 2040-05-12
Also published as: CN111614010A

Abstract

The invention discloses a 500kV welded GIL pipeline bus decomposition maintenance method, which solves the technical problems of disassembly, decomposition, reinstallation, debugging and the like of a hundred-meter-long GIL pipeline in a narrow space on site, realizes the rapid repair of discharge faults in the welded GIL, standardizes and modularizes a complex maintenance operation process flow, ensures the maintenance quality, reduces the maintenance difficulty and the operation safety risk, and shortens the maintenance period. The method provides rapid fault handling for the overhaul of the important power transmission equipment, ensures that the power transmission characteristic cannot be reduced due to the decomposition of the pipeline of the GIL, ensures the time and economic benefit of overhaul for the operation of the emergency overhaul of the important power transmission equipment, and establishes a domestic welding type GIL fault overhaul working method and a process standard.

Description

500kV welding type GIL pipeline bus decomposition and maintenance method

Technical Field

The invention relates to the field of maintenance of welding type pipeline buses of a power system, in particular to a 500kV welding type GIL pipeline bus decomposition maintenance method.

Background

GIL, known as Gas insulated transmission lines, is a Gas insulated metal enclosed power transmission line. From the installation position, the whole GIL power transmission line mainly comprises the GIL pipelines with the horizontal sections and the vertical sections and is divided into different independent gas compartments, and each gas compartment comprises a plurality of sections of GIL pipe joints.

The GIL has the characteristics of large transmission capacity, low resistance loss, long service life, high reliability, environmental friendliness, small occupied space and the like. The method is particularly suitable for large hydropower stations and nuclear power stations arranged in underground powerhouses as outgoing lines and underground corridor lines of densely populated cities. However, once a fault occurs, the maintenance is extremely difficult, the 500kV welding type GIL is a new technology and new equipment, and no corresponding maintenance technology exists at home at present, and the manufacturing and maintenance capabilities are not provided.

When one GIL fails, a large hydropower station will cause about several million-degree power generation loss every day. A large amount of clean energy is wasted, and the power station suffers huge economic loss. In order to quickly finish GIL fault maintenance and ensure the normal operation of the power station power transmission channel. The invention creates a 500kV welding type GIL pipeline bus overhaul working method and a process standard, can quickly finish overhaul of a GIL fault pipeline, and ensures reliable and stable operation of power supply.

The GIL pipelines are divided into flange connection type and welding connection type, and a plurality of sections of pipelines can form the GIL pipelines with the length of hundreds of meters and even thousands of meters. The flange connectivity GIL pipeline is assembled in a segmented mode during actual installation and maintenance, the flange face is sealed by the O-shaped sealing ring and connected with the bolts through the bolts, when the GIL pipeline has an internal serious discharge fault, the pipeline is disassembled, disassembled and assembled in a segmented mode, the operation process is simple and convenient, the repairing period is short, however, the GIL pipeline is long, the number of flange sealing faces is large, the flange sealing rings at the segmented positions have the defects that the air leakage of a compartment and the air tightness are reduced due to the installation problem and the natural aging problem, and the gas insulation performance in the GIL pipeline is influenced. The weldable GIL pipeline has stable integral air tightness and good strength because welding seams are adopted between pipe joints to replace flange sealing surfaces, and is generally used, one gas compartment can be hundreds of meters long, but because the pipeline is an integral rigid pipeline, when the GIL pipeline has an internal serious discharge fault, if the whole compartment needs to be replaced, the pipeline needs to be disassembled and disassembled section by section, the pipeline needs to be cut, the pipeline needs to be assembled back section by section and accurately butted and welded seams are welded, the repair process is complex and strict, the repair work period is long, the pipeline is disassembled and lifted due to overlong pipelines, safety accidents are easily caused by improper operation, equipment or personal injury is caused, because the welding type GIL belongs to novel domestic equipment, the disassembly and maintenance technology for the pipeline after the fault has no mature achievement, and how to realize that aluminum alloy is cut all the position of the GIL pipeline in a field space, Welding, and realizing the whole hoisting operation of the vertical pipeline of the GIL with the length of hundreds of meters in a narrow vertical shaft, dismounting and mounting the single-section pipeline and finally realizing quick fault repair are difficult.

The invention also provides a technology for overhauling a GIL pipeline in the prior art, for example, Chinese patent document CN 110797791A describes a method for overhauling a lower 500kVGIL tubular bus under the condition of no accompanying shutdown, and the gas management of a GIL device, the high-quality, safe and efficient overhauling of the 500kVGIL tubular bus and the recovery of the gas chamber management of the GIL device under the condition of no accompanying shutdown are carried out; the output load is increased; the potential safety hazard is small, less safety risks can be controlled, and the cross of working faces is less, so that the safety and civilized construction appearance can be ensured; the time consumed by continuous work is short, and the work efficiency is high; the limitation of insufficient safety distance is small, but the method is only used for checking the tubular bus at the lower layer, and cannot process the pipeline bus with serious faults, so that the method has great limitation.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a 500kV welding type GIL pipeline bus decomposition and maintenance method, which can solve a series of problems of GIL pipeline decomposition and maintenance operation technology under the conditions of narrow space and complex maintenance environment on site. A set of technical method and technological standard of maintenance operations of marking, decomposing and cutting, manufacturing new pipe joints, assembling and welding and the like of the GIL pipeline are independently initiated at home, the complex maintenance operation technological process is standardized and modularized, the maintenance quality is guaranteed, the maintenance difficulty and the operation safety risk are reduced, and the maintenance period is shortened. The technical problems of disassembly, decomposition, reinstallation, debugging and the like of the GIL aluminum alloy pipeline in a narrow space on site are solved, and the rapid repair of the discharge fault in the welding type GIL is realized.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

the 500kV welding type GIL pipeline bus decomposition and maintenance method comprises the following steps:

and (3) maintenance preparation: detecting and positioning faults of the faulted GIL pipeline, and performing gas operation on a maintenance compartment at the fault position;

removing accessories of the GIL pipeline bus: measuring and marking installation positions of a GIL pipeline, an elbow module and a support piece in an overhaul compartment, recording the installation positions, removing the elbow module, the support piece, a grounding wire, an SF gas density relay and other related accessories at corresponding positions, and locking a non-overhaul part;

hoisting and cutting a GIL pipeline bus:

the method comprises the following steps: if the pipeline needs to be disassembled, firstly disconnecting the flange connections at two ends of the linear pipe joint of the pipeline at the GIL horizontal section, disconnecting the connection of a GIL conductor, hoisting the whole pipeline at the GIL horizontal section to the ground, then cutting the welding seams at two ends of the pipeline at the GIL horizontal section to be replaced by using an automatic annular cutter, and hoisting to a specified position after the cutting is finished;

step two: if the pipeline needs to be disassembled, firstly, the flange connections at two ends of the pipeline at the vertical section of the GIL are disconnected, an automatic annular cutter is used for cutting a welding seam at the lower end of the pipeline at the vertical section of the GIL, then, a welding seam at the upper end of the pipeline at the vertical section of the GIL is cut, the pipeline is hoisted to a specified position after the cutting is finished, and conductors in single standard section can be decomposed by cutting the pipeline in sections, so that the welding type GIL pipeline can be processed in sections, the length of the pipeline for hoisting and transporting is reduced, the safety risk and the technical difficulty are reduced, and the overhaul time is greatly saved;

and (3) disassembling the GIL pipeline bus:

horizontally placing the cut GIL pipeline, and removing a GIL shell, a GIL conductor and an insulator of the GIL pipeline;

GIL New pipe segment preparation:

formulating a piping scheme according to the recorded and measured pipeline length, accurately cutting the GIL new pipe joint according to the piping scheme, polishing and smoothing internal thread welding seams within a range of 10cm inside and outside pipe orifices at two ends after the cutting is finished, and expanding the pipe orifice at the pre-assembled position of the new pipe joint to ensure that the pipe orifice expansion depth at each position of the pipeline is consistent, and the circle center of the expanded pipe is concentric with the pipeline;

pre-assembling the GIL new pipe joint:

cleaning a GIL shell and a GIL conductor which are formed by the new pipe joint and the insulator, pre-assembling GIL parts into a standard joint, and installing and fixing the GIL conductor;

pre-assembling and detecting the GIL new pipe joint:

the method comprises the following steps of detecting the size, the technological effect and the contact resistance of a conductor connecting surface of a preassembled GIL new pipe joint, wherein the inner wall of a shell and the surface of a conductor of the preassembled GIL new pipe joint are intact, clean, free of burrs and scratches, the surface of an insulator is free of cracks, burrs and bulges, a conductive contact surface on the convex side of the insulator is required to be polished smooth before butt joint installation, and the contact resistance (including the contact resistance between the conductor and the insulator and between the conductor and a female contact) of a conductor bolt fastening butt joint surface is measured;

and (3) reinstalling and welding the GIL new pipe joint:

adjusting the direction of the GIL new pipe joint, preparing a welding seam of the pipe orifice, then reinstalling and welding, and carrying out nondestructive testing on the welding seam;

and (3) recovering the bus accessories of the GIL pipeline:

according to the position mark before disassembly, reinstalling relevant accessories such as an elbow module, a support piece, a grounding wire, an SF6 gas density relay and the like;

gas operation after GIL pipeline maintenance:

vacuumizing the decomposed maintenance compartment, then carrying out pressure test and gas purging, vacuumizing again and filling SF6 gas into the maintenance compartment after the maintenance compartment is qualified, and standing to detect that the quality of the SF6 gas is qualified;

partial discharge and pressure test of GIL pipeline:

and (4) carrying out resistance measurement, partial discharge measurement and field power frequency alternating current withstand voltage test on the GIL pipeline main loop of the repair section, and finishing the overhaul after the GIL pipeline main loop is qualified.

The specific method for the maintenance preparation comprises the following steps:

after the pipeline breaks down, fault location is carried out through corresponding testing and detecting means, the fault position is searched, after the fault position is determined, SF6 gas in the overhaul compartment is completely recycled, dry air is filled to positive pressure, and the gas in the adjacent compartments is recycled to half of rated air pressure.

The method for dismounting the pipeline at the GIL horizontal section in hoisting and cutting the bus of the GIL pipeline comprises the following steps:

disconnecting the flange connection of elbow modules at two ends of a GIL horizontal pipeline to be replaced, axially displacing the whole GIL horizontal pipeline, disconnecting the connection of a GIL conductor, fixing the GIL conductor, integrally hoisting the GIL horizontal pipeline to the ground, erecting an automatic annular cutter at the welding seam of a GIL shell, enabling a cutting head of the automatic annular cutter to be perpendicular to the surface of the GIL shell, cutting the welding seams at two ends of the GIL shell, cutting straight long pipe sections according to the welding seams, and decomposing the straight long pipe sections into single standard sections to be transported to an appointed position.

The method for hoisting and cutting the GIL pipeline bus and disassembling the GIL vertical section pipeline comprises the following steps:

firstly, disconnecting flanges at two ends of a GIL vertical section pipeline to be dismantled, integrally lifting the GIL vertical section pipeline by using a bridge machine, erecting an automatic annular cutter at a welding seam at the lower end of the GIL vertical section pipeline to be dismantled, enabling a cutting head of the automatic annular cutter to be vertical to the surface of a GIL shell, cutting the welding seam at the lower end of the GIL vertical section pipeline, integrally lifting the GIL vertical section pipeline by using the bridge machine to form a gap at the cutting seam, fixing a GIL conductor at a cutting opening at the lower end of the GIL vertical section pipeline, then erecting the automatic annular cutter at a welding seam at the upper end of the GIL vertical section pipeline to be dismantled, cutting the welding seam at the upper end of the GIL vertical section pipeline, fixing the GIL conductor in the pipeline above the cutting opening, lifting the cut pipe section to a designated place for storage, integrally descending the GIL vertical section pipeline above the cutting opening by a pipe length by using the bridge machine, fixing the upper end of the pipeline, and (4) cutting and dismantling the GIL vertical section pipeline of the maintenance section compartment section by section according to the same method.

The method for installing the GIL conductor in the pre-assembly of the GIL new pipe joint comprises the following steps:

installing a GIL conductor pulley tool on the male contact side of the GIL conductor, installing a basin lifting tool in a central process hole of the insulator, connecting the basin lifting tool with the conductor lifting tool to enable the GIL conductor to be parallel to the axis of the GIL new pipeline, moving the conductor lifting tool to enable the GIL conductor to be installed back into a new shell, then installing a conductor star-shaped support on the male contact side to enable the GIL conductor to be fixed, detaching the GIL conductor pulley tool, and then installing a basin compression ring and a basin female contact back.

The GIL conductor pulley tool is detachably connected and fixed with the GIL conductor, a rolling pulley is arranged below the GIL conductor pulley tool, and when the GIL pipeline is located in a horizontal posture, the GIL conductor pulley tool can drive one end of the GIL conductor to slide in the pipeline.

The basin lifting tool is a movable lifting support.

The conductor star-shaped support can be detachably connected and fixed with the GIL conductor, and the outer side of the conductor star-shaped support can enable the GIL conductor to be fixed with the inner part of the GIL pipeline through expansion.

The invention provides a 500kV welding type GIL pipeline bus decomposition maintenance method which can complete welding type GIL equipment maintenance operation in a complex operation environment of a narrow space on site and establish a domestic welding type GIL fault maintenance working method and a domestic welding type GIL fault maintenance process standard. The feasibility of the invention is already tested and applied in two large hydropower stations in China, and creates huge economic benefits. Taking a large hydropower station in a certain country as an example, during the peak period of power generation, one GIL line fails, so that three units are shut down, the load is limited by 210 thousands, the electricity loss in 1 day is 5040 thousands DEG, and about 1700 RMB is more than ten thousands.

The welding type GIL pipeline decomposition maintenance technology is mastered, GIL fault rapid maintenance is achieved, power generation loss can be reduced to the maximum extent, stable operation of a power grid is guaranteed, and the method is significant. The application of the domestic GIL equipment is developed vigorously at present, the method is favorable for improving the research and development of the domestic GIL equipment, can play a role in promoting the manufacturing, installation and maintenance of the GIL equipment, can promote the technical progress of related subjects, and provides a reference method and a process standard for the maintenance of other types of GIL equipment.

Drawings

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

FIG. 1 is a GIL pipeline overhaul flow chart of the present invention;

FIG. 2 is a diagram of a transmission line structure of a GIL pipeline of the present invention;

FIG. 3 is a diagram of a GIL pipe section according to the present invention;

FIG. 4 is a cutting view of a GIL pipe section of the present invention;

FIG. 5 is a diagram of the hoisting of the GIL pipe joint of the present invention;

FIG. 6 is a disassembled view of the GIL pipe joint of the present invention;

FIG. 7 is a diagram of the new GIL shell expander of the present invention;

fig. 8 is a block diagram of the new GIL pipe section pre-assembly of the present invention.

In the figure: the system comprises a GIL horizontal section pipeline 1, a GIL vertical section pipeline 2, an elbow module 3, a vertical section gas compartment A4, a vertical section gas compartment B5, a flange 6, a standard section GIL pipe joint 7 in the gas compartment B, an adjusting section GIL pipe joint 8 in the gas compartment B, a GIL shell 9, a GIL conductor 10, SF6 gas 11, an insulator 12, a guide rod 13, a male contact 14, a female contact 15, a rod insulator 16, an automatic annular cutter 17, a GIL pipeline 18, a bridge crane 19, a GIL pipe joint vertical-to-horizontal-posture tool 20, a GIL conductor pulley tool 21, a conductor hoisting tool 22, a basin hoisting tool 23, a pipe expander 24, a horizontal section new GIL pipe joint 25, a vertical section new GIL pipe joint 26 and a conductor star support 27.

Detailed Description

removing accessories of the GIL pipeline bus: measuring and marking the installation positions of the GIL pipeline 18, the elbow module 3 and the supporting piece in the overhaul compartment, recording, removing the elbow module 3, the supporting piece, the grounding wire, the SF6 gas density relay and other related accessories at the corresponding positions, and locking the non-overhaul part;

as shown in fig. 4 and 5, the GIL pipeline bus is hoisted and cut:

the method comprises the following steps: if the pipeline 1 needs to be disassembled, firstly disconnecting the flange connections at two ends of the linear pipe section of the pipeline 1, disconnecting the connection of the GIL conductor 10, hoisting the whole pipeline 1 to the ground, then cutting the welding seams at two ends of the pipeline 1 to be replaced by using an automatic annular cutter 17, and hoisting to a specified position after the cutting is finished;

step two: if the pipeline 2 of the GIL vertical section needs to be disassembled, firstly disconnecting the flange connection at the two ends of the pipeline 2 of the GIL vertical section, cutting the welding seam at the lower end of the pipeline 2 of the GIL vertical section by using an automatic annular cutter 17, then cutting the welding seam at the upper end of the pipeline 2 of the GIL vertical section, then hoisting the cut pipeline 2 of the GIL vertical section by using a bridge machine 19, and cutting and disassembling the pipeline 2 of the GIL vertical section of the overhaul section compartment by the same method;

the conductor in a single standard section can be decomposed by cutting the GIL pipeline in sections, so that the welded GIL pipeline can be processed in sections, the length of the pipeline for lifting and transporting is reduced, the safety risk and the technical difficulty are reduced, and the maintenance time is greatly saved;

the automatic ring cutter 17 is a commercially available product, such as a TT-NG-610 type ring automatic cutter manufactured by Puteng machinery;

as shown in fig. 6, disassembly of GIL pipe bus:

horizontally placing the cut GIL pipeline, and removing a GIL shell 9, a GIL conductor 10 and an insulator 12 of the GIL pipeline;

as shown in fig. 7, GIL new pipe joints were made:

pre-assembling the GIL new pipe joint:

cleaning a GIL shell 9 and a GIL conductor 10 which are formed by the new pipe sections and an insulator 12, pre-assembling GIL parts into a standard section, and installing and fixing the GIL conductor 10;

pre-assembling and detecting the GIL new pipe joint:

and (3) reinstalling and welding the GIL new pipe joint:

adjusting the direction of the GIL new pipe joint, preparing a welding seam of the pipe orifice, then performing welding at the installation position in a resetting way, and performing nondestructive testing on the welding seam;

and (3) recovering the bus accessories of the GIL pipeline:

according to the position mark before disassembly, the elbow module 3, the supporting piece, the grounding wire, the SF6 gas density relay and other related accessories are reinstalled;

gas operation after GIL pipeline maintenance:

partial discharge and pressure test of GIL pipeline:

after the pipeline breaks down, fault location is carried out through corresponding test and detection means, the fault position is searched, after the fault position is determined, SF6 gas in the overhaul compartment is completely recycled, dry air is filled to positive pressure, and the gas in the adjacent compartment is recycled to half of rated air pressure.

The method for disassembling the GIL horizontal section pipeline 1 in hoisting and cutting the GIL pipeline bus comprises the following steps:

disconnecting the flange connection of elbow modules 3 at two ends of a GIL horizontal pipeline 1 to be replaced, axially displacing the whole GIL horizontal pipeline 1, disconnecting a GIL conductor 10, fixing the GIL conductor 10, hoisting the whole GIL horizontal pipeline 1 to the ground, erecting an automatic annular cutter 17 at a weld joint of a GIL shell, enabling a cutting head of the automatic annular cutter 17 to be perpendicular to the surface of the GIL shell 9, cutting the weld joint at two ends of the GIL shell 9, cutting a straight long pipeline section according to the weld joint, and decomposing the straight long pipeline section into a single standard section to be transported to an appointed position.

As shown in fig. 4 and 5, the method for dismounting the GIL vertical section pipeline 2 in hoisting and cutting the GIL pipeline bus bar comprises the following steps:

firstly, disconnecting flanges at two ends of a GIL vertical section pipeline 2 to be dismantled, integrally lifting the GIL vertical section pipeline 2 by using a bridge machine 19, erecting an automatic annular cutter 17 at a welding seam at the lower end of the GIL vertical section pipeline 2 to be dismantled, enabling a cutting head 17 of the automatic annular cutter to be vertical to the surface of a GIL shell 9, cutting the welding seam at the lower end of the GIL vertical section pipeline 2, integrally lifting the GIL vertical section pipeline 2 by using the bridge machine 19 to form a gap at the cutting seam, fixing a GIL conductor 10 at a cutting opening at the lower end of the GIL vertical section pipeline 2, then erecting the automatic annular cutter 17 at a welding seam at the upper end of the GIL vertical section pipeline 2 to be dismantled, cutting the welding seam at the upper end of the GIL vertical section pipeline 2, fixing the GIL conductor 10 in a pipeline above the cutting seam, lifting the cut pipe section to a designated place for storage, integrally lowering the GIL vertical section pipeline 2 above the cutting surface by a pipe length by using the bridge machine 19, and fixing the upper end of the pipeline, and cutting and dismantling the GIL vertical section pipeline 2 of the overhaul section compartment section by section in turn according to the same method.

The method for installing the GIL conductor 10 in the pre-assembly of the GIL new pipe joint comprises the following steps:

installing a GIL conductor pulley tool 21 on the side of a male contact 14 of a GIL conductor 10, installing a basin lifting tool 23 in a central process hole of an insulator 12, connecting the basin lifting tool 23 with the conductor lifting tool 22 to enable the GIL conductor 10 to be parallel to the axis of a new GIL pipeline, moving the conductor lifting tool 22 to enable the GIL conductor 10 to be installed back into a new shell, then installing a conductor star-shaped support 27 on the side of the male contact 14 to enable the GIL conductor 10 to be fixed, detaching the GIL conductor pulley tool 21, and then installing a basin compression ring and a basin female contact back.

As shown in fig. 6, the GIL conductor pulley tooling 21 is detachably connected and fixed with the GIL conductor 10, a rolling pulley is arranged below the GIL conductor pulley tooling 21, and when the GIL pipeline is in a horizontal posture, the GIL conductor pulley tooling 21 can drive one end of the GIL conductor 10 to slide in the pipeline.

As shown in fig. 6, the basin lifting tool 23 is a movable lifting bracket.

As shown in fig. 8, the conductor star supports 27 can be detachably connected and fixed to the GIL conductor 10, and the GIL conductor 10 can be fixed to the inside of the GIL pipe by tightening the outer sides of the conductor star supports 27.

In the following, the example is the GIL pipeline bus overhaul of a certain large power station, and the failed GIL pipeline is a large-caliber spiral welded aluminum alloy pipeline produced by linde corporation:

the vertical section GIL duct of a large power plant consists of A, B sections of independent gas cells. Wherein, the compartment B (consisting of 8 sections of GIL standard pipe joints, B109 and B110 two sections of GIL adjusting pipe joints, B101-B108) has faults, and pollutes the whole compartment pipeline, and the GIL pipeline in the compartment B needs to be disassembled for maintenance. The maintenance operation steps are as follows:

and (3) maintenance preparation: the GIL vertical pipeline is failed, and B108 and B109 pipe joints of a B compartment are found to be failed through test data and detection means. After the fault position is determined, completely recovering SF6 gas in a fault compartment B of the vertical section, and filling dry air into the compartment to slight positive pressure; the gas in the adjacent compartment a is recovered to half of the rated gas pressure.

Removing accessories of the GIL pipeline bus: and measuring and marking the installation positions of the GIL pipeline, the elbow module, the expansion joint, the sliding support and the like in the overhaul compartment B, and recording. 11500mm and 11294mm of the shell length of the GIL pipe section of the standard section from the section B101 to the section B108, 10060mm and 9854mm of the shell length of the GIL pipe section of the section B109, 8500mm and 8294mm of the shell length of the GIL pipe section of the section B110 are measured. These data are recorded after the measurement is completed. And (4) removing the right-angle elbow, the sliding support and the grounding wire thereof, the SF6 gas density relay and other related accessories at the corresponding positions, and locking the non-overhaul position.

Hoisting and cutting a GIL pipeline bus: the GIL is removed in the sequence that the lower adjusting sections B110 and B109 are removed first, and then the upper 8 standard sections B108 to B100 are removed. The method comprises the steps of erecting an automatic annular pipeline cutting machine on the lower end of a GIL vertical pipe joint of a B110 section of a B compartment section, cutting along the upper portion of a welding line central line, removing an upper-section pipeline fixing measure, integrally lifting the upper-section pipeline, installing a conductor star-shaped supporting tool in the GIL vertical pipeline to firmly fix a conductor, cutting the upper end of the pipeline at an adjusting section by using the automatic annular cutting machine, removing the upper-section pipeline fixing measure, integrally lifting the upper-section pipeline by using a bridge crane for 30cm, fixedly fixing the conductor in the pipeline above the cut by using the conductor star-shaped installing tool, lifting the cut pipe joint by using the bridge crane, conveying the whole upper-section pipeline by using the bridge crane for a length of a section of pipeline, and fixing the upper-section pipeline. The remaining GIL vertical pipes of the service compartment B are removed according to the same cutting removal method.

Transportation and disassembly of the GIL pipeline bus: the cut vertical section GIL pipe joint is moved to a lifting position from an installation position through a slide rail tool on a cutting platform, a trapezoidal hanging tool lifting hook is connected with a lifting ring on a pipe joint annular transport trolley, the pipe joint is lifted by a bridge crane and is lowered to a vertical shaft flat hole from the cutting platform, a GIL pipe joint vertical-to-horizontal posture tool is installed at the lower end of the pipe joint, the pipe joint is converted into a horizontal posture from a vertical posture, the pipe joint stably falls onto a GIL transport cart, and the pipe joint is transferred to an appointed position to be stored. And disassembling the removed GIL shell, the inner conductor and the insulators at the two ends.

Manufacturing a new pipe joint of the GIL pipeline: accurately cutting a new pipe joint, accurately cutting the new pipe joint of the GIL according to the measured actual length of the GIL of the old pipeline, wherein the length of a standard section shell of 8 sections is 11500mm, the lengths of two sections of adjusting section shells are 10060mm and 8500mm, the length of an 8 section conductor is 11294mm, and the lengths of two sections of adjusting section conductors are 9854mm and 8294 mm;

expanding a pipe orifice, polishing and smoothing internal thread welding seams within a range of 10cm inside and outside the pipe orifices at two ends of the new GIL pipe joint after cutting is finished, expanding the pipe orifices, wherein the pipe orifices at all positions of the pipeline have the same expansion depth, and the circle center of the expanded pipe is concentric with the pipeline and cannot be eccentric;

pre-assembling the GIL new pipe joint: and cleaning the new GIL shell, the inner conductor and the insulator. The process standard of the GIL pipe joint preassembly is that the inner wall of the shell and the surface of the conductor are intact, clean and free of burrs and scratches, and the surface of the insulator is free of cracks, burrs and bulges;

after the cleaning treatment is finished, the GIL parts are preassembled into a standard knot, a conductor pulley is arranged on the side of the conductor male contact, a basin lifting tool is arranged in the center process hole of the insulator, and the conductor is installed back into a new shell. And a conductor star-shaped support is arranged on the side of the male contact to fix the conductor firmly, the conductor pulley is removed, and then the basin compression ring and the basin female contact are installed again. After the conductor is preassembled, measuring the contact of the connection surface of the conductor spiral conductor (the contact resistance between the conductor and the insulator and between the conductor and the female contact);

and measuring and recording the length of the pipe joint and the length of the conductor extending out of the pipe joint after the new pipe joint is preassembled, and numbering and marking the 10-joint pipeline (numbered as B100-B110). Finally, a proper amount of adsorbent is placed in the pipe joint, and two ends of the pipe joint are sealed for standby.

And (3) reinstalling and welding the GIL new pipe joint: the back-loading sequence of the GIL is that B100 to B108 at the upper end are installed firstly, then B109 and B110 at the lower end are installed, the direction of a preassembled new GIL pipe joint is adjusted (the side with an insulator is the upper end, the side without the insulator is the lower end), the pipe joint is hoisted to a flat hole hoisting point, the preparation of a welding seam of a pipe orifice is carried out, a pipe joint annular transport trolley is installed at the side of the insulator of the pipe joint, the installation position is about 1.6m away from the pipe orifice, a bridge crane and a trapezoidal suspension tool are used for hoisting the side of a pipe joint flange, a pipe joint vertical-to-horizontal-posture tool is used for converting the horizontal posture of the pipe joint into a vertical posture, and the pipe joint;

an automatic annular welding machine rail is arranged on the pipeline, and the upper pipeline and the lower pipeline are in butt joint, so that the butt joint is required to be tight and seamless. And welding the welding seam by using a welding robot, and after the welding is finished, carrying out ultrasonic nondestructive inspection on the welding seam by using a welding seam ultrasonic flaw detector until the ultrasonic nondestructive inspection is qualified. After the pipeline welding is finished, the upper section of pipeline is integrally lifted by a height of one section of pipeline by using a bridge crane, the next section of pipeline is subjected to reinstallation welding, and finally the pipeline is installed as B110.

And (3) recovering the bus accessories of the GIL pipeline: according to the position mark before disassembly, the GIL pipeline sliding guide support and the grounding wire thereof are reassembled, the elbow module is reassembled, the disassembled fixing point of GIL pipeline transportation and steel members such as steel beams and steel gratings of the auxiliary supporting platform are reassembled, the special tool for hoisting the GIL pipeline is disassembled, and the temporary safety fixing measure is disassembled.

Gas operation after GIL pipeline maintenance: vacuumizing the decomposed maintenance compartment, then carrying out pressure test and gas purging, vacuumizing again and filling SF6 gas into the maintenance compartment after the maintenance compartment is qualified, and standing to detect that the quality of the SF6 gas is qualified;

partial discharge and pressure test of GIL pipeline: and (3) carrying out resistance measurement on a main loop of the GIL pipeline in the B compartment, wherein the test standard is that the resistance of the loop is measured at the same position and is not more than 1.2 times of a handover value or a design calculation value. And then, an alternating current withstand voltage test and partial discharge measurement are carried out, so that internal breakdown discharge, flashover and other abnormal phenomena are avoided, and the test is qualified.

Claims

The 1.500kV welding type GIL pipeline bus decomposition and maintenance method is characterized by comprising the following steps of:

removing accessories of the GIL pipeline bus: measuring and marking installation positions of a GIL pipeline (18), an elbow module (3) and a support piece in the overhaul compartment, recording the installation positions, detaching the elbow module (3), the support piece, a grounding wire and an SF6 gas density relay at corresponding positions, and locking a non-overhaul part;

hoisting and cutting a GIL pipeline bus:

the method comprises the following steps: if the pipeline (1) in the GIL horizontal section needs to be disassembled, firstly disconnecting the flange connections at two ends of the linear pipe section of the pipeline (1) in the GIL horizontal section, disconnecting the connection of the GIL conductor (10), hoisting the whole pipeline (1) in the GIL horizontal section to the ground, then cutting the welding seams at two ends of the pipeline (1) in the GIL horizontal section needing to be replaced by using an automatic annular cutter (17), and hoisting the pipeline to a specified position after the cutting is finished;

step two: if the pipeline (2) at the vertical section of the GIL needs to be disassembled, firstly disconnecting the flange connections at the two ends of the pipeline (2) at the vertical section of the GIL, cutting the welding seam at the lower end of the pipeline (2) at the vertical section of the GIL by using an automatic annular cutter (17), then cutting the welding seam at the upper end of the pipeline (2) at the vertical section of the GIL, and hoisting to a specified position after the cutting is finished;

and (3) disassembling the GIL pipeline bus:

horizontally placing the cut GIL pipeline, and removing a GIL shell (9), a GIL conductor (10) and insulators (12) at two ends of the GIL pipeline;

GIL New pipe segment preparation:

formulating a piping scheme according to the recorded and measured pipeline length, accurately cutting the GIL new pipe joint according to the piping scheme, polishing and smoothing internal thread welding seams within a range of 10cm inside and outside pipe orifices at two ends after the cutting is finished, and expanding the pipe orifice at the pre-assembled position of the new pipe joint to ensure that the pipe orifice expansion depth at each position of the pipeline is consistent, and the circle center of the expanded pipe is concentric with the pipeline;

pre-assembling the GIL new pipe joint:

cleaning a GIL shell (9) and a GIL conductor (10) formed by the new pipe joint and an insulator (12), pre-assembling GIL parts into a pipe joint with a standard length, and installing and fixing the GIL conductor (10);

pre-assembling and detecting the GIL new pipe joint:

detecting the size, the technological effect and the contact resistance of the conductor connecting surface of the pre-assembled GIL new pipe joint;

and (3) reinstalling and welding the GIL new pipe joint:

adjusting the direction of the GIL new pipe joint, preparing a welding seam of the pipe orifice, then performing welding at the installation position in a resetting way, and performing nondestructive testing on the welding seam;

and (3) recovering the bus accessories of the GIL pipeline:

and according to the position mark before disassembly, the elbow module (3), the support and the grounding wire and the SF6 gas density relay are reinstalled.
2. The 500kV welded GIL pipeline bus decomposition and overhaul method according to claim 1, wherein the disassembly method of the GIL horizontal section pipeline (1) comprises the following steps:

the disconnection needs the flange joint of GIL horizontal segment pipeline (1) both ends elbow module (3) of changing, with the whole axial displacement of GIL horizontal segment pipeline (1), throw off GIL conductor (10) and connect, fix GIL conductor (10), with the whole handling of GIL horizontal segment pipeline (1) to ground, erect automatic annular cutter (17), make automatic annular cutter (17) cutting head perpendicular to GIL shell (9) surface, cut the welding seam at GIL shell (9) both ends, handling to appointed position after cutting into the standard length tube coupling.
3. The 500kV welded GIL pipeline bus decomposition and overhaul method as claimed in claim 1, wherein the disassembly method of the GIL vertical section pipeline (2) comprises the following steps:

firstly, disconnecting the flange connections at two ends of a GIL vertical section pipeline (2) to be dismantled, integrally lifting the GIL vertical section pipeline (2) by using a bridge machine (19), erecting an automatic annular cutter (17) at the welding seam at the lower end of the GIL vertical section pipeline (2) to be dismantled, enabling a cutting head of the automatic annular cutter (17) to be perpendicular to the surface of a GIL shell (9), cutting the welding seam at the lower end of the GIL vertical section pipeline (2), integrally lifting the GIL vertical section pipeline (2) by using the bridge machine (19), forming a gap at the cutting seam, fixing a GIL conductor (10) at the cutting seam at the lower end of the GIL vertical section pipeline (2), then erecting the automatic annular cutter (17) at the welding seam at the upper end of the GIL vertical section pipeline (2) to be dismantled, cutting the welding seam at the upper end of the GIL vertical section pipeline (2), and fixing the GIL conductor (10) in the pipeline above the cutting seam, and hoisting the cut pipe sections to a designated place for storage, using a bridge crane (19) to integrally descend the GIL vertical section pipeline (2) above the cutting surface by one pipeline length, fixing the upper end of the pipeline, and sequentially cutting and dismantling the GIL vertical section pipeline (2) of the overhaul section compartment section by section according to the same method.
4. The 500kV welded GIL pipeline bus bar decomposition and overhaul method as claimed in claim 1, wherein the installation method of the GIL conductor (10) in the pre-assembly of the GIL new pipe joint comprises the following steps:

installing a GIL conductor pulley tool (21) on the side of a male contact (14) of a GIL conductor (10), installing a basin lifting tool (23) in a central process hole of an insulator (12), connecting the basin lifting tool (23) with a conductor lifting tool (22) to enable the GIL conductor (10) to be parallel to the axis of a GIL new pipeline, moving the conductor lifting tool (22) to enable the GIL conductor (10) to be installed back into a new shell, then installing a conductor star-shaped support (27) on the side of the male contact (14) to enable the GIL conductor (10) to be fixed, detaching the GIL conductor pulley tool (21), and then installing a basin compression ring and a basin female contact back.
5. The 500kV welded GIL pipeline bus decomposition and overhaul method as claimed in claim 4, wherein the method comprises the following steps: GIL conductor pulley frock (21) and GIL conductor (10) detachably connect fixedly, GIL conductor pulley frock (21) below is equipped with the rolling pulley, when the GIL pipeline was located horizontal gesture, GIL conductor pulley frock (21) can drive GIL conductor (10) one end and slide in the pipeline.
6. The 500kV welded GIL pipeline bus decomposition and overhaul method as claimed in claim 4, wherein the method comprises the following steps: the basin lifting tool (23) is a movable lifting support.
7. The 500kV welded GIL pipeline bus decomposition and overhaul method as claimed in claim 4, wherein the method comprises the following steps: the conductor star-shaped support (27) can be detachably connected and fixed with the GIL conductor (10), and the outer side of the conductor star-shaped support (27) can be used for fixing the GIL conductor (10) with the inner part of the GIL pipeline through tensioning.