500kV booster station extension interval electrical equipment installation construction method

Abstract

The invention discloses a 500kV booster station extension interval electrical equipment installation construction method. The method comprises the following steps: S1, preparation before construction; s2, engineering construction measurement; s3, earthwork engineering; s4, equipment foundation engineering; s5, channel underground facility engineering; s6, booster station road construction engineering; s7, processing and installing a transformer; and S8, electrical equipment accessory installation. By strengthening optimization creation planning, refining optimization creation targets, deepening optimization creation measures and strengthening process control and management, quality and process targets are achieved, and finally the project optimization creation target is achieved. With quality process detail control as a pushing hand, process optimization projects planned in the project comprise all equipment foundation civil engineering and electrical equipment installation construction processes; and a cable laying and wiring process. Potential safety hazards are reduced to the maximum extent, distribution of construction instruments and personnel is optimized to the maximum extent, the fund utilization efficiency is improved to the maximum extent, and balanced construction is achieved to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation step-up substations, and specifically provides a construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation. Background Technique

[0002] The expansion of the 500 kV outgoing line interval mainly includes: 500 kV incoming line frames, AIS complete sets of equipment, insulator supports and foundations, grounding, cables, secondary equipment, as well as newly built relay protection cubicles, cable trenches, expanded part of the enclosure walls, roads, drainage pipelines, and the repair of damaged roads and site gravel, etc. The average annual radiation value in the site area of the 1000 MW photovoltaic project, Phase I 500 MW EPC project is 5860.5 MJ / m2, and the annual sunshine hours are between 2700 hours and 3200 hours. Referring to GB / T 31155-2014 "Total Radiation of Solar Energy Resources", the area where this photovoltaic project is located belongs to the "very rich in resources" area, and the stability Rw is 0.36, belonging to the stable (B) area, which is suitable for building large-scale photovoltaic power stations. The overall construction layout should include the overall planning and division of the construction site, traffic organization, temporary buildings, construction water supply and power supply, material stacking, reasonable layout of equipment storage, and vertical planning. The overall construction layout should meet the following requirements: The overall layout should be reasonable, and the site allocation should be adapted to the construction tasks of each section. The terrain should be reasonably utilized to reduce the amount of earthwork for site leveling. It is advisable to utilize the positions within the site that are not to be built and postponed for construction, save land, and reduce the investment in temporary facilities and on-site transportation costs. The construction partition should conform to the requirements of the overall construction deployment and construction process, and each process should not interfere with each other. It should meet the requirements of civilized construction. Considering the characteristics of this project and combining past construction experience, reasonably arrange the construction plan and construction process, strengthen the disclosure work of the operation instruction manual, do a good job in technical guidance and service during construction, promptly solve the technical problems that occur to construction personnel during construction, and resolve some technical problems before construction as much as possible. In view of the above problems, a construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation is specifically proposed. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned existing deficiencies and provide a construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation, including the following steps:

[0005] S1, preparation before construction;

[0006] S2, engineering construction measurement;

[0007] S3, earthwork project;

[0008] S4, Equipment foundation works;

[0009] S5, Channel underground facilities works;

[0010] S6, Construction works of the road in the step-up substation;

[0011] S7, Transformer treatment and installation;

[0012] S8, Installation of electrical equipment accessories.

[0013] Preferably, the specific operation steps of the pre-construction preparation in the step S1 are as follows:

[0014] S11, Technical preparation:

[0015] Drawing review;

[0016] Equip technical specifications, codes of practice, and acceptance standards;

[0017] Elevation measurement and positioning;

[0018] S12, Equipment and material preparation:

[0019] According to the construction drawings, advance the design details of the formwork for the step-up substation building works and equipment foundation and the steel bar lofting work;

[0020] Conduct the labor and material analysis before construction, and prepare the equipment and material supply list according to the approved construction progress plan for the supervision review, formulate the selected plan for the sub-supplier, and make the entry plan for various materials;

[0021] According to the requirements of the construction plan and progress plan, prepare the construction machinery and equipment configuration plan to provide a basis for organizing transportation and determining the parking area of the machinery and equipment;

[0022] S13, Construction site preparation:

[0023] Do well in the construction site roads, water, electricity, and communication. According to the design plan for temporary water and electricity, complete the laying work of the temporary water and electricity pipelines at the construction site;

[0024] Build and harden the site and temporary roads, build temporary office, living, and production facilities, and construct the communication information system for the project;

[0025] Divide the functional areas, isolate and enclose the on-site production and living areas according to the management requirements, and do well in the on-site safety protection work.

[0026] Preferably, the specific operation steps of the engineering construction survey in the step S2 are as follows:

[0027] The survey is conducted using a total station or theodolite. According to the coordinates and elevations of the base points of the survey control network given by the survey unit, the station area control network is surveyed, fixed personnel observe and check the results, fixed level instruments and leveling rods are used, fixed leveling points are used, and observations are conducted according to the specified date, method and route;

[0028] When there are many observation points, an overall plan should be carried out on site to determine the location of the instrument to facilitate settlement observations along a fixed route each time in the future. Each time a settlement observation is carried out, various records of the observations should be made in a timely manner, the settlement amount should be calculated, relevant forms should be filled in and settlement curves should be drawn.

[0029] Preferably, the specific operation steps of the earthwork project in step S3 are:

[0030] S31, Earthwork Excavation:

[0031] The earthwork is excavated mechanically, with large excavations along the axis, manual and mechanical foundation clearing, and dump trucks transporting the earth. There are 3 1-cubic-meter excavators and 8 dump trucks on site for transportation;

[0032] Mechanical excavation leaves 200mm for manual clearing to the bottom of the foundation cushion;

[0033] Backhoe excavators are used for excavation and dump trucks are used for transporting soil. Before construction, the slope is strictly set according to the geological survey report provided by the construction unit and in accordance with the specifications;

[0034] A 300mm wide and 300mm high water retaining edge is set at 1.5m from the edge of the slope on the upper part of the foundation pit;

[0035] The excavated earth must be transported to the temporary earth pile site in time for stacking. It is strictly forbidden to pile earth around the foundation pit. The excavated earth must be transported to the designated earth pile site in time, and the temporary earth pile site must be leveled by a loader.

[0036] Control elevation, width and slope. Carefully review the drawings, measure the excavation line and elevation of the foundation pit according to the grid control points, check the width and slope of the pit bottom while digging, and make timely adjustments if they are not enough;

[0037] Earthwork transport roads are pre-specified with speed limits for transport vehicles, and all earthwork transport vehicles are covered with tarpaulins;

[0038] S32, earth backfill:

[0039] All backfill soil is compacted manually or mechanically in layers. It is required to be compacted layer by layer and section by section according to the specified layer thickness. The compaction coefficient must meet the design requirements. After passing the test, the next layer can be filled.

[0040] Preferably, the specific operation steps of the equipment foundation engineering in step S4 are:

[0041] S41, cushion construction:

[0042] After the foundation pit inspection trench is qualified, the formwork is started to be supported and the concrete cushion is poured. The cushion is supported by formwork with a width of 100 mm, and the outside is supported by wooden square timbers around the foundation pit. After the cushion is poured, it is compacted with a steel trowel.

[0043] S42, Formwork Engineering:

[0044] For the exposed foundation, high-quality film-covered wood glue formwork is used. For other foundations all located underground, formwork is used. First, the lower layer of the bearing platform is supported according to the foundation edge line, and then the upper layer of the bearing platform is supported. The formwork uses tie bolts and steel pipes for reinforcement. The outside of the foundation is supported by auxiliary 50×100 mm wooden square timbers.

[0045] S43, Steel Reinforcement Engineering:

[0046] The steel reinforcement is centrally fabricated in the steel reinforcement processing yard and transported to the site by flatbed truck for installation. After the steel reinforcement is processed, it is classified and stacked, managed by a special person, and the materials are collected according to requirements, and then transported to the foundation pit by flatbed truck for binding. First, the bottom slab is bound, and then the side wall or top slab steel reinforcement is bound. Steel stirrups are made of steel reinforcement to support between the upper and lower layers of steel reinforcement meshes to prevent the upper mesh from sinking.

[0047] S44, Concrete Engineering:

[0048] The concrete is commercial concrete, transported by tanker truck, and fed and poured by chute. The concrete is vibrated mechanically. During vibration, the iron parts and steel reinforcement shall not be touched. The concrete is vibrated in layers, with each layer not exceeding 300 mm, and the rod spacing not exceeding 500 mm. The vibration time of the vibrating rod in the concrete is about 20 - 30 s at each insertion point, and vibration is carried out until the concrete no longer sinks significantly, no bubbles appear, and the surface shows a cement paste.

[0049] After the concrete is poured, the surface is plastered and polished for the second time. After the concrete begins to set, it is covered with plastic film and watered and cured in a timely manner for not less than 7 days.

[0050] Preferably, the specific operation steps of the step S5 channel underground facility project are as follows:

[0051] When the underground facilities are relatively close to each other, following the principle of first deep then shallow, the deep foundation is constructed first, and then the shallow foundation and the channel are constructed. The bottom slab and the pool wall of the accident oil pool are constructed in one go without construction joints.

[0052] The bottom slab and the channel wall of the cable trench are poured in one go. A expansion joint is set every 25 meters for the cable trench, and a expansion joint is set every 20 meters for the plain concrete channel. An asphalt-soaked wooden board is buried from the channel wall to the bottom slab at the expansion joint and is set in the middle.

[0053] Preferably, the specific operation steps of the step S6 step-up substation road construction project are as follows:

[0054] The template uses a fixed steel template. Before supporting the template, the template installation and paving position measurement and layout are carried out on the base layer. A center pile is set every 20 meters; a temporary leveling point is arranged every 100 meters or so; the road surface elevation, panel division, expansion joint and structure position, measurement and layout quality requirements and allowable deviation are checked to be within the range specified in the specification. When constructing curved sections or intersection arcs, short templates should be used, and the midpoint of each template should be installed on the curve tangent point;

[0055] When installing the formwork, it should be installed firmly, straight, flat and without distortion. The connection between adjacent formworks should be tight and smooth, without leakage from the bottom, front and back misalignment, or high and low misalignment. The formwork should withstand the load, impact and vibration of the paving, compaction and leveling equipment without displacement or tilt. It is strictly forbidden to dig grooves on the base layer and embed the installation formwork. The surveyor should use the full section of the measuring plate with the same thickness as the designed plate for inspection;

[0056] After the formwork installation inspection is passed, the surface in contact with the concrete mixture is coated with a release agent or an isolation agent; the joints are sealed with tape or plastic film;

[0057] Before concrete construction, the surface of the base layer should be thoroughly cleaned and maintained, and the base layer should be hydrated evenly, with no unsprinkled or overly wet areas.

[0058] Commercial concrete is used and the concrete is transported by dump trucks. The dump truck compartment is required to be flat, smooth, tight, and leak-proof. It should be cleaned before and after use. The time from the beginning of mixing to pouring should not exceed 1 hour. If it exceeds the specified time, it is required to add an appropriate amount of retarder during the mixing process, and increase the unit water consumption according to the transportation distance, temperature, wind force, etc. The concrete transported to the pouring site should have the required slump and uniformity, and the slump should be controlled at 1-3cm. If there is segregation, a second mixing should be carried out;

[0059] The concrete is vibrated by row vibration, and then the edges are vibrated with an inserted vibrating rod. The insertion depth should be greater than 1 / 2 of the total depth to prevent leakage. The duration of vibration of the vibrator at each position is until the mixture stops sinking and no more bubbles appear. Half of it is 10 seconds and it should not exceed 30 seconds. After the vibrator is vibrated, the concrete is rolled with three rollers, and the edges are manually scraped flat with aluminum and gold rods. The formwork is checked at any time and any sinking or looseness should be corrected in time.

[0060] Preferably, the specific operation steps of the transformer processing and installation in step S7 are:

[0061] S71, Equipment arrival acceptance and storage:

[0062] After the transformer body arrives at the site, the appearance inspection shall be carried out in a timely manner. Check that the oil tank and all accessories are complete, without rust and mechanical damage, with good sealing and no leakage. For the transformer transported with nitrogen filling, the inside of the oil tank shall maintain a positive pressure between 0.01 and 0.03 MPa. At the same time, check the shock recorder, verify and record the impact situation of the transformer during transportation. Check that the oil level of the oil-filled bushing is normal, without oil leakage, and the porcelain body is not damaged, and make inspection records; check the quantity of each accessory one by one according to the supply list, the appearance shall be free of damage, rust and injury, and all components and parts shall be complete. Pay special attention to the inspection of vulnerable parts and make records.

[0063] S71, Insulation oil treatment and installation of the transformer:

[0064] Pump the oil from the manufacturer into the prepared large oil tank with a vacuum oil filter, and further circulate and filter it with the vacuum oil filter to make the oil quality fully meet the standard of the specification. Before oil injection, the transformer oil shall also be sampled and tested, and it can be injected into the transformer only after ensuring that it is qualified;

[0065] The main transformer is unloaded and positioned manually by a pushing device. Before positioning, the horizontal and vertical center lines of the transformer shall be marked at the bottom of the transformer body, and attention shall be paid to the correct direction of the transformer.

[0066] Preferably, the specific operation steps of the installation of electrical equipment accessories in step S8 are as follows:

[0067] S81, Installation of bushings and riser bases;

[0068] S82, Installation of cooling devices;

[0069] S83, Installation of oil conservators;

[0070] S84, Installation of gas relays;

[0071] S85, Installation of temperature measuring devices;

[0072] S86, Installation of oil and gas pipelines.

[0073] Compared with the prior art, the beneficial effects of the present invention are: by strengthening the excellent quality planning, refining the excellent quality goals, deepening the excellent quality measures, and strengthening the process control and management, the quality and process goals are achieved, and finally the excellent quality goal of the project is achieved. With the quality and process detail control as the driving force, the excellent quality process projects planned in the project include: civil engineering of all equipment foundations, installation construction technology of electrical equipment; cable laying and wiring technology. Minimize potential safety hazards, optimize the construction equipment and personnel allocation to the greatest extent, improve the capital utilization efficiency to the greatest extent, and achieve balanced construction to the greatest extent. Specific embodiments

[0074] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0075] The present invention provides the following technical solutions: A construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation, including the following steps:

[0076] S1, preparation before construction;

[0077] S2, engineering construction survey;

[0078] S3, earthwork project;

[0079] S4, equipment foundation project;

[0080] S5, channel underground facilities project;

[0081] S6, step-up substation road construction project;

[0082] S7, transformer treatment and installation;

[0083] S8, installation of electrical equipment accessories.

[0084] Preferably, the specific operation steps of the preparation before construction in step S1 are as follows:

[0085] S11, technical preparation:

[0086] Drawing review;

[0087] This project adopts the PC general contracting mode. The construction drawings are uniformly obtained by the project department's information room, and the distribution of the construction drawings is responsible by the supervisor of the information room, and a management ledger is established. The project technical person in charge organizes the professional engineering and technical personnel of each specialty to carefully review the drawings, do the preliminary work of drawing review, and record the problems and unreasonable points in the construction drawings. Before the project starts, contact the supervisor and the employer in a timely manner, participate in the drawing review organized by the supervisor, and do a good job in design clarification and drawing review. The relevant drawings of the fire protection specialty are submitted to the local fire department for review and approval.

[0088] Equip technical specifications, codes, and acceptance standards;

[0089] According to the requirements of the construction drawings, establish a list of construction technical standards for this project, and implement it after being approved by the project technical person in charge. The construction site is equipped with construction technical standards, codes, acceptance specifications, construction drawing sets, construction manuals and other standards and documents related to this project to ensure that the construction needs are met.

[0090] Elevation measurement and positioning;

[0091] The surveyors shall conduct the survey of the engineering control network based on the permanent coordinate points and level points provided by the employer, and at the same time, conduct the closed re-survey work, identify and protect the survey control piles to prevent damage.

[0092] According to the information provided by the employer, understand the underground pipe networks, facilities and surrounding environment conditions, and master the parameters such as the alignment, specific location and depth of the underground facilities and pipe networks, so as to facilitate the adoption of reliable measures for protection.

[0093] S12, Preparation of equipment and materials:

[0094] Procedures for the preparation of equipment and materials: Prepare the equipment and material requirement plan → Sign the material supply contract → Determine the material transportation plan and scheme → Organize the materials to enter the site and be stored according to the plan.

[0095] According to the construction drawings, prepare the detailed design drawings of the formwork for the building works and equipment foundations of the booster station and the steel bar lofting in advance;

[0096] Conduct the labor and material analysis before construction, and prepare the equipment and material supply list according to the approved construction progress plan for the supervision review, formulate the sub-supplier selection plan, and prepare the plans for the entry of various materials;

[0097] According to the requirements of the construction plan and progress plan, prepare the construction machinery and equipment configuration plan to provide a basis for organizing transportation and determining the parking sites of the machinery and equipment;

[0098] S13, Preparation of the construction site:

[0099] Prepare the roads, water, electricity and communication at the construction site, and complete the laying of the temporary water and electricity pipelines at the construction site according to the design schemes for temporary water and electricity;

[0100] Build and harden the site and temporary roads, build the temporary facilities for office, living and production, and construct the communication information system for the project;

[0101] Divide the functional areas, isolate and enclose the on-site production and living areas according to the management requirements, and do a good job in the on-site safety protection work.

[0102] 4. Other preparations

[0103] (1) Coordinate the external relations and create a good construction environment

[0104] The project department shall assign special personnel to contact and coordinate the external relations. Before the implementation of the project, visit the local relevant government departments, do a good job in business connection, coordinate the relations with the relevant government departments, contact the fire protection and security departments, environmental protection departments and local police stations in advance, and handle the relevant formalities in a timely manner, so as to bring the construction into the legal and reasonable track and lay a foundation for the smooth implementation of the project.

[0105] Reasonably adjust and arrange the construction plan on site to ensure that the construction does not disturb the residents. Complete various certification work on site.

[0106] (2) Coordinate the work on site and establish good relationships

[0107] Coordinate and handle the relationship with Party A, the supervision unit and the local quality supervision department, and solve various problems in the project in a timely manner.

[0108] (3) Provide job training

[0109] According to the schedule and labor demand plan, the labor force will be organized to enter the site on time, and education and training will be provided to the on-site personnel.

[0110] 1) Management personnel: Provide pre-job training for construction management personnel, so that they can master management knowledge and improve management level. Provide centralized training for engineering and technical personnel, learn new specifications and standards and strictly implement them. Conduct construction briefings for construction management personnel so that all management personnel have a clear understanding of the situation.

[0111] 2) Operators: Provide good training for operators to ensure that they master the construction technology and operation methods. Operators can only take up their posts after passing the assessment. All team members will receive safety education and training before entering the site. Operators of special types of work will receive centralized training, and they can take up their posts after passing the assessment and obtaining a certificate. Technical and safety briefings will be conducted before construction for team construction personnel to ensure that they are familiar with technical requirements, process standards, and safety measures to ensure construction safety.

[0112] Preferably, the specific operation steps of the engineering construction measurement in step S2 are:

[0113] The survey is conducted using a total station or theodolite. According to the coordinates and elevations of the base points of the survey control network given by the survey unit, the station area control network is surveyed, fixed personnel observe and check the results, fixed level instruments and leveling rods are used, fixed leveling points are used, and observations are conducted according to the specified date, method and route;

[0114] When there are many observation points, an overall plan should be carried out on site to determine the location of the instrument to facilitate settlement observations along a fixed route each time in the future. Each time a settlement observation is carried out, various records of the observations should be made in a timely manner, the settlement amount should be calculated, relevant forms should be filled in and settlement curves should be drawn.

[0115] Preferably, the specific operation steps of the earthwork project in step S3 are:

[0116] S31, Earthwork Excavation:

[0117] The earthwork is excavated mechanically, with large excavations along the axis, manual and mechanical foundation clearing, and dump trucks transporting the earth. There are 3 1-cubic-meter excavators and 8 dump trucks on site for transportation;

[0118] Mechanical excavation leaves 200mm for manual clearing to the bottom of the foundation cushion;

[0119] Backhoe excavators are used for excavation and dump trucks are used for transporting soil. Before construction, the slope is strictly set according to the geological survey report provided by the construction unit and in accordance with the specifications;

[0120] A 300mm wide and 300mm high water retaining edge is set at the top of the foundation pit 1.5m away from the edge of the slope to prevent rainwater from the ground outside the foundation pit from flowing into the foundation pit.

[0121] The excavated earth must be transported to the temporary earth pile site in time for stacking. It is strictly forbidden to pile earth around the foundation pit. The excavated earth must be transported to the designated earth pile site in time, and the temporary earth pile site must be leveled by a loader.

[0122] Control the elevation, width and slope. Carefully review the drawings, measure the excavation line and elevation of the foundation pit according to the grid control points, check the width and slope of the pit bottom while digging, and make timely adjustments if they are not enough. The excavation position, depth and slope shall be carried out according to the "Excavation Drawing", especially the elevation must be measured in time to prevent over-excavation.

[0123] Earthwork transportation roads are pre-regulated, and speed limits are set for transportation vehicles. Earthwork transportation vehicles are covered with tarpaulins to prevent soil from spilling everywhere.

[0124] S32, earth backfill:

[0125] All backfill soil is compacted manually or mechanically in layers. It is required to be compacted layer by layer and section by section according to the specified layer thickness. The compaction coefficient must meet the design requirements. After passing the test, the next layer can be filled.

[0126] Preferably, the specific operation steps of the equipment foundation engineering in step S4 are:

[0127] S41, cushion construction:

[0128] After the foundation pit is qualified, the concrete cushion layer will be cast. The cushion layer is supported by a 100mm wide template, and the outside is supported by wooden planks around the foundation pit. After the cushion layer is cast, it is compacted with an iron trowel.

[0129] S42, Formwork Engineering:

[0130] The exposed foundation uses high-quality laminated wood glue formwork, and the other foundations located underground use formwork. The lower pedestal is first supported according to the foundation edge, and then the upper pedestal is supported. The formwork uses Tension bolts and The foundation is reinforced with steel pipes and the outside of the foundation is supported by 50×100mm wooden planks;

[0131] S43, Steel Reinforcement Engineering:

[0132] The steel bars are centrally manufactured in the steel bar processing plant and transported to the site for installation by flatbed trucks. After the steel bars are processed, they are classified and stacked. A dedicated person manages and picks up the materials as required. They are transported to the foundation pit by flatbed trucks for tying. The bottom plate is tied first, and then the side wall or top plate steel bars are tied. Stirrups are made between the upper and lower layers of steel mesh to prevent the upper mesh from sinking.

[0133] S44, Concrete Works:

[0134] The concrete is commercial concrete, transported by tank trucks, poured by chutes, and mechanically vibrated. Iron parts and steel bars must not be touched during vibration. The concrete is vibrated in layers, with each layer not exceeding 300mm and the rod distance not exceeding 500mm. The vibration rod is vibrated in the concrete for about 20 to 30 seconds at each insertion point, until the concrete no longer sinks significantly, no bubbles appear, and cement slurry appears on the surface;

[0135] After the concrete is poured, the surface is smoothed and polished for the second time. After the concrete is initially set, it is covered with plastic film and watered for maintenance for no less than 7 days to prevent shrinkage cracks. The equipment foundation is cast in one step.

[0136] Preferably, the specific operation steps of the trench underground facility engineering in step S5 are:

[0137] When underground facilities are close to each other, the deep foundation is constructed first, followed by the shallow foundation and trench, and the bottom plate and wall of the accident oil pool are constructed at one time without construction joints.

[0138] The bottom plate and the wall of the cable trench are cast at one time. An expansion joint is set every 25 meters in the cable trench and an expansion joint is set every 20 meters in the plain concrete trench. Asphalt-soaked wooden boards are buried from the trench wall to the bottom plate of the expansion joint and are set in the center.

[0139] Steel bar engineering

[0140] The steel bars are centrally manufactured in the processing plant and transported to the construction site by flatbed trucks for installation. All incoming steel bars must have complete certificates and pass the re-inspection. The steel bars should be placed according to the type and clearly marked (labeled). The steel bars are mainly tied and overlapped.

[0141] The material list should be prepared according to the design and specifications for cutting steel bars. The material list should accurately indicate the number, model, type, quantity, length (including hook, total length), weight, etc. of the steel bars. The disc steel bars are cold drawn by straightening machines and winches. The maximum cold drawing rate of cold drawn steel bars is ≤4%. There should be no cracks or peeling after cold drawing.

[0142] Template Engineering

[0143] The template is made of wood glue template, and the reserved holes are made of wooden template. Before the template is constructed, the edge line and axis are popped out on the cushion layer with an ink fountain, and the template is installed according to the line during construction.

[0144] The formwork of the pool wall is reinforced with 12 pairs of tie bolts. A water stop steel plate with a size of 50×50×1.5 is welded in the middle of the tie bolts used for formwork reinforcement (inside the pool wall) to prevent water seepage at the location of the tie rods.

[0145] Concrete works

[0146] Commercial concrete is used for the concrete, which is transported by tank trucks and fed into the formwork for pouring through chutes. During the concrete pouring, formwork and steel bar maintenance personnel must be arranged to observe the formwork and steel bars in a timely manner. Once steel bar deformation or displacement is found, it should be dealt with promptly.

[0147] The concrete vibrating rod should be inserted quickly and pulled out slowly. The concrete is vibrated using a conventional Ф50 inserted vibrator with an amplitude of not less than 500mm. The vibration is carried out in a staggered plum blossom pattern with a spacing of not more than 500mm and a distance from the formwork of not more than 250mm. Each point is vibrated for not less than 20 seconds. The vibrator shall not directly vibrate the formwork, steel bars, iron parts, etc. The surfaces of the pool top slab and pool wall are all leveled and polished. The concrete at the surface of the construction joint must be fully chiseled to expose fresh stones and washed clean before formwork erection.

[0148] Preferably, the specific operation steps of the step S6 boost station road construction project are as follows:

[0149] Fixed-line steel formwork is used for the formwork. Before formwork support, measurement and lofting of the formwork installation and paving positions are carried out on the base course. A center pile is set every 20 meters; a temporary level point is arranged every about 100 meters; the road surface elevation, panel segmentation, the positions of expansion joints and structures are checked, and the quality requirements and allowable deviations of the measurement and lofting are controlled within the scope specified in the specifications. When constructing on a curved section or the arc of an intersection, short formwork should be used, and the midpoint of each formwork should be installed at the tangent point of the curve;

[0150] When installing the formwork, it should be installed stably, straight, flat, and without distortion. The connection between adjacent formworks should be tight and smooth, without phenomena such as bottom leakage, front and back misalignment, and height difference. The formwork should not be displaced or tilted when bearing the loads, impacts, and vibrations of the paving, vibrating, and leveling equipment. It is strictly prohibited to dig grooves on the base course and embed the formwork for installation. The surveyors use a measuring plate with the same thickness as the designed slab thickness to conduct a full-section inspection;

[0151] After the formwork installation inspection is qualified, a release agent or isolation agent is applied to the surface in contact with the concrete mixture; tape or plastic film, etc. is pasted at the joints for sealing; for easy formwork removal and to prevent leakage of mortar.

[0152] Before concrete construction, the surface of the base course should be comprehensively cleaned and maintained, and the base course should be replenished with water. The water replenishment should be uniform without any areas not being watered or overly wet areas;

[0153] The concrete used is commercial concrete, which is transported by self-unloading trucks. The compartments of the self-unloading trucks are required to be flat, smooth, tight, and leak-free of mortar. They should be washed clean before and after use. It is necessary to control the time from the start of mixing to pouring not to exceed 1 hour. If it exceeds the specified time, an appropriate amount of retarder should be added during the mixing process, and the unit water consumption should be increased according to the distance of transportation, temperature, wind force, etc. The concrete transported to the pouring site should have a slump and uniformity that meet the requirements. The slump is controlled at 1 - 3 cm. If there is segregation, it should be stirred for the second time;

[0154] For the vibration of the concrete, row vibration is adopted first, and then an inserted vibrator is used to vibrate the edges. The insertion depth is greater than 1 / 2 of the total depth to prevent leakage of vibration. The duration of vibration of the vibrator at each position is until the mixture stops sinking and no more bubbles emerge, generally 10 seconds, not exceeding 30 seconds. After the vibrator vibrates, the concrete is rolled with a three-roller. The edges are leveled by manual use of aluminum and alloy rods, etc., and the formwork is checked at any time. If there is subsidence or loosening, it should be corrected in time.

[0155] Surface finishing

[0156] The finishing operation is carried out when the concrete still remains plastic and workable, but the concrete should not be disturbed. Before surface finishing, first clean the edges and joints, remove the sticky mortar, repair the chipped edges and corners. Sprinkling water or cement powder on the concrete slab is strictly prohibited. The surface finishing is carried out in two steps. First, level it. When there is no bleeding on the concrete surface, then use a troweling machine to level it for the second time. After the concrete slab is cured, mechanical grooving is carried out. Longitudinal joints: Tie rods are set according to the requirements of the design drawings. The upper part of the longitudinal joints should be cut into longitudinal grooves with a depth of 8 cm by a special cutting machine, and joint fillers should be filled in the longitudinal joints.

[0157] Expansion joints: The whole expansion joint is set in the form shown in the design drawings. When pouring the concrete, the position of the expansion joint should be accurate so that the dowel bars can be kept in the correct position and perpendicular to the joint wall.

[0158] Contraction joints: Whether the cutting time is appropriate is the key to controlling the broken slab. Generally, the cutting should be carried out with a cutting machine before the concrete begins to shrink and no free cracks are found. The time should not exceed 24 hours, that is, when the concrete strength is 6 - 9 MPa, the cutting should be carried out in time. The cutting should be straight and without defects.

[0159] Construction joints: When the work ends every day or an accidental shutdown occurs during the pouring process, a flat construction joint should be set. The position of the construction joint should coincide with the position of the expansion joint or contraction joint and be perpendicular to the road center line. The construction joint should be treated according to the requirements of the transverse expansion joint.

[0160] Form removal and curing

[0161] Form removal shall start when the concrete reaches 25% of the designed strength. The form removal time shall be determined according to the air temperature and the growth of concrete strength, generally being 18 - 36 hours. During form removal, the edges and corners of the concrete slab shall not be damaged, and the formwork shall be kept intact as much as possible.

[0162] After the concrete pouring is completed, sprinkle water in time for curing for 28 days. Use a curing blanket for curing and sprinkle water every day to keep the concrete surface in a wet state.

[0163] Joint caulking

[0164] The joint groove shall be caulked in time after the concrete curing period expires. Before caulking, use an air compressor to remove the sundries in the joint groove, keep the joint groove dry and clean, prevent sundries such as sand and gravel from falling into the joint, and the caulking material shall be approved by the supervising engineer. Generally, use foam for the lower part and polyurethane for the upper 2 cm.

[0165] Grooving

[0166] Before grooving, clean the working surface. According to the layout of the plates and the performance of the grooving machine, lay out and draw ink lines at equal intervals for transverse grooving operations. It is required that the lines are straight, the depth is consistent, and there is no dislocation.

[0167] Preferably, the specific operation steps of the transformer treatment and installation in step S7 are as follows:

[0168] S71, Equipment arrival inspection and storage:

[0169] After the transformer body arrives at the site, the appearance shall be inspected in time. Check that the oil tank and all accessories are complete, without rust and mechanical damage, the seal is good, and there is no leakage. For the transformer transported with nitrogen filling, the internal pressure of the oil tank shall be kept positive, with the pressure between 0.01 - 0.03 MPa. At the same time, check the shock recorder, verify and record the impact situation of the transformer during transportation, check that the oil level of the oil-filled bushing is normal, without oil leakage, and the porcelain body is not damaged, and make inspection records; Check the quantity of each accessory one by one according to the supply list, the appearance shall be without damage, rust and injury, and all components and parts shall be complete. Pay special attention to the inspection of vulnerable parts and make records.

[0170] S71, Insulating oil treatment and installation of the transformer:

[0171] Pump the oil from the manufacturer into the prepared large oil tank with a vacuum oil filter, and further circulate and filter it with the vacuum oil filter to make the oil quality fully meet the specification standards. Before oil injection, the transformer oil shall also be sampled and tested, and it can be injected into the transformer only after ensuring it is qualified;

[0172] Construction technical preparation

[0173] 1) Inspect and accept the transformer foundation according to the design drawings and specification requirements. The concrete foundation should reach the allowable installation strength, and the axes should be complete. The axis error, levelness and elevation should meet the design requirements, and the handover for safety should be completed.

[0174] 2) Compile the operation instruction manual and safety construction measures and obtain approval. Organize the construction personnel to study and conduct safety and technical disclosure. The design drawings and the manufacturer's technical data have arrived.

[0175] 3) There should be sufficient construction site around the transformer and it should be leveled. The backfill soil should be compacted, the road should be unobstructed, and the construction power and water source should be safe and reliable. Arrange the isolation measures for the construction site and prepare an appropriate amount of fire fighting equipment and facilities.

[0176] 4) The high-voltage bushing of the transformer, the bushing CT test is qualified, and the gas relay and temperature controller are calibrated and qualified.

[0177] 5) Conduct a simplified analysis of the insulating oil to confirm that the indexes such as the strength, acidity, micro-water and gas content of the incoming oil meet the requirements.

[0178] 6) Contact the meteorological department before construction to understand the weather conditions.

[0179] (2) Do a good job in organizing the construction personnel and allocate sufficient manpower.

[0180] (3) The tools and construction materials are fully prepared.

[0181] (4) The construction machinery, fire fighting equipment and safety appliances are fully prepared.

[0182] The main transformer is unloaded and positioned manually by a pushing device. Before positioning, the transverse and longitudinal centerlines of the transformer should be marked at the bottom of the transformer body, and attention should be paid to the correct direction of the transformer.

[0183] Inspection of the core

[0184] 1) The inspection of the core should comply with the following regulations:

[0185] The inspection of the core of the transformer should be carried out on a sunny and windless day. The ambient temperature should not be lower than 0 °C, the core temperature should not be lower than the ambient temperature, generally it should be higher than the ambient temperature by 10 °C, the relative air humidity should be less than 75%, and the exposure time of the core in the air should not exceed 12 hours.

[0186] 2) Core inspection method

[0187] For the transformer transported with nitrogen filling, after vacuum pumping, dry air is injected. When the internal and external air pressures are balanced, all the sealing plates of the oil tank are opened for natural ventilation for half an hour. The oxygen content in the oil tank must reach more than 18% before internal inspection can be carried out. For the transformer transported with oil filling, the oil is drained using an oil filter. The inspection items are jointly determined by the four parties of the construction unit, the manufacturer, the supervisor, and the owner. One person from each of the four parties enters the body of the transformer for inspection. The inspectors should wear special buttonless work clothes and soft-soled oil-resistant rubber shoes, and should not carry foreign objects unrelated to the work on their bodies. They should carefully count and record the tools they carry, and must not leave them in the oil tank. Before closing, they should be verified one by one again. After the inspection, the four parties should sign and approve.

[0188] Preferably, the specific operation steps of the installation of electrical equipment accessories in step S8 are as follows:

[0189] S81, Installation of bushings and riser housings;

[0190] Before the installation of the riser housing and the bushing, relevant electrical tests should be completed according to the regulations and specifications first, and the results should meet the relevant requirements.

[0191] The riser housing should be installed in accordance with the factory markings A, B, C, and must not be misinstalled. Before installation, the sealing flange surface should be wiped and cleaned with acetone, the sealing gasket should be installed in place, the nameplate of the current transformer should face the outside of the oil tank, and the position of the air vent plug should be at the highest point of the riser housing.

[0192] The oil level gauge of the oil-filled bushing should face the outside, the end screen of the bushing should be well grounded, and the bolts should be tightened evenly and symmetrically. The connection between the lead end of the high-voltage winding and the terminal on the top of the bushing should be wiped clean and the contact should be reliable. The connection between the flexible copper strip of the low-voltage bushing and the winding should be reliable. The bolts should be checked and tightened one by one with a torque wrench. The lead of the flexible copper strip should ensure the insulation distance from the ground. When two leads are pressed by a pressure plate, the pressure plate must be installed on the outside and cannot be clamped between the two leads.

[0193] The inner wall of the bushing, the flange neck and the grading sphere should be wiped clean. The stress cone of the high-voltage bushing through which the cable passes should enter the grading hood of the bushing. The connection between its lead end and the terminal on the top of the bushing should be wiped clean and the contact should be tight; the installation of the sealing corrugated disc structure at the interface between the high-voltage bushing and the lead-out wire inside should be carried out strictly in accordance with the regulations of the manufacturer; the sealing gasket of the top structure of the bushing should be installed correctly and the sealing should be good. When connecting the lead wire, the top structure should not be loosened.

[0194] S82, Installation of the cooling device;

[0195] Before installation, the cooling device shall be subjected to a sealing test with air pressure or oil pressure according to the pressure value specified by the manufacturer. After passing the test, installation can begin. First, install the connecting pipes between the cooler and the oil tank and the cooler support in the correct positions. Before hoisting, check that the valves operate flexibly, the opening and closing position indicators are correct, the seals are good, and clean the mating sealing surfaces and debris in the pipes. After installing the connecting pipes and supports, hoist the cooler in the correct position, and tighten the flange connection bolts symmetrically and evenly. The oil pump shall rotate in the correct direction, be flexible during rotation without abnormal noise, vibration or overheating, and the oil flow relay shall be calibrated and installed in the correct direction.

[0196] S83, Installation of the conservator;

[0197] Check the connecting handle between the swinging oil level gauge and the float, and check whether the high and low oil level switch contacts of the oil level gauge open and close reliably. Check that the conservator capsule diaphragm is intact without damage. Inflate the diaphragm bag with nitrogen at 20 - 25 kPa for leak testing. The diaphragm bag should unfold and show no obvious pressure loss after 30 minutes.

[0198] Open the end plate of one side of the conservator, check whether the inside of the conservator is clean and clean it. Then install the conservator capsule in place, assemble the float of the conservator oil level gauge and the connecting rod and place them under the capsule in the conservator, and close the end plate. Then pull out the float connecting rod from the oil level gauge installation hole and assemble it reliably with the oil level gauge, and then install the oil level gauge in place. Finally, hoist the conservator support and the conservator body in place respectively.

[0199] S84, Installation of the gas relay;

[0200] Before installation, it shall be calibrated and qualified. The oil flow baffle inside the gas relay shall move flexibly. Otherwise, remove the binding or fixing of the movable baffle and clean the inside. Install the gas relay on the connecting pipe between the conservator and the transformer oil tank, with the arrow mark on the top pointing to the conservator. It shall be installed horizontally with good sealing with the connecting pipe.

[0201] S85, Installation of the temperature measuring device;

[0202] Before installing the temperature controller, it shall be calibrated and qualified. The signal contacts shall act correctly and reliably. Fill the thermometer socket on the top of the oil tank with transformer oil, with good sealing and no oil leakage.

[0203] S86, Installation of oil and gas pipelines.

[0204] The inside of the oil and gas pipelines shall be clean and unobstructed, and installed according to the factory identification number. The mating surfaces shall be well sealed.

[0205] Vacuum oil injection

[0206] Before vacuum pumping, the accessories that cannot withstand the mechanical strength of vacuum shall be isolated from the oil tank, and for the components that are allowed to withstand the vacuum degree, vacuum pumping shall be carried out simultaneously.

[0207] Vacuum the transformer body from the top of the transformer. When the vacuum degree in the oil tank reaches below 13 Pa, continue to vacuum for at least 8 hours. During the vacuum process, the elastic deformation of the tank wall should be monitored. Heat the qualified transformer oil to about 60 °C and inject the oil into the transformer through the oil injection valve at the bottom of the transformer oil tank with a vacuum oil filter. The oil injection speed should not be greater than 100 L / min. Continue to vacuum during the oil injection process. The vacuum degree inside the oil tank should be less than 20 Pa, otherwise the oil injection should be stopped. Stop injecting oil when the oil level is about 200 mm from the top cover of the oil tank, and continue to vacuum for more than 4 hours, then relieve the vacuum with high-purity nitrogen.

[0208] Supplementary oil injection and gas exhaust

[0209] Restore the accessories isolated from the oil tank, move the oil injection pipe to the oil injection valve at the top of the oil tank, and continue to slowly inject oil. Open the exhaust plug at the top of the conservator, inject oil until the oil pillow is full of oil, exhaust from each air release plug, and finally adjust the oil level to the normal oil level.

[0210] Overall sealing inspection

[0211] After the installation of the transformer is completed, conduct an overall sealing test on the conservator with air pressure or oil pressure. The pressure is 0.03 MPa and the duration is 24 hours without leakage.

[0212] Key points of quality control

[0213] Ensure that the flange surface is flat, tightly fitted, replace the sealing ring for all opened flange surfaces, tighten the flange connection bolts symmetrically and evenly, the compression amount of the sealing ring ≤ 1 / 3, and the compression is uniform; during the inspection of the transformer body, strictly control the exposure time of the transformer body according to the ambient humidity and temperature. The insulating oil injected into the transformer must be filtered, sampled and tested qualified before being injected into the transformer.

[0214] Through strengthening the excellent planning, refining the excellent goals, deepening the excellent measures, strengthening the process control and management, promoting the realization of the quality and process goals of "two types and three news" (namely resource-saving type, environment-friendly type, new technology, new material, new process), and finally realizing the excellent goal of the project. Taking the quality process detail control as the promoter, taking "leading by the model" as the leader, taking the whole-process quality control as the means, highlighting the detail management and the fine product awareness, realizing "excellent at one time", and vigorously cultivating "bright spot projects". The process excellent projects planned in the project include:

[0215] 1) The civil engineering of all equipment foundations and the installation construction technology of electrical equipment;

[0216] 2) The cable laying and wiring technology;

[0217] 3) All exposed concrete projects reach the fair-faced concrete standard.

[0218] (1) Construction project

[0219] 1) The pass rate of unit projects is 100%.

[0220] 2) Implement full-process quality control over concrete, and the pass rate of concrete strength assessment for each acceptance batch is 100%.

[0221] 3) The pass rate of allowable deviations for directly buried bolts is 100%.

[0222] 4) The concrete strength meets the design requirements, the geometric dimensions are accurate, the pouring is solid inside and smooth outside, the forming is beautiful, the large surfaces are flat, the edges and corners are straight, and the embedded parts are accurately positioned.

[0223] 5) The foundation treatment is reliable, the settlement of buildings and structures is small and uniform, and the pass rate of backfill soil quality assessment is 100%.

[0224] 6) Prevent major quality accidents, and strictly control the incidence rate of recordable accidents and general quality accidents (calculated by sub-projects) < 1‰.

[0225] 7) Prevent common quality problems in construction, and the uneven settlement of the foundation of equipment bases is within the allowable range.

[0226] (2) Installation project

[0227] 1) The quality pass rate of equipment installation projects is 100%.

[0228] 2) Specific measures should be taken for the crossing, turning and leading out of various cables to ensure neat and beautiful laying, and the wiring error rate is less than 1‰.

[0229] 3) Prevent major quality accidents, and strictly control the incidence rate of recordable accidents and general quality accidents (calculated by sub-projects) < 1‰.

[0230] 4) Completely eliminate common quality problems in electrical installation.

[0231] 5) Achieve long-term safe and stable operation after commissioning and power generation. There are no tail works in the project, no leaks on site, and the project is handed over to production with "high standards, high quality, and high levels".

[0232] (1) Requirements for the appearance quality of concrete surface

[0233] The surface is smooth and flat, without slurry leakage, and the joints are smooth; there is no exposed reinforcement, obvious indentations, or fish scales on the surface, and the large surfaces of the inner and outer surfaces are flat.

[0234] Achieve excellent quality in one go, without large-area repairs; do not solely pursue appearance quality and violate quality and process standards, pipelines do not take shortcuts, do not solely pursue aesthetics and concentrated effects, and do not arbitrarily add plastering, spraying and other processes to cover up defects; effective finished product protection; the production area is clean and tidy, without construction leftovers, etc.

[0235] (2) Installation of Electrical Accessories

[0236] 1) The steel structure is fabricated finely, installed accurately in place, the welds are dense and full, and the joint welds are standardized; the paint color is correct and the color is consistent, without running marks, wrinkles, bubbles, peeling, or contamination, and the color is uniform.

[0237] 2) The expansion joint meets the design and construction specifications; the process is beautiful; the appearance color is simple, generous, clean, and bright.

[0238] 3) The exposed engineering corner lines are straight, the large surfaces are flat, and the color is consistent.

[0239] 4) The channel is straight.

[0240] 5) The cables (including the secondary wiring inside the panel) are arranged neatly, the markings are complete, the specifications and handwriting are unified, and the hanging direction and position are beautiful.

[0241] 6) There are no traces of secondary pollution on all equipment, the ground, etc.

[0242] 7) The color of the paint surface is uniform, without running marks or scratches.

[0243] 8) The construction process is standardized and has process ornamental value.

[0244] 9) The lightning protection and grounding facilities are perfect, the grounding is standardized, unified, beautiful, the color code is consistent, and there are disconnectable test points.

[0245] 10) Sign and Marking: The signs of equipment and cables, safety warning signs, etc. are unified, complete, correct, clear, eye-catching, the color code is obvious; the production and hanging methods are neat and unified.

[0246] Strictly implement the relevant regulations and standards of electric power construction, correct violations and irregularities, and achieve "everything has a law to follow and everything has evidence to check". Enhance the awareness of learning systems and norms, and establish and improve the project management procedures for this section in a targeted manner. Improve the perfect construction management network system, implement responsibilities, authorities, and assessments, and push the project management work to a new level. Scientifically handle the relationships among safety, quality, progress, and cost; strictly implement the joint inspection of construction drawings, strictly implement the regulations of the manufacturing factory and the design, and strictly implement the construction technical plans and measures.

[0247] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction method for installing electrical equipment in an expansion bay of a 500 kV step-up substation, characterized in that, It includes the following steps: S1, Preparation before construction; S2, Engineering construction survey; S3, Earthwork; S4, Equipment foundation engineering; S5, Channel underground facility engineering; S6, Construction project of the road in the step-up substation; S7, Transformer treatment and installation; S8, Installation of electrical equipment accessories.

2. A construction method for installing electrical equipment in the expansion bay of a 500 kV step-up substation according to claim 1, characterized in that, The specific operation steps of the preparation before construction in step S1 are as follows: S11, Technical preparation: Review of drawings; Equip technical specifications, codes, and acceptance standards; Elevation measurement and positioning; S12, Equipment and material preparation: According to the construction drawings, prepare in advance the detailed design drawings of the formwork for the building project and equipment foundation in the step-up substation and the steel bar lofting; Conduct a labor and material analysis before construction, and prepare a list of equipment and material supplies according to the approved construction schedule for the supervision review, formulate a selection plan for the sub-supplier plan, and make a plan for the entry of various materials; According to the requirements of the construction plan and schedule, prepare a construction machinery and tool configuration plan to provide a basis for organizing transportation and determining the parking site of the machinery and tools; S13, Preparation at the construction site: Prepare the roads, water, electricity, and communication at the construction site, and complete the laying of temporary water and electricity pipelines at the construction site according to the design plan for temporary water and electricity; Build and harden the site and temporary roads, build temporary facilities for office, living, and production, and construct a communication information system for the project; Divide the functional areas, isolate and enclose the on-site production and living areas according to management requirements, and do a good job in on-site safety protection.

3. A construction method for installing electrical equipment in an expansion bay of a 500 kV step-up substation according to claim 1, characterized in that The specific operation steps of the engineering construction survey in step S2 are as follows: The survey is carried out using a total station or a theodolite. According to the coordinates and elevation of the survey control network base points given by the survey unit, the control network of the station area is introduced. Fixed personnel are used to observe, check, and collate the results. A fixed level and leveling staff are used, and fixed bench marks are used. Observations are carried out according to the specified date, method, and route; When there are many observation points, a overall plan should be made on-site to determine the placement position of the instrument, so as to facilitate subsequent settlement observations along a fixed route each time. When carrying out settlement observations each time, timely record all the observations, calculate the settlement amount, fill in the relevant forms, and draw a settlement curve graph.

4. A construction method for installing electrical equipment in the expansion bay of a 500 kV step-up substation according to claim 1, characterized in that The specific operation steps of the earthwork in step S3 are as follows: S31, Earth excavation: All earthwork is excavated by machinery. Large-scale excavation is carried out according to the axis, and manual work is used to cooperate with the machinery for base cleaning. The earth is transported by self-unloading trucks. 3 excavators with a capacity of 1 cubic meter and 8 self-unloading trucks are allocated on-site for transportation; When excavating with machinery, 200mm is reserved for manual base cleaning to the bottom of the foundation cushion; Backhoe excavators are used for excavation, and the earth is transported by self-unloading trucks. Before construction, according to the geological exploration report provided by the construction unit, strict slope setting is carried out in accordance with the specifications; A water retaining edge with a width of 300mm and a height of 300mm is set 1.5m away from the slope edge at the upper part of the foundation pit; The excavated earth must be transported to the temporary earth stacking site in time for stacking. It is strictly prohibited to stack earth around the foundation pit. The excavated earth is transported to the designated earth stacking site in time, and a loader is arranged to level the temporary earth stacking site; Control the elevation, width, and slope. Carefully review the drawings, introduce the excavation line and elevation of the foundation pit according to the grid control points, check the bottom width and slope of the foundation pit while excavating, and repair in time if it is insufficient; The earth transportation road is pre-specified, and the speed of the transportation vehicles is limited. All earth transportation vehicles are covered with tarpaulins; S32, earth backfill: All backfill soil is compacted manually or mechanically in layers. It is required to be compacted layer by layer and section by section according to the specified layer thickness. The compaction coefficient must meet the design requirements. After passing the test, the next layer can be filled.

5. A construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation according to claim 1, characterized in that The specific operation steps of the equipment foundation engineering in step S4 are: S41, cushion construction: After the foundation pit is qualified, the concrete cushion layer will be cast. The cushion layer is supported by a 100mm wide template, and the outside is supported by wooden planks around the foundation pit. After the cushion layer is cast, it is compacted with an iron trowel. S42, Formwork Engineering: The exposed foundation uses high-quality film-coated wood glue formwork, and the other foundations located underground use formwork. The lower pedestal is supported first according to the foundation edge line, and then the upper pedestal is supported. The formwork is reinforced with φ12 tension bolts and φ48×3.5 steel pipes, and the outside of the foundation is supported by 50×100mm wooden squares; S43, Steel Reinforcement Engineering: The steel bars are centrally manufactured in the steel bar processing plant and transported to the site for installation by flatbed trucks. After the steel bars are processed, they are classified and stacked. A dedicated person manages and picks up the materials as required. They are transported to the foundation pit by flatbed trucks for tying. The bottom plate is tied first, and then the side wall or top plate steel bars are tied. Stirrups are made between the upper and lower layers of steel mesh to prevent the upper mesh from sinking. S44, Concrete Works: The concrete is commercial concrete, transported by tank trucks, poured by chutes, and mechanically vibrated. Iron parts and steel bars must not be touched during vibration. The concrete is vibrated in layers, with each layer not exceeding 300mm and the rod distance not exceeding 500mm. The vibration rod is vibrated in the concrete for about 20 to 30 seconds at each insertion point, until the concrete no longer sinks significantly, no bubbles appear, and cement slurry appears on the surface; After the concrete is poured, the surface is smoothed and polished for the second time. After the concrete has initially set, it is covered with plastic film and watered for maintenance for a period of no less than 7 days.

6. A construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation according to claim 1, characterized in that The specific operation steps of the trench underground facility project in step S5 are: When underground facilities are close to each other, the deep foundation is constructed first, followed by the shallow foundation and trench, and the bottom plate and wall of the accident oil pool are constructed at one time without construction joints. The bottom plate and the wall of the cable trench are cast at one time. An expansion joint is set every 25 meters in the cable trench and an expansion joint is set every 20 meters in the plain concrete trench. Asphalt-soaked wooden boards are buried from the trench wall to the bottom plate of the expansion joint and are set in the center.

7. A construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation according to claim 1, characterized in that The specific operation steps of the step S6 booster station road construction project are: The template uses a fixed steel template. Before supporting the template, the template installation and paving position measurement and layout are carried out on the base layer. A center pile is set every 20 meters; a temporary leveling point is arranged every 100 meters or so; the road surface elevation, panel division, expansion joint and structure position, measurement and layout quality requirements and allowable deviation are checked to be within the range specified in the specification. When constructing curved sections or intersection arcs, short templates should be used, and the midpoint of each template should be installed on the curve tangent point; When installing the formwork, it should be installed firmly, straight, flat, and without distortion. The connection between adjacent formworks should be tight and smooth, without phenomena such as bottom leakage of mortar, front-back misalignment, and height difference. The formwork should not displace or tilt when bearing the load, impact, and vibration of paving, vibrating, and leveling equipment. It is strictly prohibited to dig grooves on the base course and embed the formwork for installation. The surveyors should use a measuring plate with the same thickness as the designed slab thickness to conduct a full-section inspection. After the formwork installation is inspected and qualified, release agents or isolating agents should be applied to the surface in contact with the concrete mixture; tapes or plastic films should be pasted at the joints for sealing. Before concrete construction, the surface of the base course should be thoroughly cleaned and maintained, and water should be replenished to the base course. The water replenishment should be uniform, without areas that are not sprinkled or overly wet areas. The concrete used is commercial concrete, and the concrete is transported by self-unloading trucks. The compartments of the self-unloading trucks are required to be flat, smooth, tight, and without mortar leakage. They should be washed clean before and after use. It is necessary to control the time from the start of mixing to pouring not to exceed 1 hour. If it exceeds the specified time, an appropriate amount of retarder should be added during the mixing process, and the unit water consumption should be increased according to the transportation distance, temperature, wind force, etc. The concrete transported to the pouring site should have a slump and uniformity that meet the requirements. The slump is controlled at 1 - 3 cm. If there is segregation, it should be stirred for the second time. The vibration of the concrete adopts row vibration, and then the side parts are vibrated with an inserted vibrator. The insertion depth is greater than 1 / 2 of the total depth. It is strictly prohibited to miss vibration. The duration of vibration of the vibrator at each position is until the mixture stops sinking and no more bubbles emerge, generally 10 seconds, not exceeding 30 seconds. After the vibrator vibrates, the concrete is rolled with a three-roller. The edges are scraped flat by manual aluminum alloy rods, etc., and the formwork should be checked at any time. If there is subsidence or loosening, it should be corrected in time.

8. A construction method for installing electrical equipment in the expansion interval of a 500 kV step-up substation according to claim 1, characterized in that, The specific operation steps of the transformer treatment and installation in step S7 are as follows: S71, Equipment arrival inspection and storage: After the transformer body arrives at the site, the appearance should be inspected in time. Check that the oil tank and all accessories are complete, without rust and mechanical damage, the seal is good, and there is no leakage. For the transformer transported with nitrogen filling, the internal pressure of the oil tank should be kept positive, with the pressure between 0.01 - 0.03 MPa. At the same time, check the shock recorder, verify and record the impact situation of the transformer during transportation. Check that the oil level of the oil-filled bushing is normal, without oil leakage, and the porcelain body is not damaged. Make inspection records; check the quantity of each accessory one by one according to the supply list. The appearance should be without damage, rust, and injury, and all components and parts should be complete. Special attention should be paid to the inspection of vulnerable parts and records should be made. S71, Insulating oil treatment and installation of the transformer: Pump the oil from the manufacturer into the prepared large oil tank with a vacuum oil filter, and further circulate and filter it with the vacuum oil filter to make the oil quality fully meet the standard specifications. Before oil injection, samples of the transformer oil should also be taken for testing, and only after ensuring compliance can it be injected into the transformer. The main transformer is unloaded and positioned manually using a pushing device. Before positioning, the transverse and longitudinal centerlines of the transformer should be marked at the bottom of the transformer body, and attention should be paid to the correct direction of the transformer.

9. A construction method for installing electrical equipment in the expansion bay of a 500 kV step-up substation according to claim 1, characterized in that, The specific operation steps of the installation of electrical equipment accessories in step S8 are as follows: S81, Installation of bushings and riser seats; S82, Installation of cooling devices; S83, Installation of oil conservators; S84, Installation of gas relay; S85, Installation of temperature measuring device; S86, Installation of oil and gas pipelines.