Combined open type 750kV booster station construction process

Abstract

The invention discloses a combined open type 750kV booster station construction process, belongs to the technical field of booster station construction, and aims to solve the problem that the construction period is lagged when equipment is installed after all frameworks and wires are completed in a conventional process by reconstructing a construction sequence and preferentially completing installation of related interval frameworks of a connection transformer, and starting installation of an equipment body in advance. The equipment body is installed in advance to provide accurate positioning for cable buried pipes, the problem of buried pipe secondary excavation caused by post-installation of conventional process equipment is fundamentally avoided, extra manpower, machinery and material consumption is reduced, layered installation of wires and finished product protection are cooperated, the defect of poor synchronism of the equipment and the wires in the conventional process is overcome, and the production efficiency is improved. A large amount of protection materials and manual maintenance cost which need to be input due to equipment collision in wire construction are reduced, and multiple optimization of shortening the construction period, reducing the cost and reducing cross interference is integrally realized.

Description

Technical Field

[0001] This invention relates to the field of substation construction technology, specifically a combined open-type 750kV substation construction process. Background Technology

[0002] In the field of power engineering, open-type 750kV step-up substations are the core hubs of new energy power generation and inter-regional power transmission systems, and their construction quality and efficiency directly affect the commissioning progress of the power system.

[0003] The existing conventional open-type substation construction process follows a fixed sequence: first the structure, then the conductors, then the equipment, and finally the conduit installation. The specific steps are as follows: first, complete the overall construction of all the substation structures; then, install the lightning protection wires and the expanded diameter conductors; only after all the above high-altitude operations are completed can the installation of core equipment such as circuit breakers and disconnect switches be started; finally, the electrical conduit installation is carried out according to the location of the installed equipment.

[0004] The above construction techniques have some problems in actual use: 1. Open-type substations have a huge demand for electrical conduits. If the conduit installation is carried out after the equipment is installed according to the conventional process, the area around the already formed equipment foundation needs to be excavated again. This not only increases the consumption of additional labor, machinery and materials, but also prolongs the construction period due to the cross-interference between excavation and equipment protection. 2. In conventional processes, the synchronization between equipment installation and conductor erection is poor. After the equipment is installed, comprehensive protective measures are required to avoid collisions and contamination during conductor erection, resulting in high consumption of protective materials and high labor maintenance costs. Summary of the Invention

[0005] The purpose of this invention is to provide a combined open-type 750kV substation construction process to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A construction process for a combined open-type 750kV substation includes the following steps: S1. The structure is constructed in sections. The installation sequence of the substation structure is adjusted. Priority is given to completing the structure installation of the interconnecting transformer bays, and then the construction of the remaining bay structures is gradually promoted. S2. The main body of the equipment is installed in advance. After the installation of the interconnecting transformer-related bay structure in step S1 is completed, the main body of the circuit breaker and disconnector is installed. The precise position of the actuator, terminal box and control cabinet is determined by the installation of the main body. The insulating bushings of the circuit breaker and disconnector are not installed for the time being, and will be completed simultaneously during the lead-up construction stage. S3. Cable duct laying is carried out in advance. Based on the location of the actuator, terminal box and control cabinet determined in step S2, the cable duct laying is carried out simultaneously to avoid secondary excavation in the future. S4. The conductors are installed in layers. First, the lightning protection conductor at the highest elevation is installed. After the lightning protection conductor has passed the acceptance test, the split conductors are then installed. S5. Finished product protection coordination: Protective measures are taken for the circuit breaker body and actuator installed in step S2 to ensure that the wire installation operation in step S4 does not interfere with or damage the equipment body. S6. Optimize resource allocation and delay the installation of new energy GIS combiner stations.

[0007] As a preferred technical solution, the interconnection transformer related bays to be installed in step S1 are bays 5 to 8 and bays C to F. After the construction of the bay structure is completed, it directly provides a supporting foundation for the subsequent installation of circuit breakers and disconnect switches.

[0008] As a preferred technical solution, the timing of installing the insulating bushing in step S2 is to install it simultaneously at the interface of the circuit breaker or disconnector after the curvature and tension of the lead wire have been adjusted to the correct position, thereby reducing cross-operation with the upper conductor.

[0009] As a preferred technical solution, before the cable burial construction in step S3, the installation coordinates of the operating mechanism, terminal box and control cabinet should be calibrated using a laser positioning instrument based on the circuit breaker and disconnector body installed in step S2, to ensure that the diameter and direction of the burial pipe are aligned with the central axis of the equipment interface.

[0010] As a preferred technical solution, in step S4, the installation height of the lightning protection conductor is higher than that of the split conductor, and the installation of the split conductor must avoid the protection area of ​​the installed equipment body. The horizontal range of the protection area is within 1 to 3 meters extending outward from the edge of the equipment body.

[0011] As a preferred technical solution, the installation of the new energy GIS combiner station is delayed, and the installation process of the new energy GIS combiner station is adjusted to be carried out after the main structure, equipment, wires, and buried pipes of the booster station are completed.

[0012] As a preferred technical solution, the segmented construction of the framework in step S1 is specifically divided into three phases; The initial phase involved the installation of the 5 to 8 and C to F bay frames; the mid-term phase involved the installation of the 5 to 7 and A to C bay frames; and the final phase involved the installation of the 1 to 4 and A to F bay frames. Furthermore, foundation settlement monitoring was conducted after each phase of framework construction.

[0013] As a preferred technical solution, the finished product protection measures in step S5 are as follows: the top of the circuit breaker and disconnector and the operating interface are covered with flame-retardant and waterproof cloth, and the sides of the body are surrounded by rigid plastic plates. The protection range only covers the equipment body and does not include the insulating sleeve to be installed, thereby reducing the amount of protective materials used.

[0014] As a preferred technical solution, the frame construction in step S1 and the equipment installation in step S2 adopt a centralized hoisting mode for the frame and equipment. The structural columns, beams, and corresponding circuit breakers and disconnector bodies of the same interval are hoisted in batches by the same crane, reducing the number of times the crane needs to enter and move.

[0015] As a preferred technical solution, in the frame construction of step S1, all frame columns are treated with waterproof mortar to create a rounded transition for waterproofing at the contact points with the ground. In addition, each frame column is equipped with 4 settlement observation points as preset, with an observation elevation of 0.50m. The settlement observation points are embedded in the steel sleeve detection position of the frame column to ensure accurate observation data.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention restructures the construction sequence, prioritizing the installation of the interconnecting transformer-related bay structure. This allows for the early initiation of equipment installation, avoiding the delays typically caused by waiting for all structures and conductors to be completed before installing equipment, as is the case in conventional processes. The early installation of the equipment provides precise positioning for cable duct laying, fundamentally avoiding the problem of secondary excavation for duct laying caused by the later installation of equipment in conventional processes. This reduces additional labor, machinery, and material consumption. Furthermore, the layered installation of conductors and the coordinated protection of finished products improve the shortcomings of poor synchronization between equipment and conductors in conventional processes, reducing the large amount of protective materials and labor costs required for equipment maintenance due to conductor construction collisions. Overall, this invention achieves multiple optimizations, including shorter construction period, lower costs, and reduced cross-interference.

[0017] 2. By prioritizing the installation of bays 5 to 8 and C to F, this invention clearly defines the priority installation of the interconnecting transformer-related bay structure, which can quickly form the equipment installation support foundation. There is no need to wait for the completion of all the structures in the conventional process before the installation of the circuit breaker and disconnector body can be started, shortening the pre-installation construction period of the equipment. At the same time, it provides stable support for the equipment, avoids the problem of equipment installation accuracy deviation caused by the non-targeted completion of the structure in the conventional process, reduces the additional costs caused by accuracy rework, and creates conditions in advance for subsequent buried pipe construction, indirectly avoiding the risk of secondary excavation.

[0018] 3. This invention uses laser positioning calibration for cable burial. Using the installed equipment as a reference, the laser positioning instrument calibrates the coordinates of the buried pipe, ensuring that the pipe diameter and direction are accurately aligned with the equipment interface. This eliminates the need for secondary excavation from the source, avoiding the extra labor, machinery, and material consumption caused by excavation damaging the equipment foundation and cross-interference with equipment protection in conventional processes. At the same time, it ensures smooth subsequent cable connection and reduces rework time caused by pipe burial deviation.

[0019] 4. This invention improves the problem of poor synchronization between conventional process equipment and conductor erection by avoiding the overlap of conductor installation height and protection area. The lightning protection conductor is installed first and at a higher height than the split conductor to avoid cross-interference between the two. At the same time, the installation of the split conductor avoids the protection area of ​​the already installed equipment, eliminating the need for full coverage protection of the equipment as in conventional processes. This reduces the amount of protective materials and labor maintenance costs required due to conductor construction collisions with equipment, while ensuring the standardization of conductor installation and the safety of the equipment.

[0020] 5. The finished product protection method of this invention adopts a precise protection method of covering key parts with flame-retardant and waterproof cloth and surrounding the sides with rigid plastic boards. It only covers the equipment body, which avoids damage to the equipment during wire construction, reduces the amount of protective materials used, reduces labor maintenance costs, and balances the protection effect with cost control. Attached Figure Description

[0021] Figure 1 This is a construction flowchart of a combined open-type 750kV substation construction process according to the present invention; Figure 2 This is a schematic diagram of the framework distribution in this invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1-2 This embodiment provides a construction process for a combined open-type 750kV substation, including the following steps: S1. The structure is constructed in sections. The installation sequence of the substation structure is adjusted. Priority is given to completing the structure installation of the interconnecting transformer bays, and then the construction of the remaining bay structures is gradually promoted. S2. The main body of the equipment is installed in advance. After the installation of the relevant bay structure of the connecting transformer in step S1 is completed, the main body of the circuit breaker and disconnector is installed. The precise position of the actuator, terminal box and control cabinet is determined by the installation of the main body. The insulating bushings of the circuit breaker and disconnector are not installed for the time being, and will be completed simultaneously during the lead-up construction stage. S3. Cable duct laying is carried out in advance. Based on the location of the actuator, terminal box and control cabinet determined in step S2, the cable duct laying is carried out simultaneously to avoid secondary excavation in the future. S4. The conductors are installed in layers. First, the lightning protection conductor at the highest elevation is installed. After the lightning protection conductor has passed the acceptance test, the split conductors are then installed. S5. Finished product protection coordination: Protective measures are taken for the circuit breaker body and actuator installed in step S2 to ensure that the wire installation work in step S4 does not interfere with or damage the equipment body. S6. Optimize resource allocation by delaying the installation of new energy GIS combiner stations. By reconstructing the construction sequence, the installation of the interconnecting transformer-related bay structures is prioritized, allowing for earlier installation of the equipment itself. This avoids the delays caused by waiting for all structures and conductors to be completed before installing equipment, as is common in conventional processes. Early installation of the equipment provides precise positioning for cable duct laying, fundamentally avoiding the problem of secondary excavation for duct laying caused by post-installation of equipment in conventional processes. This reduces additional labor, machinery, and material consumption. Furthermore, the layered installation of conductors and the coordinated protection of finished products improve the shortcomings of poor synchronization between equipment and conductors in conventional processes. This reduces the large amount of protective materials and labor costs required for equipment maintenance due to conductor construction collisions. Overall, this achieves multiple optimizations, including shorter construction period, lower costs, and reduced cross-interference.

[0024] In step S1, the tie transformer-related bays 5 to 8 and C to F are prioritized for installation. After the construction of this bay structure is completed, it directly provides a supporting foundation for the subsequent installation of circuit breakers and disconnectors. By prioritizing the installation of bays 5 to 8 and C to F, the tie transformer-related bay structure is clearly defined, which can quickly form a supporting foundation for equipment installation. There is no need to wait for the overall completion of all structures in the conventional process before starting the installation of circuit breakers and disconnectors, shortening the pre-installation period of equipment. At the same time, it provides stable support for the equipment, avoids the problem of equipment installation accuracy deviation caused by the non-targeted completion of the structure in the conventional process, reduces the additional costs caused by accuracy rework, and creates conditions for subsequent buried pipe construction in advance, indirectly avoiding the risk of secondary excavation.

[0025] In step S2, the insulating bushing is installed during the construction of the lead-in line of the substation. After the curvature and tension of the lead-in line are adjusted to the correct position, the insulating bushing is installed simultaneously at the interface of the circuit breaker and disconnector. This reduces cross-operation with the upper conductors. Therefore, it eliminates the need for a large amount of protective material to protect the installed insulating bushing, as is the case with conventional processes. It also avoids delays caused by repeated adjustments to the insulating bushing during conductor construction. At the same time, it ensures precise connection between the insulating bushing and the lead-in line and equipment body, reducing installation deviations caused by cross-operation and lowering later maintenance costs.

[0026] Before the cable duct laying in step S3, the installation coordinates of the control mechanism, terminal box, and control cabinet should be calibrated using a laser positioning instrument, based on the circuit breaker and disconnector body installed in step S2. This ensures that the diameter and direction of the duct are aligned with the central axis of the equipment interface. By using laser positioning calibration for cable duct laying, and using the installed equipment body as a reference, the coordinates of the duct are calibrated using a laser positioning instrument to ensure that the diameter and direction of the duct are accurately aligned with the equipment interface. This eliminates the need for secondary excavation from the source, avoids the extra consumption of labor, machinery, and materials caused by excavation damaging the equipment foundation and cross-interference with equipment protection in conventional processes, and ensures smooth subsequent cable connection, reducing rework time caused by duct laying deviation.

[0027] In step S4, the installation height of the lightning protection conductor is higher than that of the split conductor, and the installation of the split conductor must avoid the protection area of ​​the already installed equipment. The horizontal range of the protection area is within 1 to 3 meters extending outward from the edge of the equipment. By avoiding the protection area with the installation height of the conductor, the problem of poor synchronization between the conventional process equipment and the conductor erection is improved. The lightning protection conductor is installed first and at a higher height than the split conductor to avoid cross-interference between the two installations. At the same time, the installation of the split conductor avoids the protection area of ​​the already installed equipment, so there is no need to provide full coverage protection for the equipment as in the conventional process. This reduces the amount of protective materials and labor maintenance costs required due to the conductor construction colliding with the equipment, while ensuring the standardization of conductor installation and the safety of the equipment.

[0028] Among these measures, the installation of the new energy GIS combiner station was delayed. The installation process of the 220kV new energy GIS combiner station was adjusted to be carried out after the main structure, equipment, conductors, and buried pipes of the 750kV substation were completed. This avoided competition for manpower with the construction of the 750kV substation, and the overall construction period of the 220kV new energy GIS combiner station was controlled within 40 to 50 days. By delaying the installation of the new energy GIS combiner station, the installation was adjusted to be carried out after the main structure of the substation was completed. This avoided the problem of multiple processes competing for manpower in the conventional process, allowing manpower to be concentrated on key aspects such as the structure, equipment, buried pipes, and conductors. This reduced the delay caused by the dispersion of manpower, especially avoiding the efficiency loss caused by the superposition of secondary excavation for buried pipes and the construction of the combiner station in the conventional process. At the same time, the construction period of the combiner station was controlled, ensuring the overall progress was orderly and indirectly reducing the additional costs caused by the conflict of multiple processes.

[0029] The general steps to control the overall construction period of the 220kV new energy GIS combiner station within 40 to 50 days are as follows: I. Preliminary Preparation Stage: 1. Complete the review of the construction drawings for the 220kV GIS combiner station in advance, focusing on verifying the foundation dimensions of the GIS equipment, such as the spacing of the embedded bolts, the top elevation, the cable trench route and the compatibility with the 750kV step-up substation interconnection transformer interface, and form a "Minutes of Drawing Review" to avoid rework due to dimensional deviations during construction; Organize technical briefings for equipment manufacturers, construction teams, and commissioning units to clarify the installation accuracy requirements and airtightness test standards for circuit breakers, disconnectors, and grounding switches in GIS equipment, ensuring that all parties have a consistent understanding of the technology. Materials and site preparation should be completed in advance, and the arrival of GIS equipment, including the main body, accessories, SF6 gas, control cables, optical fibers, insulation components, etc., should be confirmed. The equipment should be stored in designated areas on site according to the installation sequence, such as the GIS main body being close to the foundation. The appearance of the equipment and insulation resistance testing should be completed to avoid delays caused by problems found after delivery. Before the main construction of the 750kV substation is completed, the site handover of the GIS combiner station construction area is completed: clearing debris from the site, verifying the flatness of the foundation and the position of the pre-embedded bolts, and setting up a temporary rain shelter to prevent rain from affecting the site. Furthermore, personnel and machinery are pre-configured and divided into 3 parallel work teams. One team is responsible for GIS equipment installation, including crane and assembly workers, with 6-8 people. Another team is responsible for cable laying and secondary wiring with 4-5 people. The third team is responsible for auxiliary work, such as material transfer and on-site protection, with 2-3 people. All personnel must have GIS installation qualifications and complete safety training in advance. The necessary machinery is allocated in advance, such as a 25t truck crane for equipment hoisting to ensure that it can be put into operation immediately upon arrival, an SF6 gas recovery and charging device, and a laser positioning instrument for equipment positioning calibration, to avoid delays caused by temporary machinery deployment. II. Proceed in parallel, modular fashion to compress the critical path: Equipment installation; 1. The GIS equipment installation module adopts a unit-by-unit assembly line operation, and is installed in the order of circuit breaker unit → disconnector unit → grounding switch unit → busbar unit of GIS combiner station. Each unit is inspected in time after completion to avoid the accumulation of subsequent problems. First, the foundation was re-measured and the equipment was placed. The position of the pre-embedded bolts and the top elevation of the foundation of each equipment unit were re-measured using a laser positioning instrument, and the bolts with deviations exceeding the standard were fine-tuned. A 25t truck crane was used to lift the GIS equipment body in batches. The circuit breaker unit was lifted first, followed by the disconnecting switch and grounding switch unit. The level of the equipment was calibrated with a level when it was in place, and it was temporarily fixed with nuts immediately after it was in place to prevent displacement. Equipment connection and sealing: Remove the protective cover from the equipment flange face, clean the flange face and sealing groove with anhydrous ethanol, replace the sealing strip with a new one, and ensure that the sealing groove is free of impurities; Tighten the flange bolts using a torque wrench according to the manufacturer's requirements, tightening them symmetrically in three stages to avoid uneven stress on the flange surface that could lead to leakage. After each unit connection is completed, an airtightness test is immediately conducted. If the test fails, the sealing surface must be re-inspected and the work reworked. SF6 gas filling and equipment fixing SF6 gas recovery and filling device fills each unit with gas: first, vacuum is drawn, and then SF6 gas is filled to the rated pressure. During the filling process, the gas purity is monitored to avoid impurities from affecting the insulation performance. After the gas filling is completed, tighten all the fixing bolts of the equipment, install the equipment nameplate and grounding terminal, clean the surface of the equipment, and make an installation record. 2. Cable laying; Furthermore, the wiring will be carried out simultaneously 3 days after the GIS equipment installation is started, to avoid wasting time due to wiring after the equipment is installed; Determine the laying path of control cables and optical fibers according to the drawings, and fix them with brackets when laying them along the cable trench to avoid cables crossing and tangling. Lay cables according to the principle of laying long cables first and thick cables first. Lay the long cables from the control cabinet to the circuit breaker unit first, and then lay the short cables. Avoid pulling or squeezing the cables during the laying process. Hang cable identification tags immediately after laying. When wiring, strip the cable insulation layer and connect it to the terminal block of the GIS equipment terminal box and the control cabinet according to the drawing requirements. Use cold-pressed terminals to ensure good contact during wiring. After each cable is connected, use a multimeter to check the continuity and insulation resistance of the circuit, and record the connection position; after the fiber optic cable is connected, use an optical power meter to test the optical attenuation to ensure that the signal transmission is normal. Third, final debugging: after the subsystems have been successfully debugged, the entire system will be integrated and debugged. 1. Subsystem debugging and control loop debugging: Power on the control cabinet, test the opening and closing operation of the GIS equipment, check whether the operating mechanism moves smoothly, and whether the auxiliary switch contacts switch accurately. Protection circuit debugging: Simulate overcurrent and overvoltage fault signals to check whether the protection device can operate accurately and whether the operating time meets the design requirements; Condition monitoring system debugging: Test the SF6 gas density monitoring and equipment temperature monitoring functions to ensure that the data can be transmitted to the background monitoring system in real time without data loss or deviation; Overall electrothermal commissioning AC withstand voltage test: Apply the rated voltage required by the specification to the GIS combiner station as a whole, and monitor the equipment for breakdown and flashover. Rated current temperature rise test: Apply rated current to the busbar for 2 hours and measure the temperature of each connection point of the equipment to ensure normal heating. Overall commissioning: Conduct a linkage test with the 750kV step-up substation interconnection transformer to test the switching function between the GIS combiner station and the interconnection transformer, and ensure the coordinated operation of the system; Acceptance and finalization: Organize the owner, supervisor and manufacturer to carry out final acceptance: check the construction records, equipment certificates of conformity and test reports, and conduct on-site spot checks of equipment appearance, grounding resistance and air tightness; After acceptance, the construction site is cleaned up, construction documents are handed over, and the project is completed and handed over. The structural segment construction of step S1 is specifically divided into three phases; The initial phase involved the installation of the 5 to 8 and C to F bay frames; the mid-term phase involved the installation of the 5 to 7 and A to C bay frames; and the final phase involved the installation of the 1 to 4 and A to F bay frames. Furthermore, foundation settlement monitoring is conducted after each phase of framework construction. By setting up segmented construction, the phased construction of the framework can flexibly connect equipment installation and pipe laying procedures, avoiding the waste of time that is usually carried out only after the overall framework is completed in conventional processes. Settlement monitoring after each phase of construction can promptly detect foundation stability issues and avoid equipment installation deviations and pipe laying rework caused by foundation settlement.

[0030] Specifically, the finished product protection measures in step S5 involve covering the top of the circuit breaker and disconnector switch and their operating interfaces with flame-retardant and waterproof cloth, and enclosing the sides of the body with rigid plastic panels. The protection area only covers the equipment body and does not include the insulating sleeves to be installed, thus reducing the amount of protective material used. By setting up finished product protection, using a precise protection method of covering key parts with flame-retardant and waterproof cloth and enclosing the sides with rigid plastic panels, and only covering the equipment body, damage to the equipment during wire installation is avoided, the amount of protective material used is reduced, labor maintenance costs are lowered, and the protection effect and cost control are balanced.

[0031] In the process of frame construction in step S1 and equipment installation in step S2, a centralized hoisting mode for the frame and equipment is adopted. The frame columns, beams, and corresponding circuit breakers and disconnector bodies of the same bay are hoisted in batches by the same crane, reducing the number of times the crane needs to enter and move. By adopting a centralized hoisting mode for the frame and equipment, the frame components and equipment of the same bay are hoisted in batches by the same crane, reducing the mechanical costs of multiple crane entries and moves caused by separate hoisting of the frame and equipment in conventional processes. At the same time, it achieves a close connection between the installation of the frame and the equipment, avoiding the time gap of waiting for the equipment to be hoisted after the frame is hoisted in conventional processes.

[0032] In step S1, during the frame construction, all frame columns are treated with waterproof mortar to create a rounded transition for waterproofing at the contact points with the ground. Furthermore, each frame column is equipped with four settlement observation markers as preset, with an observation elevation of 0.50m. The settlement observation markers are embedded in the steel sleeve detection position of the frame column to ensure accurate observation data. Through the waterproof treatment of the frame columns and the setting of settlement observation markers, the waterproof treatment of the frame columns can prevent water accumulation and erosion of the ground, avoiding the additional cost of later maintenance caused by the corrosion of the frame columns in conventional processes. At the same time, it reduces the risk of rework due to equipment support deviation and pipe position displacement caused by frame damage. In addition, the accurate setting of settlement observation markers ensures the reliability of observation data, avoiding the need for later equipment and pipe rectification due to inaccurate settlement data in conventional processes, reducing rectification costs and construction period losses.

[0033] Based on the above technical solutions, the working steps of this solution are summarized as follows: First, the framework installation of the connecting transformer bays was carried out to build a supporting foundation for the subsequent equipment installation. Then, the construction of the remaining bay frameworks was carried out in stages, and foundation settlement was monitored after each phase of framework construction to ensure the stability of the framework foundation. During the construction of the framework, waterproofing was applied to all the contact points between the framework columns and the ground. At the same time, settlement observation markers were set up according to the preset requirements to ensure the accuracy of settlement observation data and provide reliable foundation conditions for subsequent construction. In addition, the centralized hoisting mode of the structure and equipment is adopted. The structural components and corresponding circuit breakers and disconnect switches in the same interval are hoisted in batches by the same crane, which reduces the number of times the crane enters the site and moves, reduces mechanical costs and improves hoisting efficiency. After the relevant bay structure of the interconnection transformer is installed, the circuit breaker and disconnector switch body installation will be carried out in advance. The position of the actuator, terminal box and control cabinet will be accurately determined through the body installation, providing a positioning basis for subsequent pipeline construction. Meanwhile, the insulating sleeves of the equipment will not be installed for the time being. During the construction phase of the lead-in line of the substation, after the curvature and tension of the lead-in line are adjusted to the right, the insulating sleeves will be installed at the interface of the equipment body. This will reduce the cross-operation between the installation of the insulating sleeves and the construction of the upper conductor and avoid mutual interference. Based on the locations of the actuators, terminal boxes, and control cabinets determined by the installation of the equipment itself, cable burial construction is carried out simultaneously to avoid secondary excavation due to location deviations in the future. Furthermore, before construction, using the already installed circuit breakers and disconnect switches as a reference, a laser positioning instrument is used to calibrate the installation coordinates of the actuators, terminal boxes, and control cabinets to ensure that the diameter and direction of the cable conduits are precisely aligned with the central axis of the equipment interfaces, thus ensuring the smoothness and reliability of subsequent cable connections. At the same time, following the principle of installing high-level equipment first and avoiding already installed equipment, the lightning protection conductors at the highest elevation should be installed first, and the split conductors should be installed only after the lightning protection conductors have passed inspection. During the installation of split conductors, the pre-set protection area of ​​the installed equipment body must be avoided to prevent the conductor installation work from interfering with or damaging the equipment body, and to ensure equipment safety and conductor installation quality. Targeted protection measures are taken for the installed circuit breaker body and actuator. Flame-retardant and waterproof cloth is used to cover the top of the equipment body and the operating interface, and rigid plastic panels are used to surround the sides. The protection range only covers the equipment body and does not include the insulating sleeve to be installed. This reduces the amount of protective materials used and controls costs while ensuring equipment safety. In addition, in order to optimize resource allocation, the installation process of the 220kV new energy GIS combiner station will be adjusted to be carried out after the construction of the main structure, equipment, conductors and buried pipes of the substation is completed, so as to avoid competing with the construction of the main substation for human resources. At the same time, the overall construction of the new energy GIS combiner station will be controlled within a reasonable construction period to ensure the orderly progress of the overall construction.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A construction process for a combined open-type 750kV substation, characterized in that, Includes the following steps: S1. The structure is constructed in sections. The installation sequence of the substation structure is adjusted. Priority is given to completing the structure installation of the interconnecting transformer bays, and then the construction of the remaining bay structures is gradually promoted. S2. The main body of the equipment is installed in advance. After the installation of the interconnecting transformer-related bay structure in step S1 is completed, the main body of the circuit breaker and disconnector is installed. The precise position of the actuator, terminal box and control cabinet is determined by the installation of the main body. The insulating bushings of the circuit breaker and disconnector are not installed for the time being, and will be completed simultaneously during the lead-up construction stage. S3. Cable duct laying is carried out in advance. Based on the location of the actuator, terminal box and control cabinet determined in step S2, the cable duct laying is carried out simultaneously to avoid secondary excavation in the future. S4. The conductors are installed in layers. First, the lightning protection conductor at the highest elevation is installed. After the lightning protection conductor has passed the acceptance test, the split conductors are then installed. S5. Finished product protection coordination: Protective measures are taken for the circuit breaker body and actuator installed in step S2 to ensure that the wire installation operation in step S4 does not interfere with or damage the equipment body. S6. Optimize resource allocation and delay the installation of new energy GIS combiner stations.

2. The construction process of a combined open-type 750kV substation according to claim 1, characterized in that: In step S1, the interconnection transformer-related bays that are prioritized for installation are bays 5 to 8 and bays C to F. After the construction of this bay structure is completed, it directly provides a supporting foundation for the subsequent installation of circuit breakers and disconnect switches.

3. The construction process of a combined open-type 750kV substation according to claim 2, characterized in that: In step S2, the insulating bushing is installed after the curvature and tension of the lead wire are adjusted to the correct position, and then the insulating bushing is installed at the interface of the circuit breaker and disconnector to reduce cross-operation with the upper conductor.

4. The construction process of a combined open-type 750kV substation according to claim 3, characterized in that: Before the cable burial construction in step S3, the installation coordinates of the operating mechanism, terminal box and control cabinet should be calibrated using a laser positioning instrument, based on the circuit breaker and disconnector body installed in step S2, to ensure that the pipe diameter and direction of the burial pipe are aligned with the central axis of the equipment interface.

5. The construction process of a combined open-type 750kV substation according to claim 4, characterized in that: In step S4, the installation height of the lightning protection conductor is higher than that of the split conductor, and the installation of the split conductor must avoid the protection area of ​​the installed equipment body. The horizontal range of the protection area is 1 to 3 meters outward from the edge of the equipment body.

6. The construction process of a combined open-type 750kV substation according to claim 5, characterized in that: The installation of the new energy GIS combiner station will be delayed, and the installation process will be adjusted to be carried out after the main structure, equipment, wires, and buried pipes of the booster station are completed.

7. The construction process of a combined open-type 750kV substation according to claim 1, characterized in that: The structural segment construction of step S1 is specifically divided into three phases; The initial phase involved the installation of the 5 to 8 and C to F bay frames; the mid-term phase involved the installation of the 5 to 7 and A to C bay frames; and the final phase involved the installation of the 1 to 4 and A to F bay frames. Furthermore, foundation settlement monitoring was conducted after each phase of framework construction.

8. The construction process of a combined open-type 750kV substation according to claim 1, characterized in that: The specific protective measures for the finished product in step S5 are as follows: the top of the circuit breaker and disconnector and the operating interface are covered with flame-retardant and waterproof cloth, and the sides of the body are surrounded by rigid plastic plates. The protection range only covers the equipment body and does not include the insulating sleeve to be installed, thereby reducing the amount of protective materials used.

9. The construction process of a combined open-type 750kV substation according to claim 1, characterized in that: During the framework construction in step S1 and the equipment installation in step S2, a centralized hoisting mode for the framework and equipment is adopted. The structural columns, beams, and corresponding circuit breakers and disconnector bodies of the same interval are hoisted in batches by the same crane, reducing the number of times the crane needs to enter and move.

10. The construction process of a combined open-type 750kV substation according to claim 1, characterized in that: In the framework construction of step S1, all framework columns are treated with waterproof mortar to create a rounded transition for waterproofing at the contact points with the ground. In addition, each frame column is equipped with 4 settlement observation points as preset, with an observation elevation of 0.50m. The settlement observation points are embedded in the steel sleeve detection position of the frame column to ensure accurate observation data.

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