Tecnolohiya sa konstruksyon para sa pagpapalawig ug pagsulay sa 500 kV GIS operasyon nga dapit
Ang 500 kV GIS system sa Lianghekou Hydropower Station gisuloban og circuit breakers, disconnectors, earthing switches, bus-pipes, current transformers (CTs), potential transformers (PTs), arresters, ug uban pa. Adunay total nga 12 ka circuit-breaker bays, gipangayo og indoor structure ug "Z" - shaped layout, adunay 6 ka incoming lines ug 2 ka outgoing lines, ug gigamit ang 4/3 ug 3/2 wiring schemes. Aron mopasabot sa pag-access sa Kela Photovoltaic project sa unang-phase hydro-photovoltaic complementary project sa Lianghekou Hydropower Station, giadug ang usa ka bag-ong outgoing-line bay (ang tulo ka outgoing-line bay) sa Lianghekou Hydropower Station.
Ang 3/2 string diin nahimutang ang No. 1 ug No. 2 incoming lines gibag-o ngadto sa 4/3 string. Ang bay nga orihinal nga gireserba alang sa access sa Yagen-level-1 Hydropower Station giusab ngadto sa wind-ug-photovoltaic access bay, ug giadug ang equipment sa outgoing-line yard. Ang interface sa expanded GIS equipment ug ang already-commissioned GIS equipment mao ang 50132 ug 50122 disconnectors ug ang ilang associated gas compartments. Bago mag-umpisa ang GIS expansion work, sa gilid sa Unit 1, ang power plant ang responsable sa switching operations sa 50122 disconnector ug 50122 circuit breaker.
Human sa pagkumpleto, itala sa project department nga mahimo na ang half-voltage reduction operation sa gas compartment diin nahimutang ang 50122 disconnector. Sa gilid sa Unit 2, ang Lianghekou Power Plant ang responsable sa switching operation sa 50132 disconnector ug shutdown operation sa Unit 2. Human sa pagkumpleto, itala sa installation unit nga mahimo na ang half-voltage reduction operation sa gas compartment diin nahimutang ang 50132 disconnector. Human sa pag-adug, ang installation unit ang responsable sa pagbalik sa gas pressure sa 50132 ug 50122 disconnectors ug ang ilang associated gas compartments.
Ang construction period sa modification ug expansion project sa tulo ka outgoing-line bay sa Lianghekou Hydropower Station mao ra 30 ka adlaw. Sa mga 30 ka adlaw, kinahanglan i-remove ang existing bus-pipes ug ipakompleto ang installation ug testing sa new circuit breakers, CTs, ug PTs sa operating area. Ang construction period mao ang tight, ug ang safety risks mao ang taas. Giila pa, sa proseso sa installation sa equipment, limited ang lifting, ug dili makumpleto ang equipment installation pinaagi sa conventional lifting methods.
Analysis of Construction Difficulties
Installation of Newly-Added GIS Equipment
Ang interface sa newly-installed GIS equipment ug ang already-commissioned GIS equipment mao ang 50132 ug 50122 disconnectors ug ang ilang associated gas compartments. Buntag sa pag-install sa new circuit breaker, kinahanglan i-remove ang connecting bus-pipes ug supports tali sa 50132 ug 50122, resulta mao ang CTs ug PTs sa itaas sa 50132 disconnector mag-suspend, ug dili madali ang temporary support. Gisugdan pa, sa pag-install sa B-phase PT sa newly-added 50131 disconnector, gitubigan kini sa live busbar sa itaas, resulta dili mahimo ang normal nga paggamit sa GIS bridge crane para sa lifting, resulta mao ang taas ang installation difficulty.
Operations in the Operating Area
Buntag sa pag-modify ug pag-adug sa tulo ka outgoing-line bay, ang equipment sa GIS room ug ang outgoing-line yard sa Lianghekou Hydropower Station adunay normal nga commission ug live. Kinahanglan i-remove ang pipila ka live ug commissioned equipment ug lifting operations sa proximity, resulta mao ang significant nga safety risks.
Construction Preparations
Preparation of a Full-scope Management List
Buntag sa tight nga construction schedule ug heavy workload sa tulo ka outgoing-line bay, ug giingon nga ang construction gibuhat sa operating area sa power plant, aron masiguro ang smooth progress sa construction, ang owner, supervisor, power plant, equipment manufacturer, ug uban pang parte nag-discuss ug nag-prepare og full-scope management list, ug girequire ang tanang parte nga ipatuman ang ilang related responsibilities sa strict accordance sa requirements sa list. Ang full-scope list gisuloban sa sumala nga anim ka sections:
Power Outage Plan
Ang tanang parte nag-discuss ug nalistahan ang tasks nga gikinahanglan og application sa power grid ug dispatching, sama sa power grid outages ug grid-related tests sa panahon sa construction process. Ang installation unit mag-apply sa power plant usa ka semana sa unang, ug ang production department sa power plant mag-apply sa dispatching. Ang power outage plan gidefine sa clear ang name sa main equipment nga gikinahanglan i-power off, ang start ug end times sa power outage, ang main work content, ug ang required state sa powered-off equipment.
Construction and Commissioning Plan
Ang installation unit refine ang construction ug commissioning progress plan batas sa power outage plan ug ang total construction period, girequire ang refinement sa bawg proseso ug maclarify ang start ug end times sa bawg proseso. Ang installation unit mag-determine sa human resources nga invested sa bawg proseso batas sa construction ug commissioning plan, ug reasonable coordination sa human resources. Usa ka daily afternoon meeting mahimo aron matamaan ang deviations sa implementation sa construction plan, masiguro nga matapos ang tasks sa same day.
Ticket-issuing List and Plan
Aron masiguro ang normal nga operation sa operating area, ang tanang parte nag-prepare og ticket-issuing list ug plan. Human sa ticket-issuing list mokumpleto, ma-confirm niini ang operation department sa owner's power plant. Ang operation department familiarize ug prepare ang operation tickets sa advance. Ang installation unit makapagtugon sa operation human sa pagkuha sa tickets gikan sa operation department sa power plant batas sa ticket-issuing list. Buntag sa pag-issue sa tickets, ang contact person sa power plant gisulob sa work team members. Ang ticket-issuing list gidefine sa clear ang ticket-issuing name, operation content, person-in-charge sa ticket-issuing work ug contact information, operation time, ug ang contact person sa ticket-issuing sa power plant.
List of Installation and Commissioning Schemes
Buntag sa reconstruction ug expansion involve ang live connection sa pipila ka secondary cables sa operating system sa power plant, gikinahanglan ang operation sa maintenance department sa power plant, ang tanang parte agree nga ang maintenance department sa power plant mag-prepare og cooperation scheme para sa reconstruction ug expansion sa tulo ka bay, ug ang installation unit mag-prepare og construction, commissioning, ug testing schemes para sa reconstruction ug expansion. Ang list gidefine sa clear ang scheme name, responsible department, initial draft completion time, ug final draft completion time.
Plan for the Entry of Personnel and Equipment
Ang installation unit nalistahan ang specific entry times sa pipila ka types sa workers, regular testers, high-voltage testers, mobile cranes, forklifts, trucks, ug uban pang personnel ug equipment, ug maclarify ang responsible persons. Ang supervisor ug ang owner conduct assessments batas sa schedule aron mapadaya ang installation unit nga masiguro nga ang personnel ug equipment makasulod sa site on time ug ang tanang resources ma-prepare well.
Plan for the Supply of Materials and Equipment
Ang installation unit nalistahan ang entry plan sa equipment ug materials supplied sa Party B, ug ang owner nalistahan ang entry plan sa equipment ug materials supplied sa Party A. Ang tanang parte follow up ug implement batas sa entry plans sa equipment ug materials aron masiguro nga ang equipment ug materials makadlaw on time. Ang plan categorically nalistahan ang equipment name, supply time, responsible person, manufacturer, ug uban pang information.
Technical Preparations
Confirm sa power plant nga ang switching operations sa GIS equipment natapos na, ang safety measures gisulob, ug ang construction conditions napasabot.
Measurement ug Layout: Batas sa GIS installation layout diagram ug combined sa installation elevation sa outlet bushing, review ang elevation coordinate points sa GIS equipment installation, measure, mark, ug record ang installation positions.
Ang workers kinahanglan mag-change sa work shoes ug wear purification suits buntag sa pag-enter sa installation area. Ang work shoes ug purification suits dili makagamit sa wala sa installation area. Ang uban pang personnel kinahanglan mag-wear og shoe covers buntag sa pag-enter sa installation area.
Organize ang tanang construction workers aron ma-understand ang layout characteristics sa equipment sa entire expanded bay ug ma-familiarize sa installation process ug process requirements, batas sa relevant drawings ug manufacturer's materials.
Invite ang manufacturer's ug designer's on-site technicians ug ang supervision engineer aron mag-conduct og technical disclosure sa tanang construction workers, aron ma-understand ang design intent ug ang manufacturing plant's process characteristics, ug correctly master ang usage methods sa professional tools.
Prepare ang tanang kinds sa records, inspection forms, ug process cards gikinahanglan sa panahon sa installation ug commissioning processes.
Isolation between Construction Area and Operating Area
Buntag sa pag-install sa equipment, gamiton ang retractable fences aron ma-plan sa reasonable ang construction site, demarcating ang construction area, operating area, isolation area (ang side against the mountain sa main transformer incoming line sa Unit 1, 5011 circuit breaker, ug 5012 circuit breaker), equipment ug material storage area, construction passage, ug operating passage. Sa secondary switchboards sa itaas sa outlet branch busbars sa construction area, adopt hard isolation protection. Gamiton ang scaffolding pipes aron mag-erect og protective shed ug lay wooden boards sa top.
Inspection of Arrived Equipment and Materials
Ang sumala nga items gipanginspeksyon sa panahon sa arrival acceptance sa GIS equipment:
Buntag sa pag-unpack, check kon damaged ang packaging ug kon may collision, damage, o loss sa transportation.
Check ang integrity ug correctness sa delivered equipment batas sa order ug delivery documents.
Check kon ang paint, anti-rust layer, color, ug quality sa surface sa equipment naka-meet sa requirements.
Check kon ang text ug data sa nameplate correct.
Carefully check batas sa packing list kon ang product accessories, spare parts, installation supplies, ug special tools complete, ug kon may signs sa damage, deformation, o rust.
Check kon ang bushings may deformation, moisture, cracks, o defects.
Check kon ang factory certificates, relevant drawings, materials, ug documents complete.
Check kon ang value sa three-dimensional anti-tampering instrument exceeds 3 g.
Equipment Installation
Gas Recovery and Pressure Reduction
Buntag sa pag-install sa equipment, reduce ang pressure sa half sa detachable break points sa 5014 terminal CT, high-voltage side T-zone PT sa No. 2 main transformer, high-voltage side T-zone sa No. 2 main transformer, ug 5012 initial CT, as well as sa high-voltage side T-zone PT sa No. 2 main transformer (see Part 3 in the figure for details); recover ang gas sa 5013-5014 diagonal span hangtod sa 5012 initial CT (see Part 1 in the figure for details); retain a slight positive pressure of 0.05 MPa during gas recovery in the gas chamber from the 5014 terminal CT to the 5013-5014 diagonal span (see the colored block in Part 2 of the figure). The gas recovery and pressure reduction are shown in Figure 2.
Disassembly and Support of Bus-pipes
Human sa gas recovery ug pressure reduction natapos, buntag sa pag-position sa circuit breaker, unsa isip unang i-remove ang maintenance platform, ug then remove ang "L"-shaped bus-pipe sa 5013. Buntag sa pag-remove sa "L"-shaped bus-pipe, gamiton ang gantry aron hoist ug fix ang PT, CT, disconnector, 5013-5014 diagonal bus-pipe, ug 5012-5013 diagonal bus-pipe sa area sa tooling.
Foundation Point-setting and Equipment Positioning
Batas sa manufacturer's drawings, design drawings, ug ang installation status sa existing equipment, gamiton ang ink line box aron mark-out ug identify ang (X, Y) center lines sa equipment. Measure ug fix ang relative positions sa equipment sa steel tape measure batas sa center line sa B-phase sa incoming ug outgoing lines; at the same time, mark the elevation points of the equipment to determine the installation elevation of the equipment.
Install the equipment in place according to the design drawings, and review the centers and elevations of all equipment to ensure the correct installation positions.
After the GIS room equipment is transported to the on-site hoisting hole in sequence, it is hoisted to the installation position inside the GIS room by a 10-t single-girder crane. During hoisting, the "Ten No-Hoisting Rules" are strictly implemented. Each component must be test-hoisted for three times of lifting and lowering before hoisting. The hoisting area should try to avoid the operating area. The equipment must enter the site in strict accordance with the installation sequence to avoid the accumulation and congestion of equipment on-site, which may affect the installation progress. GIS equipment must be hoisted with the special lifting tools provided by the manufacturer, and the equipment should not be damaged during handling.
When the equipment of a unit is initially positioned, first position the circuit breaker, and then position other equipment. Since the diagonal-spanning bus-pipe between 5013 and 5014 has not been removed, the 10-t bridge crane in the GIS room [3-5] cannot directly hoist the circuit breaker into position. Therefore, in this installation, a manual hydraulic forklift is used to transport the circuit breaker to the installation position, and then the positioning adjustment is carried out. Ensure that the center and elevation of the circuit breaker meet the design requirements.
Refer to the elevation of existing equipment during equipment installation. Before installation or connection, the equipment should be adjusted to be straight and level. Forcing, prying, or hard-aligning the equipment manually is strictly prohibited.
Tighten all connecting bolts with a torque wrench according to the specified torque.
Installation of Voltage Transformers
Since the B-phase voltage transformer behind the 5013 circuit breaker (weighing about 1 t and with an installation height of about 6 m) is installed directly below the B-phase of Bus Ⅱ, and Bus Ⅱ is in a live-operation state, the 10-t bridge crane in the GIS room cannot directly hoist the voltage transformer into position. After consulting with multiple parties, it is decided to introduce an industrial forklift. The forklift has a rated load capacity of 1.5 t and a maximum lifting height of 7 m, which meets the on-site requirements and can move flexibly on-site.
Before installation, check whether the internal pressure value of the transformer is the original inflation pressure and conduct routine tests.
Clean the electrical contact surfaces on the sealing surface and the connecting flange with lint-free paper dipped in anhydrous alcohol.
During the installation of the voltage transformer, adjust the verticality and levelness through the screws on the base to ensure a proper connection with the bus-connection surface and complete the flange connection.
The conductor inside the detachable port at the lower end of the newly-added voltage transformer should be installed after the withstand voltage test is completed.
Conclusion
During the modification and expansion construction of the third bay of the 500 kV GIS at Lianghekou Hydropower Station, faced with unfavorable factors such as a tight construction schedule, construction in the operating area, and restricted lifting, through a series of measures including formulating a full-scope management list, manufacturing special tooling, and introducing industrial forklifts, the smooth progress of the modification and expansion construction of the third bay was ultimately ensured. This shortened the construction period, saved costs, and guaranteed safety and quality. It has set a precedent for in-depth cooperation between operations in the 500 kV GIS operating area and the power plant, and has certain reference and promoting significance for similar modification and expansion projects.
