Tecnîkê biniyê ji bo pêşketin û dervekirina herêmê operasyonê GIS 500 kV

Sistîma 500 kV GIS ya Elektrikstana Lianghekou di qada dê û disconnectoran û earthing switches û bus - pipes û current transformers (CTs) û potential transformers (PTs) û arresters û yath. Di navbera 12 circuit - breaker bays de hatî, li ser strûktûra jînî û "Z" - shaped layout da, bi 6 incoming lines û 2 outgoing lines re, û bi cihewa 4/3 û 3/2 wiring schemes re. Ji bo piştgiriya Kela Photovoltaic project di phase - one hydro - photovoltaic complementary project de ya Elektrikstana Lianghekou, bayek nû ya outgoing - line (bayek sêyem outgoing - line) hat zêde kirin ji bo Elektrikstana Lianghekou.

Cihewa 3/2 string ku li ser No. 1 û No. 2 incoming lines de ye hat zêdekirin ji bo 4/3 string. Bayek ku ji bo piştgiriya Yagen - level - 1 Hydropower Station re destnîsera hat guhertiya ji bo wind - and - photovoltaic access bay, û pirtûka outgoing - line yard hat zêdekirin duvêt. Înterfeysa GIS equipment yên zêdetir û GIS equipment yên di berda xebitandin de ye li ser 50132 û 50122 disconnectors û gas compartments an. Pêvek çawa karên zêdetir GIS dabeş bikin, ji aliyê Unit 1, elektrikstana dike wekariya switching operations ya 50122 disconnector û 50122 circuit breaker.

Pas dabeşkirina, biguheztin departmenta projeyê ku half - voltage reduction operation li ser gas compartment ku 50122 disconnector li ser e werdigire. Ji aliyê Unit 2, Elektrikstana Lianghekou dike wekariya switching operation ya 50132 disconnector û shutdown operation ya Unit 2. Pas dabeşkirina, biguheztin unita instalasyonê ku half - voltage reduction operation li ser gas compartment ku 50132 disconnector li ser e werdigire. Pas dabeşkirina, unita instalasyonê dike wekariya restore the gas pressure li ser 50132 û 50122 disconnectors û gas compartments an.

Müddeti çawa modifikasyon û zêdetir projecti bayek sêyem outgoing - line ya Elektrikstana Lianghekou tenê 30 roj e. Li nawbera wan 30 rojan, dixwazin lêz din bike bus - pipes û instalasyon û test bike new circuit breakers, CTs, û PTs di navendeya operasyon de. Müddet çawa teqîl e û risgaya taybetmendiya gir hêsan e. Navbera wan, di daweyê instalasyon de, lifting restricted ye û instalasyon pirtûka bi rêzikên çawa normale nebeşkirdin.

Analîza Çewabdarî

Instalasyon New - Added GIS Equipment

Înterfeysa GIS equipment yên nû install kirin û GIS equipment yên di berda xebitandin de ye li ser 50132 û 50122 disconnectors û gas compartments an. Lekom instalasyon circuit breaker nû, connecting bus - pipes û supports between 50132 û 50122 dixwazin bike, ku CTs û PTs li ser 50132 disconnector suspended bin, û temporary support rather difficult be. Navbera wan, lekom instalasyon B - phase PT of newly - added 50131 disconnector, blocked by live busbar above, preventing normal use of GIS bridge crane for lifting, resulting in relatively high installation difficulty.

Operations in the Operating Area

Lekom modification û zêdetir construction bayek sêyem outgoing - line, pirtûka GIS room û outgoing - line yard ya Elektrikstana Lianghekou di berda xebitandin de û live ne. Modification û zêdetir construction dixwazin bike removal of some live û commissioned equipment û lifting operations in the vicinity, posing significant safety risks.

Construction Preparations
Preparation of a Full - scope Management List

Ji ber müddeti çawa teqîl û carga zor û zêdetir bayek sêyem outgoing - line, û li ber vê çawa kar di navendeya operasyon de, bi tenê ku bi sûniyê çawa kar werbigire, malikan, supervisor, elektrikstana, manufacturer, û other parties jointly discuss û prepare full - scope management list, û require all parties to fulfill their relevant responsibilities in strict accordance with the requirements of the list. The full - scope list is divided into the following six sections:

Power Outage Plan

All parties discuss û list tasks that require applications to the power grid û dispatching, such as power grid outages û grid - related tests during the construction process. The installation unit applies to the power plant one week in advance, û production department of the power plant applies to the dispatching. The power outage plan clearly defines name of main equipment to be powered off, start û end times of power outage, main work content, û required state of powered - off equipment.

Construction and Commissioning Plan

The installation unit refines construction û commissioning progress plan according to power outage plan û total construction period, requiring refinement to each process û clarifying start û end times of each process. The installation unit determines human resources invested in each process according to construction û commissioning plan, û reasonably coordinates human resources. A daily afternoon meeting held to correct deviations in implementation of construction plan, ensuring tasks completed on same day.

Ticket - issuing List and Plan

To ensure normal operation in operating area, all parties jointly prepare ticket - issuing list û plan. After ticket - issuing list completed, confirmed by operation department of owner's power plant. Operation department familiarizes itself û prepares operation tickets in advance. Installation unit can only start operation after obtaining tickets from operation department of power plant according to ticket - issuing list. When issuing tickets, contact person of power plant included in work team members. Ticket - issuing list clearly defines ticket - issuing name, operation content, person - in - charge of ticket - issuing work û contact information, operation time, û contact person for ticket - issuing in power plant.

List of Installation and Commissioning Schemes

Since reconstruction û expansion involve live connection of some secondary cables to operating system of power plant, which requires operation of maintenance department of power plant, all parties agree that maintenance department of power plant prepares cooperation scheme for reconstruction û expansion of third bay, û installation unit prepares construction, commissioning, û testing schemes for reconstruction û expansion. List clearly defines scheme name, responsible department, initial draft completion time, û final draft completion time.

Plan for Entry of Personnel û Equipment

Installation unit lists specific entry times of various types of workers, regular testers, high - voltage testers, mobile cranes, forklifts, trucks, û other personnel û equipment, û clarifies responsible persons. Supervisor û owner conduct assessments according to schedule to urge installation unit to ensure personnel û equipment enter site on time û all resources adequately prepared.

Plan for Supply of Materials û Equipment

Installation unit lists entry plan for equipment û materials supplied by Party B, û owner lists entry plan for equipment û materials supplied by Party A. All parties follow up û implement according to entry plans of equipment û materials to ensure equipment û materials arrive on time. Plan categorically lists equipment name, supply time, responsible person, manufacturer, û other information.

Technical Preparations

• Confirm with power plant that switching operations of GIS equipment completed, safety measures in place, û construction conditions met.

• Measurement û Layout: Based on GIS installation layout diagram û combined with installation elevation of outlet bushing, review elevation coordinate points for GIS equipment installation, measure, mark, û record installation positions.

• Workers must change into work shoes û wear purification suits when entering installation area. Work shoes û purification suits not allowed to be worn outside installation area. Other personnel should wear shoe covers when entering installation area.

• Organize all construction workers to understand layout characteristics of equipment in entire expanded bay û get familiar with installation process û process requirements, based on relevant drawings û manufacturer's materials.

• Invite manufacturer's û designer's on - site technicians û supervision engineer to conduct technical disclosure for all construction workers, so as to understand design intent û manufacturing plant's process characteristics, û correctly master usage methods of professional tools.

• Prepare all kinds of records, inspection forms, û process cards required during installation û commissioning processes.

Isolation between Construction Area û Operating Area

Before equipment installation, use retractable fences to reasonably plan construction site, demarcating construction area, operating area, isolation area (side against mountain for main transformer incoming line of Unit 1, 5011 circuit breaker, û 5012 circuit breaker), equipment û material storage area, construction passage, û operating passage. For secondary switchboards below outlet branch busbars in construction area, adopt hard isolation protection. Use scaffolding pipes to erect protective shed û lay wooden boards on top.

Inspection of Arrived Equipment û Materials

Following items mainly inspected during arrival acceptance of GIS equipment:

• Before unpacking, check whether packaging damaged û whether any collision, damage, û loss during transportation.

• Check integrity û correctness of delivered equipment according to order û delivery documents.

• Check whether paint, anti - rust layer, color, û quality on equipment surface meet requirements.

• Check whether text û data on nameplate correct.

• Carefully check against packing list whether product accessories, spare parts, installation supplies, û special tools complete, û whether any signs of damage, deformation, û rust.

• Check whether bushings have any deformation, moisture, cracks, û defects.

• Check whether factory certificates, relevant drawings, materials, û documents complete.

• Check whether value of three - dimensional anti - tampering instrument exceeds 3 g.

Equipment Installation
Gas Recovery û Pressure Reduction

Before equipment installation, reduce pressure to half at detachable break points of 5014 terminal CT, high - voltage side T - zone PT of No. 2 main transformer, high - voltage side T - zone of No. 2 main transformer, û 5012 initial CT, û high - voltage side T - zone PT of No. 2 main transformer (see Part 3 in figure for details); recover gas from 5013 - 5014 diagonal span to 5012 initial CT (see Part 1 in figure for details); retain slight positive pressure of 0.05 MPa during gas recovery in gas chamber from 5014 terminal CT to 5013 - 5014 diagonal span (see colored block in Part 2 of figure). Gas recovery û pressure reduction shown in Figure 2.

Disassembly û Support of Bus - pipes

After gas recovery û pressure reduction completed, before circuit breaker positioned, first remove maintenance platform, û then remove "L" - shaped bus - pipe of 5013. When removing "L" - shaped bus - pipe, use gantry to hoist û fix PT, CT, disconnector, 5013 - 5014 diagonal bus - pipe, û 5012 - 5013 diagonal bus - pipe in this area with tooling.

Foundation Point - setting û Equipment Positioning

• According to manufacturer's drawings, design drawings, û installation status of existing equipment, use ink line box to mark out û identify (X, Y) center lines of equipment. Measure û fix relative positions of equipment with steel tape measure according to center line of B - phase of incoming û outgoing lines; at same time, mark elevation points of equipment to determine installation elevation of equipment.

• Install equipment in place according to design drawings, û review centers û elevations of all equipment to ensure correct installation positions.

• After GIS room equipment transported to on - site hoisting hole in sequence, hoisted to installation position inside GIS room by 10 - t single - girder crane. During hoisting, "Ten No - Hoisting Rules" strictly implemented. Each component must be test - hoisted for three times of lifting û lowering before hoisting. Hoisting area should try to avoid operating area. Equipment must enter site in strict accordance with installation sequence to avoid accumulation û congestion of equipment on - site, which may affect installation progress. GIS equipment must be hoisted with special lifting tools provided by manufacturer, û equipment should not be damaged during handling.

• When equipment of unit initially positioned, first position circuit breaker, û then position other equipment. Since diagonal - spanning bus - pipe between 5013 û 5014 not removed, 10 - t bridge crane in GIS room [3 - 5] cannot directly hoist circuit breaker into position. Therefore, in this installation, manual hydraulic forklift used to transport circuit breaker to installation position, û then positioning adjustment carried out. Ensure center û elevation of circuit breaker meet design requirements.

• Refer to elevation of existing equipment during equipment installation. Before installation or connection, equipment should be adjusted to be straight û level. Forcing, prying, û hard - aligning equipment manually strictly prohibited.

• Tighten all connecting bolts with torque wrench according to specified torque.

Installation of Voltage Transformers

• Since B - phase voltage transformer behind 5013 circuit breaker (weighing about 1 t û with installation height of about 6 m) installed directly below B - phase of Bus Ⅱ, û Bus Ⅱ in live - operation state, 10 - t bridge crane in GIS room cannot directly hoist voltage transformer into position. After consulting with multiple parties, decided to introduce industrial forklift. Forklift has rated load capacity of 1.5 t û maximum lifting height of 7 m, which meets on - site requirements û can move flexibly on - site.

• Before installation, check whether internal pressure value of transformer original inflation pressure û conduct routine tests.

• Clean electrical contact surfaces on sealing surface û connecting flange with lint - free paper dipped in anhydrous alcohol.

• During installation of voltage transformer, adjust verticality û levelness through screws on base to ensure proper connection with bus - connection surface û complete flange connection.

• Conductor inside detachable port at lower end of newly - added voltage transformer should be installed after withstand voltage test completed.

Conclusion

During modification û expansion construction of third bay of 500 kV GIS at Lianghekou Hydropower Station, faced with unfavorable factors such as tight construction schedule, construction in operating area, û restricted lifting, through series of measures including formulating full - scope management list, manufacturing special tooling, û introducing industrial forklifts, smooth progress of modification û expansion construction of third bay ultimately ensured. This shortened construction period, saved costs, û guaranteed safety û quality. It set precedent for in - depth cooperation between operations in 500 kV GIS operating area û power plant, û has certain reference û promoting significance for similar modification û expansion projects.