±800kV / ±1100kV VALVE HALL • CLEANROOM RIG-IN • MMC QUADRIVALVES • BUSHING ALIGNMENT

Grid Intertie Valve Hall Clean-Enclosure Rig-In & Bushing Assembly Audit

Engineering execution protocol for rigging dry-type air-core smoothing reactors, suspended MMC valve tiers, positive-pressure airlock transitions, and oil-to-SF6 wall bushing alignment inside pressurized converter hall enclosures.

Valve Hall Rating

±525kV – ±1,100kV

LCC & VSC MMC Modular

Air Environment

ISO 8 / Class 100k

<35% RH | 20 Pa Overpressure

Reactor Unit Weight

110 – 260 Tons

Air-Core Non-Magnetic Base

Bushing Angle Tolerance

±0.05° Laser Align

Dry SF6 / Gas Insulated (GIL)

Section 1: Valve Hall Environmental Staging & Air Quality

PHASE I

Positive Differential Pressure (>25 Pa) & Air Handler Interlocks

Verify continuous overpressure prevents outdoor windborne particulate ingress during primary equipment bay door cycling.

ISO Class 8 Particle Counter Verification (≤3,520,000 particles/m³ @ 0.5µm)

Laser particle counters placed at valve tier staging and wall bushing aperture collars prior to uncapping seals.

Relative Humidity Depressurization (≤35% RH @ 20°C)

Industrial desiccant dehumidifiers running ≥48h to prevent surface condensation on composite insulator housings.

Section 2: Thyristor / MMC Valve Tier Suspension & Rig-In

PHASE II

Ceiling Crane Overhead Hoist Proof Test & Dynamic Load Cell Verification

Proof-test overhead 40-ton hall crane with digital dynamometer to 125% rated capacity prior to lifting valve modules.

Seismic Pendulum Restraint & Polymer Tie-Rod Tension Calibration

Calibrate tension on FRP insulating suspension rods to absorb UBC Zone 4 lateral seismic accelerations without corona arcing.

Air Caster Pneumatic Modular Skate Rig-In Floor Protection

Install 0.25-inch high-density phenolic runway overlay to prevent floor epoxy fractures under air-bearing skidding.

Section 3: Wall Bushing, SF6 GIL & Smoothing Reactor Alignment

PHASE III

Wall Bushing Insertion Rigging & 3D Laser Theodolite Target Tracking

Maintain dual dual-boom mobile crane sling geometry with micro-stepping hydraulic turntables for ±2mm insertion tolerance.

SF6 / C4-FN Eco-Gas Pressure Decay Vacuum Leak Rate Test (<0.1% per Year)

Helium mass spectrometer leak check on all gas-tight expansion bellows connecting hall to outdoor switchyard.

Air-Core Smoothing Reactor Non-Magnetic Foundation Anchor Audit

Verify stainless steel or fiberglass anchor studs to prevent closed loop magnetic eddy current heating in rebar.

Pre-Commissioning Readiness

55 % READY

Air Cleanliness: ACCEPTABLE (ISO 8)

Valve Crane Hoist: LOAD TESTED

Bushing Alignment: PENDING TARGET

Gas Leak Integrity: INCOMPLETE

Request UHVDC Rigging Engineers

Deploy Exspeedite certified superload rigging directors and laser metrology crews for converter station hall staging.

UHVDC Converter Hall Rig-In Specifications & Grounding Protocols

High-Voltage Smoothing Reactor Eddy Elimination

Dry-type air-core reactors produce intense stray AC/DC magnetic fields. The foundation reinforcing cage must employ non-magnetic stainless steel rebar (AISI 316) or fiber-reinforced polymer (FRP) with electrical break joints to avoid magnetic induction loop fires. Exspeedite tracks anchor clearances and non-magnetic crane rigging slings to eliminate field distortion during set-down.

Wall Bushing Clean Insertion Protocol

The wall bushing connects the outdoor transformer yards directly to the indoor valve quadrivalve tiers through pressurized composite walls. Bushings weighing up to 28 tons must be tilted at a 30-degree incline and pushed through the seismic wall collar with laser theodolite crosshairs aligned to ±0.05°, followed immediately by SF6 containment gas pressurization.