First Applications on AltaLink s Network Roggero Ciofani, P. Eng. Colin Clark, P. Eng.
Overview Technology Overview Applications and Alternatives Advantages Alberta Special Considerations Operational Implications Topics Series Compensation Gas Insulated Line
High Voltage Compact Switchgear Mobile applications Closed loop gas filling system Cameras rated to -50 degrees Combination of SF6 and Mixed gas system
Vacuum Circuit breakers Dry Air Eliminate SF6 handling, temperature limits, and leaks Copper alloy axial contacts 72 kv vacuum bottle interrupter
Motor Operator Centralized controller Current signature Ice breaking Precise optical positioning device
Nursing Unit (Camlin Totus)
PD Monitoring
Dry Bushings Resin Impregnated Synthetic RIP Design 1. Terminal Connection 2. Dry Filling (foam) 3. Insulator 4. Flange (test tap) 5. RIP condenser RIS or RIF Design
Tap Changer Vibro-acoustic (Zensol) LTC Before Repair LTC After Repair
PCB Removal (PowerTech) Online decontamination Extraction cartridges Other extraction capabilities
Series Capacitor - Purpose Increased power transfer capacity Load sharing between parallel circuits Steady state voltage regulation Improved reactive power balance Block geomagnetic current flows
Simplified Transmission Equation Station A Station B
Compensated Transmission Equation Station A Station B
Compensation 118km line that is 36% compensated is equivalent to a 75km line
Capacitor Bank Comparison Shunt Capacitor Series Capacitor
Series Capacitor SLD V V = line current X impedance Rated at 48.3 kv Capacitor Damping Circuit Platform at 240 kv
Metal Oxide Varistor (MOV) MOV is overvoltage protection for the capacitor during through faults MOV spares are installed in the bank
Metal Oxide Varistor (MOV) MOVs are designed for worst case fault scenario 25MJ 20MJ 15MJ 10MJ 5MJ Fault occurred at 10ms Capacitor by-passed with bypass breaker at 40ms 10ms 20ms 30ms 40ms
Damping Circuit Damping Circuit Transmission Line Capacitor MOV Energized Platform Bypass Breaker
Power Supply Two Power Supplies - Platform power (busbar CT) - Power laser (ground level)
Protection Line distance protection Variable line impedance Two setting groups - based on status Voltage inversion - fault location dependent Line differential protection Series capacitor controller Component protection Energy Accumulation Bypass operation
Voltage Profile
Swing Current
Sub-Synchronous Resonance (SSR) Thermal unit electrical resonance with mechanical torsional frequencies Screening studies identify modal frequencies Detailed inertia model for eigen-value analysis Control Instabilities (SSCI) Wind turbine radial connection contingencies
GIL Overview A coaxial transmission line. Ideal for where overhead lines cannot be built (technical, environmental reasons) and high power requirements. 420-550 kv levels but 800 kv installed SF6 or SF6/N2 Germany: 1975 at Wehr Pump-Storage Power Plant. 400 kv 100% SF6 due to failure of an oil cable which destroyed the tunnel.
Component Overview - General 550 kv, 1800kV LIWL, 1175kV SIWL 4000 A, 3460 MVA at nominal 500 kv SC (3 sec): 80kA Enclosure OD: 26.5 Conductor OD:7, ID: 6 Distance: ~270m per circuit Overload Rating: 5200A for 10min (4500MVA)
Component Overview - Gas SF6 Gas Only 2 Gas Zones per phase Convenient gas volume Operational flexibility Gas Volume 7.93kg/phase-meter 1040kg/gas zone (~20 bottles) Gas pressure: 376 kpa (54 psi)@20 C Density and diameter coordinated for dielectric strength -50 0 +20
Component Overview Insulators and Contacts Epoxy insulators Tri-post: rollers, spring contacts, fixed on one side of plug contact epoxy resin operated 3-5 times below the gas physical insulation capability temperature and discharge tracking Plug and Socket Connection Silver plated, spring loaded, shielded Copper graphite contacts spring loaded particle free
Component Overview Particle Traps Particle traps protect insulators from contamination-move due to high voltage electrostatic forces Capture particles in low electric field region Field energized up to 590 kv incrementally-self cleaning
Component Overview Bellows Thermal expansion Stainless steel with aluminum shunts across them Bushings SF6 to air Grounding Bonding bars and ground connections at every structure Monitors Density, PD, pressure disk (back-up and overfilling)
Protection
Advantages Low capacitance for long lines no phase compensation Lower losses Reverse current of the enclosure due to inductance therefore electromagnetic field outside is negligible Arc fault burn though resistance. XLPE (2 cables) GIL OHL Power (MVA) 2000 2000 2000 Total Losses (resistive and Dielectric) (W/m) 181 180 542 AC resistance (µω/m) 6 6.7 20 Inductance (nh/m) 189 162 892 Capacitance (pf/m) 426 68.6 13 Surge Impedance (Ω) 12 48.6 263
Application Heartland Bulk Transmission Development Project New double circuit 500KV line (1206L (L16)/1212L(L14)) to the new 12S Heartland substation >3000MVA per line at nominal 500kV. CGIT installation of double circuit 550kV 3 phase Gas Insulated bus at 89S Ellerslie to facilitate the crossing of 1206/1212L under 908L, 1058L, and 946/947L.
Operational Considerations Insulation PD Testing Integrated PD test couplers for UHF portable tester Bus bar corona, insulation, floating particles Hazard awareness for the gas Safety and Procedures Gas testing, gas carts
Operational Considerations