اختيار معدات فصل وتوصيل الجهد المتوسط: العزل الهوائي (AIS) مقارنة بالعزل الغازي (GIS)

مقارنة فنية لمعدات AIS المعدنية وفق IEC 62271-200 LSC2B-PM، وتقنيات GIS بغاز SF6 والهواء النظيف، وتقليل المساحة حتى 70%، وتصنيف القوس الداخلي (IAC AFLR 25 kA 1s

1. Medium Voltage Switchgear Architecture

Selecting medium-voltage switchgear (12 kV to 36 kV) requires evaluating civil room space costs, ambient harshness (humidity, dust, chemical pollution), and maintenance access.

2. Comparative Engineering Evaluation Matrix

Engineering ParameterAir-Insulated Metal-Clad AIS (IEC 62271-200)Gas-Insulated Switchgear GIS (SF6 / Clean Air)
Insulation MediumAmbient Air (Phase clearance: 120-220 mm)SF6 / Synthetic Air (1.3 - 1.5 bar abs)
Footprint per Feeder (36 kV)1000 mm width × 2250 mm depth600 mm width × 1100 mm depth (-65% to -70%)
Loss of Service ContinuityLSC2B-PM (Partition Class Metallic)LSC2A / LSC2B sealed tank
Internal Arc WithstandIAC AFLR 25 kA / 31.5 kA 1.0 sIAC AFLR 25 kA / 31.5 kA 1.0 s
Environmental ImmunitySensitive to condensation, dust, marine salt100% Hermetically Sealed (IP65 stainless steel tank)
Cable Termination SystemAir bushings with heat-shrink bootsOuter cone / Inner cone plug-in bushings (EN 50181)
Maintenance Interval3-5 years visual inspection & busbar torquingMaintenance-free primary circuit for 30+ years

3. Internal Arc Classification (IAC AFLR)

Per IEC 62271-200, switchgear must pass internal arc testing to protect personnel:

  • A: Authorized personnel access only.
  • F, L, R: Front, Lateral, and Rear protection.
  • 25 kA / 31.5 kA 1.0 s: Fault current magnitude and duration.

Modern regulations phase out greenhouse gas SF6 in favor of Clean-Air (80% N2 + 20% O2) with vacuum interrupters, achieving Global Warming Potential (GWP) < 1.

*Reference: IEC 62271-200:2021; IEEE Std C37.20.2-2022; CIGRE TB 740.*