How to choose between porcelain and composite insulators?
Select by anti-pollution requirements and service conditions. Composite insulators FQX/FQB use silicone-rubber sheds over a core rod — light, pollution-resistant and cleaning-free — rated 25 to 27.5kV, tensile load 100kN, cantilever load 8 to 40kN, creepage 1200 to 1600mm, lightning impulse withstand at least 270kV, impact-proof without shattering, to TB/T 3199.2-2018. Porcelain QB series bodies are wear-resistant with stable freeze-thaw performance, cantilever load 8 to 25kN, creepage 1200/1400/1600mm, to TB/T 3199.1-2018 and GB/T 11030-2008. For heavy pollution and cold regions prioritizing anti-pollution and impact resistance choose composite; for ordinary sections prioritizing weathering life choose porcelain.
How to choose creepage distance by pollution level?
Creepage distance determines pollution-flashover capability — the heavier the pollution, the larger the class. Chuangwit QB/QBS cantilever porcelain insulators offer 1200/1400/1600mm classes, QBN/QBJ/QBG post-type porcelain insulators offer 1400/1600mm, antipollution glass LXWP and composite FQX/FQB are also selectable by creepage — prefer large creepage in coastal heavily polluted sections. Where needed, add double insulation QBS/QBSN beyond creepage for higher reliability.
How to choose between single and double insulation?
Double insulation offers higher reliability for critical and heavily polluted sections. The QBS27.5 series cantilever porcelain insulators are double insulation — S in the model denotes double insulation — rated 27.5kV, cantilever load 8 to 25kN, creepage 1200/1400mm, to TB/T 3199.1-2018 and GB/T 11030-2008; single-insulation QB and double-insulation QBSN/QBSJ/QBSG full series are configured with 1400/1600mm creepage for 25kV OCS. Choose double insulation for sections sensitive to reliability or flashover risk.
How to tell cantilever, post and suspension porcelain insulators apart?
Select by loading state. Cantilever QB series bear cantilever load, mechanically 8 to 25kN; post QZ series bear cantilever load, e.g. QZ27.5/16-1400 for 27.5kV, 16kN, 1400mm creepage; suspension QX series bear tensile load, e.g. QX27.5/70-1400 for 27.5kV, 70kN, 1400mm creepage. Glass suspension LXP/LXWP rated mechanical failing load 70/80kN, nominal creepage 320 to 450mm, lightning impulse withstand 100 to 125kV — LXP standard, LXWP antipollution. Choose the series by installation position and load type.
| Model | Product | Note |
|---|---|---|
| QB27.5 | Porcelain cantilever insulator | Single insulation |
| QBS27.5 | Porcelain cantilever insulator | Double insulation |
| QBN/QBJ/QBG | Porcelain post-type insulator | Series |
| QZ27.5 | Porcelain post-type insulator | For masts |
| QX27.5 | Porcelain suspension-type insulator | 70kN |
| LXP/LXWP | Glass suspension insulator | Glass sheds |
| FQX/FQB | Composite long-rod insulator | Silicone-rubber composite |
Porcelain insulators comply with GB/T 11030-2008 and the TB/T 3199 series; select the creepage factor by pollution level.
