P2 / P4 — polymer post insulators for substations 7.5–500 kV (ANSI C29.19, replacing porcelain TR)
P2 and P4 polymer post insulators for substations and switchgear at 7.5–500 kV, with a silicone sheath and a fibreglass core. They are built to ANSI C29.19 and mostly replace porcelain TR insulators directly, without modifying steel structures. Their weight is about one third of porcelain.
- Voltage class
- 7.5–500 kV (standard and high-strength up to 345 kV)
- Standard
- ANSI C29.19; mechanical heights and electrical characteristics equivalent to porcelain TR per ANSI C29.9
- P2 example (TR 227, 23 kV)
- BIL 150 kV, height 15″, SCL 4000 lb, creepage 27″
- P2 example (TR 278, 69 kV)
- BIL 350 kV, height 30″, SCL 3000 lb, creepage 72″, CIFO 390 kV
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
P2 and P4 polymer post insulators are designed for substations and switchgear of voltage classes 7.5–500 kV. They are used as busbar supports, and many disconnector manufacturers equip their devices with such insulators. There are also solid silicone products for direct replacement of legacy multi-element post insulators of the cap-and-pin type at operating substations. Standard and high-strength versions are produced up to 345 kV.
The insulators are designed to ANSI C29.19. They match the mechanical heights and comparable electrical characteristics of equivalent porcelain insulators with TR numbers of ANSI C29.9, so in most cases they directly replace porcelain post insulators without modifying the steel structures.
The load-bearing element is a fibreglass rod on an E-grade epoxy base, and the sheath is silicone with improved electrical properties and pollution resistance. On insulators of 69 kV and above, a proprietary biaxial compression seal system is used. The weight is about one third of a porcelain insulator, so transport and installation are simpler and the load on structures is lower.
P2 under TR 227 (23 kV) has BIL 150 kV, height 15″, cantilever load 4000 lb, creepage distance 27″ and compression 25 000 lb. TR 231 (34.5 kV) has BIL 200 kV, height 20″, creepage distance 40.8″ and CIFO 225 kV. TR 267 (46 kV) has BIL 250 kV and creepage distance 53″. TR 278 (69 kV) has BIL 350 kV, height 30″, cantilever load 3000 lb, creepage distance 72″, CIFO 390 kV, wet withstand voltage 145 kV and deflection at working load of 0.7″. End fittings are made of hot-dip galvanised malleable iron, including with a mounting on a 3 or 5 inch bolt circle. The sheath and ribs meet applicable ANSI and IEC standards. The P4 series covers higher classes and high-strength versions. For each insulator the catalogue gives the TR/PSP number, voltage class, BIL, height, cantilever and tensile load, compression, weight, creepage distance, deflection and electrical characteristics, which simplifies selection of a replacement.
Technical specifications
| Voltage class | 7.5–500 kV (standard and high-strength up to 345 kV) |
|---|---|
| Standard | ANSI C29.19; mechanical heights and electrical characteristics equivalent to porcelain TR per ANSI C29.9 |
| P2 example (TR 227, 23 kV) | BIL 150 kV, height 15″, SCL 4000 lb, creepage 27″ |
| P2 example (TR 278, 69 kV) | BIL 350 kV, height 30″, SCL 3000 lb, creepage 72″, CIFO 390 kV |
| Compression | up to 25 000 lb |
| Weight | about 1/3 of porcelain |
| Construction | E-grade epoxy fibreglass rod, silicone sheath, biaxial compression seal (from 69 kV) |
Request a price and lead time
P2 / P4 — polymer post insulators for substations 7.5–500 kV (ANSI C29.19, replacing porcelain TR). We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
Can P2 polymer insulators directly replace porcelain TR units?
In most cases yes. The ANSI C29.19 insulators match the mechanical heights and comparable electrical characteristics of porcelain insulators with TR numbers of ANSI C29.9, so the steel structures usually do not need modification.
For which voltage classes are P2 and P4 insulators produced?
For classes 7.5–500 kV. Standard and high-strength versions are produced up to 345 kV.
What are the characteristics of the P2 under TR 278 at 69 kV?
BIL 350 kV, height 30″, cantilever load 3000 lb, creepage distance 72″. CIFO 390 kV, wet withstand voltage 145 kV.
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