B2 / B3 / B4 / HS — braced post insulator assemblies for 115–161 kV lines and above
The braced post assembly combines a horizontal line post insulator and a suspension insulator into one high-strength unit. It replaces a metal crossarm on 115–161 kV lines and above. It is used on compact lines, over long spans and with heavy conductors.
- Assembly
- line post insulator H2/H3/H4 plus 25 kip suspension insulator S1-MXAL
- B2 (2.5″)
- standard configurations; rise 0° or 12°, with and without shielding ring
- Example (B2, 115 kV)
- SCL 9289–10,072 lb; creepage distance 116.7″; dry arc 383 kV, wet arc 355 kV, CIFO +660/−742 kV
- Example (B2, 138 kV)
- SCL 8312–9245 lb; creepage distance 157″; arc voltages 509/470 kV
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The braced post configuration combines the cantilever strength of a horizontal line post insulator with the tensile strength of a suspension insulator. The result is a high-strength insulator assembly that replaces a metal crossarm. It is used on compact lines, over long spans and with heavy conductors. Both insulators in the assembly have a silicone sheath and a fiberglass core, so the whole structure is lighter than a steel crossarm with porcelain insulation. The manufacturer offers standard and made-to-order variants.
The B2 series is a standard configuration based on the cast H2 line post insulator (2.5″ core) and the standard 25 kip S1-MXAL suspension insulator. The versions differ in rise angle (0° or 12°) and in the presence of a shielding ring. For the 115 kV class with a structure height of 56–79″, the cantilever load SCL is 9289–10,072 lb (MDCL at 50% is 4645–5036 lb), the creepage distance is 116.7″, the dry arc voltage is 383–387 kV, the wet arc voltage is 355–358 kV and the CIFO is +660/−742 kV. For the 138 kV class, SCL is 8312–9245 lb, creepage distance is 157″, arc voltages are 509/470 kV and CIFO is +885/−931 kV. Versions for 115–138 kV and 138–161 kV are available.
The B3 (3.0″), B4 (3.5″) and HS (high-strength) series are designed for increased mechanical loads. Made-to-order designs are developed for these and for nonstandard tasks. The Custom Braced Post Request Worksheet is used for selection and is submitted through the manufacturer's regional representative. The range and numbering are described in the Transmission Catalog Numbering catalog. The catalog number encodes the insulator characteristics: the type of attachment to the pole (flat base, 12° or 0° rise), height, creepage distance, shielding ring and the end fitting of the suspension insulator (eye, Y-clevis, ball). Some variants may be limited by the core diameter. The assembly drawings give the calculated mechanical load of the 25 kip (111.2 kN) suspension insulator, a proof load of 55.6 kN and the flashover voltages at 60 Hz.
Applications include new construction and rebuilding of existing 115–161 kV lines, increasing transmission capacity through compact phase geometry, and lines in confined corridors. The assembly drawings recommend shielding rings for applications at 230 kV and above. The structures are supplied complete with bases and line hardware.
Technical specifications
| Assembly | line post insulator H2/H3/H4 plus 25 kip suspension insulator S1-MXAL |
|---|---|
| B2 (2.5″) | standard configurations; rise 0° or 12°, with and without shielding ring |
| Example (B2, 115 kV) | SCL 9289–10,072 lb; creepage distance 116.7″; dry arc 383 kV, wet arc 355 kV, CIFO +660/−742 kV |
| Example (B2, 138 kV) | SCL 8312–9245 lb; creepage distance 157″; arc voltages 509/470 kV |
| B3, B4, HS | high-strength and made-to-order designs per the request worksheet |
Request a price and lead time
B2 / B3 / B4 / HS — braced post insulator assemblies for 115–161 kV lines and above. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
Which voltage classes does the B2 series cover?
For the 115 kV class the cantilever load SCL is 9289–10,072 lb, and for the 138 kV class it is 8312–9245 lb. Versions for 115–138 kV and 138–161 kV are also available.
How do the B3, B4 and HS series differ from B2?
B2 is built on a 2.5″ core, B3 has a 3.0″ core, B4 has a 3.5″ core, and HS is a high-strength series. All three are designed for increased mechanical loads, and made-to-order designs are developed for nonstandard tasks.
Is a shielding ring needed on the insulator assembly?
B2 versions are made with and without a shielding ring. The assembly drawings recommend shielding rings for applications at 230 kV and above.
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