937758.1 115kV & 230kV Polymer Horizontal Post Insulators
Click here for a PDF of this Material Standard
Revision 1
Nov 21, 2013
1. Scope
This specification applies to the District's requirements for composite, non-ceramic, polymeric horizontal post insulators for conductors on a 115kV electrical transmission system. The polymeric covering, including the weathersheds, shall be made of silicone rubber.
2. Reference Standards
Insulators shall meet the applicable requirements of the latest revisions of the following standards.
| Industry Standards | |
| ANSI C29.7-2002 | Wet Process Porcelain Insulators - High Voltage Line - Post Type |
| ANSI C29.17-2002 | Insulators - Composite Line Post Type |
| ASTM-153-09 | Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware |
| District Standards | |
| Compatible Unit I0706 | 115kV Polymer Horizontal Post Insulator - Back to Back |
| Compatible Unit I0707 | 115kV Polymer Horizontal Line Post Insulator (49" Pole Clearance) |
| Compatible Unit I0708 | 115kV Polymer High-Strength Horizontal Line Post Insulator |
| Compatible Unit I0709 | 230kV Polymer Horizontal Line Post (102" Pole Clearance) |
3. Mechanical Ratings & Material ID Numbers
| Cat. ID | Section Length | Core Diameter | Tilt | Weight (lb) | MDCL1 (lb) |
MDTL2 (lb) |
Corona Ring |
|---|---|---|---|---|---|---|---|
| 937758 | 47"-50" | 2.5" | 12° | 60 | 1,650 | 2,500 | Retrofittable |
| 937782 | 48"-50" | 3" | 12° | 90 | 3,000 | 2,500 | Retrofittable |
| 1003389 | 102" | 3" | 17° | 134 | 1,446 | 2,500 | 6" |
| 1 - Minimum Design Cantelever Load (MDCL) 2 - Minimum Design Tensile Load (MDTL) |
|||||||
Upon request, manufacturers shall provide a combined loading chart for review by the District.
4. Minimum Electrical Ratings & Material ID Numbers
| Cat. ID | Dry Arcing Distance | Leakage Distance | 60Hz Dry Flashover | 60Hz Wet Flashover |
|---|---|---|---|---|
| 937758 | 36" | 93" | 350 kV | 350 kV |
| 937782 | 30" | 68" | 290 kV | 290 kV |
| 1003389 | 92" | 207" | 839 kV | 753 kV |
5. Dimensions And Drawings
| Material ID | Section Length | Tilt |
|---|---|---|
| 937758 | 47"-50" | 12 Degrees |
|
||
| Material ID | Section Length | Tilt |
|---|---|---|
| 1003389 | 102" | 17 Degrees |
|
||
| Material ID | Section Length | Tilt |
|---|---|---|
| 937782 | 48"-50" | 12 Degrees |
|
||
6. Construction
Insulator strength member shall be made of fiberglass rod. All parts of the fiberglass rod shall be completely covered with the same silicone rubber polymeric material as the weathersheds. The entire length of the polymeric covering, including the weathersheds, shall be one continuous, seamless piece of material. Weathersheds shall retain their original shape after severe deformation. Weathersheds shall shed water and be self-cleaning with rain.
7. Corona Ring
All insulators shall either be equipped with a corona ring or be easily retrofittable with a corona ring as indicated in Section 3.
8. End Fittings
Each insulator shall be equipped with a horizontal trunnion adapter for attaching a conductor clamp. The adapter shall be dimensioned per ANSI C29.7, latest revision. Base shall have a pole-face style mounting bracket with 12" hole spacing to accomodate 3/4" bolts. End fittings may be constructed from high strength aluminum alloy or malleable or ductile iron, galvanized in accordance with ASTM A153, latest revision. End-fittings shall have sealant applied to protect against moisture penetration. Insulator, mounting bracket, and horizontal adapter clamp shall be shipped assembled.
9. Identification
Each insulator shall be permanently marked with the manufacturer's name or logo and the date of manufacture. Each insulator shall be marked with the designed cantilever load rating (DCL) with appropriate units. The markings shall be legible and durable. Packages containing multiple insulators shall be marked with the manufacturer's name, the type of insulator and the insulator part number.