S1 / S5 / S2 (MX, VX) and Bell Equivalent — polymer suspension and strain insulators for 35–161 kV lines and above
Polymer suspension insulators S1, S5, S2 and Bell Equivalent are used on lines in suspension and strain strings. Cast MX series are standard for strain applications of 69–161 kV, and modular designs are rated for lines of 230 kV and above. The specified mechanical load SML ranges from 111.2 to 222.4 kN.
- S1 (25 kip)
- SML 111.2 kN, RTL 55.6 kN, 16 mm core
- S5 (30 kip)
- SML 133.4 kN, RTL 66.7 kN, 16 mm core
- S2 (50 kip)
- SML 222.4 kN, RTL 105 kN, 24 mm core
- Voltage classes
- MX (cast, standard) 69–161 kV; VX (made to order) 46–161 kV; modular, 230 kV and above
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Polymer suspension insulators are used on overhead lines in suspension and strain strings. Cast MX insulators are standard products for strain applications of 69–161 kV. VX units are made to order for specific lengths, creepage distances and end fittings. Modular designs are intended for lines of 230 kV and above and are adapted to the customer's conditions. The insulators have a silicone sheath and a reinforced biaxial compression seal on the end fittings, and the core is made of corrosion-resistant E-glass fiberglass.
The series are distinguished by strength. S1 (25 kip) has a specified mechanical load SML of 25,000 lb (111.2 kN), RTL 55.6 kN and a 16 mm core. S5 (30 kip) has SML 133.4 kN, RTL 66.7 kN and a 16 mm core. S2 (50 kip) has SML 222.4 kN, RTL 105 kN and a 24 mm core.
The catalog lists versions for the 46, 69, 115, 138 and 161 kV classes. For example, the cast S1/S5 MX insulator of the 69 kV class has a dry arc voltage at 60 Hz of 268 kV, a wet arc voltage of 242 kV, a critical impulse flashover of +467/−501 kV and a creepage distance of 75.3″. Insulators of the 138–161 kV classes reach up to 535/475 kV and 911/962 kV. Shielding (corona) rings are added by changing the index MX to MA.
Bell Equivalent (BE) insulators are for 35–69 kV and directly replace strings of 4, 5 and 6 disc insulators in length, and they are compatible with standard ANSI 52-5 ball and socket hardware. SML is 25,000 lb (112 kN) against 15,000 lb for disc units, the creepage distance is 20% longer than that of porcelain (1400–2134 mm), and the weight is 82% lower (2.5–3.3 kg).
The insulators have a hydrophobic surface and a sealed design, perform well in polluted conditions, do not fail by brittle fracture, reduce installation labour and are convenient for maintenance. They are supplied as individual units or as part of strings with line hardware from the same manufacturer. The catalog numbering allows the configuration to be selected by voltage class, length, creepage distance and end fitting type.
Technical specifications
| S1 (25 kip) | SML 111.2 kN, RTL 55.6 kN, 16 mm core |
|---|---|
| S5 (30 kip) | SML 133.4 kN, RTL 66.7 kN, 16 mm core |
| S2 (50 kip) | SML 222.4 kN, RTL 105 kN, 24 mm core |
| Voltage classes | MX (cast, standard) 69–161 kV; VX (made to order) 46–161 kV; modular, 230 kV and above |
| Example (S1/S5 MX, 69 kV) | dry arc 268 kV, wet arc 242 kV, CIFO +467/−501 kV, creepage distance 75.3″ |
| Bell Equivalent | 35–69 kV, replaces 4, 5 or 6 discs; SML 112 kN; creepage up to 2134 mm; 82% lighter than porcelain |
| Housing / core | silicone / corrosion-resistant E-glass fiberglass |
| Hardware | ball and socket clevis, Y-clevis, ANSI 52-5 socket and others; option: grading rings (index MA) |
Request a price and lead time
S1 / S5 / S2 (MX, VX) and Bell Equivalent — polymer suspension and strain insulators for 35–161 kV lines and above. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What mechanical loads do the S1, S5 and S2 series have?
S1 has SML 111.2 kN and RTL 55.6 kN, S5 has SML 133.4 kN and RTL 66.7 kN, both with a 16 mm core. S2 has SML 222.4 kN, RTL 105 kN and a 24 mm core.
What does Bell Equivalent replace on 35–69 kV lines?
One insulator replaces a string of 4, 5 or 6 disc insulators in length and is compatible with ANSI 52-5 ball and socket hardware. SML is 112 kN, creepage distance reaches 2134 mm, and the weight is 82% lower than porcelain.
Which voltage classes do the MX, VX and modular designs cover?
The cast MX series covers 69–161 kV, the made-to-order VX covers 46–161 kV, and modular designs cover 230 kV and above. Grading rings are added by changing the index MX to MA.
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