Zforce ZNP / ZHP / ZRP — distribution class surge arresters for overhead lines
Zforce ZNP, ZHP and ZRP are distribution class surge arresters in a polymer housing for overhead distribution networks. Rated discharge current is 5 kA for ZNP and 10 kA for ZHP and ZRP, with short-circuit withstand of 20 kA. The arresters protect lines against overvoltages caused by lightning, switching and equipment failures.
- Versions
- ZNP (normal duty), ZHP (heavy duty), ZRP (cable entry on pole)
- Rated voltage Ur (ZNP, example)
- 9, 10, 18 kV; MCOV 7.65 / 8.4 / 15.3 kV
- Rated discharge current (IEC)
- 5 kA (ZNP), 10 kA (ZHP, ZRP)
- High-current impulse
- 65 kA (ZNP), 100 kA (ZHP, ZRP)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Zforce covers voltages from 3 to 36 kV and protects overhead distribution networks from overvoltages caused by lightning, switching and equipment failures. The range has been updated. The housing is now cast by direct moulding from HTV silicone, which the manufacturer has used for over 40 years on its transmission insulators, and the arresters have been tested to the current edition of IEEE C62.11. Form, connection dimensions, brackets, electrical characteristics and catalogue numbers remain unchanged.
Moisture ingress is the main cause of failure of conventional arresters, so the housing is formed under high pressure directly onto a reinforced composite core, with no air gaps (Zero Air Interface). Inside stands a column of metal-oxide varistors (MOV) in a woven fibreglass wrap, which gives mechanical strength and resistance to short-circuit currents. The top and bottom end fittings are primed and bonded to the sheath. The built-in ground lead disconnector (GLD) in epoxy encapsulation disconnects the arrester at the end of its service life. It operates in less than 2 s at 1 A (5 A for ZHP) and in less than 2 cycles at 1000 A. An insulating polymer bracket, a cast nameplate and several top terminal options are available.
ZNP operates in normal mode. High-current impulse 65 kA, long-duration impulse 150 A, rated discharge current 5 kA, duty cycle 10 kA, line discharge class 1, short-circuit withstand 20 kA. Among the Ur ratings are 9, 10 and 18 kV (MCOV 7.65, 8.4 and 15.3 kV). For example, the ZNP018 (Ur 18 kV, MCOV 15.3 kV) has a residual voltage of 61.0 kV at 10 kA. ZHP is rated for heavy duty, and ZRP is intended for cable entries on poles. Both give a high-current impulse of 100 kA, long-duration 250 A, rated discharge current 10 kA, specific energy of at least 2.7 kJ/kV at 100% control and short-circuit withstand 20 kA.
All versions are listed by REA. The arresters are manufactured in York, South Carolina, at a facility with an integrated ISO 9001, 45001 and 14001 system. They can be supplied in combination with fuse cutouts.
Technical specifications
| Versions | ZNP (normal duty), ZHP (heavy duty), ZRP (cable entry on pole) |
|---|---|
| Rated voltage Ur (ZNP, example) | 9, 10, 18 kV; MCOV 7.65 / 8.4 / 15.3 kV |
| Rated discharge current (IEC) | 5 kA (ZNP), 10 kA (ZHP, ZRP) |
| High-current impulse | 65 kA (ZNP), 100 kA (ZHP, ZRP) |
| Long-duration impulse | 150 A (ZNP), 250 A (ZHP, ZRP) |
| Line discharge class (IEC) | 1 |
| Specific energy (ZHP, ZRP) | 2.7 kJ/kV (100% control) |
| Short-circuit withstand | 20 kA |
| Residual voltage ZNP018 at 10 kA | 61.0 kV |
| Housing | HTV silicone moulded directly onto the reinforced core (Zero Air Interface) |
| Standards | IEEE C62.11; REA (RUS) |
| Manufacturing | York, South Carolina, USA |
Request a price and lead time
Zforce ZNP / ZHP / ZRP — distribution class surge arresters for overhead lines. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
How do the ZNP, ZHP and ZRP versions differ?
ZNP operates in normal mode with a discharge current of 5 kA and a high-current impulse of 65 kA. ZHP (heavy duty) and ZRP (cable entry on a pole) have a discharge current of 10 kA and a high-current impulse of 100 kA.
How does the arrester disconnect at the end of its service life?
The built-in ground lead disconnector (GLD) in epoxy encapsulation operates in less than 2 s at 1 A (5 A for ZHP). At 1000 A it operates in less than 2 cycles.
Which standards were these arresters tested to?
Tests were carried out to the current edition of IEEE C62.11, and all versions are listed by REA. Short-circuit withstand is 20 kA.
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