How Arresters Protect Against Lightning-Induced Outages

Ohio Brass (Hubbell Power Systems) Protecta*Lite® systems are an important key to helping utilities shield against lightning interruptions to the power supply. By selectively installing surge arresters in parallel with insulators, utilities can limit the voltage across the insulator to a level below its flashover voltage. For distribution or transmission, as an alternative or supplement to shield wire, and for new construction or retrofitting an existing line, the arrester/insulator combination is a cost-effective way to improve power quality. The Protecta*Lite® system has a lightning-interruption rate as good as or better than with the traditional overhead shield wire. The assembly provides good protection even in areas with poor tower-footing resistance – often the cause of back flash on a line protected with an overhead shield wire.

The Protecta*Lite surge arrester is available in a variety of designs and can be applied horizontally or vertically, on struts, suspension or pole top insulators.

Applications include:

Line Compaction
For maximum reduction in the width and height of transmission lines by elimination of overhead shield wires.

Line Up rating
Increased phase-conductor clearances required for voltage up rating can be obtained without major structure modifications by elimination of shield wires and the replacement of porcelain insulators with lightweight polymer insulators. The system provides primary system insulation as well as improved reliability.

Improve outage performance
Improvement in outage performance of existing shielded and unshielded lines is accomplished by greatly reducing the frequency of line insulation flashover due to shielding failure and back flash. Protecta*Lite systems improve coupling factors and compensate for high ground (tower footing) resistance.

Unbalanced insulation
This technique is used in double circuit construction to create a sacrificial circuit in exposed locations. Lightning induced flashover of the circuit with less insulation usually protects the parallel circuit. Protecta*Lite eliminates the need for a sacrificial circuit and can restore such circuits to full service.

Ohio Brass Catalog Section 35 provides detailed information regarding Protecta*Lite. [Download Here]

Hubbell Power Systems, 210 North Allen, Centralia, MO 65240. Phone: 573-682-5521. Fax: 573-682-8714.
E-mail: hpsliterature@hps.hubbell.com. Web: www.hubbellpowersystems.com