The products are used for limiting transient over voltages in distribution networks, and they offer effective and reliable surge protection for expensive equipment such as transformers, reclosers, switches, and cables - at reduced cost. Hence, they are of key importance in guaranteeing the reliability of the electricity supply.
Optimized Size with One Metal Oxide Resistor
Frédéric Malpièce, Technical Expert and Technical Support Manager at Ensto tells, that the sub range is built with one single metal oxide resistor for three voltage ratings of 3 kV, 5 kV and 6 kV.
“We have optimized the size in height and outside diameter, and the HE 03-05-06 Surge arresters are manufactured with a shorter housing. As the earlier range of HE 09-10-12 products is built with two resistors, a longer housing is necessary”, tells Malpièce.
The compact size is of advantage as the new surge arresters are easier to integrate in the equipment: the products can be placed as close to the devices as possible, for instance aside motors, or in cubicles in the underground cable network substations.
Excellent Protection
“These new generation products have low residual voltages under high current values. Because the arresters are shorter in height, there is less inductance, and hence, the residual voltages are lower. And the lower the residual voltage, the better as along with that, the equipment is better protected”, says Malpièce.
The gapless surge arresters with polymer housing, metal oxide resistors and fiberglass reinforced wrapping have a high energy absorption capability. Thanks to their specific alternating weather-sheds the creepage is long, which enables an outstanding pollution withstand for the insulator.
Cost-efficient, Win-Win Solution
Malpièce concludes: “In addition to other benefits this sub range of products is cost-efficient. As we are using smaller parts, the total cost is lower for the customer. This is a true win-win situation.” Today, globally more than five million VARISIL™ surge arresters are installed in the grid – and more are to come.
The Products in the Sub Range of VARISIL™ HE Distribution Surge Arresters Provide:
- restrained residual voltages for higher protection margin
- a compact size for better integration in e.g., cubicles
- a specific, long creepage for outstanding pollution performance
- a negligible response time and Instantaneous reset.