Thomas And Betts' Backup Current-Limiting Fuse Reduces Risk Of Transformer Failure
Hi-Tech 38kV Trans-Guard OS Shorty Backup Current-Limiting Fuse Designed for Distribution and Wind Farm Applications
The new Thomas & Betts (T&B) Hi-Tech 38kV Trans-Guard OS Shorty Backup Current-Limiting Fuse provides the greatest risk reduction of disruptive transformer failure of any protective device currently available. Designed for use in 26.4 to 34.5kV distribution and wind farm transformers that have a primary or secondary delta connection or that feed more than 50 percent delta-connected loads, it significantly reduces fault energy and offers a high interrupting capability for protection against ever-increasing available fault currents. This reduction in fault energy results in a reduction in arc-flash potential.
As a backup current-limiting fuse, the 38kV Trans-Guard OS Shorty fuse must always be applied in series with a properly sized, low-current protective device such as an expulsion fuse or the Elastimold Molded Vacuum Interrupter (MVI). Both devices provide fault protection over a given range of currents. The expulsion fuse or MVI clears low-magnitude currents, such as those caused by faults external to the transformer and high-impedance faults inside the transformer, which are generally below the minimum interrupting current rating of the current-limiting fuse.
Backup current-limiting fuses, such as the 38kV Trans-Guard OS Shorty fuse, clear all other currents, such as those resulting from low-impedance faults within the transformer and, most importantly, limit the amount of energy from the fault source to a value below what the transformer tank is capable of withstanding. The 38kV Trans-Guard OS Shorty fuse is capable of interrupting fault currents as high as 50,000 amperes symmetrical.
"By limiting the amount of energy from the fault's source, the Hi-Tech 38kV Trans-Guard OS Shorty fuse minimizes the likelihood of disruptive equipment failure," said Dan Gardner, Thomas & Betts director of engineering. "These examples include transformer tank ruptures, damaged accessories and accessories broken from the mountings. No other protective device available can reduce the risk of transformer failure to the degree that the 38kV Trans-Guard OS Shorty fuse can."
The 38kV Trans-Guard OS Shorty fuse's L-L voltage rating allows smaller backup fuses to be used to reduce arcing time and the amount of energy originating from a fault. In addition to increasing transformer protection, this feature greatly improves upstream coordination.
The 38kV Trans-Guard OS Shorty fuse provides current-limiting protection for transformers as large as 2,850KVA at 26.4kV; 3,000KVA at 27.6kV; and 3,800KVA at 34.5kV. It meets ANSI and IEEE standards that include 100 percent physical inspection, resistance measurement and helium mass spectrometer leak testing.
For more information about the T&B Hi-Tech 38kV Trans-Guard OS Shorty Backup Current-Limiting Fuse, visit utility.tnb.com.
About Thomas & Betts Corporation
Thomas & Betts Corporation is a leading designer and manufacturer of electrical components used in industrial, construction, communications and utility markets. The company is also a leading producer of commercial heating and ventilation units and highly engineered steel structures used for utility transmission. Headquartered in Memphis, Tenn., the company has manufacturing, distribution and office facilities worldwide. For more information, visit www.tnb.com.
SOURCE: Thomas & Betts Corporation