Subject: 38kV Trans-GuardTM OS Shorty Backup Current-Limiting Fuses File: PCUP-09-001_OS Date: 2/8/09 Page: 1 The 38kV Trans-GuardTM OS Shorty is a backup type current-limiting fuse specifically designed for use in 26.4-34.5kV distribution and wind farm transformers that have a primary or secondary delta connection or that feed more than 50% delta connected load. Its ability to significantly reduce fault energy and its very high interrupting capability provide state-of-the art protection against today's ever-increasing available fault currents. As a back-up type current-limiting fuse (refer to ANSI C37.40 for fuse definitions), the 38kV TransGuardTM OS Shorty must always be applied in series with a properly-sized low current protective device. The device typically used with this fuse is a 34.5kV under-oil weak link expulsion fuse. The expulsion fuse and the current-limiting fuse are each selected to provide fault protection over a certain range of currents. The expulsion fuse is chosen to clear the low magnitude currents such as those caused by faults that occur external to the transformer and high impedance faults within the transformer. Such currents are generally below the minimum interrupting current rating of the currentlimiting fuse. The back-up type current-limiting fuse is selected so as to clear all other currents. In addition to interrupting the fault currents resulting from low impedance faults within the transformer, the back-up current-limiting fuse serves the very important function of limiting the amount of energy that is let through to the source of the fault to a value below the withstand capability of the transformer tank. By doing this, the current-limiting fuse minimizes the likelihood of disruptive equipment failures (i.e. transformer tank ruptures, accessories being damaged or broken loose from their mountings, etc.). No other protective device is available to similarly reduce the risk of disruptive transformer failures. Subject: Trans-Guard EXT CLF - Eyebolt Terminals Improvement File: PCUP-08-003_EXT Date: 2/8/09 Page: 2 Features Benefits * L-L voltage rating Allows smaller backup fuses to be used in order to substantially reduce arcing time and energy let-through during a fault. This provides increased transformer protection and greatly improves upstream coordination. * Broad range of ratings Makes it possible to provide current-limiting protection for transformers as large as 2850KVA at 26.4kV, 3000KVA at 27.6kV, and 3800KVA at 34.5kV. * Rigorous testing to meet ANSI/IEEE standards Internal quality requirements including 100% physical inspection, resistance measurement, and helium mass spectrometer leak testing * Durable design For long life including machined brass end caps, filament wound high temperature epoxy tubular bodies, sand filler and hermetic sealing system * High fault current interrupting capability 25,000 amperes symmetrical ELECTRICAL CHARACTERISTICS: Nominal Fuse Current Voltage Rating Rating (kV) (Amps) 38.0 65 80 100 125 165 Fuse Catalog Number HTSS372065 HTSS372080 HTSS372100 HTSS372125 HTSS372165 Rated Maximum Voltage (kV) 38.0 Peak Arc Voltage (kV) (2) 104 102 Minimum I/C (Amps) Minimum Melt I2T (A2Sec) Maximum Total I2T (A2Sec) 450 570 720 950 1,200 2,600 5,600 9,500 19,300 43,500 11,600 23,500 36,100 68,000 155,000 Notes: 1. All fuses have a rated maximum interrupting current of 25,000 A rms symmetrical. 2. Peak arc voltages quoted are for 25,000 A currents at the rated maximum voltage listed. Reduced voltages and currents will reduce the peak arc voltage. Consult the factory for information. Subject: Trans-Guard EXT CLF - Eyebolt Terminals Improvement File: PCUP-08-003_EXT Date: 2/8/09 Page: 3 DIMENSIONAL INFORMATION: B C 1/4-20 threaded hole 1/2" deep A Nominal Fuse Voltage Rating (kV) 38.0 Current Rating (Amps) Fuse Catalog Number 65 HTSS372065 80 HTSS372080 100 HTSS372100 125 HTSS372125 165 HTSS372165 Overall Diameter (A) 3.25-3.32" (82.5-84.3mm) Overall Length (B) Body Length (C) Fuse Weight 19.29-19.41" (490.0-493.0mm) 18.29-18.37" (464.6-466.6mm) 12.0lb 5.44kg 21.94-22.06" (557.3-560.3mm) 20.94-21.02" (531.9-533.9mm) 13.5lb 6.12kg Subject: Trans-Guard EXT CLF - Eyebolt Terminals Improvement File: PCUP-08-003_EXT Date: 2/8/09 Page: 4 FUSE SELECTION For a detailed explanation on selecting the appropriate backup current limiting fuse for a given application, please refer to Hi-Tech Fuses Application Bulletin FS-10. For a quicker method of selecting the proper 38kV Trans-GuardTM OS Shorty fuse for applications involving coordination with ABB 34.5kV under-oil weak link expulsion fuses please refer to the following table. ABB 34.5kV Protective Links (345B995G__) & 38kV Trans-Guard OS Shorty Fuses TRANSFORMER VOLTAGE (kV) L-L 26.4 27.6 34.5 KVA Assumed Impedance Z% Link Shorty Link Shorty Link Shorty 75 112.5 150 225 300 500 750 1000 1100 1250 1500 1750 1850 2000 2250 2500-2850 3000 3250-3800 1.6 1.8 2.0 3.0 3.5 4.0 5.75 5.75 5.75 5.75 5.75 5.75 5.75 5.75 5.75 5.75 5.75 5.75 2 3 3A 4 5A 6 7 8 8 9 9 9 10 10 10 10 65 65 65 65 65 65 65 80 100 125 125 125 165 165 165 165 2 3 3A 4 5 6 7 8 8 9 9 9 9 10 10 10 10 65 65 65 65 65 65 65 80 80 125 125 125 125 165 165 165 165 2 2 3 3A 4 5A 7 7 7A 7A 8 9 9 9 9 10 10 10 65 65 65 65 65 65 65 65 80 80 100 125 125 125 125 165 165 165 Note: Backup fuses are selected to melt only on internal transformer faults, where transformer impedance is equal to, or greater than, the value given. For transformers having lower impedances, consult the factory.