Waukesha® UZDvac UZDvac is a new load tap changer using vacuum interrupter technology. Development of this product began over 10 years ago; today, all tests and requirements described in IEEE C57.131-2012 have been passed and met. This on-tank, high speed, resistance bridging, arcing in vacuum design is unique in that all arcing takes place inside the vacuum interrupters, eliminating the need for bypass switches. Additionally, UZDvac can successfully complete 20,000+ tap changes arcing in oil if a vacuum interrupter fails to open, thereby eliminating the need for a vacuum interrupter failure detection circuit. If a problem is discovered in your next annual DGA/oil quality test, you have a year to detect and another year to remedy at your convenience. Ratings and Features • 600 A at 600 V, 200 kV BIL, 34.5 kV • educed transformer lead cable size, weight, heating and labor R (use of a series transformer is typical to achieve lower current) • All arcing in vacuum interrupters—no by-pass switches, no arcing in oil, reduced risk due to vacuum interrupter failure • 1,000,000+ electrical and mechanical operations • Use of transition resistor eliminates need for preventive auto • If a vacuum interrupter fails to open: - No safety issues?—reverts to arcing in oil, similar to UZD - Oil quality and DGA samples detect problems - Eliminates monitoring circuitry and associated problems - 0,000 operations contact life at maximum current rating 2 when arcing in oil (years) • Designed for quick field repairs and interchangeability • Slip clutch in motor drive protects parts • No by-pass piping to main tank required • Operates with hand crank while energized and fully loaded • Progress wheel indicates exact position in tap change • nly maintenance recommended is lubrication in air compartments O every 7-10 years (if annual DGA and oil quality tests are done) • No oil filter system • Dashpot eliminates brake maintenance T ransformers

TIMING DIAGRAM Lower Lower Performing a high potential (hi-pot) test is not necessary on the UZDvac’s High potential (hi-pot) test vacuum interrupters. If a vacuum interrupter fails to open, switching simply shifts to the tap selector switches where arcing takes place in oil. The UZDvac can successfully The arcing in oil — vacuum interrupter failed to open — should be detected by annual dissolved gas analysis (DGA) testing. As nameplate rating under these conditions. Vt complete 20,000+ operations at maximum contact erosion is a function of I2t, if the transformer is, on average, loaded to half...