figure 17. A 138-kV three-phase oil breaker mounted on a skid base. (From Westinghouse Descriptive Bulletin 33-252, Sept. 1977.) desire to reduce the volume of oil required. this resulted in special tank designs to conform to the voltage gradients around the internal high-voltage components. One such design is shown in Figure 18 as an example of the progress made in reducing the quantity of oil. the live tank type of breaker (Figure 19) was a conservative design in oil quantity; however, this type of breaker did not provide the magnitude of interrupting currents desired and did not become a major design for the U.S. market as noted previously. the OCBs reached their highest voltage of 345 kV (Figure 20), originally designed for 40-ka interrupting duty and subsequently modified to meet 63 ka, with internal shields to CONNECTION SYSTEMS ShawFlex DSG-Canusa There is no limit to what we can accomplish together Backed by the strengths of Shawcor, the Connection Systems group combines the industry trusted brands of ShawFlex and DSG-Canusa. We work with our clients to deliver custom solutions that meet the requirements of their most demanding applications with: * Customized designs for specific project requirements * Customer focused testing * Supply chain partnering * Products manufactured to the highest quality standards To learn more about how we can service your business visit us at: shawcor.com/ connection-systems SHAWCOR.COM may/june 2018 ieee power & energy magazine 95http://www.shawcor.com/connection-systems http://www.shawcor.com/connection-systems http://www.SHAWCOR.COM