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Unformatted text preview: Page 1 Fundamentals of Power Systems Lecture 7 1 Changing Bases Â¡ Â¢Â¡ Â¢ Â¡ Â¢ 2 3 Base LL Base Actual p Base Actual p pu V S Z Z Z Z Â£ Â£ Â£ Â£ I 2 3 3 Â¸ Â¸ Â¹ Â· Â¨ Â¨ Â© Â§ Â¸ Â¸ Â¹ Â· Â¨ Â¨ Â© Â§ Â£ Â£ Â£ Â£ Â£ Â£ Â£ Â£ Â£ Â£ new Base LL old Base LL old Base new Base pu old pu new V V S S Z Z I I z The impedances of generators, transformers, transmission lines, and loads are supplied by the manufacturers in per unit based on the equipmentÂ¡s own rating. z When placing the equipment into a system, the impedance must be converted to the system base Only within one voltage zone! Fundamentals of Power Systems Lecture 7 2 Changing Bases z Voltage, current, and impedance base values change at transformers as they step the voltage up or down. z The power base remains the same across a transformer z The pu values of impedance, voltage, and current across a transformer is independent of the reference side: primary or secondary Page 2 Fundamentals of Power Systems Lecture 7 3 Example A one-line diagram of a three-phase power system is shown. Draw the impedance diagram of the power system, and mark all impedances in per unit. impedance diagram of the power system, and mark all impedances in per unit....
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This note was uploaded on 02/01/2012 for the course EEL 3216 taught by Professor Brooks during the Spring '08 term at FSU.
- Spring '08