This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Page 1 Fundamentals of Power Systems Lecture 7 1 Changing Bases 2 3 Base LL Base Actual p Base Actual p pu V S Z Z Z Z I 2 3 3 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 equipments 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....
View Full Document
- Spring '08