1 / 38

Electrical Transients in Power System

Electrical Transients in Power System. January 2009 Mehdi Vakilian. Text Books:. 1-Transients in Power Systems by: Lou van der Slius, 2001 2- Electrical Transients in Power System by: Allan Greenwood, 1991.

tad-higgins
Download Presentation

Electrical Transients in Power System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electrical Transients in Power System January 2009 Mehdi Vakilian

  2. Text Books: • 1-Transients in Power Systems by: Lou van der Slius, 2001 • 2- Electrical Transients in Power System by: Allan Greenwood, 1991

  3. COURSE OUTLINE • Fundamental Notions About Electrical Transients • Basic Concepts and Simple Switching Transients • Damping Effect on Switching Transients • Abnormal Switching Transients • Testing of Circuit Breakers • Transient Analysis of 3Ph Power Systems

  4. Course Outline …..continued • Transient Analysis of 3Ph Power Systems • Traveling Waves and Other Transients on Transmission Line • Modeling Power Equipments for Transients • Numerical Simulation of Elec. Transients • Lightning and its Induced Transients • Insulation Coordination • Protection Against Over Voltages

  5. Evaluation System • Assignments : 10% • Mid Term One (items 1 to 4) : 10% • Mid Term Two (items 5 to 7) : 10% • Final : 60% • Class Project : 10%

  6. Chapter One : Fundemental Notions about Electrical Transients • Time Scale in Power System Studies: planning, Load Flow, Dynamic Stability Switching, external disturbances Frequency Content Differential Equations Solution Distributed and Lumped Parameters Calculatable,Controllable, Preventable Tools for Study

  7. CCT Parameters • In Steady State and Transient • Mathematical Presentation & Physical Interpretation

  8. Simple RC Circuit, Closing Ideal Sw.

  9. Equations of RC Circuit

  10. RC Circuit Response

  11. RC Circuit Discharge

  12. Capacitor Voltage of RC CCT

  13. Simple Circuits Characteristic (thumbprint)RC , RL , LC Circuits

  14. Thumbprints: • RC CCT: Time Constant ; RC • RL CCT : Time Constant ; L/R • LC CCT : Period of Oscillation ;

  15. Principle of Superposition • If stimulus s1 produces R1 & s2 produces R2 applying s1+ s2 simultaneously responds R1+R2 in Linear System Linear System: response proportional to : stimulus

  16. S.P. Application in Switching

  17. CCT Detail I1: Pre-opening current I2: Superposed current to simulate current cease

  18. S.P. application in Closing switch • V1 : voltage across contacts pre-closing • Therefore: -V1 fictitious stimulus superposed simulating the closing action

  19. The LaplaceTransform Method

  20. Laplace Transform Continued

  21. Transform of Simple Functions

  22. Laplace Transform continued

  23. Laplace Transform Application

  24. Laplace Transform Continued

  25. Solving RC problem with Lap. Trans. • In terms of I in the CCT: Applying L.P. :

  26. Continuing RC CCT solution • The L.T. solution: • The time solution:

  27. RL CCT excited by Battery V • Solving for I in CCT • The L.T. of Eq.: • The response:

  28. RL Time solution

  29. Example: 377 MVA Gen field windingL=0.638H, Exciter noload:1.2 MW(480V) • Energy stored in F.W.:

  30. How must the exciter voltage be changed to reduce the field current to zero in 5 Sec

  31. Example on LC CCT Transient

  32. Two energy stored elementsSecond order O.D.E.

  33. LC CCT solution Ass. I(0)=0

  34. LC CCT cont. solving for Vc • Surge Imp.

  35. If I(0)=0 then: V`c(0)=0 and Vc(0)

  36. Vc characteristic • Vc Osc. Amp depend on V-Vc(0) • Vc starts at Vc(0) as expected • Response for : 1-Vc(0)=-V 2-Vc(0)=0 3-Vc(0)=+V/2 Voltage and Current Relation

  37. Solution of an RL CCT Stimulatedby an Exp. Drive (Ass. I(0)=0)

  38. Exp. Stimulated RL CCT, Cont. • If

More Related