Power Transformer Transients& EMTP

1. Power Transformer Transients& EMTP Aljankawey, Abdualah 3201836 EE6643 Supervisor Dr. A.M. Sharaf

2. Power system problems 1 Harmonic Distortion

3. Power system problems 1 Harmonic Distortion 2 Switching Transients

4. Power system problems 1 Harmonic Distortion 2 Switching Transients 3 Line Noise

5. Power system problems 1 Harmonic Distortion 2 Switching Transients 3 Line Noise 4 Frequency Variations

6. Power system problems 1 Harmonic Distortion 5 Power Surges 2 Switching Transients 3 Line Noise 4 Frequency Variations

7. Power system problems 1 Harmonic Distortion 5 Power Surges 2 Switching Transients 6 Power Sags 3 Line Noise 4 Frequency Variations

8. Power system problems 1 Harmonic Distortion 5 Power Surges 2 Switching Transients 6 Power Sags 3 Line Noise 7 High Voltage Spikes 4 Frequency Variations

9. Power system problems 1 Harmonic Distortion 5 Power Surges 2 Switching Transient 6 Power Sags 3 Line Noise 7 High Voltage Spikes 4 Frequency Variations 8 Brownouts

10. Power system problems 1 Harmonic Distortion 5 Power Surges 9 Power Failures 2 Switching Transients 6 Power Sags 3 Line Noise 7 High Voltage Spikes 4 Frequency Variations 8 Brownouts

11. Power system problems 1 Harmonic Distortion 5 Power Surges 9 Power Failures 2 Switching Transients 6 Power Sags 10 power transformer transient 3 Line Noise 7 High Voltage Spikes 4 Frequency Variations 8 Brownouts

13. Power transformer transients • transient in power transformer happened when … - Inrush Current - Short Circuit fault . - Over voltage.

15. Inrush current • The saturation current that can occur when transformers are first switched into serves . • core saturation produces inrush . 1-Power switched off at Bmx. 2- flux density .Br 3- power switched back on . 4- flux density = 2Bmx+ Br 5- Core saturation = 2Bmx +Br- Bsat

16. Inrush currant in power transformer 1- calculation parameters • Peak value • Wave Shape. • Integral of I^2 *dt (energy parameter ). • Mix. di /dt . • Min. % ratio of 2nd harmonic peak.

17. Cont 2- Effective of transformer design parameters • Number of phases and winding connection. • Size of transformer . • Design induction .(peak inrush increase with induction). 2nd harmonics , peak decrease with induction . • Core material , Geometry ,design induction and type of joint .

19. Cont. • The inrush current determines the rating of input Switches , relays , Fuses , connector and cables .

22. Minimum % ratio of 2ndharmonic /peak • Use these value to distinguish between inrush current and short circuit current . • this minimum ratio % occur when the transformer is energized at voltage angle = 0 which also condition that result in maximum peak inrush current value .

26. EMTP • Engineering used EMTP program to simulate transients Electrical power system . • EMPT input , output and plotting . • Switched and circuit breaker model . • Capacitor Switching . • Transformer model. • Transient recovery voltage . • Lighting transient and transmission line model.

27. Advantages • Simplicity .. • Numerical stability . • EMTP built in models . - Basic components. - signal and multi-phase lumped parameter components. - signal phase distributed parameter components. - ideal ( transformer ,switches and sources ) • Overhead lines - POWER Transformer - Rotating Machines. - control system .

28. EMTP built-in models 􀁺 Basic components 􀂋 Single- and multi-phase lumped parameter Components 􀂋 Single-phase distributed parameter components 􀂋 Ideal and storable transformers 􀂋 Ideal switches 􀂋 Ideal sources 􀁺 Overhead lines and insulated cables (frequency-dependent models Power transformers 􀁺 Rotating machines 􀁺 Control systems

29. EMTP- Package includes:- EMTP-, the Engine;- Networks, the GUI;- Scope View, the Output Processor

30. Digital simulation ( EX.)

31. EMTP- key features • Reference in transients simulation • Solution for large networks • Provide detailed modeling of the network component including control, linear and non-linear elements • Open architecture coding that allows users customization and implementation of sophisticated models • New steady-state solution with harmonics • Automatic initialization from steady-state solution • New capability for solving detailed semiconductor models • Simultaneous switching options for power electronics applications

32. Lightning surges Switching surges Temporary over voltages Insulation coordination Power electronics and FACTS General control system design Power Quality issues Capacitor bank switching Series and shunt resonances Motor starting Steady-State analysis of unbalanced system Distribution networks and Distributed generation Power system dynamic and load modeling Sub synchronous resonance and shaft stresses Power system protection issues EMTP- Applications:

34. Simulation Options • Load-Flow solution • Steady-state solution • Time-domain solution • Frequency scan solution

36. Built-in Libraries:

37. Built-in Library of Examples:

38. Scope View Scope View is a data acquisition and signal processing software adapted very well for visualisation and analysis of EMTP-RV results. It may be used to simultaneously load, view and process data from applications such as EMTP-RV, MATLAB and Comtrade format files. Multi-source data importation Cursor region information

39. Scope View(Can't) Typical mathematical post-processing Function editor of Scope View

41. References • A.M.Sharaf and Pierre Kreidi ,Modulated power filter for Signal phase inrush transient loads. • A.M.Sharaf . And Pierre Kreidi modulated low cost power filter for signal phase inrush Type transient loads. • A. P. Sakes Meliopoulos , power system Grounding and transients . • IEEE Standard Transformer Committee ,Oct 15 ,2001 , Florida. • www. IEE ProcGener. Trawsnr. Dislrib., Vol. 148, No. 5, September 2001 presentation in transinat\Inrush Seminar Orlando.htm IEE ProcGener. Trawsnr. Dislrib., Vol. 148, No. 5, September 2001