impedance sequence

[VertaAsi Manullang]

hi...can anyone help me how to calculate impedance sequence for groundfault calculation?..

 

[magoo2]

For a ground fault or single-phase-to-ground fault, the symmetrical component solution is a series connection of Z1, Z2 and Z0. The resulting current, I1, will be obtained from V/(Z1+Z2+Z0). For the actual fault current, If, you need to multiply I1 by 3.

 

[HamburgerHelper]

Ifault = 3V/(Z1 + Z2 + Z0 + Zfault) if you want to include fault impedance


Here is a link to some stuff that will can help you get your head around faults and sequence components.

http://powerprotection.wikia.com/wiki/Analyzing_Faults_with_Symmetrical_Components

I would also recommend -

Power Systems Analysis by Grainger and Stevenson.

Symmetrical Components for Power System Engineering - by Blackburn - this was meant to be a companion to his relaying book

Circuit Analyses of A-C Systems vol. 1 and 2 by Edith Clarke - both of these volumes are very well written. She does a very good job at explaining and giving insight into her analyses. This is out of print and it is hard to find original copies but it is out of copyright and you can get a pdf through most universities if you have access or can purchase a copy of from India as a print on demand hardcover for $15-20 a vol. (

https://www.abebooks.com/book-search/title/circuit-analysis-a-c-power-systems/)

 

[Mbrooke]

Not sure if this will help, but here it is:

http://stevenblair.github.io/seq/

 

[7anoter4]

I think what do you need to know-or calculate-are the positive, negative and zero sequence impedances of different elements of a schematic diagram in order to calculate the phase-to-ground fault short-circuit current.
If you intend to follow IEC way-IEC 60909-0 for instance-you have IEC 60909-2 SECTION 2: DATA FOR ELECTRICAL EQUIPMENT. You could find here data on typical synchronous, induction machines, transformers, overhead line and cables.