how do you manually calculate the f
how do you manually calculate the f
(OP)
how do you manually calculate the fault level at a substation for big multi source network for the purpose of specifying CTs, CVTs, Transformers, Circuit Breakers, earthing transformers.






RE: how do you manually calculate the f
RE: how do you manually calculate the f
RE: how do you manually calculate the f
Thanks a lot!
RE: how do you manually calculate the f
with an example of fault level calculation at the end of it.
It is "Cahier technique # 158. Calculation of short-circuit currents" (English)
Best regards
RE: how do you manually calculate the f
RE: how do you manually calculate the f
Michael Sidiropoulos
Transmission Planning Engineer
RE: how do you manually calculate the f
RE: how do you manually calculate the f
1. IEEE Std 141-1993 IEEE Recommended Practice for Electric Power Distribution for Industrial Plants, (Red Book)
2. Donald Beeman, Industrial Power Systems Handbook, McGraw-Hill Book Company, Inc., 1955
RE: how do you manually calculate the f
Knowing the branches' reactances the current in each branch can be calculated.
This approach might be applicable only for three-phase faults and provides reliable values for switchgears, current transformers, and cables sizing. In general, it is not possible to calculate in this way: subtransient, transient and aperiodic components.
The case becomes much more complicated for phase-to-phase and phase-to-ground faults. Besides, negative and homopolar-sequence network must be considered, the latter for phase to ground fault only. Symmetrical current components (positive, negative and homopolar-for phase to ground fault only) must be calculated and then the phase current at the fault location, based on symmetrical components.
Much care should be exercised when calculating the equivalent reactances: all must be calculated at a base voltage, usually the normal operating voltage at the fault location, transformers' connection must be also considered and so on.
Useful information can be found here: www.schneiderelectric.com, CT-158.
Manual calculation of short-circuit current in complex networks is difficult and time consuming.
There are available many programs that accurately solve the problem. I would recommend EDSA, SIMULINK/MATLAB and ABB DOC win.
RE: how do you manually calculate the f