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My favourite is the following: " When nothing goes right, take left"

I would be shortly working on offshore electrical installations and would use IEC 61363 for short circuit calculations. Presently I do not have the standard with me, but soon will be getting it.It would be interesting to discuss the additional parameters (time constants, I guess)which is...

An addition to my question :The short circuit analysis is IEC 909 based and I have found the relevant IEC standard containing the references to HV and LV breakers. Thanks for the posting. Another question: In HV switchgears the calculated symmetrical rms and peak are much lesser than the...

I would like to know the standard time constants or X/R ratios of HV and LV circuit breaker. I am presently trying an IEC909 based short circuit calculation and have a value of X/R = 14 (for 50 Hz) for HV breakers. For LV breakers,I have a table with list of power factors, multiplication factors...

This may be very basic for the expert members of this forum.On what basis do you select the short circuit withstand time on a switchgear (say HV switchgear)? For example 40kA,1sec or 3sec ? Low voltage switchgears are generally found to have 3sec withstand time.

I have to make a check to find the suitable vector group for a main transformer. Whether Dy11 or Dy0 ? What studies would you experts recommend? Also, could someone say any added advantage of using a Dy0 transformer other than using it for appropriate phase displacement?

I would like to have some information about usage of three winding power transformers. At my work I come across a 140 MVA, 220/34.5kV, 50 Hz . The primary is star connected with its neutral solidly ground. The secondary too is star with neutral earthed through resistor.The tertiary winding is...

I want to know about type 2 coordination. References / Books will be helpful.

Valuable posts. About the terminology of "inrush current" of transformers, I have a colleague with me who says that inrush current is referred as through fault current of an equipment (transformer, motor)???? Does this inrush current has in it 2nd and 5th harmonic currents and the transformer...

Thanks Dandel. This leaves me with another question on relay setting whether the relay at the trfr incomer has to be set for the value of the fault current at the Switchgear or less than that? (70 % ?????)

Considering a single transformer feeding a switchgear, for a fault in the downstream of the Switchgear, what will be the through fault current of the upstream transformer? Will that be equal to the fault current at the switchboard?

Can someone brief me about the effect of source (Grid) X/R ratio in power system harmonic analysis? Also the effect of voltage regulation in the main grid on the harmonic voltage distortion?

I would like to know the effect of re-acceleration of motors on transient stability. What would be the effect of load transfer (induction motor loads) from one bus to another in the event of failure of supply if my motors do not have any reacceleration feature? Will natural reacceleration come...