I came across a formula for circuit protective conductors in bS76761 18th edition page 196 which states S=sqrt(12*t)/k
where S is the csa (mm2) of the conductor
I is the fault current
t is the time in seconds for disconnection
k is the factor taking account of coefficient...
Hello Everyone,
I found out from IEC 60364-5-52 that for a multiphase circuit you can actually reduce the size of the neutral conductor than it`s active size if the harmonic distortion current is less than 15%. I would like to know by how many percent can one reduce the neutral.
Hello Everyone,
Which of these current ratings is used as the standard current ratings for cable:
Cyclic, Sustained or Distribution.
For example;
A 630mm2 Cu cable (dry XLPE type) has a "Winter SUSTAINED Current Rating" of 841 Amperes, a "Winter CYCLIC Current Rating" of 948 Amperes and a...
hello everyone,
Please I have been getting this error message on ETAP, can anyone help me out with it? how do I resolve this?
Error 2000: (Substation) Number of energized buses is less than two.
Error 2001: (Substation) The system has no swing power grid or generators.
Error 2002...
Hello Everyone,
Please how do you find the earth fault at the load side where you need to connect an RMU only at the load side?, the Resistance of the combined HV/LV earthing system(TN-C) can be taken as ≤10 Ohms. The available data I have from the source substation are:
1. 11kV Fault level -...
Hello please can anyone refer me to the first principle formula I can use to calculate the loop impedance and fault currents at LV cutouts?, at the point of use, e.g. in the building. The source information is known.
Hello Everyone,
I was given a task by my boss to determine the EARTH FAULT CURRENT of a secondary substation (500kVA,6.6kV/0.433kV) using values from the primary substation, see the values below:
Primary Substation voltage - 6.6kV
Primary Earth Grid Resistance (Ra) - 0.1Ω
Primary Substation...
