Fault Current

Which one is the more common mode of fault in a power system?

• Three phase bolted to ground

• Phase to phase

• Three phase bolted

• Phase to phase to ground

Which is one the ways of calculating fault current?

• F=ma

• V=IR

• E=mc²

• I_F=MVA/sqrt(kV)

Which statement is NOT correct?

• Sequence Impedance simplifies the asymmetrical fault calculations

• Positive sequence current flows in the path of positive sequence impedance

• Zero sequence impedance influences magnitude of zero sequence current

• Positive, negative and zero sequence current have equal magnitude and displaced 120deg each other

As fault current cannot be avoided, the following approaches are taken to reduce its effect, EXCEPT:

• Confine the fault into as small as possible area

• Cutting danger trees

• Managing the fault current phase angle

• Managing the fault current magnitude

What is the typical standard for calculating fault current?

• IEC 60990

• IEC 60909

• IEC 61009

• IEC 69100