← All revision guidesSEMESTER 4 · DI04009011
6FLASHCARDSSubstation Engineering
Substation layouts, equipment, earthing and protection coordination.
Substation equipment
Q1What is the function of a busbar?
It is a common conductor that collects and distributes electrical power among incoming and outgoing circuits.
Q2Differentiate an isolator and a circuit breaker.
An isolator provides visible off-load isolation; a circuit breaker can make, carry and interrupt normal and fault current.
Q3Why is a lightning arrester connected near protected equipment?
It diverts surge current to earth and limits the voltage reaching insulation.
Layout and safety
Q1What is the purpose of a substation earth mat?
It provides a low-impedance fault path and limits touch and step potentials across the site.
Q2Why are control and power cables separated?
Separation reduces electromagnetic interference and limits the effect of power-cable faults on control circuits.
Q3What is busbar protection required to do?
It must clear an internal bus fault rapidly while remaining stable for faults outside its protected zone.