Switchgear protections questions with answers
93 multiple-choice questions. Open any question for its answer and explanation.
- In Railway applications ______ circuit breaker is used.
- For which of the following protection from negative sequence currents is provided ?
- To limit short-circuit current in a power system are used
- The reflection co-efficient at the open circuited end of a transmission line.
- The arc voltage produced in
- Air blast circuit breakers for 400 kV power system are designed to operate in
- The ground wire should not be smaller than No ______ copper.
- The under voltage relay can be used for
- H.R.C. fuse, as compared to a rewirable fuse, has
- The fuse wire, in D.C. circuits, is inserted in
- The torque produced in induction type relay (shaded pole structure) is
- Thermal overload relays are used to protect the motor against over current due to
- Circuit breakers usually operate under
- A fuse is never inserted in
- If the fault occurs near the impedance relay, the VII ratio will be
- For the protection of power station buildings against direct strokes the requirements are
- Which of the following parameter can be neglected for a short line?
- On which of the following routine tests are conducted ?
- Protective relays are devices that detect abnormal conditions in electrical circuits by measuring
- A balanced 3-phase system consists of
- The short circuit in any winding of the transformer is the result of
- Overheating of relay contacts or contact born out is due to
- The inverse definite mean time relays are used for over current and earth fault protection of transformer against
- Directional relays are based on flow of
- Interruption of large currents by relay requires