MGVCL Exam Paper (30-07-2021 Shift 1)
Which type of connection is employed for current transformers for the protection of delta- star connected 3-phase transformer?
The connection of CT on primary and secondary side is always reverse to the connection of transformer. To protect the power transformer with star-delta against fault, the type of connection of CTs should be in the delta–star connection otherwise the relay will operate when an external fault occurs due to zero sequence currents
The magnitude of earth fault current for a given fault position within a winding demands upon the winding connections and method of neutral grounding. Earth fault protection for an electric motor is provide by instantaneous relay having a setting of approximately 30% of motor rated current in the residual circuits of two CTs and with ground wire.
As per the key statistics data of IEA With electricity consumption reached to 1,164 TWh in the country till November 2019, India ranked third among the top ten electricity consuming countries across the globe.
EXAMIANS