MGVCL Exam Paper (30-07-2021 Shift 1)
Stability of power system can be improved by 1. Reducing voltage of transmission 2. Using parallel transmission lines 3. Using series compensators Which of the above statements are correct?
The methods often employed in practice to improve system stability are: 1. Increasing System Voltage 2. Reduction in Transfer Reactance 3. Using High Speed Circuit Breaker 4. Automatic Reclosing 5. Transient Stability 6. Turbine Fast Valving 7. Application of Braking Resistors 8. Single Pole Switching:
Intern turn winding fault can be easily detect by differential protection relay. Also detect by buchholz relay (gas operated relay), cause buchholz relay is used to detect the internal fault of transformer.
Voltage sag: It is usually associated with system faults but can also be caused by energization of heavy loads or starting of large motors. Voltage sag is the short reduction in the RMS voltage between 0.1 to 0.9 pu for a duration of 0.5 cycle to 1 minute
EXAMIANS