01-05-2013, 12:47 PM
PRESENTATION ON CT & PT SIZING CALCULATIONS
CALCULATIONS.ppt (Size: 1.95 MB / Downloads: 139)
INTODUCTION
This course describes the how to Design the Instrument Transformers
Basic about the CT & PT.
This information will prepare you for additional safety Precautions to be taken for CT & PT.
Overall view of the different types of CT & PT in the Indian Power Systems.
Single Line Diagram Of Power Monitoring & Controlling of an Power Plant.
CURRENT TRANSFORMERS
Current transformers are used extensively for measuring current and monitoring the operation of the power grid. (Protection)
The CT is typically described by its current ratio from primary to secondary
CURRENT TRANSFORMERS SAFETY PRECAUTIONS
Care must be taken that the secondary of a current transformer is not disconnected from its load while current is flowing in the primary,
As the transformer secondary will attempt to continue driving current across the effectively infinite impedance.
This will produce a high voltage across the open secondary (into the range of several kilovolts in some cases), which may cause arcing.
VOLTAGE TRANSFORMERS SAFETY PRECAUTIONS
Manufacturer instructions,
Never short-circuit the secondary's of a voltage transformer when fed on primary, for it would be destroyed in a matter of seconds.
Location
Ventilation(1/2 Inch rod)
Clearance
Earthing
Winding resistance measurements,
Polarity verification,
Insulation power factor, and
e.tc