CT & PT The Current Transformer and Potential Transformer are both measuring device. A CT lowers the current signals for measurement purpose, a PT lowers high voltage value into lowers ones. The transformer are designed to measure weather power systems are both accurate and safe.
- A potential transformer (P.T.) is an instrument transformer which is used for the protection and measurement purposes in the power systems. A potential transformer is mainly used to measure high alternating voltage in a power system.
- Potential transformers are step-down transformers, i.e., they have many turns in the primary winding while the secondary has few turns. The figure shows a typical potential transformer for the measurement of high alternating voltage. From the figure, it is clear that a P.T. is a well designed step down transformer.
- The primary winding of the potential transformer is connected across the high voltage power line whose voltage is to be measured and a low-range AC voltmeter (usually 0-110 V) is connected across the secondary winding of the P.T.
