Instrument transformers are important high voltage electrical devices that isolate and transform currents or voltages from higher magnitudes to lower magnitudes to provide safety of an end user and to protect a measuring device being used, such as a current or voltage measuring bridge, ammeter, or voltmeter. High currents are transformed using a current transformer (CT) and high voltages are transformed using a voltage transformer (VT), otherwise known as a potential transformer (PT).
Haefely / Tettex has a long-standing tradition of providing highly accurate instrument transformer test systems used to precisely measure current/voltage ratio errors, phase displacement, and excitation. Performing these tests helps to diagnose problems due to poor manufacturing or shipping damages, or identify changes in an instrument transformer due to ageing of the insulation. Complete test systems are suitable for current transformer and voltage transformer testing according to the latest IEC and ANSI/IEEE standards. Individual components, such as measuring bridges or electronic burdens can be individually integrated into an existing current transformer or voltage transformer test system.