Optical Current Transformers

Current measurement plays a significant role in electronic power systems in terms of protection and control. Recently, with the increase in power line voltage, considerable attention has been paid to optical current transformers as they are of a host of advantages compared to conventional current transformers having an iron core and a copper coil.
For instance, unlike normal current transformers, optical types will not explode when an internal fault causes a flashover as they have no oil. Also, they provide relatively better electromagnetic characteristics for the posts’ electronic control. Noteworthy, optical CT has better saturation and electrical insulating effects, smaller size and lower weight compared to the oil types.
These advantages prompted Nirou trans company to develop the production project of optical current transformers. The prototype of this product has been produced and tested at a voltage level of up to 145 kV and will be produced in due course. Some advantages of optical current transformers are as follows:

• Oil-free
• Much lower weight compared to the oil type one
• Eliminated risk of high voltage in the secondary open circuit
• The ability to transmit the measured signal up to a distance of 500 meters using optical fiber.
• Reducing costs of installation, cabling, repairs, and maintenance.
• The use of silicone insulation makes it possible to operate under high pollution levels.
• Eliminated risk of explosion.
• Coverage of primary currents lower than 50 A.