Wound Primary Current Transformers

Function:

Wound Primary Current Transformers (CTs) offered in 600v class. These current transformers have high accuracy. They are designed for use with ammeters, watt meters, or for relay driver applications.

Wound Primary Current Transformers have high efficiency and a higher burden capacity than usual current transformers, and are a No Window Type of ct. Ratios from 2.5 to 100 amps Primary are available, with a Secondary of 5 amps ac.

What is a Current Transformer?

A Current Transformer (CT) is a type of transformer that is used to reduce or multiply an alternating current (AC). It produces a current in its secondary which is proportional to the current in its primary.

Current Transformers, along with voltage or potential transformers, are instrument transformers. Instrument transformers scale the large values of current to small, standardized values. These values are easy to handle for measuring instruments and protective relays. The Instrument transformers isolate measurement or protection circuits from the high voltage of the primary system. These units provide a secondary current that is accurately proportional to the current flowing in its primary. They present a negligible load to the primary circuit.

These units are the current sensing units of the power system and are used at generating stations, electrical substations, and in industrial and commercial electric power distribution.

Advantages:

Advantages of Current Transformers are that the units can measure high current easily, high electrical isolation, simple construction, and easy maintenance and installation.

Features:

• Higher accuracy
• Higher burden capacity
• Higher efficiency
• Insulation Level of 600V, 10kv BIL Full Wave, 50-500 Hz
• No Window Type
• Ratios from 2.5 to 100:5 amps ac

Applications:

• Ammeters
• Cross current compensation
• Relay driver applications
• Wattmeters

Approvals:

• CSA
• UL

Auxiliary current transformers are designed for connection in the secondary circuit of a main current transformer. They change the effective ratio on meters or relays. These units are used in protective relaying circuits for a multitude of applications. They are often used to adjust the secondary current to the proper level for the relay. This is done using one primary auxiliary CT input winding and one secondary winding feeding the relay.

Summation current transformers are used to add up secondary currents of multiple main current transformers. This allows measurement with one instrument only. The output signal is again a standardized signal. It is received by adding the input currents and dividing the sum by the quantity of inputs.