A current transformer is a type of electrical instrument that is produced to provide a flow of current in the secondary circuit which is accurately perpendicular to the current flowing in its primary circuit. To measure current and monitor the operation of the power grid Current transformers are used extensively and is typically defined by its current ratio from primary to secondary.

Current transformers (Current Transformer) are the most commonly used in metering and protective relaying in the electrical power industry where they facilitate the safest requirement of a huge currents, often in the presence of high voltages on the circuit. The current transformer is safely isolates to measure and to control a circuitry from the high voltages basically present on the circuit is beingcalculated. Current transformers are often maintained by passing a single primary turn under a well-insulated toroidal core with many turns of wire wrapped. Current transformers are used for measuring the flow of current and monitoring the operation of the power used. The Current ransformer is basically defined by its current ratio flowing from primary to secondary.

There are some factors improves the current transformer accuracy.They are like burden, rating factor, load, external electromagnetic fields, temperature and physical Current Transformer configuration. Here, the factor of burden is given below.

The amount of impedance is the cause for the burden in a Current transformer circuit. The basic items that are reasons for the burden in the current measurement circuit are switch blocks meters and intermediate conductors and the sources are the conductor between the meter and the Current Transformer. Also, a problem of producing high resistance occurs due to placing a substation meter at some distance from meter which can be overcome by using current transformer with 1 amp which produce low voltage drop.

The Rating factor of a Current Transformer which is dependent on ambient temperature, is a factor used to determine the absolute maximum measurable primary current by multiplying the full load of a Current Transformer.To maintain the accuracy in raising of the ambient temperature, the Current Transformer will have low capacity, and the rating factors of the Current Transformer s will range from 35 degrees Celsius and 55 degrees Celsius.

Another factor for the accuracy ofCurrent Transformer is Physical Current Transformer configuration. If the conductors are not centered in circular or oval, the inaccuracy occurs in Current Transformer and this should be notified for correct accuracy.

Normally, the Current Transformer’s are constructed in many ways like passing a single primary turn through a well-insulated toroidal core wrapped with many turns of wire. To measure waveforms of high frequency or pulsed currents within high pulsed power systems wideband current transformers are used specially.
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