CABLE TYPE TRANSFORMERS

CABLE TYPE CURRENT TRANSFORMERS Instrument Transformers: An instrument transformer is a piece of electrical equipment which converts primary electrical values current or voltage-into comparable secondary values which are suitable for the devices to which it is connected. They are defned in two kinds; Current transformers convert primary rated current to a proper current level (1A…5A) which can be used by metering or protection devices. They can have several secondary windings with magnetically separated cores of the same or different characteristics. Extended Current Rating; It is the value that Current Transformer can withstand at defned current value while remaining in the limits of current error. As described in IEC 61869-2, Standard values of rated primary current 120%, 150% and 200% of primary current. Limits of current error and phase displacement for measuring current transformers As described IEC 61869-2; For classes 0.1 – 0.2 – 0.5 and 1, the current error and phase displacement at rated frequency shall not exceed the values given in table when the secondary burden is any value from 25 % to 100 % of the rated burden. For classes 0,2 S and 0,5 S the current error and phase displacement at the rated frequency shall not exceed the values given in table when the secondary burden is any value from 25 % and 100 % of the rated burden.