Instrument Transformers are used in ac power system for the measurement of electrical quantities i.e. ac voltage, ac current, ac power, energy, power factor, frequency e.t.c. As we know there are two types of instrument transformer ( current transformer and potential transformer). Current transformers convert high value of ac current to low safe value and potential transformer convert high value of ac voltage to low safe value so that they can be safely measured by using low range measuring instruments i.e. low range ammeter and low range voltmeter.
In other words, we can also say that instrument transformers are used to extend the range of measuring instruments. Instrument transformers are also used with protective relays for the protection of power system. Due to the low current and voltage levels in measuring and protective circuits, there is low power consumption by the measuring and protective equipments.
Instrument transformer isolate the measuring system from the main line i.e it is safe for both measuring instrument and the operators to measure electrical quantities in high power lines. This isolation also reduces the requirement of high insulation for protective and measuring instrument. In the case of any instrument damage it can be easily replaced.
Instrument transformer also reduces cost of measurement of these electrical quantities as they convert high value of voltage and current to low. so, here no needs to design large and expensive measuring instrument to measure higher electrical quantities. Electrical quantities measured by measuring instrument associated with these instrument transformer is further multiplied in same proportion it is reduced to low value to get actual value.
Conclusion
Hope, you have clearly understand why instrument transformers are used in ac power system. Make sure to leave your opinion and suggestion about this post in comment section below.