Distribution transformer : Monitoring & protection

Abstract

The basic aim of our project is to protect the transformer against internal faults and ensuring security of the protection scheme for external faults. System conditions that indirectly affect transformers often receive less emphasis when transformer protection is specified. Overloading power transformers beyond the nameplate rating can cause a rise in temperature of both transformer oil and windings. If the winding temperature rise exceeds the transformer limits, the insulation will deteriorate and may fail prematurely. Prolonged thermal heating weakens the insulation over time, resulting in accelerated transformer loss-of-life. Power system faults external to the transformer zone can cause high levels of current flowing through the transformer. Through-fault currents create forces within the transformer that can eventually weaken the winding integrity. A comprehensive transformer protection scheme needs to include protection against transformer overload, throughfault, and over excitation, as well as protection for internal faults. This paper focuses on liquidimmersed transformers because the majority of medium and high-voltage transformers are of this type. If there is a fault in the transformer, by our project we can detect the fault in the transformer and there will be notification to the control room regarding the fault.