Transformer Short Circuit Test
Short circuit test is performed on a transformer to measure the equivalent series resistance and reactance. Series resistance provides information…
Ground Potential Rise, Step and Touch Potential
Ground Potential Rise [GPR] Ground potential Rise (GPR) per IEEE Std 80 is defined as “The maximum electrical potential that…
What is KNAN / KNAF transformer?
KNAN is a transformer that uses less flammable non-mineral oil such as silicone oil, synthetic ester or natural ester (FR3)…
Types of Transformer Cooling
Power transformers can have different kVA depending on the type of cooling method used. Heat is one of the main…
Line Protection Using Impedance (Distance) Relays
When a system has too many radial lines protection using time delay overcurrent relay becomes impractical. Time delay for relay…
Magnetic Circuit for Power Engineers
Terminology: Magnetic Flux: The total flow of a field is called its flux. Example total light emitted from a source…
Positive and Zero Sequence Impedance of Cable
Positive, Negative and Zero sequence impedance values of cable systems are needed for performing fault current calculations and other power…
Earth Resistance Calculator for Single Electrode
Driving metallic earth rod in to ground is one of the basic steps in creating suitable earth or ground reference…
Substation Grounding: Role of Crushed Rock
Ever wondered why crushed rock is spread over the surface of an electric substation? This article goes through the reasons…
Zero Sequence Impedance of Core and Shell Type Wye Wye Transformer
Sequence impedance for typical winding connections can be found in most text books. These ignore magnetizing impedance branch and is…