Transmission Line Parameter Calculation

Transmission line length formula:   the velocity of light in km/s Now supposeĀ  a transmission line parameter data is as follows R= 0.010 pu, X= 0.085 pu, B=0.176 pu. The base value of power and voltage is given as Vb=230 kV , Sb= 100 MVA Then the length is Length = 97.33 km…
thermal overload relays

Why is both RTD temperature and thermal overload protection needed?

Although both methods give protection against overload and thermalĀ rise, both have own pros and cons. Especially with the important objects, both methods are used because they complement each other. RTD basics A fundamental physical property of a metal is that its resistivity changes with temperature. For many metals,…

Protection relay codes

Introduction: Numerical codes are sometimes used when defining the protection relay, whereas in other cases symbols are used. The numerical codes refer to the IEEE C37-2 Standard, whereas the symbols refer to the IEC Standards. In the definition of the symbols the IEC Standards have not detailed all…

All About Induction Machines

Introduction Induction machines, also called asynchronous machines, can be used as generators or motors. Induction machines can be either of one or three-phase construction. The following discussion focuses on the three-phase machines and their properties. The maximum of the applications for three-phase induction machines is with power ranges…

Electrical characteristics

(Peak) making current: The peak value of the first major loop of the current in one pole of a switching device during the transient period following the initiation of current during a making operation. Peak current: The peak value of the first major loop of current during the…