Medium Voltage Indoor Dry Type Transformers Rating, Rated Voltage, Frequency and Ratio

The rated voltage ratio of the transformers at no load normally is specified at 50 Hz, this being related to the principal tapping of the transformer. Tapping shall be provided on the primary winding to provide a ratio variation of +7.5% and –2.5% in steps of 2.5%. The tap charge mechanism is of the off load… Read More »

How To Measure Transformer Winding Resistance

Transformer winding resistance is very important factor for the life of any transformer, this test is part of type tests, routine tests and field tests. The purpose of winding resistance test is to determine the following: Calculation of the I2R losses in transformer. Calculation of winding temperature at the end of temperature rise test of transformer. As a benchmark… Read More »

Typical Limiting Values of Electrical Substation Equipments

On this page you can find permissible limits for different equipment’s which are part of a power distribution electrical substation. Also where available reference to the international standard is also available in last column. Typical values are provided for transformers, reactors, circuit beakers, current transformers, capacitors, isolators, surge arrestors, batteries and other miscellaneous equipment’s. 1.… Read More »

Cable Tray Ladder Trunking Wire Basket Installation Guidelines

What Are Cable Trays? An assembly of units/sections with associated fittings that form a rigid structural system to securely fasten or support cables. Think of a roadway bridge that supports traffic.  Cable Tray Systems must provide protection to life & property against faults caused by electrical disturbances Lighting and failures which are part of the… Read More »

Capacitor Bank Installation Method Statement

Installation of capacitor bank shall be carried out in accordance to project specifications and approved drawings and technical submittals etc. Installation will be carried out by skilled and suitably experienced electricians under supervision of highly competent site supervisors and engineers to ensure the correctness and quality of the work. Prior to dispatch of capacitor bank equipment,… Read More »

Dielectric Constant of Different Materials or Relative Permittivity

Dielectric Materials A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric… Read More »