Secondary injection tests are always done prior to primary injection tests. The purpose of secondary injection testing is to prove the correct operation of the protection scheme that is downstream… Read more
Nov 22, 2017 | Protection
On transformer feeders, the transformer and line or cable are connected in series and form a unit. In this manner, one CB can be saved. On feeders with tee-offs, transformers… Read more
Nov 20, 2017 | Protection
Most compensation banks are controlled stepwise. For this purpose it is essential to ‘know’ when it is allowed to (de)activate a capacitor step by the power factor relay (controller). The… Read more
Nov 15, 2017 | Energy and Power
This debate continues. Both designs have advantages (see Table 1). The major advantage of overhead circuits is cost. An underground circuit typically costs anywhere from 1 to 2.5 times the… Read more
Nov 13, 2017 | Cables
Distribution transformers (commonly mineral-oil-immersed type) are output rated and their loading and sizing guidelines of many utilities are based on ANSI/IEEE C57.91. Distribution transformers can deliver their rated kVA without…...
Nov 09, 2017 | Premium Content ♛
Like the asynchronous motor, the synchronous motor consists of a stator and a rotor separated by the air gap. It differs from the asynchronous motor in that the flux in… Read more
Nov 08, 2017 | Electric Motor
Failure of transformer in power substation is not a sudden phenomenon, for that matter each and every failure will take place only after alerting through some pre-signs. If they went… Read more
Nov 06, 2017 | Maintenance
This technical article explains how to calculate and draw a single line diagram of the three-phase, 60-Hz system power system with generators, motors, transformers and lines. The following components comprise… Read more
Nov 01, 2017 | Energy and Power
Numerical protection is based on a number of microprocessors that can be programmed to reproduce virtually any type of protection and relay. It represents important advantages in reliability, space and… Read more
Oct 30, 2017 | Protection
Capacitors are used in industrial premises for two basic functions: the first, to correct the load power factor, usually to meet the supplying authority’s supply requirements and avoid tariff penalties…...
Oct 27, 2017 | Premium Content ♛
