SURGE IMPEDANCE LOADING OF TRANSMISSION LINE
Surge impedance loading [SIL] of a transmission system is the power delivered by a lossless line to a purely resistive…
Difference between Control Power Transformer and Potential Transformer
Control Power Transformer Control power transformers [CPT] are transformers designed to provide control voltage to contactors, starter control panels, solenoids,…
NEUTRAL CURRENT TRANSFORMER APPLIED WITH ELECTRONIC TRIP UNITS
Neutral Current Transformer [NCT] is required for residual ground fault detection and power metering in three-phase four wires systems. Residual…
INCORRECT MOTOR CONTROL CIRCUIT WIRING
Motor control circuits are typically fed from motor phase wiring by tapping phase circuits with control power transformer. This control…
Non-Shielded Medium Voltage Cable
National Electric Code [NEC] 2005 edition and later editions requires shielded medium voltage [MV] cables for all circuits operating above…
Zero Sequence Current Transformer
Zero Sequence Current Transformer [ZSCT] also known as Core Balance Current Transformer [CBCT] is a type of current transformer [CT]…
Percentage insulation level of medium voltage cables
Medium Voltage [MV] cable insulation is made of different variations of extruded solid or laminar (oil paper). Most common insulation…
Transformer Tap Changer: How to Select Transformer Taps?
Taps are provided on a transformer to adjust secondary voltage of power transformer for high or low voltage conditions. Common…
CURRENT UNBALANCE: CAUSES, EFFECTS AND PROTECTION
In three phase systems, current unbalance is defined as the maximum deviation of any phase current from average divided by…
THREE-PHASE TO GROUND SHORT CIRCUIT WAVEFORM
Characteristics of a Three Phase to Ground fault Following are some of the characteristic ‘signatures’ of a three phase to…