VACUUM BREAKER vs VACUUM CONTACTOR
Vacuum Circuit Breakers (VCB) and Vacuum contactors (VC) uses the insulation properties of vacuum to perform current interruption. Both VCB…
POWER FLOW AND VOLTAGE STABILITY ON AC TRANSMISSION LINES
Transmission line power flow is an integral part of power systems studies and is used to calculate steady state voltage,…
CORNER GROUNDED DELTA TRANSFORMER CONNECTION
Ungrounded delta secondary connected transformers were used extensively in the early era of industrial electrical distribution. Ability to operate machinery…
IMPORTANCE OF TRANSFORMER CORE GROUNDING
Laminated steel core of a power transformer is insulated from ground and is typically referenced to ground (earth) at a…
What is a slash-voltage-rated breaker?
Some circuit breakers have dual voltage ratings stamped on them, such as 240/120V or 480/277V. These breakers are known in…
Nuisance Breaker Trip Due to Voltage Phase Angle Variation: Case Study
Negative sequence overvoltage protection [ANSI 59Q] is used for detecting phase voltage unbalance or reverse phase condition. Variation of individual…
Negative Sequence Overvoltage Protection
Negative sequence overvoltage protection is used for protection of service main, motor circuits, sensitive loads for conditions such as reverse…
Why are Grounding Transformers Used ?
Grounding transformers are used in utility and industrial distribution systems to ‘create a grounded system’ from an otherwise ungrounded source.…
What happens when Phase and Neutral are reversed ?
There are some regions of the world such as North America, where polarized receptacles are used, while other parts of…
Circuit Breaker Trip Due To Control Circuit Ground Fault
Control circuit for medium and high voltage circuit breakers have protective relay contacts to trip and close circuit breaker. Control…