Notesale: Turn your study into money

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 Reactive power is a result of AC and produced from inductive and capacitive loads
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It is measured in units of volt-ampere reactive (VAR)
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 Series capacitors are generally employed to improve the stability of the system and shunt capacitors are
generally employed to improve the power factor of the system
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 At very low levels of system load, transmission lines act as capacitors (generating Q) and
increase voltages
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Star delta starting
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Can only be used with a motor where both ends of its three stator windings are fitted to a terminal board
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Resistant stator starting
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This starting system is therefore suited to machines with a resistive torque that increases with the speed (fans, pumps)
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This could be lowered by increasing the resistance value but that would
cause the voltage to drop further at the motor terminals and thus a steep drop in the starting torque
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Equipment rather expensive because of the high cost of the autotransformer
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Resistors must therefore be inserted in the rotor circuit
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Fire risk and earthling systems
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earthling the frames (IT & TT) minimizes the hazard of fire
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As the PE and neutral conductors are one and the same, RCDs cannot be used
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Continuity of service not essential and no maintenance service: Prefer the TT
Fire hazard: IT if maintenance service and use of 0
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Synchronous condenser
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Running at no-load, compensating lagging power factors caused by induction motors, transformers…
It can compensate either a leading or lagging power factor, by absorbing or supplying reactive power to the line
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IEC 61850
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a standardized communications language among devices
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