User manual 09/2009 - Schneider Electric

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User manual 09/2009 - Schneider Electric

The Metering FunctionPower Metering (Micrologic E)PresentationThe Micrologic E trip unit calculates the electrical quantities required for power management:• The instantaneous values of the:• Active powers (total Ptot and per phase) in kW• Reactive powers (total Qtot and per phase) in kvar• Apparent powers (total Stot and per phase) in kVA• Fundamental reactive powers (total Qfundtot and per phase) in kvar• Distortion powers (total Dtot and per phase) in kvar• The maximum and minimum values for each of these powers• The Demand values and the peaks for the total Ptot, Qtot and Stot powers• The cos ϕ and power factor (PF) indicators• The operating quadrant and type of load (leading or lagging)All these electrical quantities are calculated in real time and their value is updated once a second.Principle of Power MeteringThe Micrologic E trip unit calculates the powers from the rms values of the currents and voltages.The calculation principle is based on:• Definition of the powers• Algorithms depending on the type of trip unit (4-pole or 3-pole)• Definition of the power sign (circuit breaker powered from the top or underside)Calculation AlgorithmThe calculation algorithm, based on the definition of the powers, is explained in Power CalculationAlgorithm, page 83.Calculations are performed taking account of harmonics up to the 15th.80 LV434104 09/2009

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