User manual 09/2009 - Schneider Electric

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User manual 09/2009 - Schneider Electric

Operating AssistanceInterpreting the Cos ϕ MAX and the Cos ϕ Values According to IEC ConventionThe cos ϕ MAX value corresponds to the minimum value of the load cos ϕ, whether leading or lagging:this gives the user information on how the equipment is performing from a cost point of view.The value of cos ϕ alone cannot be used to define the action to be taken to increase its value: shouldinductances or capacitors be installed?The alarm on the cos ϕ according to IEC convention integrated in the Micrologic trip unit is used to sendan alert if a critical situation occurs. This alarm, associated with an alarm defining the type of load or theoperating quadrant, can be used to monitor the 2 critical situations automatically.Setting the Cos ϕ Alarm Parameters According to IEEE ConventionMonitoring of the cos ϕ indicator is applied to management of the workshop described above:• When the power is started, too high a value of cos ϕ (lagging), for example higher than — 0.6, resultsin tariff penalties. The capacitive compensation value to be used is determined by the value of theQfund reactive power.• When the power is stopped, too low a value of cos ϕ (leading), for example less than + 0.6, results intariff penalties. The capacitive compensation element must be disconnected.2 alarms monitor the indicators fully:• Alarm 124 (monitoring of the lagging cos ϕ) on a superiority condition for operation in quadrant 1(inductive reactive energy consumed)• Alarm 121 (monitoring of the leading cos ϕ) on an inferiority condition for operation in quadrant 4(capacitive reactive energy consumed)Setting the parameters for monitoring the cos ϕ (codes 121 and 124) according to IEEE convention usingthe RSU software:124 Monitoring the lagging cos ϕ121 Monitoring the leading cos ϕSetting the SDx Output ParametersThe 2 alarms defined can each be associated with an SDx module output (see Setting the SDx ModuleOutput Parameters, page 127):• With output Out1, alarm code 124 (monitoring of the lagging cos ϕ)• With output Out2, alarm code 121 (monitoring of the leading cos ϕ)On starting the power at t2, since the load is lagging too much, output Out1 will be activated (1). TheMicrologic trip unit display will indicate:(1) The output must be configured in permanent latching mode.Acknowledging the Out1 ScreenThe Out1 screen can only be acknowledged if the alarm is no longer active.After startup of the capacitive compensation, the alarm is no longer active. The Out1 output isacknowledged by pressing the OK key twice (validation and confirmation).LV434104 09/2009 141

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