Temporary Motor Control Center Data

HP and Total kVA: These list the totals of the items which are connected to the MCC. If an item has "Off" in the status column of the Description tab library of the regular database dialog, it will not be included in this total.

This indicates the choice made in the Power Flow tab of the regular database dialog box—either MCC Specifications or SCADA.

Provides an easy way of adjusting the total motor load used in determining power flows. By changing the scaling factor, the actual HP (total connected value) entered in the HP field can remain static. This reduces modeling errors and eliminates multiple databases for different contingencies.

MCCs can be modeled for the power flow solution in several different ways.

• Constant kVA: This is the most common model. It is conservative, and will result in slightly lower voltage values than would be measured on an actual system.
• Constant Current: This model is generally not used in motor modeling. It more closely matches an induction motor's characteristics in the reactive component than other models, but is technically incorrect because kW is relatively constant throughout the voltage range for an induction motor.
• Constant Impedance: This model is used for starting induction and synchronous machines, and closely matches motor characteristics during low voltages.
• Constant kW + j Current: This model is a combination of the above models and more closely matches actual motor characteristics within normal operating voltages.