The following explanation refers to the examples in Configuration C of the Bus Load Configuration Examples documentation.
The example below illustrates a configuration in which a single load is connected to a bus through a feeder circuit and a VFD.
The load parameters are as follows:
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Motor rated power = 10 kW
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Break power = 7.5 kW
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Standby operation mode (Z = 0.1)
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Efficiency at full level = 0.9
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Power factor at full load = 0.85
When operating as a converting equipment device, the VFD parameters are as follows:
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Resistive power losses = 1 kW
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Reactive power losses = 1 kVAR
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Continuous operational mode (X = 1.0)
When operating as a load, the VFD parameters are as follows:
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Rated active power = 8 kW
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Rated reactive power = 2 kVAR
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Consumed reactive power = 1.5 kVAR
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Continuous operating mode (X = 1.0)
The following two images show the connection of Motor M-9.
In the Electrical Engineer:
In a single line diagram:
Accounting for Converting Equipment Power Losses
When running bus load calculations, you can instruct the software to take into account converting equipment power losses. The software adds these power losses to the upstream feeding bus and circuits. The software treats them as continuous loads and includes their values in both compensated and uncompensated calculations. The same losses are also taken into account in the All Feeder Load Summary and PDB Load Summary reports.
To account for converting equipment power losses, select the Account for converting equipment power losses check box on the Reports tab of the Preferences dialog.
Defining Converting Equipment as Consumers
You can define converting equipment items as consumers. This allows you to include these items in the calculations of load summaries, load associations, and when generating all feeder load summary reports.
For details, see Define Converting Equipment as Consumers.
After you define the VFD as a consumer, the load properties of the converting equipment replace the load parameters of the loads that are connected downstream of the VFD. The operation mode and coincidence factors that are used for the bus totals are now derived from the VFD and not from the downstream loads.