PART 3 OF A SERIES:
VARIABLE SPEED DRIVES – SELECTION & COMPLIANCE CHECKING TO IEEE 519 UTILISING POWERCAD-5 ELECTRICAL DESIGN SOFTWARE.
PowerCad-5 electrical engineering design software allows engineers to rapidly integrate variable speed drives (VSD) into the LV electrical distribution model for an Industrial project.
VSD configuration
The VSD location:
- Within the motor control centre,
- Remote, or
- Close coupled to the motor
Harmonic Mitigation
PowerCad-5 offers the following Harmonic mitigation solutions:
- Passive Filter: Line Passive filters can be added to the VSD
- Active Filter: An Active filter added to the MCC bus
VSD motor feed cable
A VSD/EMC variable speed drive cable with 3 cores plus 3 earths and a copper tape screen can be selected as the feed cable from the VSD to the motor.
Figure 1
Codes/Standards
PowerCad-5 electrical engineering design software allows the user to select Codes/Standard for compliance checking from the following options.
Power Distribution - Conductor Loss:
- Hong Kong Code of Practice for Energy Efficiency of Electrical Installations – 2002 Edition
Maximum Total Harmonic Distortion (THD):
- IEEE Std 519:1992
- Emirate of Abu Dhabi – Limits for Harmonics in the Electricity Supply System (2005)
- Hong Kong Code of Practice for Energy Efficiency of Electrical Installations – 2002 Edition
Maximum Allowable Harmonic Current:
- Emirate of Adu Dhabi - Limits for Harmonics in the Electricity Supply System (2005)
User defined:
- Total Harmonic Current Distortion (THD) as %Fundamental or % RMS
- Total Harmonic Voltage Distortion (THD) as %Fundamental
Variable Speed Drive selection
PowerCad-5 electrical engineering design software allows engineers to automatically select the variable speed drive based on the electric motor size selected. (See Figure 2 without filter) The variable speed drive can be selected with or without a Passive line filter. (See Figure 3 with filter)
Figure 3
PART 4 of this series will be published in Industrial Electrix, January – March 2010.