Fuji Electric FRENIC MEGA G2 Series - Page 927

Appendix B Japanese Guideline for Suppressing Harmonics by Customers Receiving High
Voltage or Special High Voltage (General-purpose Inverters)
Appendix-17
APPENDICES
(3) Maximum availability factor
• For a load like elevators, which provides intermittent operation, or a load with a sufficient designed motor rating,
reduce the current by multiplying the equation by the “maximum availability factor” of the load.
• According to the Appendix to Guideline, “Maximum availability factor of equipment refers to the ratio of the
maximum capacity of the operating equipment to the total capacity of the harmonic generation equipment.
Capacity of the operating equipment shall be an average value over 30 minutes.”
• In general, the maximum availability factor is calculated according to this definition, but the standard values
shown in Table B.2-5 are recommended for inverters for building equipment, and therefore these values should
also be referred to when handling similar equipment.
Table B.2-5 Availability factors of inverters, etc. for building equipment (standard values)
Equipment type
Inverter capacity category
Single inverter availability
Air conditioning systems
200 kW or less
0.55
Over 200 kW
0.60
Sanitary pumps
-
0.30
Elevators
-
0.25
Refrigerators, freezers
50 kW or less
0.60
UPS (6-pulse)
200 kVA
0.60
Correction coefficient according to contract demand level
Since the total availability factor decreases if the scale of a building increases, the calculation of reduced harmonics
with the correction coefficient β defined in Table B.2-6 is permitted.
Table B.2-6 Correction coefficient according to the building scale
Contract demand (kW)
Correction coefficient β
300
1.00
500
0.90
1,000
0.85
2,000
0.80
Note: If the contract demand is between two specified values listed in Table B.2-6, calculate the value by
interpolation.
Note: The correction coefficient β is to be determined as a matter of consultation between the customer and electric
power company for the customers receiving the electric power over 2000 kW or from the special high voltage
lines.
(4) Degree of harmonics to be calculated
The higher the degree of harmonics, the lower the current flows. This is the property of harmonics generated by
inverters so that the inverters are covered by “The case not causing a special hazard” of the term 3.(3) in the above
Appendix for the 9th or higher degrees of the harmonics.
Therefore, “It is sufficient that the 5th and 7th harmonic currents should be calculated.”