Mitsubishi Electric FR-A700 Series, Техническое руководство

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510
SELECTION
(2) Harmonic suppression guideline in Japan
1) Application to the guidelines
Harmonic currents flow from the inverter to a
power receiving point via a power transformer.
The harmonic suppression guideline was
established to protect other consumers from these
outgoing harmonic currents.
The three-phase 200V input specifications 3.7kW
or less are previously covered by "Harmonic
reduction guideline for household appliances and
general-purpose products" and other models are
covered by "Harmonic reduction guideline for
consumers who receive high voltage or special
high voltage". However, the general-purpose
inverter has been excluded from the target
products covered by "Harmonic reduction
guideline for household appliances and general-
purpose products" in January 2004 and
"Harmonic reduction guideline for household
appliances and general-purpose products" was
repealed on September 6, 2004.
All capacity and all models of general-purpose
inverter used by specific consumers are covered
by "Harmonic reduction guideline for consumers
who receive high voltage or special high voltage".
• Harmonic reduction guideline for consumers receiving
power of high voltage or specially high voltage
The upper limit of the outgoing harmonic current
per 1kW contract power is determined for the
power receiving point of a consumer who receives
power of high voltage or specially high voltage.
Note that whether the reduction technique is
required or not depends on whether the sum of
outgoing harmonic current values of a consumer
exceeds the upper limit of the permissible
outgoing current determined by the contract
power.
2) How to judge whether harmonic reduction
technique is required or not at the consumer who
receives power of high voltage or especially high
voltage
When updating the contract power, a consumer is
requested to present a calculation sheet in the
format as shown on page 516.
Calculation using the predetermined procedure
clarifies whether the reduction technique is
required or not. A specific procedure will be
described below.
(a) Calculation of rated capacity [kVA]
Used to calculate the 6-pulse equivalent
capacity to judge whether the inverter is
covered by the <Harmonic reduction guideline
for consumers receiving power of high voltage
or specially high voltage>.
Independently of whether the inverter has a
reactor or not, the rated capacity [kVA] is
standardized according to the motor capacity
and found by the following formula:
Rated capacity
= V fundamental wave current
coefficient 10
-3
[kVA]
V : 200V or 400V (input voltage)
Fundamental wave current :
see the table on the following page
Coefficient : 1.0228
Refer to the table for specific calculation
results.
The above rated capacity is a value used to judge
whether the inverter is covered by the harmonic
guideline. Therefore, note that these are different
from capacities of power supply equipment (such
as power transformers) required for use of actual
inverters.
The power supply equipment capacity required is
1.3 to 1.6 times greater than the above rated
capacity (for specific values, refer to the inverter
catalog).
(b) Calculation of 6-pulse equivalent capacity
6 pulses equivalent capacity
Where, conversion factor Ki is as follows:
• Without reactor : 3.4
• With AC reactor : 1.8
• With DC reactor : 1.8
• With AC and DC reactors : 1.4
If the sum of equivalent capacities is higher
than the limit found by the above formula,
outgoing current of harmonics must be
calculated with the following procedure:
(c) Conversion of received power voltage into
rated current
= Rated capacity Conversion factor Ki [kVA]
Received Power Voltage Reference Capacity
6.6kV system 50kVA
22kV or 33kV 300kVA
66kV or more system 2000kVA
Rated current converted from received
power voltage
= Fundamental wave current
(200V or 400V inverter power supply
voltage/received power voltage) [A]