Справочник Пользователя для Mitsubishi Electronics A800
Power supply harmonics
69
3
• Calculation of equivalent capacity P0 of harmonic generating equipment
"Equivalent capacity" is the capacity of a 6-pulse converter converted from the capacity of consumer's harmonic generating
equipment and is calculated by the following equation: If the sum of equivalent capacities is higher than the limit in (refer to
equipment and is calculated by the following equation: If the sum of equivalent capacities is higher than the limit in (refer to
), harmonics must be calculated with the following procedure:
• Calculation of outgoing harmonic current
Outgoing harmonic current = fundamental wave current (value converted from received power voltage)
operation ratio
harmonic content
• Operation ratio: Operation ratio = actual load factor
operation time ratio during 30 minutes
.
• Rated capacities and outgoing harmonic currents of inverter-driven motors
• Determining if a countermeasure is required
A countermeasure for harmonics is required if the following condition is satisfied: outgoing harmonic current > maximum
value per 1 kW contract power
value per 1 kW contract power
contract power.
• Harmonic suppression techniques
P0 = ∑ (Ki
Pi) [kVA]
Rated capacity: Determined by the capacity of the
applied motor and found in Table 5. The rated
capacity used here is used to calculate the generated
harmonic amount and is different from the power
supply capacity required for actual inverter drive.
applied motor and found in Table 5. The rated
capacity used here is used to calculate the generated
harmonic amount and is different from the power
supply capacity required for actual inverter drive.
Ki: Conversion coefficient (Refer to
)
Pi: Rated capacity
of harmonic generating equipment [kVA]
i: Number indicating the conversion circuit type
Applicable
motor
(kW)
Rated
current (A)
Fundamental
wave current
wave current
converted
from 6.6 kV
(mA)
Rated
capacity
(kVA)
Outgoing harmonic current converted from 6.6 kV (mA)
(With a DC reactor, 100% operation ratio)
400 V
5th
7th
11th
13th
17th
19th
23rd
25th
75
123
7455
87.2
2237
969
626
373
350
239
224
164
90
147
8909
104
2673
1158
748
445
419
285
267
196
110
179
10848
127
3254
1410
911
542
510
347
325
239
132
216
13091
153
3927
1702
1100
655
615
419
393
288
160
258
15636
183
4691
2033
1313
782
735
500
469
344
220
355
21515
252
6455
2797
1807
1076
1011
688
645
473
250
403
24424
286
7327
3175
2052
1221
1148
782
733
537
280
450
27273
319
8182
3545
2291
1364
1282
873
818
600
315
506
30667
359
9200
3987
2576
1533
1441
981
920
675
355
571
34606
405
10382
4499
2907
1730
1627
1107
1038
761
400
643
38970
456
11691
5066
3274
1949
1832
1247
1169
857
450
723
43818
512
13146
5696
3681
2191
2060
1402
1315
964
500
804
48727
570
14618
6335
4093
2436
2290
1559
1462
1072
560
900
54545
638
16364
7091
4582
2727
2564
1746
1636
1200
No.
Item
Description
1
Reactor installation
(FR-HAL)
(FR-HAL)
The converter unit (FR-CC2) is equipped with the DC reactor on its DC side, and outgoing harmonic
current can be suppressed. By installing an AC reactor (FR-HAL) on the AC side of the inverter, the
outgoing harmonic current suppression performance can be improved.
current can be suppressed. By installing an AC reactor (FR-HAL) on the AC side of the inverter, the
outgoing harmonic current suppression performance can be improved.
2
high power factor
converter
(FR-HC2)
converter
(FR-HC2)
This converter trims the current waveform to be a sine waveform by switching the rectifier circuit
(converter module) with transistors. Doing so suppresses the generated harmonic amount significantly.
Connect it to the DC area of an inverter. Use the high power factor converter (FR-HC2) with the
accessories that come as standard.
(converter module) with transistors. Doing so suppresses the generated harmonic amount significantly.
Connect it to the DC area of an inverter. Use the high power factor converter (FR-HC2) with the
accessories that come as standard.
3
Installation of power
factor improving
capacitor
factor improving
capacitor
When used with a reactor connected in series, the power factor improving correction capacitor can
absorb harmonic currents.
absorb harmonic currents.
4
Transformer multi-phase
operation
operation
Use two transformers with a phase angle difference of 30° as in -
and - combinations to provide an
effect corresponding to 12 pulses, reducing low-degree harmonic currents.
5
Passive filter
(AC filter)
(AC filter)
A capacitor and a reactor are used together to reduce impedances at specific frequencies. Harmonic
currents are expected to be absorbed greatly by using this technique.
currents are expected to be absorbed greatly by using this technique.
6
Active filter
(Active filter)
(Active filter)
This filter detects the current in a circuit generating a harmonic current and generates a harmonic current
equivalent to a difference between that current and a fundamental wave current to suppress the
harmonic current at the detection point. Harmonic currents are expected to be absorbed greatly by using
this technique.
equivalent to a difference between that current and a fundamental wave current to suppress the
harmonic current at the detection point. Harmonic currents are expected to be absorbed greatly by using
this technique.