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EMC and Harmonics
THD(V)
Table 9.11 Compatibility Levels for the Total Harmonic Voltage Distortion THD(V)
9.10 IEEE Harmonics Standards
The IEEE 519 standard (Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems)
provides specific limits for harmonic voltages and currents for individual components within the supply network. The
standard also provides limits for the sum of all loads at the point of common coupling (PCC).
To determine allowable harmonic voltage levels, IEEE 519 uses a ratio between the supply short-circuit current and the
maximum current of the individual load. For allowable harmonic voltage levels for individual loads, see Table 9.12. For
allowable levels for all loads connected to the PCC, see Table 9.13.
I
/I
(R
)
SC
L
SCE
10
20
50
100
1000
Table 9.12 Allowable Voltage THD at the PCC for Each Individual Load
Voltage at the PCC
V
≤69 kV
Line
Table 9.13 Allowable Voltage THD at the PCC for all Loads
Harmonic currents must be limited to specified levels, as shown in Table 9.14. IEEE 519 utilizes a ratio between the supply
short-circuit current and the maximum current consumption at the PCC, averaged over 15 minutes or 30 minutes. In certain
instances when dealing with harmonic limits containing low harmonic numbers, the IEEE 519 limits are lower than the
®
61000–2–4 limits. VLT
Parallel Drive Modules observe the total harmonic distortion as defined in IEEE 519 for all R
individual harmonic current fulfills table 10–3 in IEEE 519 for R
I
/I
(R
)
h<11
SC
L
SCE
<20
4%
20<50
7%
50<100
10%
100<1000
12%
>1000
15%
Table 9.14 Allowable Harmonic Currents at the PCC
9.11 VLT
®
Parallel Drive Modules Harmonics Compliance
®
The VLT
Parallel Drive Modules comply with the following standards:
•
IEC 61000-2-4
•
IEC 61000-3-4
•
IEEE 519
•
G5/4
MG37N102
Design Guide
Class 1
5%
Allowable individual harmonic voltages
2.5–3%
2.0–2.5%
1.0–1.5%
0.5–1%
0.05–0.1%
Allowable individual harmonic voltages
11≤h<17
17≤h<23
2.0%
3.5%
4.5%
5.5%
7.0%
Danfoss A/S © 6/2016 All rights reserved.
Class 2
8%
Typical areas
Weak grid
1–2 large loads
A few high-output loads
5–20 medium-output loads
Strong grid
3%
≥20.
sce
23≤h<35
1.5%
0.6%
2.5%
1.0%
4.0%
1.5%
5.0%
2.0%
6.0%
2.5%
Class 3
10%
Allowable THD(V)
5%
. Each
sce
35≤h
Total demand
distortion TDD
0.3%
5%
0.5%
8%
0.7%
12%
1.0%
15%
1.4%
20%
103
9
9
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