Multi-Tech Systems 7500 - Manual (Page 319)

ION 7500 / ION 7600 User’s Guide Interharmonic Voltage
Power Quality: ION Meters and EN50160 Technical Note Page 319
Interharmonic Voltage
Interharmonics are the entire band of frequencies between two successive integer
multiples of the fundamental. All harmonic measurements are performed as
defined in IEC 61000-4-7.
Observation period of one week with fixed steps of 10 minutes.
N = number of 10-minute intervals in which the supply voltage is within ±15% of
nominal.
N
1
= number of intervals in which one or more of the interharmonic levels
defined in the table below are exceeded and the supply voltage is within ±15% of
nominal. Levels for interharmonic bands up to the 25th harmonic are defined in
the table below.
Apply your own compliance evaluation criteria to the interharmonic statistics
provided by the meter.
In the table below, order 2 specifies all frequencies between the fundamental and
the 2
nd
harmonic; order 3 specifies all frequencies between the 2
nd
harmonic and
the 3 rd ; etc.
EN 50160 data (current observation period): The meter generates the N and
N1counts described above for each phase. These counters are reset at the
beginning of the next observation period.
EN 50160 data (previous observation period): The meter stores the N and N
1
counter values at the end of each observation period before these counters are
reset. These registers are also stored in a data recorder for each observation period.
Events: The meter creates a message in the Event log every time the N
1
counter
increases.
Odd Harmonics Even Harmonics
Not Multiples of 3 Multiples of 3 Order Threshold
Order Threshold Order Threshold Order Threshold 2 2%
5 6% 17 2% 3 5% 4 1%
7 5% 19 1.5% 9 1.5% 6…24 0.5%
11 3.5% 23 1.5% 15 0.5%
13 3% 25 1.5% 21 0.5%