Multi-Tech Systems 7600 User Manual

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.

 = 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%