In the formula, U
1
is RMS value of the voltage fundamental and U
h
is RMS value of the voltage harmonic with order n.
Harmonic parameter : Each harmonic rate
The percentage of each harmonic divided by fundamental.
Demand
Demand of total power and reactive power of system, demand of 3-phase current. The demand statistics method in MIB is sliding
windows. The total sliding windows time can be chosen from 1 to 30 minutes. Each window slides once per minute.
Example
The sliding window time is supposed to be three minutes. If average power of the first minute is 12, 14 of the second
minute and third minute is 10.
Result of the total power demand the last three minutes is:
( 12 + 14 + 10 ) / 3 = 12 at the end of the third minute. If another minute passed, the average power of the minute is then 9,
then the total power demand of the last three minutes is ( 14 + 10 + 9 ) / 3 = 11 at the end of the forth minute.
Minutes
W, AAC, var, or VA
Example: 8 periods of 1 minute.
Sliding windows
Total of sliding windows
1 sliding window
Present MD Input
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Unbalance factor
MIB can measure the unbalance factor of 3-phase voltage and current, using the method of sequence vector.
Max/Min: MIB can measure the max value of a system’s total power, reactive power and apparent power and the max/min of the 3-
phase voltage and current. The value of the measured data is stored in NV-RAM.
Alarm function
When the measured data value has reached the pre-set alarm limit and pre-set alarm time has expired, an alarm will be generated.
Digital output (only MIB 8000C with Extension module)
The digital output (DO) can be used to trigger a light or sound alarm indication. The following example describes how the over-limit
alarming works.
DESIGNER'S HANDBOOK 4189320063D EN Page 10 of 23
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