120
Power Quality Analyzer PowerPad
®
IV Model 8345
20.2.5 Level of Unbalances
The quantities are calculated in accordance with standard IEC 61000-4-30,
edition 3.0, § 5.7.1.
The supply voltage’s is evaluated by the method of symmetrical components. In
addition to direct component U1, an unbalance will add at least one of the following
components: inverse component U2 or zero sequence component U0.
Inverse voltage component:
Zero sequence voltage component:
Inverse current component:
Zero sequence current component:
With:
U
0
Voltage zero (or homopolar)
sequence unbalance
I
0
Current zero (or homopolar)
sequence unbalance
U
1
Voltage positive (or direct)
sequence unbalance
I
1
Current positive (or direct) sequence
unbalance
U
2
Voltage negative (or inverse)
sequence unbalance
I
2
Current negative (or inverse)
sequence unbalance
u
0
Voltage zero (or homopolar)
sequence unbalance ratio
a
0
Current zero (or homopolar)
sequence unbalance ratio
u
2
Voltage negative (or inverse)
sequence unbalance ratio
a
2
Current negative (or inverse)
sequence unbalance ratio
20.2.6 Mains Signaling Voltages (MSV)
The quantities are calculated in accordance with standard IEC 61000-4-30,
edition 3.0, § 5.10.
The voltage amplitude of the signal for a specified carrier frequency is obtained
by calculating the square root of the sum of the squares of the RMS values, for
10/12 periods, of the four closest interharmonic spikes.
