ABB ESI-S, Installation, Operation And Maintanance Manual

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Manual Energy Storage Inverter ESI-S  Commissioning instructions 163
L1
L2
L3
Load side Supply side
K L
I k
K L
I k
K L
I k
ESI
L1 L2 L3
Positive direction
Ch1 Ch2
N
N
X21.1
X21.2
X21.3
X21.4
X21.5
X21.6
X21.7
X21.8
X21.9
Figure 84: Connection of the scopemeter for checking the CT in phase L1
On the scopemeter screen, two waveforms should appear. The voltage waveform should
be approximately a sine wave and the current waveform would normally be a well-
distorted wave because of harmonic distortion. Usually, it is quite easy to extrapolate
the fundamental component as it is the most important one (
Figure 85 ).
Remark: If the earthing of the system is bad, the phase to ground voltage may appear
like a much distorted waveform. In this case, it is better to measure the phase-to-phase
voltage (move the black clamp to the phase L2) and subtract 30° on the measured phase
shift.
Figure 85: Extrapolation of the fundamental component from a distorted waveform
From the fundamental component of both signals, the phase shift must then be
evaluated (
Figure 86 ). The time
Δ
T between zero crossing of the rising (falling) edge of
both traces must be measured and converted to a phase shift ϕ by the following formula:
° =
360 *
Τ
1
ΔΤ
φ
where T1 is the fundamental period duration.
I
I1