MI 2883 Energy Master
Theory and internal operation
142
5.1.14
Rapid voltage changes (RVC)
Standard compliance: IEC 61000-4-30 Class A (Section 5.11)
Rapid Voltage Change (RVC) is generally speaking an abrupt transition between two
“steady state” RMS voltage levels. It is considered as event, (similar to dip or swell) with
start time and duration between steady state levels. However, those steady state levels
does not exceed dip or swell threshold.
RVC event detection
Instrument RVC event detection implementation strictly follows
IEC 61000-4-30
standard requirements
.
It begins with finding a voltage steady-state. RMS voltage is in a
steady-state condition if 100/120
U
Rms(1/2)
values remain within an
RVC threshold
(this
value is set by the user in MEASUREMENT SETUP
RVC Setup screen) from the
arithmetic mean of those 100/120
U
Rms(1/2)
values. Every time a new
U
Rms(1/2)
value is
available, the arithmetic mean of the previous 100/120
U
Rms(1/2)
values, including the
new value, is calculated. If a new
U
Rms(1/2)
value crosses
RVC threshold
, RVC event is
detected. After detection instruments wait for 100/120 half cycles, before searching for
next voltage steady-state.
If a voltage dip or voltage swell is detected during an RVC event, then the RVC event is
discarded because the event is not an RVC event.
RVC event characterisation
An RVC event is characterized by four parameters: start time, duration, ∆Umax and
∆Uss.
RVC Threshold
Arithmetic mean
of the previous
100/120 U
RMS(
½
)
values
DIP Threshold
RVC threshold
with 50% hysteresis
U
RMS(
½
)
values
Δ
Uss
Δ
Umax
Time
V
o
lt
ag
e
U
R
M
S
RVC event duration
100/120
U
RMS(
½
)
Figure 5.13: RVC event description
Start time
of an RVC event is time stamp when
U
Rms(1/2)
value cross
RVC
threshold
level
RVC event
duration
is 100/120 half cycles shorter than the duration between
adjacent steady states voltages.
∆Umax
is the maximum absolute difference between any of the
U
Rms(1/2)
values during the RVC event and the final arithmetic mean 100/120
U
Rms(1/2)
value just prior to the RVC event. For poly-phase systems,
the ∆Umax is the
largest ∆Umax on any channel.
