Table 1049: PHQVVR Technical data
Characteristic Value
Operation accuracy ±1.5 % of the set value or ±0.2 % of reference voltage
Reset ratio Typically 0.96 (Swell), 1.04 (Dip, Interruption)
10.4 Voltage unbalance VSQVUB
10.4.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Voltage unbalance VSQVUB PQUUB PQVUB
10.4.2 Function block
Figure 585: Function block
10.4.3 Functionality
The voltage unbalance function VSQVUB monitors voltage unbalance conditions
in power transmission and distribution networks. It can be applied to identify a
network and load unbalance that can cause sustained voltage unbalance. VSQVUB
is also used to monitor the commitment of the power supply utility of providing a
high-quality, that is, a balanced voltage supply on a continuous basis.
VSQVUB uses five different methods for calculating voltage unbalance. The
methods are the negative-sequence voltage magnitude, zero-sequence voltage
magnitude, ratio of the negative-sequence voltage magnitude to the positive-
sequence voltage magnitude, ratio of the zero-sequence voltage magnitude to
the positive-sequence voltage magnitude and ratio of maximum phase voltage
magnitude deviation from the mean voltage magnitude to the mean of the phase
voltage magnitude.
VSQVUB provides statistics which can be used to verify the compliance of the
power quality with the European standard EN 50160 (2000). The statistics over
selected period include a freely selectable percentile for unbalance. VSQVUB also
includes an alarm functionality providing a maximum unbalance value and the date
and time of occurrence.
Power quality measurement functions
1MRS757644 H
1108 620 series
Technical Manual
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