10.3.11 Technical data
Table 1640: 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 (ANSI PQMV UB)
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 978: 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
1MRS759142 F
1848 REX640
Technical Manual
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