5.4.14. Sequence voltage U1/U2>/<(59P/27P/47)
Sequence voltage function (VUB) is used for instant- and time delayed voltage protection for various
feeder, machine, utility and industry applications. It has positive- and negative sequence over- and
under voltage protection of which user chooses the needed function. Each IED with voltage protection
module has four available instances of the function. Function constantly measures fundamental
frequency components of phase to earth voltage magnitudes or line- to line and neutral voltage
magnitudes to calculate the positive or negative sequence voltage. Used voltage is user selectable.
VUB protection is based on system line- to line voltage level. Protection stages can be set to protect
against under- or overvoltage. Blocking signal and setting group selection controls the operating
characteristics of the function during normal operation.
Positive sequence voltage calculation
Below is presented the formula for symmetric component calculation and therefore to VUB positive
sequence calculation.
See positive sequence calculation examples below.
Figure. 5.4.14. - 81. Positive sequence component vector examples.
Earth fault in isolated network.
AQ-F255
Instruction manual
Version: 2.00
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