4.5.2.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Single-phase overvoltage protec-
tion, secondary side
PHAPTOV
U_A>
59_A
4.5.2.2
Function block
Figure 334: Function block
4.5.2.3
Functionality
The single-phase overvoltage protection function PHAPTOV is applied on power
system elements, such as generators, transformers, motors and power lines, to
protect the system from excessive voltages that could damage the insulation and
cause insulation breakdown.
PHAPTOV includes both definite time ( DT) and inverse definite minimum time
( IDMT) characteristics for the delay of the trip.
The function contains a blocking functionality. It is possible to block function
outputs, timer or the function itself, if desired.
4.5.2.4
Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of PHAPTOV can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
Figure 335: Functional module diagram
Level detector
The fundamental frequency component of the measured voltage is compared
phase-wise to the set value of the
Start value setting. If the measured value is
Protection functions
1MRS757644 H
638
620 series
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