ABB Relion REG670, Technical Manual

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Table 287: OEXPVPH Group settings (advanced)
Name Values (Range) Unit Step Default Description
t1Tailor 0.00 - 9000.00 s 0.01 7200.00 Time delay t1 (longest) for tailor made
curve, in sec
t2Tailor 0.00 - 9000.00 s 0.01 3600.00 Time delay t2 for tailor made curve, in sec
t3Tailor 0.00 - 9000.00 s 0.01 1800.00 Time delay t3 for tailor made curve, in sec
t4Tailor 0.00 - 9000.00 s 0.01 900.00 Time delay t4 for tailor made curve, in sec
t5Tailor 0.00 - 9000.00 s 0.01 450.00 Time delay t5 for tailor made curve, in sec
t6Tailor 0.00 - 9000.00 s 0.01 225.00 Time delay t6 (shortest) for tailor made
curve, in sec
Table 288: OEXPVPH Non group settings (basic)
Name Values (Range) Unit Step Default Description
MeasuredU PosSeq
L1L2
L2L3
L3L1
- - L1L2 Selection of measured voltage
MeasuredI L1L2
L2L3
L3L1
PosSeq
- - L1L2 Selection of measured current
GlobalBaseSel 1 - 12 - 1 1 Selection of one of the Global Base Value
groups
9.4.6 Monitored data
Table 289: OEXPVPH Monitored data
Name Type Values (Range) Unit Description
TMTOTRIP REAL - s Calculated time to trip for
overexcitation, in sec
VPERHZ REAL - V/Hz Voltage to frequency ratio
in per-unit
THERMSTA REAL - % Overexcitation thermal
status in % of trip level
9.4.7 Operation principle
The importance of Overexcitation protection (OEXPVPH) function is growing as the
power transformers as well as other power system elements today operate near their
designated limits most of the time.
Modern design transformers are more sensitive to overexcitation than earlier types.
This is a result of the more efficient designs and designs which rely on the
improvement in the uniformity of the excitation level of modern systems. If an
emergency that causes overexcitation does occur, transformers may be damaged
Section 9
1MRK502052-UEN B
Voltage protection
518
Technical manual