PU_37
=
70%
(of
IBase
); Current level for undercurrent pickup
tUC
=
5s
; Time delay for undercurrent trip
Undercurrent feature is blocked by operation of Reconnection inhibit
feature.
Reactive power overload feature:
Operation QOL
=
Enabled
; to enable this feature
UP_QOL
=
130%
(of SCB MVAr rating); Reactive power level required for pickup.
Selected value gives pickup recommended by international standards.
tQOL
=
60s
; Time delay for reactive power overload trip
Harmonic voltage overload feature
:
OperationHOL
=
Enabled
; to enable this feature
Settings for definite time delay step
HOL_DT_V
=
200%
(of SCB voltage rating); Voltage level required for pickup
tHOL_DT
=
10s
; Definite time delay for harmonic overload trip
Settings for IDMT delay step
PU_HOL_DT_V
=
110%
(of SCB voltage rating); Voltage level required for pickup of
IDMT stage. Selected value gives pickup recommended by international standards.
k_HOL_IDMT
=
1.0
; Time multiplier for IDMT stage. Selected value gives operate
time in accordance with international standards
tMax_HOL_IDMT
=
2000s
; Maximum time delay for IDMT stage for very low level of
harmonic overload
tMin_HOL_IDMT
=
0.1s
; Minimum time delay for IDMT stage. Selected value gives
operate time in accordance with international standards
9.15.3.1
Restrike detection
GUID-114747A5-0F7C-4F48-A32D-0C13BFF6ADCE v1
Opening of SCBs can be quite problematic for certain types of circuit breakers (CBs).
Typically such problems are manifested as CB restrikes.
1MRK 504 163-UUS A
Section 9
Current protection
Transformer protection RET670 2.2 ANSI
599
Application manual
Summary of Contents for RELION RET670
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