Entec EVRC2A-N6-NT - 7.18. Time Overcurrent Curves

RECLOSER CONTROL EVRC2A-N6,NT http://www.entecene.co.kr
180
ENHANCED TECHNOLOGY
7.18. Time Overcurrent Curves
The EVRC2A is equipped Standard ANSI/IEEE curves, IEC curves, ESB curves, user-defined
curves and all 37 non standard recloser curves are available.
A Configuration setting determines whether elements set to use ANSI/IEEE curves, IEC curves,
ESB curves, user-defined curves reset instantaneously, or corresponding with electromechanical.
The operation times and reset times refer to ANSI/IEEE C37.112 and IEC 255-3.
The operation times and reset times are defined as follows :
ANSI/IEEE
Trip Time(Sec) = TD × ( (α / (M
β
-1) + γ) + TA)
IEC
Trip Time(Sec) = TD × ( (α / (M
β
-1)) + TA)
ESB
Trip Time(Sec) = TD × ( (α / (M
β
-1) + γ) + TA)
USER-DEFINED
Trip Time(Sec) = TD × ( (α / (M
β
-1) + γ) + TA)
Reset Time(Sec) = TD × (Rt / (1-M
2
))
Table 7-2. Curve Factor
TD
Time dial
TA
Time adder
α, β, γ
Characteristic constant
M
Multiples of pickup current
Rt
Reset characteristic constant
NOTE )
1) “Time Dial” and “Time Adder” settings of each Time Overcurrent(Fast/Delay) menu are
applied to Time dial(TD) and Time adder(TA) respectively.
2)
“Recloser clearing time curves”
are used when rated voltage of recloser is 15
㎸
or 27
㎸
,
otherwise which added 30
㎳
(
±
4
㎳
) are used when it is 38
㎸
.