ABB RELION REX640 Technical Manual page 932

Section 4
Protection functions
926
slip counter is incremented after the set Operate delay time has elapsed. If the slip
counter value is equal to the set number of slips in the respective enabled zone, the
OPERATE output is activated. If the swing impedance passes through both zone 1 and
zone 2, only the zone 1 slip counter is incremented. The zone 2 slip counter is
incremented if the impedance passes through the Mho circle but only through the zone
2 portion. The zone 3 slip counter is incremented if the impedance misses the Mho
circle entirely and the setting Zone 3 enable is also set to "Yes". Increment of the slip
counter triggers also the Reset timer. All of the zone slip counters reset after the set
Reset time has elapsed and the impedance does not cross into the outer blinder again,
or on activation of the OPERATE output.
When the "Way out" or "Adaptive" option is selected, the breaker open time, if
known, can be incorporated to optimize breaker trip time when a way out trip
command is issued. The ideal time for the breaker to interrupt current is when the
swing angle approaches zero. If the swing angle is δ
outer blinder, the dynamic Trip delay, T
1 2 f ( T BrkropenTm
− ⋅ ⋅ +
slip co
T
=
od
2 f
⋅
slip
GUID-32D8985D-B625-4C19-8C77-983D0B72E707 V1 EN
T Dynamic Trip delay
od
T The time for the impedance to travel from the center impedance line (where the swing
co
angle is π radians) to the outer blinder on the opposite side from which it entered.
Breaker open time
BrkopenTm Set
f Slip frequency
slip
The Breaker open time setting should include the time from when the relay issues a
trip command to the time when the breaker receives the command. The function uses
the Breaker open time setting to determine the trip delay time if it is not set to "0". If the
Breaker open time is set to "0", the function does not dynamically calculate a trip delay
but uses the fixed Operate delay time before activating the OPERATE output.
The slip frequency is calculated using
δ δ
−
i
0
f
=
slip
T
2
π
⋅ ⋅
oi
GUID-AAF711D1-8B47-4C8A-AB1C-CAA4A9495075 V1 EN
f Slip frequency
slip
T The time for the impedance to pass from the outer to the inner blinder.
oi
δ Swing angle at the outer blinder
0
δ Swing angle at the inner blinder
I
when the impedance exits the
0
, can be set as shown in
od
)
Equation 230.
1MRS759142 C
Equation 229.
(Equation 229)
(Equation 230)
REX640
Technical Manual