ABB RELION 620 Series Technical Manual page 513

1MAC504801-IB E
620 series ANSI
Technical Manual
If "Way out" option is selected, after detecting an OSB condition, the function further
checks if impedance exits the outer blinder. On exiting the outer blinder, Way out timer
defined by Trip delay time setting is triggered and the respective zone slip counter is
incremented after the set Trip delay time has elapsed. If the slip counter value is equal to
the set number of slips in the respective enabled zone, the TRIP output is activated.
Increment of 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 TRIP output.
When the "Way out" option is selected, the breaker open time, if known, can be
incorporated to optimize breaker trip time when a 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 when the impedance exits the outer blinder, the dynamic Trip delay, T
0
be set as shown in Equation
f ( T BrkropenTm
1 2 − ⋅ ⋅ +
slip co
T
=
od
f
2 ⋅
slip
GUID-43B1AF3E-06F3-44C6-AA3F-AD0F8EF18FE6 V1 EN
T Dynamic Trip delay
od
T The time for the impedance to travel from the center impedance line (where the swing angle is π
co
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 Trip delay time before activating the TRIP output.
The slip frequency is calculated using
−
δ δ
i
0
f
=
slip
T
2 ⋅ ⋅
π
oi
GUID-F94B7BCA-473F-42E1-95D5-EF5DF2DCC7C6 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
82.
)
Equation 83.
Section 4
Protection functions
, can
od
(Equation 82)
(Equation 83)
507