If the “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. 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 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” 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
0
when the impedance exits the outer blinder, the dynamic Trip
delay, T
od
, can be set as shown in
Equation 128.
T
f T BrkropenTm
f
od
slip co
slip
=
− ⋅ ⋅ +
⋅
1 2
2
( )
GUID-43B1AF3E-06F3-44C6-AA3F-AD0F8EF18FE6 V1 EN (Equation 128)
T
od
Dynamic Trip delay
T
co
The time for the impedance to travel from the center impedance line (where the swing angle is π
radians) to the outer blinder on the opposite side from which it entered.
BrkopenTm Set
Breaker open time
f
slip
Slip frequency
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
Equation 129.
Section 4 1MAC059074-MB A
Protection functions
690 615 series ANSI
Technical Manual
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