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If T2ø type and/or T2G Type was selected as Torque Control:
(selection of the CO Inverse time settings)
2.3.3
Zone3 Trip
For Zone3 phase faults, the Zone3Ø will identify the faults and operate the Zone3
phase timer T3P, in the forward or reverse direction, depending on the Zone3 setting.
The Zone3Ø (Z3P) output plus the T3P timer output satisfy AND-20 (as shown in Fig-
ure 2-7). The AND-20 output provides time delay trip signal TDT via OR-3. Signal TDT
picks up OR-4 (Figure 2-5) and operates the trip relay. The tripping and targeting are
similar to Zone1 trip, except for the Zone3 phase time delay trip indicator Zone3Ø.
For Zone3 single-phase-to-ground faults, Zone3G identifies the fault and operates.
This, plus the operation of the IOM, satisfies AND-7; the TDT signal then trips via OR-
3 with Zone3 ground time delay trip indicator (Z3G). The TDT signal can be connected
to the reclosing block logic. For security, the (Z3G) unit is also supervised by the signal
of FDOG when it is set for forward looking (or by the signal of RDOG when it is set for
reverse looking) via logic OR-171B, AND-171C or AND 171D (as shown in Figure 2-7).
A similar operation for ØØG faults (shown in Zone2), is applied to Zone3, through OR-
170, (T3P) and AND-20 gates.
The settings for Zone3 timers (phase and ground units) are independent, as follows:
• T3Ø(T3P) Zone3 phase
• T3G (T3G) Zone3 ground
Either or both Zone3 phase and Zone3 ground function(s) can be disabled by setting
Zone3Ø (Z3P) and/or Zone3G (Z3G) to the (OUT) position or by setting (T3P) and/or
(T2G) to Block.
2.3.4
Zone1 Extension
This scheme provides a higher speed operation on end Zone faults without the appli-
cation of pilot channel.
If the REL 301/302 functional display "SystType" is set on Z1 Extension position, the
Zone1Ø/Zone1G unit will provide two outputs: one is overreach which is set at 1.25 x
(10/94)
Table 5:
T2ø CV and
C0-2; C0-5; C0-6; C0-7;
T2G CV
C0-8; C0-9; C0-11
Table 6:
T2ø PkUp and
0.5 to 10.0 Amperes
T2G PkUp
0.5 to 10.0 Amperes
Table 7:
T2ø TC and
T2G TC
0.1 to 9.99 seconds or Block
0.1 to 9.99 seconds or Block
1-63
1-63
I.L. 40-386.3
2-5
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