SERVICE MANUAL R5888C
QUADRAMHO Chapter 2
Page 69 of 74
6.10 Timer setting ranges
Zone 2 timer tZ
2
0 to 2.55s in 10ms steps
Zone 3 timer tZ
3
0 to 5.1s in 40ms steps
Scheme timer t
p
0 to 90ms in 6ms steps
Scheme timer t
D
0 to 90ms in 6ms steps.
Timer settings are by a series of switches arranged in a binary series. The time
delay associated with each switch is effective only when the switch is set to the
right hand position.
Formula Link Positions Available
t
Z2
=(∑
t2
) ms t
2
= 10, 20, 40, 80, 160, 320, 640 & 1280
t
Z3
=(∑
t3
) ms t
3
= 40, 80, 160, 320, 640, 1280, 2560 & ∞
t
p
=(∑t
p
) ms t
p
= 6, 12, 24 & 48
t
D
=(∑t
d
) ms t
d
= 6, 12, 24 & 48
6.11 Polarising
Proportion and type of cross polarising for Zones 1 and 2 partially cross polarised
mho and for Zones 1 and 2 directional lines.
Phase-earth faults
Phase-phase-earth faults 16% square wave from healthy phases
Phase-phase faults
Three phase faults – 16% square wave from synchronous
polarising system
Synchronous polarising is effective for 8 cycles after fault incidence.
Synchronous polarising start up time is 140ms from energisation of line.
6.12 Switch-on-to-fault
The switch-on-to-fault system is enabled either 200ms or 110s (as selected by a
switch SW2) after all poles of the line have been de-energised and remains active
for 240ms after the line has been energised.
Switch-on-to-fault tripping is by any Z1/Z2/Z3 comparators or voltage and current
level detectors (as selected by a switch SW1 on the front of the relay).
Voltage level detector setting: 44.5V phase-earth (70% V
n
)
Current level detector setting: 0.05
I
n
x 4.8/(K1 + K2)
Condition for fault detection: Current level detector operated and voltage
level detector not operated, on any phase,
for 20ms.
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