Alstom SHPM 101 - Page 161

SERVICE MANUAL R5888C
QUADRAMHO Chapter 2
Appendix A
Page 25 of 71
Figure 24: Block diagram board ZH0736
Summing
circuitry
Input amplifier
and low
pass filter
Voltage
comparator
Drop off
timer
Zero sequence voltage
level detector output
‘A’ phase
‘B’ phase
‘C’ phase
High gain
amplifier
Input amplifier
and low
pass filter
Voltage
comparator
Drop off
timer
‘A’ phase high set current
level detector output
Replica‘A’
phase
High gain
amplifier
Input amplifier
and low
pass filter
Voltage
comparator
Drop off
timer
High gain
amplifier
Input amplifier
and low
pass filter
Voltage
comparator
Drop off
timer
Replica‘B’
phase
Replica‘C’
phase
‘B’ phase high set current
level detector output
‘C’ phase high set current
level detector output
Input
protection
Optically
coupled isolator
Time
delay
Fault
detected
by DEF
Fault detected by DEF
optical isotator output
Input
protection
Optically
coupled isolator
Time
delay
Circuit
breaker
open
Circuit breaker open
optical isolator output
Input
protection
Optically
coupled isolator
Time
delay
Block Z2T
and Z3T
Block Z2T and Z3T
optical isolator output
Input
protection
Optically
coupled isolator
Time
delay
Carrier channel in service
optical isolator output
Input
protection
Optically
coupled isolator
Time
delay
Carrier signal receive
optical isolator output
Carrier
channel
in service
Carrier
signal
receive
Power swing
(from scheme
logic)
S1A
Block zone 1 comparators
S1B
Block zone 2 comparators
S1C
Block zone 3 comparators
Power swing contact
S1D
Power
swing
indication
Power swing
indication
(from scheme logic)
Option switch 9
(to scheme logic)