SERVICE MANUAL R5888C
QUADRAMHO Chapter 2
Page 11 of 74
constructed by logically ‘AND’ing the outputs of a forward main comparator
and a reverse main comparator. Both comparators are inhibited by the side
lines QINHZ3 which are generated on the Z1/Z2 comparator board.
4.9 Scheme logic module RCL 10
General
The complete Quadramho scheme logic is contained in one 10" x 2" module.
This module consists of two circuit boards and one interboard screen:
a) The left hand board is the scheme logic microcontroller board which contains
the microcontroller, expansion input and outputs, four switch banks, eight LED
indications, the interconnecting wiring on the two code switches and the socket
SK1.
b) The right hand board contains the five opto-isolators, three high set phase
current level detectors, the zero sequence voltage level detector used by the VTS
and also the power swing components which consist of the four way switch
bank and the PSB LED. See Figure 24.
c) The centre board is a blank board with copper plating on one side; this board
is earthed and forms a screen between the opto inputs and the scheme logic.
4.9.1 Scheme logic functions
The scheme logic performs the following functions:
a) Provides five standard schemes, these are Basic, Permissive Underreach,
Permissive Overreach, Blocking and Zone 1 extension which are selectable by
using the code switches.
b) Switch onto fault logic.
c) Voltage transformer supervision.
d) Selectable power swing blocking logic.
e) Synchronous polarising.
f) Time delayed Zone 2 and Zone 3 tripping.
g) Block auto reclose logic.
h) Indications logic.
i) Fault locator logic.
j) Pole dead logic.
k) Comparator level detector checks.
l) Band pass filter switching logic.
m) Amplitude and angular hysteresis control.
n) Tripping and latching logic.
o) Selectable minor options.
p) Self test features.
q) Processor fail monitor.
r) Relay inoperative alarm
s) Comprehensive test options.
The majority of these features are described in Section 5.16
To Next Page
Loading...