ABB Modures LZ92-1 User Manual

The operating mode is set on the main processing unit KZ91-1 with the aid of
switch 1 (Fig. 9.23). This switch has four sections which have to be set in
accordance with Table 3 .1. 'l'he same information is printed on the frontplate
behind the withdrawing handle (Fig. 9.8).
~·
switch
section *
Mode
-
No.
1
No. 2 No.
3 No.
4
Phase preference Setting
OFF ON ON OFF
grounded systems
±
OFF OFF
ON
OFF
R'rS acyclically RTS acyc.
ON ON OFF OFF
RTSR cyclically R'l'SR eye.
OFF ON OFF OFF TRS acyclically
TRS acyc.
ON OFF OFF OFF
TRS'l' cyclically TRST eye.
ON OFF
ON OFF TSR acyclically TSR acyc.
ON ON
ON
ON
RST acyclically RST acyc.
OFF
OFF OFF
OFF
STR
acyc lie ally
**
STR acyc.
OFF
OFF OFF ON
SRT
a<:Y_<:l_i_~~l _ _1-y
**
SRT acyc.
* In position "ON" the white lever is toward the PCB.
** Only for units with the designation "AEND. :B" on PCB 1.
Table 3.1 - Positions of the switch sections of switch 1 on PCB 1 of unit
KZ91-1 in relation to operating mode
3.2 Setting the starting units
3.2.1 Overcurrent starting
6
The pick-up setting of the overcurrent uni ts must be at the very least so
high that it cannot be reached by the maximum current in healthy phases. The
following must be taken into account when calculating this current:
- In the case of double-circuit lines the load current can briefly double
when one line is tripped.
- An additional balancing current IA can flow in the healthy phases during
earth faults.
A relay which has picked up must also be able to reset at the level of the
maximum load current I after a fault has been tripped in the first zone
Bmax .
of another relay. Taking the reset ratio and accuracy of the relay into
account, the lowest permissible setting is given by:
lr;max +~I
~~~~~~~- + 0.06
The maximum pe.rmissible setting (I/I ) is calculated from the minimum
fault current IK for a fault at the rerWo.r~xend of the next section of line.
(

ABB Modures LZ92-1 Specifications

General

Brand	ABB
Model	Modures LZ92-1
Category	Relays
Language	English