Voltage Measurement Mode - Allen-Bradley 857 Quick Start Manual

Chapter 2 Mounting and Wiring Instructions

Voltage Measurement Mode

20
Table 10 - Terminal X6 with DI19/DI20 Option
No:
1
2
3
4
5
6
7
(1) Arc sensor itself is polarity free.
The 857 Protection System can be connected to line-to-line or phase-to-
ground voltages. The connection is dependent on the application and available
voltage transformers. Set the configuration parameter "Voltage measurement
mode" according to the used connection.
Table 11 - Available Voltage Modes
Mode Description
"2LL+U " The device is connected to line-to-line voltages U
0
X1-14). Also to zero sequence voltage U
voltages are calculated. The network must use only three wires. Any neutral wire must not
exist (two PTs/VTs in open Delta).
"3LN" The device is connected to phase-to-ground voltages U
and X1-14), and U
wire can exist (three PTs/VTs "Y" connected).
"1LL+U /LLy" This mode is used with the Synchrocheck function. See
0
(25) of the user guide for more information.
2LL/LLy" This mode is used with the Synchrocheck function. See
(25) of the user guide for more information.
"LL/LLy/LLz" This mode is used with the Synchrocheck function. See
(25) of the user guide for more information.
The overvoltage protection is based on the line-to-line voltage regardless of the
measurement mode.
The wiring of the secondary circuits of voltage transformers to the device
terminal depends on the selected voltage-measuring mode.
Rockwell Automation Publication 857-QS001B-EN-P - April 2017
Symbol Description
DI19 Digital input 19
DI19 Digital input 19
DI20 Digital input 20
DI20 Digital input 20
— —
S1>+ Arc sensor 1, positive connector
S1>– Arc sensor 1, negative connector
12
(X1-17 and X1-18). The phase-to-ground
0
(X1-17 and X1-18). The zero sequence voltage is calculated. A neutral
L3
(1)
(1)
(X1-11 and X1-12) and U (X1-13 and
23
(X1-11 and X1-12), U (X1-13
L1 L2
Chapter 3, Synchrocheck Protection
Chapter 3, Synchrocheck Protection
Chapter 3, Synchrocheck Protection