GE 745 TRANSFORMER MANAGEMENT RELAY User Manual

6-4 745 Transformer Management Relay GE Power Management
6.3 A2 METERING 6 ACTUAL VALUES
6
6.3 A2 METERING 6.3.1 DESCRIPTION
The 745 measures all winding currents and their harmonic components as well as system frequency and volt-
age, tap changer position, ambient temperature and an auxiliary analog input channel. From these, derived
values including neutral, sequence components, differential and restraint currents, THD, harmonic derating
factors and current demand are calculated. These processed values are both displayed and used to perform
the required protection and monitoring functions.
6.3.2 CURRENT
For each monitored winding, the fundamental frequency magnitude and phase angle of phase A, B, C and
ground currents are recalculated every half-cycle for use in differential and overcurrent protection. From these
values, neutral, positive, negative and zero-sequence as well as differential, restraint and ground differential
currents are calculated. These are displayed and updated approximately twice a second for readability.
a) WINDING 1/2/3 CURRENTS
The following Actual Values messages are repeated for Windings 1, 2 and 3.
yy ACTUAL VALUES
yy A2 METERING
This is the header of Actual Values page A2 METERING. To view these
actual values press or press to go to the next page header.
y CURRENT
y [ENTER] for more
This message indicates the start of the Current actual values. To view these
actual values press or press for the next section.
y W1 CURRENT
y [ENTER] for more
This message indicates the start of the Winding 1 Current actual values
(Windings 2 and 3 are similar). To view these actual values press or
press for the next section.
W1 PHASE A CURRENT:
0A at 0°Lag
The fundamental frequency current magnitude and phase for Winding 1 (2/
3), phase A is shown. The current angle for Winding 1, phase A is always set
to zero as this angle is used as a reference for all other currents, both
measured and derived.
W1 PHASE B CURRENT:
0A at 0°Lag
This message displays the fundamental frequency current magnitude and
phase for Winding 1 (2/3), phase B.
W1 PHASE C CURRENT:
0A at 0°Lag
The fundamental frequency current magnitude and phase for Winding 1 (2/
3), phase C is displayed.
W1 NEUTRAL CURRENT:
0A at 0°Lag
This Winding displays the fundamental frequency current magnitude and
phase for winding 1 (2/3), neutral.
W1 GROUND CURRENT:
0A at 0°Lag
This message displays the fundamental frequency current magnitude and
phase for Winding 1 (2/3), ground current input, if used.
WINDING 1 LOADING:
0% of rated load
This message displays what percentage of its maximum specified load
Winding 1 (2/3) is currently carrying.
W1 AVERAGE PHASE
CURRENT: 0 A
The average phase current value in the corresponding winding is displayed.
MESSAGE
ACTUAL
ENTER
MESSAGE
ENTER
MESSAGE

GE 745 TRANSFORMER MANAGEMENT RELAY Specifications

General

Brand	GE
Model	745 TRANSFORMER MANAGEMENT RELAY
Category	Relays
Language	English