GE Power Management
745 Transformer Management Relay
5-5
5 SETPOINTS
5.2 AUTO-CONFIGURATION
5
Tap changers are operated by means of a motor drive unit mounted on the outside of the transformer tank. The
motor drive is placed in a protective housing containing all devices necessary for operation, including a tap
position indication circuit. This indication circuit has a terminal for each tap with a fixed resistive increment per
tap. A cam from the drive shaft that provides local tap position indication also controls a wiper terminal in the
indication circuit, as illustrated below.
Figure 5–1: TAP POSITION INPUT
The “zero position” terminal and the “wiper” terminal of the tap position circuit are connected to the positive and
negative 745 tap position terminals. Polarity is not consequential. The following setpoints configure the 745 to
determine tap position.
Under
S2 SYSTEM SETUP / ONLOAD TAP CHANGER
:
WINDING WITH TAP
CHANGER: Winding 2
NUMBER OF TAP
POSITIONS: 33
MINIMUM TAP POSITION
VOLTAGE: 61.0 kV
VOLTAGE INCREMENT
PER TAP: 0.50 kV
RESISTANCE INCREMENT
PER TAP: 33
Ω
Maximum value resistance on top tap is 5 K
Ω
ZERO
POSITION
TAP 1
TAP 2
TAP 3
TAP 4
TAP 6
TAP 7
TAP 8
TAP 9
etc.
WIPER
AT TAP 5
R
R
R
R
R
R
R
R
R
ZERO POSITION
TERMINAL
(to TAP POSITION -)
WIPER
TERMINAL
(to TAP PO)
Summary of Contents for 745 TRANSFORMER MANAGEMENT RELAY
Page 30: ...2 8 745 Transformer Management Relay GE Power Management 2 3 SECURITY 2 GETTING STARTED 2 ...
Page 210: ...7 36 745 Transformer Management Relay GE Power Management 7 2 BLOCK DIAGRAMS 7 SCHEME LOGIC 7 ...
Page 322: ...9 12 745 Transformer Management Relay GE Power Management 9 3 USING 745PC 9 745 PC SOFTWARE 9 ...
Page 396: ...A 4 745 Transformer Management Relay GE Power Management A 1 FIGURES AND TABLES APPENDIXA A ...
Page 400: ...C 2 745 Transformer Management Relay GE Power Management C 1 WARRANTY INFORMATION APPENDIXC C ...
Page 406: ...vi 745 Transformer Management Relay GE Power Management ...
Page 407: ...GE Power Management 745 Transformer Management Relay NOTES ...