GE L30 Instruction Manual page 240

5.4 SYSTEM SETUP
b) IN-ZONE TRANSFORMER

PATH: SETTINGS SYSTEM SETUP
 IN-ZONE
 TRANSFORMER
The in-zone transformer settings described below ensure that the 87L element correctly applies magnitude and phase
compensation for the in-zone transformer. To accommodate for the difference in CT ratios at line terminals, the

GROUPED ELEMENTS
setting should be used. It is important to properly program the in-zone transformer setting for all terminals to
DIFF CT TAP
ensure correct 87L performance.
• IN-ZONE TRANSFORMER CONNECTION: This setting is used to indicate the presence and group connection of the
in-zone transformer. The winding angle selection specifies the phase shift of the remote terminal side winding with
respect to the local terminal side winding. For example, for the Dy1 group where the delta winding is connected to the
local terminal side, and wye winding is connected to the remote terminal side, you need to select "30° lag" for the local
terminal side. (At the remote terminal relay, select "330° lag" for this transformer group connection.) If there is no in-
zone transformer connected, then program this setting as "None" (note that the "0° lag" value does not correspond to
"None"). Only one in-zone transformer is allowed for both two-terminal and three-terminal applications. Enabling in-
zone transformer functionality forces the L30 to automatically remove the zero-sequence component from all terminals
currents. It also disables ground differential 87LG functionality and zero-sequence current removal functionality
defined by the
ZERO SEQ CURRENT REMOVAL
• TRANSFORMER LOCATION: This setting selects the transformer location and is applicable only if the
5
setting is not programmed as "None".
CONNECTION
– Select the "LOCAL-TAP" value if the transformer is present between the local terminal and the tap point or for two-
terminal applications.
– Select the "REM1-TAP" if the transformer is present between remote terminal 1 and the tap point.
– Select the "REM2-TAP" if the transformer is present between remote terminal 2 and the tap point.
Figure 5–22: ILLUSTRATION OF IN-ZONE TRANSFORMER FOR TWO-TERMINAL AND THREE-TERMINAL LINES
When the L90 ordered has in-zone functionality, it does not support the multi-ended fault locator.
Do not set the
NOTE
value other than "None." 87L is blocked under these circumstances.
5-100

87L POWER SYSTEM
IN-ZONE TRANSFORMER
CONNECTION: None
TRANSFORMER LOCATION:
MESSAGE
LOCAL-TAP
 
SETTING GROUP 1(6) LINE DIFFERENTIAL ELEMENTS
setting.
IN-ZONE TRANSFORMER CONNECTION
L30 Line Current Differential System

IN-ZONE TRANSFORMER
Range: None, 0 to 330° lag in steps of 30°
Range: LOCAL-TAP, REM1-TAP, REM2-TAP

CURRENT DIFFERENTIAL
setting to "None" at one terminal and set other terminals to a
5 SETTINGS
SETTINGS

CURRENT
TRANSFORMER
GE Multilin