Schweitzer Engineering Laboratories SEL-311L Instruction Manual page 43

1. Voltage Channel VS does not need to be connected. It is used only in voltage and synchronism check
elements and voltage metering.
2. In this example, current Channel IP provides current polarization for a directional element used to control
ground elements.
Figure 2.12: SEL-311L Relay Provides Line Current Differential, Backup Distance and
Overcurrent Protection, and Reclosing for a Transmission Line
(Current
Date Code 20010625
Polarization Source Connected to Channel IP; Setting APP= 311L)
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Installation
SEL-311L Instruction Manual
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