Date Code 20170601
Instruction Manual
SEL-387-0, -5, -6 Relay
Section 5
Metering and Monitoring
Overview
The SEL-387 Relay provides metering information in several report formats
for each of the 4 three-phase winding current inputs and for the 3 differential
elements. A DC Battery Monitor reports on the supply voltage to the relay and
can be programmed to alarm for voltage excursions. There is also a Breaker
Monitor function that keeps track of breaker trips, the cumulative current
interrupted over time, and the amount of estimated contact wear. These
functions and their associated reports are discussed in this section.
Metering Functions
There are three types of fundamental frequency metering functions in the
SEL-387:
➤
Instantaneous
➤
Demand (thermal)
➤
Peak demand
Quantities metered include the following:
➤
Phase currents for all four winding inputs
➤
Positive-, negative-, and zero-sequence (residual) currents for
all four winding inputs
➤
Operate, restraint, second-harmonic, and fifth-harmonic
currents for the three differential elements
There are several report formats, employing different groups of the above
quantities, accessible by variants of the
METER
command through the relay
serial port. This information is also available at the relay front panel via the
LCD display.
There is also a specialized metering function, Harmonic Metering. It provides
a snapshot of harmonic current magnitudes in the phase currents, fundamental
through the fifteenth harmonic.
This section will discuss which quantities are used in each of the report
formats and show the format for each of the
METER
command displays, as
they would appear on the screen. The relay front-panel LCD displays the same
quantities but requires several stages of keystrokes to select the data of
interest. These displays are covered in
Section 8: Front-Panel Interface
All
METER
displays herein show the default Analog Input Labels (
IAW1
,
IBW1
,
etc.). Relay displays show the user setting values of the Analog Input Labels.
Summary of Contents for SEL-387-0
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