U.6.4
SEL-421 Relay
User’s Guide
Date Code 20090715
Testing and Troubleshooting
Testing Features and Tools
Testing Features and Tools
The SEL-421 provides the following features to assist you during relay
testing:
➤
Metering
➤
High-resolution oscillography
➤
Event reports
➤
Event summary reports
➤
SER (Sequential Events Recorder) reports
Certain relay commands are useful in confirming relay operation. The
following commands, for example, aid you in testing the relay:
➤
TAR
➤
PUL
➤
TEST DB
➤
TEST FM
➤
TEST DNP
In addition, the SEL-421 incorporates a low-level test interface where you can
interrupt the connection between the relay input transformers and the input
processing module. Use the low-level test interface to apply reduced-scale test
quantities from the SEL-4000 Relay Test System; you do not need to use large
power amplifiers to perform relay testing.
Test Features
Metering
The metering data show the ac currents and voltages (magnitude and phase
angle) connected to the relay in primary values. In addition, metering shows
many other quantities including the power system frequency (FREQ) and the
voltage input to the station dc battery monitors (Vdc1 and Vdc2). Compare
these quantities against quantities from other devices of known accuracy. The
metering data are available at the serial ports, from the
AC
SEL
ERATOR
QuickSet
®
SEL-5030 software HMI, and at the front-panel LCD
METER
menu.
,
, and
Examining Metering Quantities on page U.4.33
for more
information.
High-Resolution Oscillography
The SEL-421 takes an unfiltered data snapshot of the power system at each
event trigger or trip. The relay samples power system data at high sample rates
from 1 kHz to 8 kHz. You can use the SEL-5601 Analytic Assistant or other
COMTRADE viewing program to export and view these raw data in a binary
COMTRADE file format. Use high-resolution oscillography to capture fast
power system transients or to examine low frequency anomalies in the power
system. See
Raw Data Oscillography on page A.3.8
for more information.
NOTE:
Control Inputs are sampled
16 times per cycle, and the raw binary
data (prior to debounce timer
conditioning) is available in high-
resolution oscillography—see
. The
COMTRADE data labels for raw
control input data are IN101–IN107,
and optionally IN201–IN2nn, IN301–
IN3nn, where nn = 01–08 or 01–24.
Summary of Contents for 421
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