Date Code 20151029 Protection Manual SEL-411L Relay
Section 13
P.Protection Manual
Time-Synchronized Measurements
The relay records power system events with very high accuracy when you
provide high-accuracy clock input signals, such as from a GPS receiver.
Relays placed at key substations can give you information on power system
operating conditions in real time.
Based on the high-accuracy time input, the relay calculates synchrophasors for
currents and line voltages (for each phase and for positive-sequence), as
specified in C37.118, IEEE Standard for Synchrophasors for Power Systems.
You can then perform detailed analysis and calculate load flow from the
synchrophasors.
See Section 6: Synchrophasors in the Communications Manual for more
information about phasor measurement functions in the relay.
This section presents details on these measurements as well as suggestions for
further application areas. The topics of this section are the following:
➤ Relay Configuration for High-Accuracy Timekeeping on
page P.13.1
➤ Fault Analysis on page P.13.11
Relay Configuration for High-Accuracy Timekeeping
The relay features two IRIG-B timekeeping modes, IRIG and high-accuracy
IRIG, called HIRIG.
The relay must be in the HIRIG mode in order for the synchrophasor features
to operate.
Configuring High-Accuracy Timekeeping
The relay features high-accuracy timekeeping when supplied with an IRIG-B
signal. When the supplied clock signal is sufficiently accurate, the relay can
act as a phasor measurement unit (PMU) and transmit synchrophasor data
representative of the power system at fixed time periods to an external data
processor. The relay can also record COMTRADE event report data using the
high-accuracy time stamp. See Events Directory on page C.1.16 for details on
these applications.
IRIG-B
The relay has two input connectors that accept IRIG-B (Inter-Range Instrumentation
Group-B) demodulated time-code format: the IRIG-B pins of Serial Port 1, and the
IRIG-B BNC connector—see TIME Inputs on page P.2.9.
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