Date Code 20171006 Instruction Manual SEL-400 Series Relays
Instruction ManualInstruction Manual
SECTION 18
Synchrophasors
Most SEL-400 series relays can be configured to function as a phasor measure-
ment unit (PMU).
This section covers:
➤ Synchrophasor Measurement on page 18.3
➤ Settings for Synchrophasors on page 18.6
➤ Synchrophasor Quantities on page 18.18
➤ View Synchrophasors by Using the MET PM Command on
page 18.21
➤ C37.118 Synchrophasor Protocol on page 18.23
➤ SEL Fast Message Synchrophasor Protocol on page 18.29
➤ Control Capabilities on page 18.33
➤ PMU Recording Capabilities on page 18.42
Introduction
The word synchrophasor is derived from two words: synchronized phasor. Syn-
chrophasor measurement refers to the concept of providing measurements taken
on a synchronized schedule in multiple locations. A high-accuracy clock, com-
monly a Global Positioning System (GPS) receiver such as the SEL-2407 Satel-
lite-Synchronized Clock, makes synchrophasor measurement possible.
The availability of an accurate time reference over a large geographic area allows
multiple devices, such as a number of relays, to synchronize the gathering of
power system data. The accurate clock allows precise event report triggering and
other offline analysis functions.
The Global settings class contains the synchrophasor settings, including the
choice of Synchrophasor Protocol and the synchrophasor data set the relay will
transmit. The Port settings class selects which port(s) are configured for Synchro-
phasor Protocol use.
The high-accuracy timekeeping function generates status Relay Word bits and
time-quality information that is important for synchrophasor measurement. Some
protection SEL
OGIC variables, and programmable digital trigger information
(C37.118 protocol only) is also added to the Relay Word bits for synchrophasors
(see Synchrophasor Relay Word Bits).
When synchrophasor measurement is enabled, the relay creates the synchropha-
sor data set at a rate of either 50 or 60 times per second, depending on the nomi-
nal system frequency (Global setting NFREQ). This dataset, including time-of-
sample, is available in analog quantities in the relay (see Synchrophasor Analog
Quantities). You can view synchrophasor data over the relay ASCII terminal
interface (see View Synchrophasors by Using the MET PM Command on
page 18.21).
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