10.30
SEL-421 Relay Instruction Manual Date Code 20171021
Communications Interfaces
Synchrophasors
Synchrophasors
General synchrophasor operation is described in the Section 18: Synchrophasors
in the SEL-400 Series Relays Instruction Manual. This section describes charac-
teristics of synchrophasors that are unique to the SEL-421.
The SEL-421 has 6 current channels and 6 voltage channels. Current Terminals
W, X and voltage terminals Y, Z are three-phase channels. The PMU combines
channels W and X to create a pseudo Terminal S.
From these 12 channels, the PMU can measure as many as 20 synchrophasors; 15
phase synchrophasors, and 5 positive-sequence synchrophasors. Synchrophasors
are always in primary, so set the CT and PT ratios in the group settings appropri-
ately. Note that CTRW applies to all the channels in Terminal S.
Table 10.17 shows the voltage synchrophasor name, enable conditions and the PT
ratio used to scale to the Primary values.
Table 10.18 shows the current synchrophasor names, enable conditions, and the
CT ratio used to scale to the Primary values.
Table 10.19 describes the order of synchrophasors inside the data packet when
operating in legacy mode (LEGACY = Y).
Table 10.17 Voltage Synchrophasor Names
Phasor Name Phasor Enable Conditions PT Ratio
V1YPM PHDVq = V1 or ALL AND Terminal Y included PTRY
VAYPM PHDVq = PH or ALL AND Terminal Y included PTRY
VBYPM PHDVq = PH or ALL AND Terminal Y included PTRY
VCYPM PHDVq = PH or ALL AND Terminal Y included PTRY
V1ZPM PHDVq = V1 or ALL AND Terminal Z included PTRZ
VA Z P M P H D V q = PH or ALL AND Terminal Z included PTRZ
VBZPM PHDVq = PH or ALL AND Terminal Z included PTRZ
VCZPM PHDVq = PH or ALL AND Terminal Z included PTRZ
Table 10.18 Current Synchrophasor Names
Phasor Name Phasor Enable Conditions CT Ratio
I1SPM PHDIq = I1 or ALL AND Terminal S included CTRW
IASPM PHDIq = PH or ALL AND Terminal S included CTRW
IBSPM PHDIq = PH or ALL AND Terminal S included CTRW
ICSPM PHDIq = PH or ALL AND Terminal S included CTRW
I1WPM PHDIq = I1 or ALL AND Terminal W included CTRW
IAWPM PHDIq = PH or ALL AND Terminal W included CTRW
IBWPM PHDIq = PH or ALL AND Terminal W included CTRW
ICWPM PHDIq = PH or ALL AND Terminal W included CTRW
I1XPM PHDIq = I1 or ALL AND Terminal X included CTRX
IAXPM PHDIq = PH or ALL AND Terminal X included CTRX
IBXPM PHDIq = PH or ALL AND Terminal X included CTRX
ICXPM PHDIq = PH or ALL AND Terminal X included CTRX
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