Schweitzer Engineering Laboratories SEL-700G Series, Instruction Manual

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H.18
SEL-700G Relay Instruction Manual Date Code 20170814
Synchrophasors
IEEE C37.118 PMU Setting Example
controls the PMU functions of the SEL-700G, with IEEE C37.118 commands,
including commands to start and stop synchrophasor data transmission, and
commands to request a configuration block from the relay, so the
synchrophasor processor can automatically build a database structure.
The SEL-700G does not begin transmitting synchrophasors until an enable
message is received from the synchrophasor processor. The relay stops
synchrophasor transmission when the appropriate command is received from
the synchrophasor processor. The SEL-700G can also indicate when a
configuration change occurs, so the synchrophasor processor can request a
new configuration block and keep its database up-to-date.
The SEL-700G only responds to configuration block request messages when
it is in the non-transmitting mode.
IEEE C37.118 PMU Setting Example
A utility is upgrading its system to use the SEL-700G Relay for power-system
state measurement. The utility also wants to install phasor measurement units
(PMUs) in each substation to collect data to monitor voltages and currents
throughout the system.
The PMU data collection requirements call for the following data, collected at
10 messages per second:
➤
Frequency
➤
Positive-sequence voltage from the generator
➤
Three-phase, positive-sequence, and neutral current for the
generator
➤
Indication when the breaker is open
➤
Indication when the voltage or frequency information is
unusable
The utility is able to meet the requirements with the SEL-700G for the
generator, an SEL-2407 Satellite-Synchronized Clock, and an SEL-3306
Synchrophasor Processor in each substation.
This example covers the PMU settings in the SEL-700G relays. Some system
details:
➤
The nominal frequency is 60 Hz.
➤
The generator PTs and wiring have a phase error of 4.20 degrees
(lagging) at 60 Hz.
➤
The generator CTs and wiring have a phase error of 3.50 degrees
(lagging) at 60 Hz.
➤
The neutral CTs and wiring have a phase error of 3.50 degrees
(lagging) at 60 Hz.
➤
The synchrophasor data use Port 3, and the maximum data rate
allowed is 19200 bps.
➤
The system designer specifies integer numeric representation for
the synchrophasor data, and rectangular coordinates.
➤
The system designer specifies integer numeric representation for
the frequency data.
➤
The system designer specifies C37.118 synchrophasor response,
because the data are being used for system monitoring.