Schweitzer Engineering Laboratories SEL-421-4, Instruction Manual

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18.37
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Synchrophasors
Control Capabilities
PMODC
Select the data configuration set to be sent out from that port. This setting is only
available when the PMUMODE=SERVER.
Table 18.23 shows the Global settings that need to be configured for RTC applications.
NOTE:
The maximum channel delay
is available in the COM RTC command.
Descriptions for the settings in Table 18.23 are as follows.
RTCRATE
Rate at which to expect messages from the remote synchrophasor device.
When the PMU is operating as a synchrophasor client (PMUMODE set to
CLIENTA or CLIENTB), the relay will only accept incoming messages at this
rate. Make sure the remote synchrophasor source(s) is configured to send mes-
sages at this same rate.
MRTCDLY
Selects the maximum acceptable delay for received synchrophasor messages.
When the PMU is operating as a synchrophasor client (PMUMODE set to CLI-
ENTA or CLIENTB), the relay only accepts incoming messages that are not
older than allowed by this setting. When determining an appropriate value for
this setting, consider the channel delay, the transfer time at the selected baud rate,
plus add some margin for internal delays in both the remote and local relay.
When you use the PMU for synchrophasor acquisition, the delayed and aligned
analog quantities specific to that relay are available. Be aware that these quanti-
ties are only valid when RTCROK is asserted and only for the enabled channels.
The specific channel quantities are also valid whenever their respective
RTCROK
p Relay Word bit is set (see Table 18.11 ).
When using the relay as a synchrophasor client, the Relay Word bits in
Table 18.24 indicate the state of the synchronization.
Table 18.23 Global Settings for RTC
Setting Description Default
RTCRATE Remote Messages per Second
(1, 2, 5, 10, or 50 when NFREQ := 50)
(1, 2, 4, 5, 10, 12, 15, 20, 30, or 60 when NFREQ := 60)
2
MRTCDLY Maximum RTC Synchrophasor Packet Delay (20–1000 ms) 500
Table 18.24 Synchrophasor Client Status Bits
Name Description
RTCEN p
a
Asserts for one processing interval when a valid message is received on
Channel p.
RTCROK p
a
Asserts for one processing interval when data are aligned for Channel p. Use
this bit to condition usage of the Channel p data.
RTCROK Asserts for one processing interval when data for all enabled channels are
aligned. Use this bit to condition general usage of the aligned synchrophasor
data.
RTCDLY p
a
This bit is asserted when the last received valid message on Channel p is
older than MRTCDLY.