For example if the maximum primary current is 50 kA:
● If the CT ratio is set to 1000:1 the converted secondary current is up to 50 A. This is less than 64 A so is
acceptable.
● If the CT ratio is set to 500:1 the converted secondary current is up to 100 A. This is above 64 A so is not
acceptable.
4.6 IED ALARMS
Sampled Value IEDs have additional alarms.
9-2 Configuration Alarm (9-2 Sample Alarm)
This alarm is raised if analogue channels in the IED are assigned incorrectly (Illegal Channel Map). For example, if
you assign two current inputs to the same Logical Node.
Sampled Value quality alarm (9-2LE Cfg Alarm)
This alarm is raised if any of the following conditions exist:
● One or more of the Sampled Value frames received are not synchronised as required by the IED
configuration.
● One or more of the Sampled Value frames expected are not received.
● One or more of the Sampled Value frames received are of Invalid quality.
● One or more of the Sampled Value frames received are of Questionable quality and the IED is configured not
to accept such Sampled Value frames.
● One or more of the Sampled Value frames received has a test flag, and the IED is configured to inhibit
protection functions when receiving frames with a test flag.
● One or more of the Sampled Value frames received does not have a test flag, and the IED is configured to
receive only frames with a test flag.
● Sampled Values received have a nominal frequency different to that set in the IED.
● The secondary current or voltage exceeds the acceptable limit.
4.6.1
P446, P546, P841B ALARMS
Sampled Value global synchronisation alarm (GLOBALAV_SYN_FAIL)
This alarm is raised if the global synchronisation for Sampled Values has failed, inhibiting the current differential
function.
Inverse settings alarm (ALARM_INV_SETTING_SAV)
This alarm is raised if Phase Diff is set to Enabled but GPS Sync is set to GPS disabled.
4.6.1.1 ALARM SIGNAL SETTINGS
MENU TEXT Col Row Default Setting Available Setting
Description
Process Bus Alarm 18 45 Self Reset Self-Reset, Alarm Latched
This alarm shows there is an error on the Process Bus.
SAV Absence 18 51 00000000
This is a data cell with 8 binary flags. It shows the presence or absence of Sampled Values from each of the Merging Units the
IED is communicating with. There is a maximum of 8 Logical Nodes. The cell data for each Logical Node is continuously
refreshed.
0: No Sampled Values being received from the Merging Unit.
1: Sampled Values being received from the Merging Unit.
Chapter 6 - Sampled Value Operation P446SV
102 P446SV-TM-EN-1
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