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Fail-safe operation (Hybrid EMS)
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Note
The content on this page refers only to the blue'Log XC combined with the Hybrid EMS licence.
Communication failure with a meter
For accurate active power control, the blue'Log XC relies on measured data from a connected meter. If the meter fails, or if communication is temporarily lost, the blue’Log will go into predefined error behavior.
Since the feedback signal from the grid connection point is no longer available, closed-loop control is not possible. In this case, the blue’Log switches to open-loop operation and applies the error behavior.
The error behavior is only activated after a user-defined waiting time has elapsed. During this time, it continues to control the PV and battery systems using the last values sent to the inverters.
There are two options for the error behavior:
Default value: Define a default value to be sent to the inverters.
Hold last value: The last calculated correction value is sent to the inverters.
Note
If the meter fails, the grid operator can further curtail the active power of a plant. Due to the missing measured values, the grid operator can no longer implement control at the grid connection point (feed-in/import limitation).
Example 1
Error behavior: Default value = 0%
Waiting time: 5 seconds
Last value sent to inverters = 50%
After a communication loss, the blue’Log XC first continues to send 50% to the inverters for 5 seconds. After 5 seconds, the blue’Log XC switches to the configured default value of 0%.
Example 2
Error behavior: Hold last value
Waiting time: 5 seconds
Last value sent to inverters = 50%
After a communication loss, the blue’Log XC continues to send 50% to the inverters.
Communication failure with the grid operator
Communication failure between a blue'Log master and slave
In a master-slave setup, the blue'Log XC master sends the error behavior that has been configured for meter failure cyclically to the blue'Log XM slave.
If a communication failure between the master and slave occurs, the slave adopts the error behavior and acts accordingly.
Configure fail-safe operation for a meter
Prerequisites
Hybrid EMS license
Steps
Go to Power control > Active power > Fail-safe operation.
Under Meter failure, select the Default setpoint or Hold last setpoint for both PV and battery.
If you selected Default setpoint, enter the Fallback value as a %.
Enter a waiting time in seconds. The default is 60 seconds.
The error behavior is configured.