Following the investigation into 9 August 2019 power outage, approximately 550MW of embedded generation was disconnected. In some cases, due to the expected operation of the rate of change of frequency protection system but in other cases because some generators may be operating incorrect protection settings.
To avoid future outages, the ALoMCP was initiated to amend the loss of mains (LoM) settings on generation in GB. In summary these are to remove vector shift (VS) as an allowable LoM technique, and to change any rate of frequency protection (RoCoF) settings to new, less sensitive values.
The vast majority of the SMA inverters do not explicitly rely on RoCoF or VS techniques, as we decided either to use an active LoM protection or to disable the LoM protection for those inverters with a power higher than 50 kW. To sum up, the LoM settings in the following inverters do not need to be changed and do not use RoCoF / Vecor shift as a means of disconnection:
For the inverters MLX/STP 60-10 and SHP75-10, we have defined three country settings for the UK. Two of them contain RoCoF settings in accordance with the G59/3. Similarly, for the inverters TLX and FLX, the country setting contains RoCoF settings in accordance with the G59/3. The RoCoF settings need to be changed or set to disable as specified in the ALoMCP.
Inverters that do use RoCoF / Vector shift as a means of disconnection:
Inverter Type | RoCoF or Vector shift used | Information on how to change the settings |
---|---|---|
SMA | ||
STP 60-10 | Yes | files.sma.de/downloads/STP60-SHP75-ALoMCP-SG-en-10.pdf |
SHP 75-10 | Yes | files.sma.de/downloads/STP60-SHP75-ALoMCP-SG-en-10.pdf |
The Sunny Central inverters from type SC xxx0 CP(-XT) do not use Vecor shift as LoM detection method. Furthermore all anti-islanding methods implemented in the inverters firmware (such as RoCoF or AID) are deactivated by default when delivered in European regions. This means there is no need to change any settings for this function.
However, it is strongly recommended to check the setting values of the frequency trip-limits for compliance with the recommendations of the ALoMCP and adjust the settings if necessary. You can find a description of the relevant parameters („HzCtlxxLim“; „HzCtlxxLimTm“) in the corresponding operation manual of your device. If you are not sure about how to identify or change the relevant parameters please contact the SMA UK Service Line for assistance.
For the following inverters please check if they were delivered with the FW version in the table below. If not then the RoCoF setting should be changed from 0,25 Hz/s to 4 Hz/s.
Inverter | Version | Release date | RoCoF |
---|---|---|---|
WB1100/ WB1200/ WB1700 | Earlier than 2.91 | July 2009 | 0.25Hz/s must be set to 4 |
WB100LV | Earlier than 1.23 | August 2008 | 0.25Hz/s must be set to 4 |
WB2500/ WB2800/ WB3000 | Earlier than 2.82 | October 2008 | 0.25Hz/s must be set to 4 |
WB4600A/ WB5000A/ WB6000A SMC5000A/ SMC6000A | Earlier than 1.42 | June 2010 | 0.25Hz/s must be set to 4 |