Tales of BESS #1 - Case Study : Root Cause Analysis

Root Cause Analysis – Internal Communication issue: 20MW / 20MWh (UK)​

The client was looking for an independent third party to review a 20MW/20MWh BESS asset capability to enter and participate in ancillary services (DC/DM/DR) as well as assessing the overall reliability of the control systems (coms between RTM, SCADA and BESS/PCS)​.

Greensolver team has been appointed to establish the root cause of 3 main issues encountered during the SAT period, and evaluate the reliability of the mitigation action carried out :​

• Issue 1: communication misfunction between the Battery OEM’s BMS and the PLC of the SCADA​
• Issue 2: impossibility to pass the tests for DC, DM et DR services​
• Issue 3: communication outage between Battery containers and the PLC of the SCADA​

Greensolver also assessed in parallel the Balancing Strategy of the Battery OEM.

Greensolver team well conducted the analysis by flagging the root cause and mitigation action reliability:​

• Issue 1: bad MODBUS protocol configuration due to uncompliant MSS setting in the Battery OEM BMS​
• Issue 2: uncompliant operational policy of the Battery BMS during standby period leading to greater latency of the system response and preventing being compliant with DC/DM/DR requirements​
• Issue 3: uncompliant MODBUS protocol configuration following the mitigation action done to solve issue 2​

Regarding Balancing Strategy, main risks raised concerned improving the SOC calibration and SOC calculation accuracy.

Written by David Roissé