High Power Steel Mill – Troubleshoot Meter Communications & Upgrade EPMS Software for Active Power Management
Affinity Energy helps a high-power steel mill maximize output and maintain visibility to voltage disturbances.
This southeastern steel mill is one of the largest mini-mill steel producers in North America and one of the largest power consumers in their state. They produce rebar, which is used to reinforce concrete in bridges, buildings, and other structures.
Scrap metal is melted in the facility’s Electric Arc Furnace (EAF), which requires approximately 40MW to run. Because of the EAF’s high demand, the steel mill has a demand limit set by their utility.
In the late 2000’s, they developed an Allen Bradley PLC-based active power management program that curtails or shuts down the EAF if, during a 30-minute block, it determines that it will exceed the peak limit.
The utility allows the steel mill to wirelessly access their four Schneider Electric ION 8600 electric meters to ensure no billing/output discrepancies exist. For the EAF’s active power management to work properly, it requires real-time meter information interfaced directly to the Allen Bradley PLC controlling EAF curtailment via a ProSoft network module.
The meter data was also directly interfaced to the local PowerLogic ION Enterprise EPMS system to allow the steel mill to gain visibility into power quality issues.
Affinity Energy was super responsive and flexible with our timeframe. We needed this work done in January to ensure optimum reliable operation of our plant. In the same trip, they were able to come up with a new solution to help us curtail correctly and have detailed power quality diagnostics from meters.
–Plant Electrical Engineer, High Power Steel Mill in the Southeast
In 2017, the utility upgraded their meters from ION 8600 to ION 8650. They also changed their phone modem connection to cell modem, which took away the Ethernet connection the steel mill’s wireless radios relied on. After the change, the ability for the PLC and ION Enterprise system to see those meters didn’t exist.
In the event of communication failure, the PLC was configured to automatically use conservative default load settings. The side effect of using default load profiles meant the EAF would shut down more frequently than if it was using "real" load data from the meters. This would result in less product production which meant less revenue generated.
In addition to communications loss, it was discovered that the 10-year-old ION Enterprise system had a corrupt database. Their monitoring system was totally offline.
As a system integration partner the mill had worked with in the past, Affinity Energy was selected to find a way to get the meters and EPMS system back online in January 2018.
The new ION 8650 utility meters have two serial ports in addition to the single Ethernet port. These two serial ports were ultimately needed to restore the system to full functionality. To get full power quality functionality, the ION protocol must be used; however, the ProSoft network module in the Allen-Bradley PLC requires Modbus TCP protocol. So, Affinity Energy engineers had to install two ethernet gateways at each meter radio location, one for connection to the EPMS software (ION) and one for connection to the PLC (Modbus).
Because the steel mill wanted to run on the latest Windows operating system and Microsoft SQL database, that required a complete EPMS upgrade. Affinity Energy upgraded the ION Enterprise EPMS to Schneider Electric Power Monitoring Expert (PME). With PME software, they’ll be able to examine power quality events that originate at the service points from the utility.
In the end, Affinity Energy was able to restore the real-time information from the utility meters to the Allen Bradley PLC via Modbus, and also allow full functionality within PME using the ION protocol to communicate with the utility meters.
The steel mill is now back on track to its normal production schedule. With accurate data from the utility meters, the EAF will curtail only as needed based on actual load data moving forward.
The mill is now looking into another project with Affinity Energy that involves troubleshooting the wireless network communication failures from their oxygen meter to PME that render the data less than 50% reliable.