Overview
Our client operates a pulp and paper mill in Alabama, relying on two steam turbines to provide critical power for mill operations. As part of a broader controls modernization effort, the facility sought to improve integration between its turbine control and excitation systems while preparing for future reliability and maintenance needs.
The project began as a plan to migrate hardwired communication points between the facility's Mark VIe turbine controls and EX2100 excitation system to a Unit Data Highway (UDH) network connection. As project planning progressed, the client elected to move forward with a full EX2100 to EX2100e upgrade through the OEM. Recognizing the complexity of the effort and the importance of maintaining operational continuity, the client asked AP4 to serve in an Owner's Engineer (OE) capacity throughout the upgrade.
Over the following months, AP4 provided critical engineering oversight, technical guidance, startup support, and operator training that helped navigate project changes and ultimately bring the upgraded system into service successfully.
Challenge
The original scope (migration to UDH) was scheduled for an October 2025 outage. However, shifting plant priorities delayed the outage until April 2026. During that period, the client finalized plans for a full EX2100e upgrade led by the OEM.
The upgrade introduced an important consideration: Any modifications made to the existing EX2100 as part of the original AP4 scope could be overwritten during the migration process. Rather than proceeding with work that might later be replaced, the client and AP4 reevaluated the project approach. The client needed independent technical expertise to help validate configurations, identify potential risks, and ensure the new system met operational expectations.
Solution
Working collaboratively with the client, AP4 repurposed the remainder of the original scope and assumed an Owner's Engineer role for the excitation system upgrade.
During the upgrade phase, AP4 engineers worked alongside site personnel and the OEM to review system designs, monitor implementation progress, and provide practical guidance based on extensive experience with both Mark VIe turbine controls and EX2100/EX2100e excitation systems. The AP4 field engineer (FE) who served as the OE during the first phase brought more than 25 years of experience, including many years with the OEM. That expertise proved instrumental in helping the project overcome hurdles such as:
Identifying configuration issues
Validating system communications
Identifying missing parts related to the excitation system while auditing the BOM as received onsite, such as a special circuit for the 86 lockout and a DC-AC converter
Multiple other troubleshooting efforts related to software implementation and system integration.
This was made possible by our FE's deep understanding of the systems and extensive familiarity with the OEM processes and architecture. Following drawings and standard installation procedures is one thing, but recognizing that these systems are not a one-size-fits-all solution and knowing how to navigate unique challenges requires expertise that goes far beyond what is documented in a drawing. As a result, the site engineering team relied heavily on AP4's knowledge and guidance to help ensure success.
After approximately a two-month delay unrelated to the migration work, the project continued and entered the startup phase.
Two AP4 field engineers returned to the site to provide hands-on startup support and assist with final commissioning activities.
The startup effort ultimately required thorough review and correction (where required) of system wiring, software configurations, operator displays, and the HMI between the turbine controls and excitation system. AP4 personnel worked closely with plant staff to resolve outstanding issues, verify proper operation, and ensure critical functionality was performing as intended before the units returned to service.
Following startup, site leadership recognized AP4's field engineering team for providing critical expertise throughout the project. Their involvement helped the facility overcome complex technical challenges, reduce uncertainty, and successfully upgrade to the EX2100e while avoiding potentially significant startup delays.
Because AP4 engineers had been involved throughout the project lifecycle, they were also able to deliver site-specific training tailored to the mill's actual system configuration. Operators and maintenance personnel received customized instruction based on their own software, hardware, and operating environment rather than generic training materials.
Results
The facility successfully completed the EX2100 to EX2100e migration and returned its steam turbine generating assets to operation with improved confidence in the upgraded control environment.
By maintaining involvement throughout planning, implementation, startup, and training, AP4 helped provide continuity during a project that evolved significantly from its original scope. The Owner's Engineer approach ensured that technical decisions remained aligned with the client's operational objectives despite schedule changes and shifting project requirements.
Key outcomes included:
Successful startup and commissioning of the upgraded EX2100e system
Validation of communications between the excitation and turbine control systems
Resolution of configuration, wiring, and software integration issues prior to operation
Delivery of site-specific training for operations and maintenance personnel
Improved visibility into system functionality and future support needs
Through consistent technical guidance and startup support, AP4 helped the client navigate changing project conditions and achieve a successful outcome while maintaining focus on safe, reliable mill operations.
