Project Overview
Tucson Electric Power (TEP) requires their Valencia plant in Nogalez, AZ to be highly reliable, given its location at the end of a long transmission line. It was also required to perform in “island” mode—supplying power independently to the city of Nogales, if disconnected from the grid.
Although the existing system served for many years, advancing technology led to the obsolescence of individual systems. The customer’s goal was to standardize the control platform across the facility using Rockwell Automation ControlLogix simplex controllers, a distributed I/O platform, FactoryTalk View SE, and FactoryTalk Historian SE.
About the Plant
- 3x GE Frame 5LA
- 1x GE LM2500
- The GE Frame 5 units were originally relocated from Japan and commissioned in the early 1990s with TTS controls on the GE Fanuc 90-70 platform.
- A single GE LM2500 was commissioned with a GE Fanuc 90-70 platform sequencer and a Woodward Atlas governor. TTS performed a partial upgrade in the early 2010s to convert the sequencer and governor to the GE RX3i platform.
The Solution: A Phased Controls Upgrade
TTS proposed a two-stage control replacement turnkey project. This phased approach was designed to ensure that at least part of the facility could remain operational if called upon to provide power during the upgrade process. Over a dozen engineers, technicians, and skilled labor worked together to deliver this complex modernization.
Phase 1: 1x GE LM2500
The LM2500 controls were housed in a standalone building including generator protection/excitation, generator breaker, MCC, batteries, and HMI. TTS de-terminated, labeled, and routed field wires below the floor for removal of existing cabinets, then collaborated with local labor to terminate the wires to the new system.
Specific parts of the upgrade included:
- Basler Electric DEC250 Excitation (with Power System Stabilizer)
- Schweitzer Engineering Laboratories (SEL) 700G Generator Protection
- Allen-Bradley ControlLogix L8x Processor
- Allen-Bradley ControlLogix Chassis-Based I/O
- Isolated Analog Input Cards
- Isolated Thermocouple Cards
- Isolated Analog Output Cards
- RTD Input Cards
- Digital In/Out Cards
- Integration of new Bentley Nevada Vibration Monitoring System
- Allen-Bradley XM Independent Overspeed
A new, customized HMI was created for the first phase of the project that included graphics that were similar in content and function to the outgoing system, so there was minimal impact on operator familiarity and usability. The new system was integrated with the existing Woodward Gas, Liquid and Water injection fuel valves using the latest Woodward drivers applicable to each valve.
The LM2500 was fully loop checked, tested, and each field device interrogated. This process proved to be valuable to enhance the continued reliability of the engine as well as identify potentially faulty existing devices.
The TTS commissioning team worked in conjunction with a vendor to commission the generator protection relay and the Basler DECS250. As part of the extended testing requirements, PSS (Power System Stabilizer) testing was performed to ensure the proper function of that system as well as a black start test which tested the full capability of the plant to power the greater Nogales area in a blackout condition.
Phase 2a: 3x GE Frame 5LA Units
The Frame 5 controls were installed in a single standalone building for all 3 gas turbines including controls, AC/DC MCC (Motor Control Center), BOP (Balance of Plant) and HMI. Extensive modifications were needed to the exterior and interior of the building to carefully remove the existing panels. The existing turbine control, generator control, and BOP panel field wiring was carefully de-terminated, labeled and placed below the floor for removal of the original control panels.
TTS engineers then worked with local labor to re-terminate the existing field wires in new system panels provided by TTS. In addition, new wires were installed to accommodate new instrumentation being added to each turbine package.
Specific parts of the upgrade included:
- SEL 700G Generator Protection & Synchronizing
- Allen-Bradley ControlLogix L8x Processor
- Allen-Bradley ControlLogix Chassis-Based I/O:
- Isolated Analog Input Cards
- Isolated Thermocouple Cards
- Isolated Analog Output Cards
- RTD Input Cards
- Digital In/Out Cards
- Kollmorgen AKD valve driver
- Allen-Bradley XM Independent Overspeed
- Allen-Bradley Dynamix Condition Monitoring (Vibration)
In a continuation of phase 1, customized screens were added to the HMI system that included graphics that were similar in content and function as the outgoing system, so there was minimal impact on operator familiarity and usability. This final addition gave the operators full visibility and control over the plant from any single operator workstation. In addition, multiple points of redundancy were created in the event of an individual HMI failure.
TTS integrated the previously provided TTS Electroflow control valves with the new system utilizing a Kollmorgen AKD valve driver – extending the long life of the control valves and potentially saving the customer thousands of dollars in new parts and spares.
Like the LM2500, the Frame 5 units were fully loop checked, tested, and each field device interrogated. This process proved to be valuable to enhance the continued reliability of the engine as well as identify potentially faulty existing devices.
After the plant upgrades were complete, the customer required all four units to run simultaneously at a pre-configured load level to prove their reliability in remote operation.
Later, a scheduled outage on the power lines meant that the station was required to run overnight in an “island” configuration where Nogales was isolated from the grid and the plant was supplying power for the city.
Phase 2b: Reverse Osmosis (RO) Automation
The customer had an antiquated manually operated reverse osmosis system that required an operator to be present to monitor the production of Demin Water for use in the water injection (emissions abatement) systems. To better align with the goal of fully automating the plant, the decision was made to fully instrument the system, as well as motorize the manual valves required for the process.
The system became an extension of the BOP control system that was provided as part of the upgrade. It was fully automated using Allen-Bradley Flex 5000 -series I/O modules, and monitoring was provided via a local PanelView, and the new integrated TTS plant HMI system.
Conclusion
TTS Energy Services successfully delivered a Controls Modernization and Upgrade project, which has provided the Valencia plant with upgraded power generation capabilities. “TTS’ team worked closely with TEP’s Maintenance Manager Todd Smith and Project Manager Dan Mahoney to ensure a project outcome that met their expectations and delivered an integrated, reliable, flexible and efficient plant control system. This upgrade has not only enhanced site reliability but also ensured that power generation is available when needed, meeting the demands of the modern energy landscape.
TTS appreciates Dan’s closing feedback that “TTS worked hard to successfully complete this project on time and on budget” and looks forward to working with the TEP team on future projects.
About TTS
TTS Energy Services is a global leader in gas turbine engineering, with decades of experience serving the power industry. Headquartered in Orlando, Florida, with a major operations center in Houston, Texas, TTS provides a wide range of services to the power generation and midstream natural gas industries. From control system modernization and turbine installation to upgrades, repairs, commissioning, field services, and parts—TTS brings industry-best practices and a commitment to excellence to every project.
