Generator Excitation Systems

With an expanding portfolio of advanced generator control & protection platforms and services, we provide design, installation, and commissioning services with experience gained from over 2,000 gas, steam, and hydro turbine upgrades in more than 70 countries.

The Nexus Controls team works with customers to deliver modernization solutions across a wide range of excitation applications with offerings structured to meet both technical and budget requirements.  We have developed platform partnerships to deliver cost-effective configurable Automatic Voltage Regulator products to fully programable redundant static excitation systems for small industrial gas and steam, to heavy duty gas or large utility steam driven turbine-generators.

As standalone generator control project or integrated with the Nexus OnCore™ Control System or the GE Mark™ control platform, Nexus Controls can tailor flexible retrofit solutions from a global team of experts in the control and protection of critical generating assets.

Offerings include:

• Excitation platforms from a variety of global providers
• Flexible form factors and packaging to optimize retrofits
• Hardware, software, and integration engineering
• Application expertise to support custom solutions
• Engineering Design Packages (EDP) – Installation design and documentation
• Single point system responsibility – PPT, cable, bus, networks, enclosures
• Comprehensive PSS and IEEE Modeling documentation and validation services
• Installation Services – Project management, installation, and commissioning services
• Expert integration of excitation systems with the balance of turbine-island and plant controls
• Nuclear grade retrofit packages and DCN support

While the Alterrex excitation control system stood as an industry standard for nearly 30 years, technology and operating demands have changed. It’s time to modernize.

We offer a comprehensive set of control and mechanical modernization options to help ensure the performance of your Alterrex systems.  

The EX2100e Alterrex Regulator replacement provides precise control and protection for your main generator and the Alterrex alternator. 

Our drop-in EX2100 Alterrex Diodes feature modern flat-pack diodes, machined billet aluminum heat sinks, and all stainless-steel fluid path and fittings for a virtually maintenance-free replacement. 

And while the Alterrex utilizes the highly reliable stator water cooling (SWC) system to cool the fixed diodes, adding our dual Alterrex SWC filter assembly can enhance reliability.

Successful generator control system retrofits require more than just hardware. We specialize in integrating new controls into existing plant infrastructure. Our multi-disciplinary team of experienced engineers and designers are happy to tailor controls retrofits for your unique situation.  

Our scalable Engineering Design Package (EDP) is tailored to meet your critical planning and execution requirements with greater efficiency, improved safety, less risk, and lower total costs. Depending on the complexity of your project, this may include:

• Wiring transition tables
• General arrangement and equipment layout options
• Demolition drawings
• Electrical and system designs that include routing, material lists, and detailed installation drawings
• Civil and mechanical designs for verification and/or modification of plant structure, and installation of new equipment
• Updates of existing plant drawings for new equipment
• Subcontractor specifications for materials and development of work packages

A reliable starter delivers a key element in the profitable operation of heavy-duty gas turbines. That’s why we provide a variety of system retrofits and upgrades to improve starting reliability of existing Innovation Series Control or LS2100 static starters.  

The LS2100e Static Starter is the third generation of load commutated inverter (LCI) drives for static starting applications and provides improved performance, protection, and flexible operational profiles for stand-alone or redundant cross-over configuration. 

Available as either a full drive or a Controls Migration (digital front end), upgraded LS2100e controls offer new operability and performance features, and can support enhanced starting profiles and improved plant performance. Systems relying on a single static starter can be redesigned to include a second starter to provide a fully-redundant starting system for single or multiple gas turbines.  

We deliver a total scope LCI cross-over system, including medium and low voltage system design, safety interlocking, network design, software development, Engineering Design Package, and installation and commissioning support.

When installed with Mark VIe unit controls, the system provides an integrated software environment with common programming and engineering tools, consolidated HMI, alarm management and historian, and start sequencing (without the need for external PLC cross-over control), all on the same control system platform and product lifecycle.