Engineered for Combined Cycle Power Plants

Combined cycle power plants rely on gas turbines paired with Heat Recovery Steam Generators (HRSGs), where exhaust gases are used to convert water into steam to drive additional turbines. Within this process, governor and control valves play a critical role in regulating steam and gas flow, directly impacting plant efficiency, responsiveness, and safety. 

Accurate and reliable valve position feedback is essential to maintaining stable turbine operation. For over 15 years, the PG Series LVDT sensing solutions have been a trusted, field-proven technology for this application.

Purpose-Built LVDT Sensing for Harsh Environments

The Alliance Sensors Group PG Series LVDT linear position sensors are specifically engineered for turbine valve control in demanding power generation environments. Unlike legacy or general-purpose sensors, this solution is designed to withstand:

• High vibration typical of turbine decks 
• Elevated ambient temperatures up to 350°F (175°C) 
• Contaminants such as oil, steam, and particulates

Key Design Features

• Captive core construction prevents mechanical separation during operation 
• Heavy-duty 3/8-inch push rod for enhanced strength and durability 
• Double-contact shaft seals to protect against environmental ingress 
• Screw clamp terminals eliminate fragile connectors and improve reliability 
• Multiple measurement ranges from 0–3 inches to 0–16 inches 

Available in both heavy-duty and super-duty configurations, the PG Series delivers long-term durability in continuous operation applications.

Redundant LVDT Architecture for Critical Valve Control

To address failure modes and ensure uninterrupted operation, the system incorporates a dual-LVDT redundant configuration.

Redundancy Strategy

• Two independent LVDTs mounted on each critical valve 
• Continuous signal comparison for validation and drift detection 
• Automatic fault identification in the event of: 
• Sensor failure 
• Signal deviation 
• Mechanical binding or misalignment 
 

This redundant architecture ensures:

• Fail-safe operation in turbine control systems 
• Increased system availability and reduced unplanned downtime 
• Compliance with modern reliability and safety expectations 

In the event of a fault, the system seamlessly isolates the affected sensor while maintaining control using the secondary channel.

Smart Signal Conditioning with Advanced Diagnostics

The S2A Smart AC-LVDT Signal Conditioner complements the sensor system by delivering intelligent signal processing, simplified commissioning, and robust diagnostics.

Core Capabilities

• Compatibility with LVDTs, RVDTs, and legacy turbine sensors 
• Hot-swappable design for maintenance without system shutdown 
• Push-button or remote calibration via RS-485 
• Microprocessor-controlled setup reducing commissioning time from hours to minutes 

Built-In Diagnostics

• Detection of 11+ fault conditions including wiring issues, signal loss, and drift 
• Continuous health monitoring of both primary and redundant sensors 
• Real-time alerts for predictive maintenance

Cybersecurity Features

• Tamper detection and alerting 
• Secure configuration access 
• Designed to align with modern plant cybersecurity requirements 

Integrated, Modular Solution for Modern Power Infrastructure

When deployed together, the PG Series LVDTs and S2A signal conditioner form a fully integrated valve position feedback system that delivers:

• High-accuracy measurement 
• Enhanced visibility into system health 
• Long-term operational reliability

This modular architecture supports both new installations and retrofit upgrades in combined cycle plants.

Optimized for AI Data Facility Power Systems

As AI-driven data centers demand increasingly reliable and scalable power, modular combined cycle plants are being deployed to support high-density computing loads.

These facilities require:

• Rapid response to load fluctuations 
• Continuous uptime with zero tolerance for control failure 
• Compact, modular power generation blocks 

The PG Series LVDT-based valve control solution is well-suited for these environments, offering:

• Proven reliability in continuous-duty operation 
• Redundant sensing for mission-critical uptime 
• Fast commissioning for modular plant deployment

Boiler Integration (BOGLET Concept)

In advanced modular configurations, compact boiler and HRSG systems, often referred to as BOGLET (Boiler Generator Lightweight Energy Transfer) modules are used to optimize thermal efficiency and footprint.

Within these systems, precise valve control enabled by redundant LVDT feedback is essential for:

• Steam flow regulation 
• Thermal efficiency optimization 
• Protection of downstream turbine assets

A Proven Standard in Power Generation

With over 15 years of successful deployment, this LVDT sensing and signal conditioning solution represents a time-tested standard in turbine valve control.

Key Benefits at a Glance

• Proven reliability in harsh environments 
• Dual-LVDT redundancy for critical applications 
• Advanced diagnostics and cybersecurity 
• Reduced installation and commissioning time 
• Scalable for modern modular and AI-driven power systems