Pull rope displacement sensors, known for their dust resistance, vibration tolerance, easy installation, and wide measurement range, are widely used in thermal and hydroelectric power plants to monitor valve openings, equipment displacement, and safety conditions, providing reliable data for stable unit operation.
In hydropower plants, they are primarily used for real-time monitoring of the opening of intake gates, tailrace gates, and surge tank valves. Integrated with control systems, they enable automatic opening and closing as well as limit protection. They can also detect minute displacements in dam slopes and powerhouse structures, offering early warnings of deformation risks.
In thermal power plants, these sensors are commonly applied to measure the stroke of dampers, slide gates, and ash discharge valves in boilers and flue gas desulfurization and denitrification systems, accurately reflecting damper positions to ensure stable air volume and flue gas ratios. They are also used for controlling coal bunker levels and the displacement of unloading trolleys, adapting well to harsh conditions involving high temperatures and heavy dust.
Additionally, they are employed in turbine speed control mechanisms, hydraulic cylinder strokes, and positioning of lifting equipment. Their non-contact design ensures long-term stability and durability, effectively reducing downtime for maintenance and enhancing automation and operational safety in power plants.
Pull Rope Displacement Sensor · Typical Application Case in Power Plants
1. Dam/Intake Gate Opening Monitoring
Pull-string sensors are installed on working gates, emergency gates, and tailrace gates at hydropower station intakes to continuously monitor gate opening height in real time. The sensors output a 4–20 mA signal connected to a PLC, enabling automatic gate control and upper/lower limit protection, replacing traditional mechanical limit switches with higher accuracy and greater operational stability.
2. Surge Tank/Spillway Arc Gate Displacement Detection
Used for measuring the stroke of arc gates and flap gates, this system precisely provides feedback on gate angle and opening during reservoir water level regulation and flood discharge operations, ensuring stable operation of the power plant’s pressure regulation system and preventing drastic water level fluctuations.
3. Power Plant Dampers and Baffle Positioning
Pull-string sensors measure the angular position and travel of boiler air supply dampers, induced draft dampers, and flue gas baffles in desulfurization and denitrification systems, enabling precise control of airflow and flue gas volume to improve combustion efficiency and meet environmental emission standards.
4. Coal Silo Unloading Car and Coal Feeder Displacement Control
In coal handling systems of thermal power plants, pull-string sensors are used for positioning unloading cars and monitoring the stroke of scraper feeders. They operate reliably even in dusty and vibrational environments, preventing coal pile imbalance and equipment collisions.
5. Hydraulic Hoist Cylinder Stroke Monitoring
For hydraulic-driven gates, butterfly valves, and ball valves equipped with cylinders, pull-string sensors are added to provide real-time piston displacement feedback, enabling multi-cylinder synchronized control and closed-loop regulation, thereby improving the smoothness of opening and closing operations.
6. Turbine Auxiliary Mechanism Displacement
Used for feedback on speed governor actuators, main steam valve travel, and guide vane opening, these sensors deliver high-precision position signals essential for turbine speed regulation and load control, ensuring safe grid connection and stable power generation.
7. Factory and Hydraulic Structure Settlement/Displacement Monitoring
Long-term monitoring of minute displacements in critical structures such as power plant buildings, retaining dams, and slopes is achieved using wire-pull displacement transducers, which record deformation data to support structural safety assessments and disaster early warning.