Application Guide of Pressure Sensors in Hydropower Generation

Overview of Hydropower Generation and the Role of Pressure Sensors

Hydropower generation converts the potential energy of water at higher elevations into kinetic energy, driving a turbine to rotate and ultimately powering a generator to produce electricity. This process is clean and efficient, but it involves complex hydraulic, mechanical, and electrical systems that require precise monitoring to ensure safety.

Pressure sensors are indispensable components in hydropower systems. They use stainless steel isolation diaphragms as core sensing elements and apply laser trimming technology for temperature compensation, ensuring high-precision output over a wide temperature range. Nexisense pressure sensors convert pressure signals into standard 4–20 mA electrical signals, enabling seamless integration with control systems for real-time monitoring and automated control.

During hydropower station operation, pressure sensors primarily monitor pressure air tanks, hydraulic oil tanks, and sump water levels, helping prevent unit accidents and risks of powerhouse flooding.

Core Advantages of Pressure Sensors

Pressure sensors offer significant advantages in hydropower applications. First, they provide high reliability. Nexisense products feature stainless steel housings and advanced amplification circuits, allowing them to withstand high-pressure and high-humidity environments and operate stably over long periods.

Second, they deliver excellent accuracy. With automated testing and temperature compensation, zero drift is minimal, ensuring accurate measurement data. This is particularly important under complex operating conditions in hydropower stations, enabling timely detection of pressure anomalies.

In addition, strong redundancy support is available. Typically, two to three sets of sensors are installed as backups to avoid shutdowns caused by single-point failures. Standard signal outputs allow easy integration into SCADA systems for remote monitoring.

From an economic perspective, pressure sensors help optimize maintenance and reduce losses from unexpected downtime. Practical applications show that using high-quality sensors can improve overall plant efficiency by 5%–10%.

Typical Application Scenarios

Pressure sensors are widely used across multiple critical links in hydropower generation.

Pressure Air Tank and Hydraulic Oil Tank Monitoring

In governor systems and hydraulic control systems, pressure air tanks provide compressed air, while hydraulic oil tanks supply hydraulic oil. Nexisense pressure sensors continuously monitor tank pressure. If pressure drops significantly, turbine overspeed or brake failure may occur.

Through multiple redundant sensors, the system can trigger safety alarms and switch to backup units, ensuring that the generating unit does not shut down due to abnormal pressure. This is particularly critical in large hydropower stations, helping avoid substantial economic losses.

Sump Water Level Monitoring

Hydropower plant buildings often collect leakage water in sumps. Submersible pressure sensors are installed at the bottom of the sump to measure static pressure and calculate water level. If water levels rise excessively without timely drainage, flooding may occur, damaging equipment.

Sensor signals trigger automatic startup of drainage pumps, combined with backup systems to ensure reliable drainage. Nexisense submersible sensors feature strong waterproof performance and are suitable for long-term immersion.

Other Key Scenarios

In turbine inlet pipelines, differential pressure sensors monitor head pressure to optimize power generation efficiency. In air compressor control systems, sensors regulate air supply to maintain system balance.

Additionally, during maintenance or leakage drainage control, multiple sensors can be deployed to form a comprehensive monitoring network, supporting predictive maintenance.

Measurement Methods of Pressure Sensors

Pressure sensor measurement is based on the principle of static pressure: P = ρgh, where P represents pressure, ρ is fluid density, g is gravitational acceleration, and h is height. Liquid level is calculated through bottom pressure measurement, or pressure is measured directly.

Common Types and Installation

Nexisense offers submersible sensors (for water level measurement) and flange-mounted sensors (for tanks). Submersible sensors are directly immersed in liquid to measure absolute or gauge pressure, while tank sensors are connected via threaded or flanged fittings.

Signals are converted into 4–20 mA current outputs and support HART or Modbus protocols for remote transmission. During installation, vibration sources should be avoided, and atmospheric compensation should be applied to improve accuracy.

Compared with other methods, pressure measurement provides strong anti-interference capability and is suitable for turbid water bodies or high-pressure environments.

Detailed Technical Parameters

Typical parameters of Nexisense pressure sensors include:

• Measurement range: 0–10 MPa (air/oil tanks) or 0–50 meters water column (water level), customizable.
• Accuracy: ±0.1% FS to ±0.5% FS, temperature compensation range -20°C to 80°C.
• Output signal: 4–20 mA, RS485, HART protocol, supporting digital communication.
• Protection rating: IP68 (submersible), optional explosion-proof design.
• Power supply: 24 V DC, low power consumption suitable for remote stations.
• Overload capacity: 200% FS, shock-resistant and corrosion-resistant.

These parameters ensure that sensors can adapt to harsh conditions in hydropower stations, such as high temperature, high humidity, or vibration.

Maintenance and Care Guidelines

Proper maintenance is key to extending sensor service life.

Routine Maintenance

Regularly inspect cables and connectors to prevent loosening or corrosion. Calibrate zero and full scale quarterly, using dedicated tools to verify output.

During flood seasons or before maintenance shutdowns, conduct functional tests by simulating pressure changes to check responsiveness.

Maintenance Precautions

Use neutral cleaning solutions to avoid damaging diaphragms. Store sensors in dry environments at temperatures between 5°C and 40°C.

For submersible sensors, periodically remove sediment buildup. Nexisense provides remote diagnostic functions to facilitate predictive fault detection.

With proper maintenance, service life can reach 8–15 years, significantly reducing replacement costs.

Practical Cases and Development Trends

After introducing multiple Nexisense sensor sets, a large hydropower station reduced pressure anomaly alarm response time to seconds, preventing several potential incidents. By integrating IoT technology, the system enables cloud-based data analysis, further improving efficiency.

In the future, pressure sensors will evolve toward greater intelligence, combining AI to predict pressure trends and support unattended hydropower stations.

Frequently Asked Questions

Why do hydropower stations need multiple backup pressure sensors?
To provide redundancy and prevent safety risks caused by single sensor failure, such as shutdowns triggered by sudden pressure drops.

How do submersible sensors handle turbid water?
They adopt anti-clogging designs and self-cleaning diaphragms. Nexisense products offer strong resistance to sediment interference.

How are pressure sensor signals integrated into control systems?
They support standard 4–20 mA and digital protocols, allowing direct connection to PLC or SCADA systems.

What should be considered when installing pressure sensors?
Select an appropriate range to avoid overload; for submersible sensors, secure cables properly to prevent drift.

Conclusion

The application of pressure sensors in hydropower generation is directly related to plant safety and efficiency. From air and oil tank monitoring to sump water level control, Nexisense products provide strong support with high reliability and precision. Proper selection and maintenance can maximize their value and promote sustainable development of the hydropower industry. If you are planning a hydropower monitoring system, the Nexisense team is always ready to provide professional consultation and support the development of green energy.