Selection and Application of Temperature Sensors for Hydroelectric Generator Sets
In the operation management of hydropower stations, temperature monitoring is the key defense line to ensure the safe, stable and efficient operation of the units. The core components of a hydroelectric generator set - the thrust bearing, guide bearing, stator winding and cooling system - any abnormal temperature rise at any part could lead to shutdown or even major accidents.
As a manufacturer with over 10 years of experience in the field of sensing technology, Weilian Fengran Sensing Technology, drawing on its years of service experience in the hydropower industry, will help you understand the key points for selecting Temperature Sensors for hydroelectric generating units and the application techniques, assisting technicians in accurately controlling the operating status of the equipment.
- Why are water turbine generators so demanding of Temperature Sensors?
The operating environment of hydropower stations is complex, and the sensors need to endure multiple tests such as vibration, oil contamination, humidity, and electromagnetic interference over a long period. If the temperature measurement components fail, the operation personnel will be unable to accurately determine the actual temperature rise, which may lead to serious accidents such as cracking of the turbine blades and insulation damage.
Therefore, a reliable "thermometer" - the temperature sensor of the hydroelectric power generator, must possess:
- High precision and long-term stability (typically requiring Pt100 with A-class or 1/3B-class accuracy)
- A sturdy structure that is resistant to oil, moisture and vibration
- Anti-electromagnetic interference capability (especially near the stator windings)
- Quick response and redundant design (critical components use dual-element design)
- Key Temperature Measurement Points and Sensor Selection Guidelines for Hydroelectric Generators
The requirements for the structure, material, and installation method of sensors vary significantly depending on the specific location. The following are selection suggestions for the four core temperature measurement scenarios:
1.Thrust bearing and guide bearing - bearing housing temperature sensor
Monitoring significance: The bearing housing temperature is the most critical monitored parameter for hydroelectric generators, directly reflecting the lubrication and bearing load conditions.
Recommended Solution:
- Embedded Pt100 platinum resistance, the probe adopts a longened copper or heat-resistant stainless steel structure, and is closely embedded in the reserved hole of the housing.
- It is recommended to adopt a dual-pole three-wire connection. One line is used to send to the local PLC, and the other line is used to send to the protection instrument, achieving redundant monitoring.
- Insulation requirements: The insulation resistance to ground must be ≥ 100 MΩ (measured with a 500V megohmmeter), to prevent axial current interference.
- Stator winding - Embedded temperature measurement resistor
Monitoring significance: Excessive temperature of the stator winding will accelerate insulation aging and even lead to short circuit and burnout.
Recommended Solution:
- Use wound or armored Pt100 type, with a flat structure that is convenient for embedding between the winding wire rods.
- Key indicators: Voltage endurance, vibration resistance, long-term thermal stability.
- Signal transmission: It is recommended to use three-wire or four-wire connection to eliminate the error caused by lead resistance.
- Cooling System (Technical Water Supply/Air Cooler)
Monitoring significance: Monitor the temperature difference between the inlet and outlet of the cooling medium to assess the cooling efficiency and detect any blockages.
Recommended Solution:
- Select waterproof armored temperature sensors, with probe materials of 304 or 316L stainless steel, and a protection level of IP68.
- Signal output options are available: Pt100 resistance signal or 4-20mA two-wire transmission signal, which is convenient for remote transmission to the monitoring system.
- Oil tank/bag temperature
Monitoring significance: Monitoring the temperature of the lubricating oil to ensure the formation of the oil film and its fluidity.
Recommended Solution:
- Plug-in Pt100, with movable sleeve threads, adjustable installation depth, facilitating maintenance.
- The probe can be selected as either φ6 or φ8 mm, with a balance between response speed and mechanical strength.
- Four Common Problems and Velenfaran Solutions
| Common Problems | Velenfaran Solutions |
| Q1: The original sensor is damaged and there is no similar model available for replacement. What should we do? | We support customization based on samples. Just provide the physical object or the drawing, and we can replicate the shape, installation dimensions, and electrical parameters.
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| Q2: There is strong signal interference on site, and the display jumps. What should we do? | We adopt a three-wire/ four-wire low-resistance balanced design, and optional shielded cables and EMC protection structures can be selected.
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| Q3: The sensor leaks oil after long-term immersion in the oil tank? | We use a fully sealed laser welding process, which is resistant to pressure and oil, and eliminates leakage.
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| Q4: It needs to be connected to the existing PLC/diaphragm, but the resistance or signal does not match? | We can select resistance curves such as Pt100, Cu50, NTC, or have built-in 4-20mA, RS485 conversion outputs.
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- How to Ensure that the Purchased Water Temperature Sensors "Are Purchased Correctly and Can Be Used for a Long Time"?
It is recommended that the technical and procurement personnel of the water and electricity projects examine the suppliers from the following five aspects:
- Accuracy grade certificate: Will the factory inspection records or third-party test reports be provided?
- Material and Process: Probe material (304/316L/copper), lead wire temperature resistance range (-40℃~200℃), sealing process.
- Seismic resistance and insulation performance: Are there any vibration test reports or on-site application cases?
- Customization capability: Whether non-standard lengths, threads, and probe shapes (such as square heads, round heads, etc.) can be customized.
- Service response: Many of the water and electricity projects are located in remote areas. Can the suppliers provide rapid technical support and spare parts services?
- Conclusion: Precise Temperature Measurement Ensures Steady and Far-reaching Progress
The long-term safe operation of hydroelectric generating units is inseparable from every single precise and reliable temperature sensor. Whether it is for new units or for the renovation and upgrading of old power stations, choosing the appropriate temperature measurement components is like equipping the power station with a "smart thermometer".
If you are looking for highly reliable temperature sensors for the shaft bearings, stator, and cooling system of hydropower stations, please contact Weilian Fengran Sensor Technology. We will provide you with professional selection suggestions and customized solutions.