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Overhaul and transformation of temperature measurement system of hydropower station
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2019-10-12
As an important judgment basis for normal operation of power equipments, temperature plays an important role in equipment monitoring and protection, fault diagnosis and analysis. As a part of the monitoring system, the temperature measurement system of hydropower station, which integrates measurement, processing, analyzing, alarm and protecting functions of the equipment temperature, plays an important role in the automation system of hydropower station. Stable, reliable and accurate temperature measurement system is the basis of safe and stable operation of the power station.
 
 
Overhaul and reconstruction of temperature measurement system in hydropower station
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As an important judgment basis for normal operation of power equipments, temperature plays an important role in equipment monitoring and protection, fault diagnosis and analysis. As a part of the monitoring system, the temperature measurement system of hydropower station, which integrates measurement, processing, analyzing, alarm and protecting functions of the equipment temperature, plays an important role in the automation system of hydropower station. Stable, reliable and accurate temperature measurement system is the basis of safe and stable operation of the power station.

 
Features of temperature measurement system of hydropower station
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Compared with the general temperature measurement system, the temperature measurement system of hydropower station has its own particularity, which is mainly reflected in:
Difficult maintenance: Taking the temperature measurement of the bearing bush of the hydropower unit as an example, the bearing bush of its temperature measurement resistor is installed in the oil groove. Overhaul and maintenance can only be carried out after the oil groove has been shut down and drained. During the overhaul of generator stator temperature measurement resistor,the stator bar will need to be disassembled. With the extension of unit overhaul period, it requires that the temperature measurement element of hydropower station can operate stably for a long time.
 
Great importance: The bearing bush temperature of each bearing of the unit is an index indirectly measuring the vibration of the unit. As an important water turbine protection, the bearing bush temperature protection will directly trip out of the unit after action. With the continuous increase of the installed capacity of a single unit, it is required that the temperature measurement of the bearing bush of the hydropower station is reliable and the linearity is good.
 
Poor operation environment: The temperature measurement system of the unit of the hydropower station works in a humid and vibration environment for a long time, especially the temperature measurement resistor of each bearing bush and its wires are immersed in high-temperature turbine oil for a long time and bear the impact from oil flow. This requires that the temperature measuring resistor and the temperature measuring conductor of the unit of the hydropower station shall be moisture-proof, vibration-resistant and oil-resistant.
 
Great electromagnetic interference: The strong electromagnetic field generated by the generator, especially the strong magnetic field generated by magnetic leakage, has great interference on the upper guide bearing, thrust bearing bush and stator temperature measurement resistor. This requires that temperature measurement resistor and temperature measurement conductor of the unit shall have a capacity of strong anti-electromagnetic interference.
 

Analysis and solution of common problems in the temperature measurement system of hydropower station
1. The design is not reasonable, and the sensor cannot adapt to the working conditions of the power station. Some of water turbine temperature sensors are general industrial products. The design is not based on the working conditions of the turbine in combination with the particularity of the temperature sensor of the hydropower station, resulting in that the sensor cannot adapt to the harsh working conditions of the water turbine, sensor is damaged and signal is interfered. Testeck focuses on the temperature measurement system of hydropower station, the targeted development and design of the temperature sensor of hydropower station and customized services according to the requirements of the power stations.It has maintained its cooperation with turbine manufacturers such as DFEM, Harbin Electric and Alstom and participated in the promotion of turbine temperature measurement and resistor technology.
 
2. There are turbine oil corrosion and sensor wire cracking. The bearing bush temperature measurement resistor is soaked in high-temperature turbine oil for a long time and subject to oil flow disturbance, so the general industrial cable is easy to crack. In order to ensure high temperature, oil and corrosion resistance of the cable, Testeck has established a cable subsidiary to develop and produce special signal cables for hydropower station, which can work stably in oil temperature of 100℃ for 8 years.
 
3. The operation environment of the sensor is bad, and the long-term stability is poor. Taking the temperature sensor of the thrust pad as an example, the temperature sensor will suffer impact and vibration in the high-temperature turbine oil for a long time. Unreasonable design, quality defects and improper installation will cause the temperature sensor to be damaged and fail to work normally. Testeck has many years of experience in the design and production of temperature sensors for hydropower stations. Our engineers put forward reasonable design schemes according to the different conditions of each power station on site. All the delivered products have passed strict inspection, and we provide reasonable installation, wiring and other supporting service at the later period.
 
4. There is interference from strong electromagnetic field, and temperature measurement signal has a deviation. In the interference of strong electromagnetic field of power station, there are not enough anti-interference measures for the industrial temperature sensor in the strong electromagnetic field, electromagnetic field interference often occurs in the process of signal measurement and transmission. The signal deviation is serious. Testeck temperature sensor adopts imported Class-A precision temperature sensing chip and laser welding process. The shielding layer of the conductor adopts the shielding density which is higher than the national standard, and it has strong anti-interference capacity.
 
 
 
Customer performance
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As of December 2013, the temperature sensors of Testeck have been successfully operated in more than 2,000 power stations and 6,000 generator sets across the country. The following is a list of some projects. Project name  Installed capacity Manufacturer Supply time  Operation condition. The list of some of Testeck hydropower projects  32×700MW Harbin Electric, DFEM, Alstom, Voith, Ge 2010   So far, all of them are in normal operation.  Gezhouba 21×125MW  Harbin Electric and DFEM 2010, 2011 and 2012   So far, all of them are in normal operation. Xiaowan 6×700MW  Alstom 2010, 2011 and 2012  So far, all of them are in normal operation.  Pubugou 6×600MW DFEM 2010  It has been successfully transformed.   Longtan 7×700MW  DFEM  Harbin Electric 2010 So far, all of them are in normal operation. Goupitan 5×600MW DFEM  Alstom 2010  The first three units have been transformed intensively, generating obvious effects. 4# and 5# units have been ordered.  Xiluodu 4×800MW DFEM, Harbin Electric, Alstom 2011, 2012  The products have been ordered and installed successfully.
 

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