During the operation of the steam turbine in a power plant, the normal operation of the bearing is crucial. Abnormal temperature of the bearing may lead to serious consequences, such as burning accidents, which in turn affects the safe and stable operation of the entire turbine. As an important temperature measurement element, the Temperature probe WZPM2-201 plays an irreplaceable role in the temperature monitoring and protection of the bearing.

I. Basic characteristics of Temperature probe WZPM2-201

1. Structural features

The Temperature probe WZPM2-201 is a double-branch platinum thermal resistance with a graduation number of Pt100. It adopts the design of end-face Temperature probe, which enables the temperature sensing element to be close to the measured end face and reflect the temperature more directly and accurately. For example, in the measurement of the bearing of the turbine, its probe can fit closely on the surface of the bearing. The specifications can be designed according to the specific installation and use environment of the turbine bearing. The double-branch structure also increases the reliability of the measurement.

2. Performance advantages

The Temperature probe WZPM2-201 has high-precision temperature measurement capabilities. In the range of 0 – 150℃ (such as the range of the #6 bearing metal temperature measuring point and the #8 bearing metal temperature measuring point in a 600MW thermal power generator), the measurement accuracy can reach ±0.15℃. It has high stability and can maintain stable performance in a complex power plant environment during long-term operation. This is because the platinum resistance material used has good chemical stability and is not easily affected by factors such as oil pollution and water vapor in the turbine operating environment.

II. Working principle in bearing protection

1. Temperature monitoring principle

When the turbine is running, the probe of the Temperature probe WZPM2-201 contacts the surface of the bearing, and the heat of the bearing will be transferred to the probe part of the Temperature probe. According to the temperature-resistance characteristics of the Temperature probe, as the bearing temperature increases, the resistance of the Temperature probe will also change according to the characteristic curve of Pt100. For example, when the bearing temperature rises from room temperature to 100℃, the resistance of Pt100 will increase from about 100Ω to about 138.5Ω accordingly.

This change in resistance is transmitted to the control system through the signal line. For example, in the DCS (distributed control system), the signal is processed by the card (such as ASI23-6 and ASI23-8 channels) and the actual temperature value of the bearing is displayed on the operation interface.

2. Alarm and protection trigger mechanism

In the control system of the steam turbine, there is a set alarm value for the bearing temperature (such as 100℃ in the above example). When the temperature value measured by the Temperature probe WZPM2-201 reaches or exceeds this alarm value, the control system will trigger an alarm signal. This alarm signal can be displayed on the DCS operation screen, and an audible and visual alarm will also be issued.

In some more advanced control systems, when the temperature continues to rise or exceeds a higher dangerous set value, a protection action will be triggered. For example, the control system may automatically reduce the steam intake of the steam turbine, thereby reducing the speed and load of the steam turbine to reduce the friction heat of the bearing and prevent the temperature from rising further.

III. Installation and protection points in practical applications

1. Installation position and method

In the installation of the turbine bearing, the Temperature probe WZPM2-201 is usually fixed on the lower bearing block by pressing. For example, in a 600MW thermal power generator, the temperature measuring element is accurately installed in the appropriate position of the bearing in this way. Such an installation position can ensure good contact between the probe and the bearing so as to accurately measure the temperature of the bearing.

During installation, attention should be paid to the spacing with surrounding components to avoid interference from other components or affecting its normal operation.

2. Protection measures

Due to the complexity of the turbine operating environment, the Temperature probe at the bearing needs good protection. During installation, care should be taken to avoid scratches or damage to the leads. For example, in the actual operation of a 600MW thermal power generator set, the lead-out line arrangement method adopted in the early stage was prone to line wear. Later, by re-opening a hole in the oil seal ring body, the lead-out line was directly led out from the front of the oil seal ring body, and a yellow wax tube was used for protection. At the same time, a fixed point was added at a certain distance (such as 200mm) to prevent the lead-out line from swinging, achieving good results.

IV. Continuous impact on bearing protection

1. Fault case analysis

In the previous operation of the 600MW thermal power generator set, faults related to the overheating resistor WZPM2-201 occurred. For example, after the transformation of the flow-through part, the temperature measurement points of #6 and #8 failed successively, mainly due to the wear of the lead-out line at the connection with the top shaft oil pipe and other components, resulting in an open circuit. This reveals the hidden dangers in the design and installation process, such as the unreasonable position of the lead-out line hole.

2. Solution measures and their significance

In response to the above faults, the lead-out hole of the oil seal ring body was re-opened to allow the lead-out line to be directly led out from the front of the oil seal ring body. This solution completely solved the problem of lead wire wear. After the transformation, it has been running for more than two years without any defects, and the accuracy of bearing temperature monitoring has been continuously guaranteed, thus ensuring the safety of bearings during turbine operation.

Temperature probe WZPM2-201 plays a vital role in the protection of bearings of power plant turbines. Its accurate and reliable temperature measurement, reasonable installation and protection measures, and experience summary in fault handling all provide strong guarantees for the safe operation of turbine bearings.

When looking for high-quality, reliable temperature probe, YOYIK is undoubtedly a choice worth considering. The company specializes in providing a variety of power equipment including steam turbine accessories, and has won wide acclaim for its high-quality products and services. For more information or inquiries, please contact the customer service below:

E-mail: sales@yoyik.com
Tel: +86-838-2226655
Whatsapp: +86-13618105229