In the complex operation system of steam turbines, the precise measurement of actuator displacement plays a vital role in ensuring the stable and efficient operation of steam turbines. Control system LVDT 2000TDGNK has become a leader in the field of displacement measurement of actuators in steam turbines with its excellent performance.

Working principle

Control System LVDT 2000TDGNK works based on the principle of linear variable differential transformer. Its core structure includes a primary coil, two secondary coils and an axially movable iron core. When an AC excitation signal is passed into the primary coil, an alternating magnetic field is generated. Under the action of this magnetic field, the two secondary coils generate induced electromotive force. Under normal circumstances, the iron core is in the middle of the two secondary coils. At this time, the induced electromotive force of the two secondary coils is equal in magnitude and opposite in direction, and the output voltage is zero. Once the actuator moves the iron core, this balance is broken, the induced electromotive force of the two secondary coils differs, the output voltage is no longer zero, and the magnitude and polarity of the output voltage are directly related to the displacement of the iron core. By detecting the output voltage, the displacement information of the actuator can be accurately obtained. For example, when the actuator pushes the valve to open and drives the iron core to move, the output voltage of the sensor changes. After processing by the supporting circuit, the displacement value can be converted to provide accurate data support for the steam turbine control system.

Performance characteristics

1. High-precision measurement: In the scenario of turbine actuator displacement measurement, accuracy is crucial. The Control System LVDT 2000TDGNK can achieve an accuracy of 0.01% or even higher, with high linearity and stability. Taking a 300MW steam turbine as an example, if the stroke range of its actuator is 0-100mm, the measurement error of the control system can be controlled within 0.01mm, ensuring that the control system regulates the actuator based on precise displacement data, ensuring accurate control of the steam inlet of the steam turbine, and maintaining stable speed and load.

2. Wide measurement range: It can meet the displacement measurement needs of different turbine models of actuators. The measurement range is usually from several millimeters to several centimeters, or even larger. Whether it is a small turbine or a large megawatt-class turbine, the LVDT 2000TDGNK can provide an adaptive measurement range according to the actual working conditions, and it is highly adaptable.

3. Non-contact measurement: As a non-contact sensor, it will not wear or damage the object being measured during the measurement process, which is particularly important for turbines that need long-term stable operation. It avoids wear and failure caused by mechanical contact, greatly improves the reliability and service life of the equipment, and is suitable for applications that require long-term continuous measurement.

4. Good dynamic response: It can quickly track the displacement changes of the actuator and output the measurement signal in time. Its excellent dynamic characteristics can be used for high-speed online detection. Under conditions such as sudden changes in turbine load and emergency load shedding, it ensures that the control system obtains displacement information in time, quickly adjusts the actuator action, and ensures safe and stable operation of the turbine.

5. Strong durability: Made of high-quality materials, it can withstand harsh working environments such as high temperature, high pressure, and corrosion. The operating environment of steam turbines is complex. LVDT 2000TDGNK can still work stably in such an environment, providing reliable guarantee for the accuracy of displacement measurement, so it is widely used in the industrial field.

Technical parameters

1. Measuring range: The common range is 0-100mm. Of course, according to the design requirements of different steam turbines, there are also many other ranges to choose from, such as 0-50mm, 0-150mm, etc., to meet diverse measurement requirements.

2. Output signal: Output DC voltage or current signal with a large amplitude, which can be directly recorded or displayed by recorders, digital panel meters, PLCs, DCS, etc. to achieve displacement measurement; it can also be connected to the feedback system after the amplifier to achieve automatic control of the position closed loop, which is convenient for integration and data interaction with the steam turbine control system.

3. Excitation power supply: The excitation frequency is generally around 2.5kHz, and can also be adjusted within the range of 400Hz-10kHz according to actual applications. The primary excitation voltage is usually a certain value to ensure that the sensor works stably and outputs accurate signals.

4. Working temperature: The working temperature range is – 40℃ – 150℃, which can adapt to the temperature changes of the turbine at different stages such as startup, operation, and shutdown. Whether it is the low temperature environment at the beginning of the unit startup in cold winter or the high temperature condition when it is running at full load in high temperature in summer, it can work normally.

5. Primary impedance: The primary impedance is generally 500Ω, which ensures the stability and accuracy of signal transmission.

6. Temperature drift coefficient: The temperature drift coefficient is only 0.03% F.S/°C. When the temperature changes, the measurement accuracy is minimally affected by the temperature, ensuring reliable measurement results under different temperature conditions.

7. Vibration tolerance: It can withstand vibrations up to 20g. In the strong vibration environment generated by the operation of the turbine, it can still maintain stable measurement performance without affecting the accuracy of data output.

Application in turbine actuator

1. Actuator stroke monitoring: Real-time monitoring of the actuator piston displacement, and continuous transmission of displacement data to the turbine control system. Operators can intuitively understand the working status of the actuator through the control system interface, judge whether it is operating according to the command, and whether the stroke is within the normal range, providing key basis for the evaluation of the turbine operation status. For example, during the start-up of the turbine, by monitoring the stroke of the actuator, it is ensured that it operates smoothly according to the predetermined program, the valve is opened or closed smoothly, the steam intake is controlled, and the normal start-up of the turbine is achieved.

2. Valve opening control: closely related to the steam inlet valve of the turbine, the valve opening is indirectly and accurately controlled by accurately measuring the displacement of the actuator. When the turbine load is adjusted, the control system adjusts the displacement of the actuator according to the set load and actual speed and other parameters. The Control System LVDT 2000TDGNK feeds back the displacement information in real time to ensure accurate adjustment of the valve opening, control the steam intake, and achieve stable control of the turbine speed and load. For example, when the power grid load increases, the control system increases the displacement of the actuator according to the command. The LVDT 2000TDGNK monitors the displacement change and feeds it back to the control system to ensure that the steam inlet valve is accurately opened to the appropriate opening, increase the steam intake, increase the turbine output power, and meet the power grid demand.

3. Fault diagnosis and early warning: During the continuous monitoring of the displacement of the actuator, if the displacement fluctuates abnormally or exceeds the normal range, the output signal of the control system LVDT 2000TDGNK will also be abnormal. After the control system captures the abnormal signal, it can trigger an alarm in time to remind the staff to check the actuator and related equipment, check whether there are problems such as component wear, jamming, and hydraulic system failure, prevent the expansion of the fault in advance, and ensure the safe operation of the steam turbine. For example, when the actuator is jammed and the displacement cannot change normally, the LVDT 2000TDGNK detects the abnormality and sends a signal, and the staff can perform maintenance in time to avoid the normal operation of the steam turbine due to the actuator failure, reducing downtime and economic losses.

The control system LVDT 2000TDGNK plays an irreplaceable role in the displacement measurement of the steam turbine actuator with its unique working principle, excellent performance characteristics and precise technical parameters. With the continuous development of steam turbine technology, the requirements for displacement measurement accuracy and reliability are increasing. The LVDT 2000TDGNK will also continue to be optimized and upgraded to provide a more solid guarantee for the safe and efficient operation of the steam turbine.

By the way, we have been supplying spare parts for power plants around the world for 20 years, and we have rich experience and hope to be of service to you. Looking forward to hearing from you. My contact information is as follows:

Tel: +86 838 2226655

Mobile/Wechat: +86 13547040088

QQ: 2850186866

Email: sales2@yoyik.com