Zero sequence voltage transformer is a device used in power systems to measure three-phase unbalanced voltage, which is of great significance for ensuring the safe, stable, and reliable operation of power systems. The following is a detailed introduction to zero sequence voltage transformers: 1. Definition and working principle
Zero sequence voltage transformers can detect the imbalance of three-phase voltage in power systems through specific designs. The working principle is roughly as follows: the three-phase voltage is connected to the three phase windings of the transformer, which generate a magnetic field with a relative phase difference of 120 degrees inside the transformer. Subsequently, the magnetic flux of these three magnetic fields is added up through a central winding and an output signal is induced. In the case of three-phase voltage balance, this output signal should theoretically be zero; When the three-phase voltage is unbalanced, a non-zero output signal will be induced in the central winding, which represents the magnitude of the zero sequence voltage. 2、 Application scenarios
1. Improving the safety of the power system: Different types of faults will produce different changes in zero sequence voltage. By measuring zero sequence voltage, electrical faults in the power system can be quickly located, and measures can be taken in a timely manner to avoid the expansion of faults and improve the safety of the power system.
2. Protecting power equipment: Zero sequence voltage transformers can monitor the zero sequence voltage in power equipment in real time. Once an abnormality is detected, the protection mechanism can be triggered immediately to prevent damage to power equipment due to overvoltage.
3. Improving the stability of the power system: By continuously monitoring the zero sequence voltage in the power system, potential unstable factors can be detected and dealt with in a timely manner, thereby maintaining the stable operation of the power system. 3、 Type and Characteristics
There are various types and characteristics of zero sequence voltage transformers according to different application scenarios and requirements. For example, the through type zero sequence transformer has the advantages of easy installation and accurate measurement, and is suitable for situations where cables can directly pass through the center hole; The open type zero sequence transformer is suitable for situations where the cable cannot pass through the center hole, and is measured by placing the cable at the opening of the transformer. 4、 Precautions for use
To ensure the accuracy and reliability of zero sequence voltage transformers, the following points should be noted when using them:
1. Correct installation: The zero sequence voltage transformer should be installed in the correct position and wired and debugged strictly according to the instructions.
2. Stability: Ensure the stability of the pressure and temperature of the gas inside the transformer to avoid affecting the measurement results.
3. Anti interference: Pay attention to preventing electromagnetic interference and the influence of external environmental temperature to ensure the accuracy of measurement results.
4. Regular calibration: Regularly calibrate and inspect zero sequence voltage transformers to ensure their measurement accuracy and performance meet requirements.
Zero sequence voltage transformer is one of the indispensable and important equipment in the power system. It provides strong guarantee for the safe, stable and reliable operation of the power system by monitoring and measuring the imbalance of three-phase voltage in real time.