What is the appropriate setting for the distortion protection of the reactive power automatic compensation controller?

The distortion protection of the reactive power automatic compensation controller is mainly to prevent the harmonic distortion in the system from adversely affecting the power compensation equipment (especially power capacitors). The purpose of setting the distortion protection is to ensure that the compensation system can effectively prevent faults caused by excessive harmonics, such as overcurrent or capacitor damage, even when there is harmonic interference.

1. Appropriate values for distortion protection settings:

⑴ Setting of Total Harmonic Distortion Rate (THD):

1. The total harmonic distortion rate (THD) is an important parameter for measuring the degree of harmonic distortion in the power grid. Generally speaking, industrial power compensation systems should activate distortion protection when the total harmonic distortion rate (THD) exceeds a certain threshold to prevent the safety of the compensation equipment from being affected due to excessive harmonics.

2. The common THD protection settings usually range from 5% to 10%. The specific settings need to be adjusted according to the actual conditions of the power grid:

⑵ Setting of protection actions:

1. Once the THD of the system exceeds the set value, the automatic compensation controller should immediately switch to the protection mode and stop the capacitor switching operation to prevent the harmonics from causing damage to the capacitors and other compensation equipment.

2. Action Delay: To prevent overly frequent protection actions caused by short-term fluctuations, a certain delay (such as a few seconds) is usually set to allow the system sufficient time for self-adjustment and stability.

3. Current Limit Protection Settings:

The controller will monitor the current of the capacitor. If the current of the compensation capacitor exceeds the rated value (such as overload current), it will trigger a protection action. This value is usually set to 1.1 to 1.2 times the rated current of the capacitor.

II. Other Considerations:

1. Load type: The sensitivity of distortion protection can be adjusted according to the type of compensated load (such as inductive load, nonlinear load, etc.). If the load is a nonlinear load (such as high-power motor, frequency converter, etc.), the tolerance for harmonics is relatively low. In such cases, the set value of THD protection can be appropriately reduced.