Operation And Maintenance Of Constant Voltage Transformer Grounding System: Resistance Standards And Practical Technical Guide

In the daily inspection of the power system, the stable operation of 3 phase constant voltage transformer is closely related to the quality of grounding. This special transformer maintains a constant output voltage through magnetic saturation, but its internal electromagnetic environment is complex, placing stringent requirements on the unobstructed flow path. If there are obstructions at the grounding grid connection points, the equipment is highly susceptible to abnormal heating or increased magnetic noise.

Technical Standards for Constant Voltage Transformer Resistance Limits

Technical regulations clearly define parameter thresholds for different operating environments. Under normal power load, the resistance of the grounding branch where constant voltage transformer for home is located should be controlled below 4Ω. In areas with high soil resistivity or where the equipment's rated capacity is small, the standard can be appropriately relaxed to 10Ω.

Chain Reaction Caused by Abnormal Resistance

Once the grounding electrode corrodes or experiences poor contact, the induced high-order harmonics cannot dissipate quickly through the grounding grid. This directly leads to increased core losses in the constant voltage transformer and can even cause severe distortion of the output voltage waveform. For precision experimental equipment or automated production lines, such voltage fluctuations can result in catastrophic downtime.

Optimized Grounding Path Measurement Procedure

When measuring various parameters of a constant voltage transformer in the field, clamp-on testing or the three-electrode method is typically used for verification.

Core Steps of the Three-Electrode Method Measurement

To obtain the most accurate feedback data, the operation should strictly avoid the period after rain:

• Auxiliary Electrode Placement: Insert the current and voltage electrodes vertically into the soil at a specific distance, avoiding interference from underground metal pipes.

• Lead Wire Compensation Calculation: Measure the resistance of the conductor itself and subtract it from the final reading, especially for long-distance connections.

• Multi-Point Sampling: Select sampling points at different locations on the constant voltage transformer base and take the average value as the final judgment basis.

Improvement Paths to Enhance System Current Discharge Performance

If the initial test values ​​deviate from the predetermined range, physical intervention is required. Increasing the burial depth or length of the grounding electrode is a common strategy to improve the working environment of the constant voltage transformer. In areas with thick rock layers, laying resistance-reducing agents or replacing the copper busbars with higher conductivity can significantly reduce the voltage drop of the grounding return current.

Regularly applying anti-corrosion paint to connection points not only extends equipment lifespan but also maintains the phase reference of the constant voltage transformer in the power grid. When the grounding network maintains a consistently low impedance, electromagnetic compatibility (EMC) will reach an ideal level, and the system's self-healing capability will be enhanced.

Note: Always turn off nearby high-power inductive loads during measurement to prevent induced current from affecting reading accuracy.