The Underlying Logic Of Insulator Voltage Instability Under Single-sided Power Supply Mode In Distribution Network

In the daily operation and maintenance of power systems, a common headache is the fluctuating voltage distribution of components suspension type insulator in single-sided power supply lines. This is not merely a matter of numerical variation, but a hidden test of equipment lifespan. Many people believe that as long as current flows, everything is fine, but from the perspective of microscopic electric field distribution, single-sided power supply does introduce significant variables into the system.

Charge Accumulation Caused by Line Asymmetry

Because the power supply is only connected from one end, the electromagnetic field distribution along the entire line exhibits a clear gradient decrease from the source. The electrostatic induction intensity experienced by composite tension insulator is completely different near the power source and at the end. When current flows through a long conductor, the charging current generated by the conductor's capacitance to ground will shift to one side. This physical asymmetry directly disrupts the potential balance. This phenomenon causes the part near the power supply end to bear an excessively high voltage difference, while the far end is relatively lower.

Several Core Factors Affecting Potential Distribution

• Imbalance of Distributed Capacitance: In a unidirectional transmission path, the stray capacitance between the conductor and the ground, and between the conductor and the tower, is no longer uniformly distributed.

• Accumulated Impedance Voltage Drop: As the line lengthens, the unilateral load current creates a voltage drop across the impedance, widening the potential difference between the beginning and end.

• Interference from Air Humidity: Moisture in the environment often adheres to surfaces, making the weak leakage current from unilateral power supply more prone to partial discharge under an asymmetrical electric field.

What actual damage does this fluctuation cause to the hardware?

If this uneven voltage distribution persists for a long time, stress fatigue will occur in the skirt area of the high voltage transmission line insulators. The voltage that should be shared by the entire string of components is now concentrated on a few pieces, accelerating the aging of the insulation. Corona loss or microcracks found during field inspections are often the result of this long-term "chronic torture" of voltage fluctuations.

Targeted Optimization of the Operating Environment

To address this voltage fluctuation, it's usually necessary to consider changes in the physical structure. For example, adding an equalizing ring to redirect the electric field lines, or adjusting the arrangement density of overhead power line insulators. Through physical intervention, the previously chaotic potential distribution caused by unilateral power supply can be smoothed out. This reduces the stress on individual wafers and maintains the overall insulation performance at a relatively stable level, preventing flashover due to temporary voltage spikes.

In routine maintenance, paying close attention to the terminal's operating status and promptly cleaning surface contaminants are the most direct ways to reduce this voltage instability. After all, a clean and clear tension insulator surface can reduce the interference of many external impurities on the electric field distribution.