How Do Severe Fluctuations In The Power System Affect The Voltage Distribution Of Insulators?

When large-scale equipment is put into or disconnected from the power grid, the balance between current and voltage is instantly disrupted. This physical phenomenon not only involves power distribution, but also poses a severe test to the suspension insulator at the end of the cable or at the corner. Understanding the transient processes caused by sudden load increases or decreases is a crucial step in maintaining line operation.

The Physical Logic of Power Quality Fluctuations Caused by Sudden Load Changes

During energy conversion, the transition between inductive and capacitive loads generates electromagnetic transients. At the moment a high-power motor starts, the system's reactive power demand surges, and the rapid adjustment of magnetic field energy storage causes voltage waveform distortion. This distortion directly affects the suspension composite insulator mounted on the tower, causing it to experience a potential gradient far exceeding the steady-state operating value.

Energy Accumulation on Insulator Surfaces Due to Transient Overvoltages

Transient overvoltages typically occur in the microsecond to millisecond range, and their amplitude can reach several times the rated voltage. Due to the uneven capacitance distribution across different sections of the insulator string, the high-voltage end is often the first to be affected.

• Voltage gradient imbalance: The steep wave front generated by a sudden load jump will be concentrated on a few composite suspension insulator chips near the conductor.

• Partial discharge risk: Extremely high electric field strength leads to air ionization, thus enhancing corona discharge.

• Increased dielectric loss: Instantaneous high voltage increases polarization losses within the material, which, over time, shortens equipment lifespan.

Superposition effect of resonance and induced voltage:

Line inductance and capacitance to ground may form series or parallel resonance under drastic load changes. This resonance amplifies the peak value of the overvoltage, putting the polymer suspension insulator, which was originally within the safety margin, at risk of flashover. Especially in heavily polluted areas, transient voltage peaks can easily induce surface creepage, causing permanent damage.