How Do High Load Conditions Affect The Voltage Distribution Of Insulators?
In power systems, the load carried by transmission lines is not constant. When the grid enters a high-load operation state, the current flowing through the conductors surges, and the resulting enhanced electromagnetic field directly acts on the dead end insulators string. This change in field strength disrupts the original voltage distribution balance of dead end suspension insulators, leading to more significant voltage fluctuations along the surface compared to normal operating conditions.
Increased Potential Distribution Gradient
polymer deadend insulator is a capacitive device, and under normal operation, the voltage along the string length exhibits a non-linear distribution, with the high-voltage end bearing a higher field strength. Under high-load conditions, the increased capacitance of the conductor exacerbates the field strength distortion at the fittings, further increasing the proportion of voltage borne by the high-voltage side porcelain dead end insulators. This trend of voltage concentration at one end widens the potential gradient difference between the insulators in the string, making the overall voltage distribution curve steeper.
The cumulative effect of environmental factors
Heavy loads are often accompanied by an increase in conductor temperature. If exposed to humid climates such as fog or dew, the conductivity of the suspension insulator surface contaminant layer will change dynamically after it becomes damp. This complex scenario, resulting from the combined effects of load current thermal effects and ambient humidity, leads to fluctuations in insulator string leakage current, which in turn manifests as frequent changes in power frequency voltage distribution. The amplitude of voltage fluctuations is particularly pronounced in the morning or during periods of load fluctuation.
These changes in voltage distribution characteristics are valuable for interpreting insulation test values during line operation and maintenance.
