Insulation Protection Upgrade of kv High-Voltage Power Supplies

In the operation of kv-level high-voltage power supplies, insulation protection is a core link to ensure equipment safety and avoid breakdown accidents. Traditional kv high-voltage power supplies mostly adopt a single insulating material (such as epoxy resin casting) and a simple shielding structure. Under long-term high electric field, high humidity, and temperature fluctuation environments, they are prone to insulation aging, intensified partial discharge, and other problems. In severe cases, insulation breakdown may occur, leading to power supply shutdown. Therefore, the insulation protection upgrade needs to be systematically promoted from three aspects: material selection, structural optimization, and monitoring system construction.
In terms of material upgrade, new composite insulating materials have become a key breakthrough direction. Compared with traditional materials, the composite structure of epoxy glass cloth tube and polyimide film reduces the dielectric loss factor (tanδ) by more than 30%, increases the breakdown field strength to 25kV/mm, and expands the temperature resistance range to -60℃~180℃, which can adapt to extreme temperature changes in industrial environments. At the same time, the introduction of nano-modified coatings (such as Al₂O₃ nanoparticle coatings) on the surface of insulating materials can effectively suppress surface leakage current, increase the surface flashover voltage by 15%~20%, and solve the insulation failure risk in humid environments.
Structural design optimization should focus on electric field homogenization. The electrode edge of traditional kv high-voltage power supplies is prone to electric field concentration, and the local field strength can reach 3~5 times the average field strength, which becomes a weak point of insulation breakdown. By adopting a stepped electrode structure instead of the traditional flat electrode, and optimizing the electrode curvature radius (usually controlling the curvature radius above 5mm) with finite element simulation, the uniformity of electric field distribution can be improved by 40%. In addition, adding a graded shielding layer (adopting a structure of alternating copper foil and insulating paper winding) between the high-voltage winding and the shell can effectively absorb space charges, reduce the partial discharge amount, and control the partial discharge level below 5pC, which is far lower than the 10pC required by national standards.
The integration of online insulation monitoring system is an important supplement to the upgrade. By implanting partial discharge sensors (such as ultra-high frequency UHF sensors) and dielectric loss monitoring modules inside the power supply, real-time collection of insulation status data can be realized. The system adopts edge computing technology to extract features from partial discharge signals (such as phase-resolved pattern analysis), which can early warn the insulation aging trend 3~6 months in advance. At the same time, combining humidity and temperature sensor data to build a multi-parameter early warning model can avoid the misjudgment problem of single-parameter monitoring, and improve the accuracy of insulation fault diagnosis to more than 95%.
In practical applications, the upgraded kv high-voltage power supplies have been operating stably in power system DC de-icing devices and industrial flaw detection equipment. Taking the de-icing power supply of a 220kV substation as an example, after the insulation protection upgrade, the equipment has been operating continuously for 12 months without insulation faults, and the fault rate has been reduced by 80% compared with traditional power supplies. At the same time, the maintenance cycle has been extended from 3 months to 6 months, significantly reducing operation and maintenance costs. In the future, with the further development of insulating materials and monitoring technologies, the insulation protection of kv high-voltage power supplies will move towards the direction of "active early warning + adaptive protection", further improving the reliability and safety of equipment.