Method for evaluating inner insulation performance of monolithic suspension insulator by testing direct-current leaked currents

Provided is a method for evaluating inner insulation performance of a monolithic suspension insulator by testing direct-current leaked currents, which comprises the steps of first establishing a direct-current leakage current testing system: utilizing a direct-current generator to serve as a test power supply, utilizing a connecting wire to add direct-current high voltage to two ends of the insulator, and connecting a microammeter for measurement into the system; then utilizing shielding measures to shield leaked currents on the surface of the insulator: arranging a shielding ring on an insulation material of a tested insulator and enabling the shielding ring not to have any contact with a metal bowl head of the insulator; connecting a shielding line of equal potential onto the shielding ring; after voltage adding, enabling the leaked currents on the surface of the insulator to pass through the shielding ring to perform short current but not to flow through the microammeter; and then performing voltage raising test: raising the voltage of the direct-current generator, enabling the microammeter to read the leaked currents in the insulator, and when large leaked currents appear, determining inner insulation defects exit in the insulator. The method for evaluating the inner insulation performance of the monolithic suspension insulator by testing the direct-current leaked currents can achieve evaluation on the inner insulation performance of the monolithic suspension insulator, has the advantages of being simple and easy to implement, high in sensitivity and good in measurement repeatability, and can serve as one of basic detection methods for detecting the insulation performance of the suspension insulator.