Direct Observation Method: Observe directly under the line using binoculars. This method makes it difficult to detect internal defects of insulators; sometimes it is necessary to climb poles for confirmation, which is time-consuming and labor-intensive.

insulator Resistance Measurement Method: It is a contact-based measurement method. It has high requirements for environmental conditions such as humidity during measurement and is not suitable for large-area testing.

Distributed Voltage Measurement Method: It involves live contact operation, which is extremely dangerous.

AC Withstand Voltage Method: This method is direct and reliable, but it requires disassembly and replacement of insulators, making on-site measurement difficult.

Infrared Thermography Detection Method: It allows long-distance ground measurement, but is greatly affected by temperature changes and is not sensitive to discharges with long gaps.

Ultraviolet Imaging Method: It uses electronic ultraviolet optical detection and can conduct live testing. However, it needs to be carried out in a high-humidity environment; the results are easily affected by the observation angle, and the equipment is relatively expensive.