Principles and Characteristics of Partial Discharge Detection Methods

Radio Frequency Scanning (RFS) is a non-invasive, live-testing method that detects partial discharge-generated electromagnetic signals by capturing them via an antenna placed in the air around the inspection area. Based on the selected frequency range and the level of electromagnetic signals, it produces a comprehensive graphical representation, enabling real-time measurement of the electromagnetic signals emitted by discharge defects. Theoretically, this method can effectively identify defects in any substation.

Typically, the detection method involves collecting reference comparison signals near the substation entrance, followed by partial discharge testing and subsequent RF inspection within the test area. During actual detection, given the complex electromagnetic environment of the substation, it is essential to carefully analyze the measured signals, eliminate interference, and accurately identify the type of defect through a comprehensive analysis combining frequency-domain and time-domain approaches.

Meanwhile, RF inspection can pinpoint partial discharge signals over a wide range based on the magnitude of the discharge, giving it a significant advantage for large-scale, general-purpose detection and localization. Due to its technical characteristics, RF inspection is typically used for routine inspections and initial fault location.

Partial discharge refers to the phenomenon of localized discharge or breakdown occurring within an insulating medium due to uneven electric field distribution and excessively high local field strength in the insulation structure. It is a major cause of insulation degradation, as well as a key indicator and manifestation of such deterioration, closely linked to the aging and eventual failure of insulating materials.

Therefore, effective detection of partial discharge is crucial for the safe and stable operation of power equipment. Partial discharge detection relies on various phenomena generated by partial discharge itself, using physical quantities that accurately represent these phenomena to characterize the state and properties of the partial discharge.