The basic principle of electrical detection for partial discharge is to measure the high-frequency current pulses generated by partial discharge in the insulation structure of the test sample under a certain voltage. During actual testing, it is necessary to distinguish and eliminate the high-frequency pulse signals caused by external interference. Otherwise, such false signals will lead to a decrease in detection sensitivity and an increase in the minimum measurable level, and even cause serious consequences such as misjudgment.
In a certain predetermined testing environment, how to distinguish the interfering signals and take several necessary measures to ensure the correctness of the test has become a relatively important issue. The currently effective method is to enhance the ability of the test personnel to identify the interfering waveforms, and correctly grasp the characteristics of the test item’s discharge, as well as the patterns of the applied voltage and time. Experience shows that the correctness of the judgment largely depends on the tester’s experience. The more waveform diagrams one masters, the faster and more accurate the methods for identification and solution will be.
Currently, using computers for spectrum analysis to aid in identification is possible, but the prerequisite for applying computers also requires the ability to predict the characteristics of various interference waves and the discharge waveforms of the test samples. Based on our country’s long-term practical experience and some previously published graphs from abroad, this text has been compiled for reference. It should be noted that the discharge waveforms described here are mostly presented in typical graphical forms and cannot possibly cover all possible contents.
Interference will reduce the detection sensitivity of the partial discharge test. During the test, the interference level should be suppressed to a low level. The types of interference usually include: power supply interference, grounding system interference, electromagnetic radiation interference, discharge interference from various components of the test equipment, and various contact interference. These interferences and their pathways into the test circuit.
The basic basis for identifying interference: The interference in partial discharge tests is random and disorderly, making it difficult to establish a comprehensive identification method. However, by mastering the characteristics such as the time, location, scanning direction of various discharges, as well as the voltage-time relationship curves, it is helpful to improve the identification ability.
Post time: Jul-30-2026