Partial discharge not only affects the performance of transformers, but can also accelerate the aging of insulating materials, ultimately leading to failures. Below is some information and methods about transformer partial discharge detection:
Detection Methods
Pulse Current Method: This is one of the earliest methods applied to partial discharge detection. It obtains the pulse current caused by partial discharge by connecting detection impedance or current transformers into the detection circuit, and combines with a digital signal processing system to obtain relevant information about partial discharge.
Ultrasonic Detection: Measures the magnitude and location of partial discharge by detecting the ultrasonic signals generated by partial discharge in dry-type transformers. The frequency band of ultrasonic sensors is approximately 70~150 kHz (or 300 kHz) to avoid ferromagnetic noise from the iron core and mechanical vibration noise from dry-type transformers.
Gas Chromatography: When partial discharge occurs, the gases produced by the insulating materials of power transformers are mainly acetylene and hydrogen. Gas chromatography can determine the existence of problems in transformers by detecting these two gases. However, the detection accuracy of this method is relatively low because it has strong sensitivity to all gases.
High-Frequency Instrument Monitoring Method: Uses high-frequency instruments to monitor the high-frequency signals generated during partial discharge, suitable for online monitoring of partial discharge.
Ultra-Wideband Measurement Method: Detects partial discharge by measuring the ultra-wideband signals generated, suitable for partial discharge detection in large industrial transformers.
Non-Electrical Measurement Methods: For example, using thermal imaging cameras to detect temperature changes caused by partial discharge.
Measurement Significance
Insulation Deterioration: Partial discharge is both a cause and a precursor and manifestation of insulation deterioration. Compared with other insulation tests, partial discharge detection can reflect the insulation condition of transformers in advance, promptly identify internal insulation defects, and prevent latent and sudden accidents.
Technical Support
Huaying Amorphous Alloy Transformer Co., Ltd. provided supporting information that partial discharge is very weak and difficult to detect by human intuition alone, emphasizing the need to use highly sensitive partial discharge measuring instruments for detection.
Precautions
Interference Factors: When conducting partial discharge detection, attention should be paid to avoiding various interference factors such as electromagnetic interference and mechanical vibration.
Data Interpretation: The results of partial discharge detection need to be analyzed and interpreted by professionals to determine the degree and possible causes of partial discharge.
Operating Guidelines
Preparation: Ensure that all test equipment has been calibrated and maintained according to relevant regulations.
Select Detection Method: Choose the most suitable detection method based on actual conditions.
Implement Detection: Conduct partial discharge detection according to the selected method.
Data Analysis: Carefully analyze the detection results to determine the location and severity of partial discharge.
Maintenance Recommendations: Develop maintenance plans or repair measures based on the detection results.
Specific Applications
Dry-Type Transformer Partial Discharge Detection: Suitable for partial discharge detection in dry-type transformers, typically using ultrasonic detection technology.
Oil-Immersed Transformer Partial Discharge Detection: Gas chromatography can be used to detect gas components in insulating oil, or methods such as the pulse current method can be used to detect partial discharge.
Conclusion
Transformer partial discharge detection is a complex engineering issue involving multiple detection technologies and methods. Correctly selecting and using appropriate detection tools and technologies is crucial for ensuring the safe operation of power systems. If you need more detailed technical parameters or operating guidelines, please inform me of the specific details so that I can provide more precise assistance.
