The interference elimination during partial discharge detection mainly involves eliminating interference signals based on the principle of electromagnetic radiation. During on-site testing, the following methods are often used to eliminate interference in the test:
1. Stagger time or turn off interference sources
For some interference sources (such as mobile communication signals, broadcast signals, rail transit, etc.), selecting a smaller signal for partial discharge detection can effectively avoid the interference signal; If there are interference sources that can be turned off during the detection process (such as various rotating motors, electronic fences, lighting, SF6 leak detection devices, air conditioning, etc.), the interference sources can be turned off to avoid affecting the detection results.
2. Choose the appropriate filter
For interference signals with fixed frequencies, appropriate filters can be installed to filter out the interference signal, in order to avoid affecting the partial discharge detection results.
3. Analyze the power frequency correlation of detection signals
Analyzing the power frequency correlation of the detection signal can effectively determine whether the signal is related to the power frequency signal. If it is related, the signal is emitted in the power frequency environment, which is likely to be a partial discharge signal, but it may also come from interference in the power system, such as lights, air conditioning, meter cabinets, and secondary circuits. However, if there is no power frequency correlation, most of it comes from interference signals.
4. Positioning method for eliminating interference signals
When pulse signals are detected, the power frequency correlation of the signal can be preliminarily determined, but further positioning analysis of the signal source is needed. The time difference method can be used to roughly locate and analyze the signal, in order to confirm whether the signal comes from internal partial discharge signals or external interference signals of the equipment.
Analysis method for partial discharge test results:
1. Trend analysis method
Analyze the detection results of the same switchgear at different times, and make a longitudinal comparison to determine the operating trend of the switchgear. Detect the switchgear in the switchgear room according to specific cycles, retain each test result, and then analyze the trend of partial discharge status changes of the equipment based on the test results;
2. Horizontal analysis method
Horizontal comparison is made between the detection results of the switchgear in the same switchgear room. If the detection result of one switchgear is greater than the background value on site and the test results of other switchgear, it can be determined that the equipment may have defects;
3. Threshold comparison refers to providing a judgment threshold, comparing it with the detection results of the switchgear, and analyzing the results to determine the operating status of the switchgear.
ZC-830 Partial Discharge Detector with portable structure and embedded signal receiving and data processing module, has multiple analysis modes and can conveniently measure the UHF signals and the ultrasonic signals generated by the partial discharge of the electric equipment. Compared with similar products, this product has convenient operation and strong function.Besides the embedded ultrasonic sensor, the host machine of the product is also configured with an external sensor interface for connecting UHF sensor, TEV sensor and external ultrasonic sensor thereto. The uniform interface is adopted for convenient and simple operation.This product widely used in theater testing of power systems, including insulation status testing of high-voltage switchgear, ring-network cabinets, voltage/current transformers, transformers (including dry-type transformers), GIS, overhead lines, cables, and other equipment.
Kvtester Electronics Technology Co.,Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. It has been engaged in the electrical testing industry for many years, and its products are of high quality. We welcome customers to come and purchase. Service hotline: 0086-27-81778799, to learn more, visit the official website: www.kvtester.com
