PD CHECK is currently the most widely used high-frequency detection equipment in China. It adopts a broadband detection method. Most power supply companies, electrical research institutes, and universities are equipped with this equipment. The high-voltage state detection technical specifications and other related testing procedures are also based on the equipment map as an example , It has the advantages of high detection accuracy, easy analysis, simple operation, easy to carry, etc., suitable for general cable survey work. PD CHECK adopts the method of calculating the equivalent frequency and equivalent duration of the signal to classify the collected signals. A certain aggregated signal can be selected for analysis, which can distinguish signals from different sources. The classification method is shown in Table 1.
5
Typical Case
5.1 Anomaly Overview
In December 2017, the cable company found that a certain 35kV cable had a partial discharge abnormality during the live detection of the 35kV cable outlet of a 220kV substation. The PRPD spectrum has obvious power frequency phase correlation, and the discharge amplitude is large. , Showing the characteristics of insulation defects.
5.2 Test objects and items
The specific situation of the cable line is shown in Table 2. The test item is high-frequency partial discharge test.
5.3 Testing equipment and standards
See Table 3 for information about the equipment used in the test.
The determination of the test results is based on the following standards:
1. Q/GDW 11400-2015 "Guidelines for the Field Application of High Frequency Partial Discharge Detection Technology for Power Equipment"
2. Q/GDW 11223-2014 "Technical Specification for High Voltage Cable Condition Detection"
3. Q/GDW11224-2014 "Technical Specification for Partial Discharge Detection Equipment for Power Cables"
4. DL/T664-2016 "Application Specification for Infrared Diagnosis of Live Equipment"
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