The development of Condition Based Maintenance for 33kV Oil-Filled cable

The aim of the project is to identify suitable diagnostic test for Oil-Filled cable and subsequently to develop Condition Based Maintenance (CBM) guideline. From the literature review, Dissolve Gas Analysis (DGA) of the oil inside the cable is the most suitable screening test for Oil-Filled cable. Besides DGA test, another type of testing for the oil recommended is laboratory moisture test using the Karl Fischer method. From the DGA and laboratory moisture test results, the requirement of onsite tests is determined. The onsite tests namely Partial Discharge (PD) measurement and moisture evaluation using Frequency Dielectric Spectroscopy (FDS). Through this exercise a correlation between laboratory test results and requirement of the onsite test were developed. This correlation was then used to develop Condition Health Indexes calculation which is a part of CBM guideline. In the CBM guideline, besides Condition Health Indexes calculation, description of the identified test, step-by-step procedure to perform the identified test and interpretation of the test results are also available. As a conclusion, this project has successfully identified the suitable diagnostic test for Oil-Filled cable and the developed CBM guideline for Oil-Filled cable shall be incorporated into the existing Condition Based Maintenance (CBM) system for medium voltage underground cables.