Since power cables are mainly composed of two parts—metallic conductors and insulators—the electrical performance tests for power cables revolve around these two aspects.
Conductor Electrical Performance and Related Tests:* These mainly involve measuring the DC resistance of the conductor, checking the cable phase, and calculating the cable's current carrying capacity.
Insulation Electrical Performance and Related Tests:This is the most important and complex type of test for power cables, including two main categories: inspection tests (non-destructive tests) and withstand voltage tests (destructive tests).
Inspection tests refer to indirectly judging the insulation condition by measuring certain characteristics of the cable insulation at lower voltages. There are many methods, such as insulation resistance testing and dielectric loss tangent testing. These tests reveal, to a certain extent, the different natures and developmental stages of insulation defects.
Withstand voltage tests, on the other hand, simulate various voltages that may occur during operation, applying equivalent or more severe voltages to the insulation to test its withstand capability. This type of test is the most effective, feasible, and irreplaceable. However, withstand voltage tests can only reveal insulation defects when they have developed to a relatively severe level, in the form of breakdown, and cannot clearly reveal the nature and root cause of the insulation. Withstand voltage tests typically take the form of DC withstand voltage tests, AC withstand voltage tests, impulse withstand voltage tests, and partial discharge tests under high voltage.
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