Power Cable Test Methods Flashcards
7 cards from real NETA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Power Cable Test Methods flashcards as text
What is the recommended VLF test voltage for a new 15 kV (8.7/15 kV) XLPE cable acceptance test per IEEE 400.2?
Answer: 3 × U0 (approximately 26 kV)
IEEE 400.2 specifies a VLF withstand acceptance test at 3 × U0 for 30–60 minutes on new extruded dielectric cables.
During a cable shield continuity test, which instrument is most appropriate?
Answer: Low-resistance ohmmeter (micro-ohmmeter)
A low-resistance ohmmeter measures the milliohm-level resistance of the metallic shield to verify it is continuous and properly bonded.
What condition is indicated when a TDR trace shows a positive (upward) reflection at the far end of a cable?
Answer: Normal open-circuit termination
An open-circuit termination presents infinite impedance, causing a positive polarity reflection at the cable's far end in a TDR trace.
Which partial discharge (PD) measurement unit is used to quantify discharge magnitude in cable testing?
Answer: Picocoulombs (pC)
Partial discharge magnitude is expressed in picocoulombs, representing the charge transferred during each discharge event within the insulation.
A technician measures conductor resistance on a three-phase cable and finds phase C is 15% higher than phases A and B. What is the most likely cause?
Answer: Phase C conductor has a high-resistance splice, broken strands, or poor connection
A significant resistance deviation in one phase typically indicates a conductor splice defect, broken strands, or a corroded connection point increasing resistance.
When comparing present insulation resistance values to historical baseline values, what trend is considered a warning requiring investigation?
Answer: IR values that decrease by more than 50% from the previous test
A 50% or greater reduction in IR from prior test results is a NETA-recognized warning threshold indicating progressive insulation deterioration.
What test best evaluates the integrity of a cable's outer jacket (not the insulation) for moisture intrusion pathways?
Answer: DC jacket integrity test (holiday test)
A DC jacket integrity test (holiday test) applies DC voltage between the shield and the outer surface to detect pinholes, cuts, or voids in the jacket.