Partial discharge in electrical equipment insulation can lead to catastrophic failure. NETA Certified Technicians must understand the reasons partial discharge may occur and how to properly detect, diagnose, and correct it.
1. What is partial discharge within an insulating system?
a. A brief short circuit
b. A voltage spike
c. A small explosion
d. A small electrical discharge
2. How frequently might partial discharge events occur on an insulation void that has significant PD activity?
a. 1 event per half minute
b. 1 event per half cycle
c. 1 event per minute
d. 1 event per cycle
3. What is often analyzed to determine the type of partial discharge deficiency?
a. PRPD pattern
b. Time of year
c. Repeatability
d. Localized heating
4. During off-line cable partial discharge testing, what is the term for determining where in the cable the PD event is coming from?
a. Cable thumping
b. Amplification
c. Attenuation
d. Localization
5. In off-line cable PD testing, what does the term “velocity of propagation” refer to?
a. The speed to reach extinction voltage
b. The speed to reach inception voltage
c. The signal speed along the cable
d. The signal speed to arc across the void
6. When partial discharge activity is recorded, what is the required action by the equipment owner?
a. Repair the equipment as soon as possible
b. Repair the equipment within 1 year
c. It is a trend only, no action is required
d. Full analysis should be completed prior to determining action
7. Which of the following nearby conductive objects may produce partial discharge data during testing?
a. Solidly grounded objects
b. Ungrounded objects
c. Two-point grounded objects
d. Resistively grounded objects
Morgan Gieni, CET, PSE, is the Technical Support Lead — Technical Field Services (TFS) at Magna IV Engineering. He is a Certified Engineering Technologist through ASET — The Association of Science & Engineering Technology Professionals of Alberta and a Power System Electrician. Gieni has extensive knowledge and experience regarding the commissioning, repair, and maintenance of electrical power systems equipment. He has spent the past few years of his career building technical training programs, providing technical support, and mentoring field service employees. Gieni holds NETA Level IV Senior Technician Certification and is on NETA’s Technical Resource Committee.