The Insulated Conductor Committee’s groups, which include engineers and scientists, met in Orlando, Florida, for the fall 2018 IEEE/ICC meeting from October 29–31, 2018. The Insulated Conductors Committee (ICC) is a professional organization within the Power Engineering Society (PES) of the Institute of Electrical and Electronics Engineers (IEEE).
This is an ongoing opportunity for the InterNational Electrical Testing Association to be recognized and to offer a field-testing perspective to the working groups as documents are developed. The working groups are made up of cable manufacturers, utilities, test equipment manufacturers, and end users.
Discussion
Several presentations followed the working group meetings.
Table 1: Fall 2018 Working Groups/Discussion Groups Meetings for Subcommittee F
Diagnostics to Manage Water-Treeing in MV Cables
Dr. Nigel Hampton, Josh Perkel, Thomas Parker, NEETRAC, USA
The underground distribution system makes up approximately 18 percent of the distribution infrastructure (EEI). This system is comprised of terminations/elbows, cable, and joints, which all contribute to the reported SAIDI and SAIFI data (see sidebar). Most of the reported failures are associated with the accessories, which can be addressed easily (relative to the whole system) through replacement and diagnosis because they are discrete devices. However, the system continues to age while being required to deliver increased reliability (lower CAIDI). Thus, the longevity and degradation rate of the backbone cables remains of paramount importance.
Measuring Reliability
SAIFI and SAIDI are commonly used indices used by electric power utilities to measure reliability as defined in IEEE Std. 1366.
- System Average Interruption Duration Index (SAIDI) is the average duration of interruptions per consumers during the year. It is the ratio of the annual duration of interruptions (sustained) to the number of consumers: total duration of sustained interruptions in a year / total number of consumers. If duration is specified in minutes, SAIDI is given as consumer minutes.
- System Average Interruption Frequency Index (SAIFI) is the average number of sustained interruptions per consumer during the year. It is the ratio of the annual number of interruptions to the number of consumers: total number of sustained interruptions in a year / total number of consumers.
- Consumer Average Interruption Duration Index (CAIDI) is the average duration of an interruption, calculated based on the total number of sustained interruptions in a year. It is the ratio of the total duration of interruptions to the total number of interruptions during the year: total duration of sustained interruptions in a year / total number of interruptions. It can be seen that CAIDI equals SAIDI / SAIFI.
Partial Discharge Monitored Voltage Testing by Damped AC Voltages of Power Cables up to 220 kV
Edward Gulski and Rogier Jongen, onsite HV solutions ag, Switzerland; Jaroslaw Parciak, onsite HV solutions Central Europe, Poland
Abstract: For transmission grid operators, important questions about reliable network operation include:
- How do you perform the detection of poor workmanship defects of newly installed cable circuits in a sensitive and non-destructive way?
- How do you perform non-destructive diagnostics of in-service cable circuits to determine the actual condition?
Condition Assessment of Aged SCFF & HPFF Cables via On-Line and Off-Line PD Measurements
Mark Fenger, Prysmian Cable and Systems
Abstract: Over the past number of years, a larger portion of SCFF and HPFF cable circuits have been subjected primarily to on-line partial discharge measurements as complementary to or instead of traditional dissolved gas analysis (DGA). The presentation discusses how on-line and off-line PD measurements can be performed in a meaningful way on fluid-filled cable systems. Multiple case studies are presented and discussed.
The 2018 fall meeting in Orlando, Florida, was a great success. The discussion that followed these presentations will allow the working groups to better understand the ongoing research that can be incorporated into the revision of the guidelines and allow us to prepare for the 2019 spring meeting in Savannah, Georgia.
Ralph Patterson is the owner and President of Carolina Electrical and former owner of Power Products and Solutions. His professional background includes working as a design engineer of transformers and as a specifying engineer of insulated conductors. He has more than 25 years in power engineering, particularly in insulation diagnosis and evaluation of electrical distribution equipment. He serves on the NETA Standards Review Council, is the NETA liaison for the IEEE Insulated Conductor Committee’s working groups, and received NETA’s 2001 Outstanding Achievement Award.