Thursday: Morning Technical Seminars

Thursday: Morning Technical Seminars

8:00 AM-11:45 AM
Acceptance and Maintenance Testing for Medium-Voltage Electrical Power Cables

Speakers: Tom Sandri, Shermco Industries

Over the years there have been several methods and/or philosophies regarding the acceptance and maintenance field testing of medium voltage underground electrical power cable.  Time honored methods such as direct current (DC) High Potential, Insulation Resistance (IR), and Dielectric Absorption (DA) testing have been employed for many years by utilities and industrial facilities for both field acceptance testing and periodic maintenance evaluation of medium voltage insulated power cables.

Insulation Resistance provides a simple test for identifying gross defects in the cable and accessories, but offers little to no diagnostic value.  A test like dielectric absorption is useful because it can be performed on even the longest of cables, and yields a self-contained evaluation based on relative readings rather than absolute values.

In the early 1990s the benefits of using DC high potential testing for maintenance purposes of extruded dielectric cables has been questioned and written out of most industry guides.  Since the days of high potential DC, other testing methods have been developed that may provide a better indication of the integrity of cables, splices, and terminations.  These methods include Very Low Frequency (VLF) high potential testing, Tan Delta, and both Online and Offline Partial Discharge testing.

So where do we stand today?  What are the modern techniques and what value do they offer?  Do we treat Installation and Acceptance testing the same as Maintenance testing?  What is the difference?  This seminar will explore developments in testing and evaluation of medium voltage cable seen over the last 25-30 years.  The intended application of each technique along with the advantages and limitations of the technique will be reviewed providing the knowledge necessary to develop an effective cable testing program.

8:00 AM-11:45 AM
Full Time Partial Discharge Monitoring

Speakers: Bill Higinbotham, EA Technology

Periodic online partial discharge testing has now been added as a requirement in the 2019 MTS standard. This will raise awareness of the phenomenon and how to test for it within NETA companies. Annual, bi-annual, and semi-annual testing is good, but it can miss evolving or conditional problems. PD can evolve from non-existent to catastrophic in a few months. PD can exist only under specific conditions that may not be present at the time a survey is done. For these reasons, full time monitoring is the best alternative when the consequence of failure is high.  Full time monitoring can provide significant technical and economic benefits to the asset owner and the service company.

This paper will give several examples of where full time monitoring detected PD that went from undetectable to failure in a few months. It will explain the advantages of full time monitoring as it applies to both metalclad switchgear and shielded cables. The technology of full time monitoring will described and the difference between invasive and non-invasive monitoring will be covered. Monitoring can be deployed as a product or as a service and this can have a big impact on the customer and the service company. The structure of both types of deployment are reviewed from a practical and economic standpoint.

8:00 AM-11:45 AM
Get Up-to-Date on the Latest Guides for Transformer Diagnostics from IEEE

Speakers: Diego Robalino, Megger; Nick Perjanik, Weidmann

During the last few years a number of standards have been revised and new documents have been generated. As technology and experience expands, the industry has responded with the development of advanced diagnostics to assess the condition of electrical equipment. In our daily changing world, information is paramount and access to it imperative.

In this seminar, presenters aim to share and discuss with the audience some of the latest standards/guides published by IEEE related to power transformers and focused on transformer liquid and solid insulation testing and diagnostics.

Mainly two standards will be reviewed during this seminar: 1) the recently published IEEE C57.161 “Guide for Dielectric Frequency Response” Test; and, 2) the revision made to IEEE C57.104 “Guide for the interpretation of Gases generated in Oil-immersed transformers”.

The complexity of the material deserves special attention and clarification of each and every single chapter of these documents is warranted. This is a great opportunity for service companies to obtain the latest information on the most relevant revision and new guides/standards developed by IEEE. The knowledge acquired in this session will improve the knowledge of field testing specialists on the use and interpretation of Dielectric Frequency Response (DFR) & Dissolved Gas Analysis (DGA).

8:00 AM-11:45 AM
Relay Troubleshooting

Speakers: Ryan McDaniel, Schweitzer Engineering Laboratories 

Want to know some basics about troubleshooting application problems with protective relays? This half-day session will guide you through troubleshooting techniques using common distribution and transformer protection relays.

Topics of this tutorial include:

  • Troubleshooting problems, such as reclosing and logic settings issues, with a distribution feeder relay.
  • Troubleshooting problems, such as current differential winding compensation settings issues, with a transformer protection relay.
  • Troubleshooting problems, such as thermal element and motor lockout issues, with a motor protection relay.

REQUIREMENTS: For full participation, attendees should bring their own laptop with acSELerator QuickSet® SEL-5030 and SEL-5601-2 synchroWAVe® Event Software installed prior to this event, as well as a calculator. Attendees must be familiar with how to connect to relays, send and receive settings, and download event reports. It is recommended that attendees have experience applying relays for transformers and distribution lines.