The group met on Tuesday, April 19 at 2:00 PM.  The following members and guests were present:

The Chair welcomed attendees and presented a group member list to confirm the validity of the contact details because we are entering a phase of evaluating the draft.

1. William Z. Black presented his view on relationship between temperature measurement and cable ratings.  The discussion that followed did not lead to an agreement on what and how the draft is supposed to be corrected.  Rusty Bascom, who is the author of this part, agreed to review his chapter.
2. Discussed “corrected vs. measured” resistivity.
3. Proposed using DTS (Distributed Temperature Sensing) as system name for measuring temperature with fiber optic.
4. J-Power presentation about their system of temperature measurement.
5. Allen MacPhail presented further development of BC Hydro temperature monitoring their 525kV system.
6. Jay Williams amended Scope & Objectives – his version will be sent to all participants.

The group met on Monday, October 31 at 3:30 PM.

Minutes:

In the absence of Mohamed Chaaban, the vice chair welcomed attendees and presided the meeting.

1. Since the C24D discussion group has been created almost 4 years ago, the group leaders decided that there is time to finalize the initial contents and wording of the Scope and Mission of the group and apply for PAR to start working on a final version of a guide which would help utility engineers to prepare and utilize this systems in their grids.

The presented Scope has been discussed several times and its final version before the meeting was presented as follows:

                The Scope

                This guide presents an overview of the existing and emerging thermal monitoring systems related to cable installations and outlines the calculation procedures to evaluate, with high confidence, the current rating both off-line and in real time.  It summarizes the risks and benefits associated with simpler, systems based on discrete temperature measurement with thermocouples, RTD’s, thermistors, etc, compared with more sophisticated and more expensive systems like the new emerging one based on distributed temperature measurement.  The various rating calculation methods are also presented, namely the conventional analytical method of Neher-McGrath and IEC60287, and the more recent one based on the numerical methods using finite element or finite difference techniques.  This guide addresses also the various aspects of user-interface and data communication issues needed to make the system more effective and more user-friendly.

                The objective

                The purpose of this guide is to assist potential users in making an informed decision prior to purchasing and operating a real time monitoring and rating system by addressing the following major issues:

a.        Type of cable system installation: existing or new

b.       Circuit length, type of terrain and backfill along the cable route that may favor the use of distributed rather than discrete temperature measurement or vice versa

c.        Cost-benefit of using a real time monitoring and rating system vs. a calculated limit

d.       System complexity, performance, reliability and maintenance

e.        Recommended operating criteria with trend forecasting

f.         Influence of adjacent circuits

g.       System contingencies and acceptable risk

2. This presentation and statement of the vice chair that we were going to apply for the PAR caused a passionate discussion about contents of the scope and objectives.
3. In the opinion of many participants the scope, at this time, should be limited to creation of a guide for measuring temperature only.
4. Adding criteria to use the measuring system in dynamic rating would be too difficult at this time and that the document would be too large to finish it in a foreseeable time frame.
5. In the opinion of many discussants, such a big document would not be easily approved and they suggested that the guide could be expanded later.  Getting a PAR with the SCOPE as above and not including all intended subjects in the guide would not have a chance for guide’s approval.
6. After the discussion, the participants proposed the following very limited Scope:

THE SCOPE

This guide will present an overview of the existing and emerging temperature monitoring systems related to underground power cable installations.  It summarizes the features, benefits and limitations of both discrete and distributed temperature monitoring for cable ratings.

7. The vice-chair promised to present this scope to Mohamed Chaaban for further deliberations.
8. Chris Grodzinski proposed also that since the sections of the guide referred to optical measurement were less known to cable engineers they would require terminology explanations in the guide.
9. John Downes presented explanation of the terminology used in the optical measurement.

The meeting was adjourned at 5:45pm.