- Handouts available via web.
- Discussions around using IEC 61000-4-30 & the addition of other methods for charactering voltage sags leading to a voltage sag system indices.
- Describe what the guide is to be used for?
- Objectives
- Methods for counting dips
- Why is one voltage sag more sever than another.
- This is another method for determining system performance.
- Another possible chapter for P1564:
- Last Meeting Discussion:
- Scott Peele presented an alternative way of obtaining voltage-sag indices from monitors. His utility uses fault current data to determine the number of faults per circuit mile. This gives, according to him, a better measure of the performance of the utility network. The number of voltage sags experienced by a customer can be calculated from the number of faults per circuit mile by using the methods described in Chapter 9 of the Gold Book and in IEEE 1346. It was noted that where monitoring data is not available, such methods may be an alternative means of obtaining voltage sag performance data.
We broke up into groups for the Chapter discussions:- Group Members
- Math Bollen, Randy Collins
- Main Discussion around 1159
- Will put in what is needed now and wait for 1159.2 for further developments.
- ? The extraction of complex phasors and symmetrical components from measurements has to be explained. Using a window-function gives "window artefacts" which also have to be explained.
- Sections 6.3.3 and 6.3.4 are useful for analysis of individual events, but not for development of indices
- A separate method for three-phase signals is needed, but the extraction method based on symmetrical components may be hard to follow. A more detailed description of the method is needed.
- Group Members
- ?,?
- Need a Diagram
- Nominal voltage for study
- Sag no Dip
- Referenced in definitions for Dip
- Retained voltage
- Group Members
- Dan Sabin,?
- Dan Sabin will e-mail notes to Math Bollen.
- Have multiple methods
- Sarfi/Unipede
- Monitor availability, recommendation
- Aggregation windows
- How to choose "worst case" for aggregation?
- SARFI-ITIC are not appropriate for MV & HV systems
- More detailed examples needed.
- Don’t show CBEMA
- Re-org 8.5.2
- Details from CIGRE paper missing
- 8.7.3 – Table not used as shown
- Eskom table is not widely used
- Group Members
- Dave K., Bob S., Chris M., Scott P., Greg O., Marek W., Greg A., Dave V. & Russ E.
- Major discussion between Scott P & Marek W
- Scott’s system looks at # or faults/feeder.
- Current data available.
- Marek’s system is based on the end user – customer
- Customer Type (Manufacturing,C&I)
- Substation (common bus)
- Feeders (Exposure, Construction)
- Where to monitor – Customer Base
- What implications are there associated with monitoring points
- Transmission vs. Distribution
- Cause of events (Cable failure/lightning/equipment failure/dig in)
- What can be done to protect?
- Possibly use Scott P’s as additional P1564 chapter?
- Still need to determine weighting factors used in obtaining system indices from sites.
- Math and Mike will update the working group document.
- Chris Melhorn – Will provide what he has been working on.
- Scott Peele: Can you method of "predicting sag indices" fit into another chapter of P1654?
- Mike Sheehan will write a discussion of who the voltage sag index is intended for. (Last meeting
- Jim Burke will write a discussion on using pre-event voltage or nominal voltage as a reference. (Last meeting)
- Working group members are encouraged to read and comment on the revised draft prior to the next meeting.
- The aggregation time period to be used for voltage sag calculations needs to be defined.
- Loss of information when moving from samples to system indices.
- What and for whom is the index intended.
- Next meeting at IEEE PES Summer Meeting in Chicago.
- Quarterly meetings via web, like 1366.
- Look to IEEE for sponsorship for software
His proposal resulted in an interesting and lively discussion. The main issue of the discussion was: there is no direct link between voltage-sag frequency and faults per circuit mile; and the customer is not interested in network performance but in sag frequencies.
It was suggested to add a chapter for the working group document on predicting sag indices from fault frequencies. Scott Peele volunteered to write a first draft.
Action Items:
Issues that need resolution (Did we get any of these?)
4. Determination of weighting factors used in obtaining system indices from site.
Respectfully Submitted,
Russ Ehrlich
Secretary, P1564