Task Force on Single-phase Harmonics Limits

Winter Power Meeting - Tampa, FL

February 3, 1998

 

  1. Introductions
    2.
  2. Summary of Document - Jim Howell presented an update of the document outline. Copies were distributed.
  3. Discussion of Developments in Related Industry Standards - Several topics were discussed concerning other industry standards including IEC 1000-3-2. Girts Zeidenbergs of IBM expressed concerns that the IEC standard is too stringent and not based on real world data. He also requested that more input from manufacturers be included in any efforts to develop IEEE standards.

    4. A recent Consolidated Edison paper was cited that shows no real problems with harmonics on the utility grid in Manhattan, which serves millions of switch-mode power supply loads. The Con-Edison paper that describes the voltage THD for a period of 6 months at a commercial installation is published in IEEE Transactions on Industry Applications, Vol. 33. No. 4, July/August 1997, the title of the paper is "An Evaluation of Energy Storage Techniques for Improving Ride-Through Capability for Sensitive Customers on Underground Networks"

    Dan Ward emphasized that manufacturers' input is both welcome and solicited. It was suggested that the Con-Edison paper may not be a good representation of US systems, because the grid in Manhattan is stiffer than most. Concerns for single-phase harmonics primarily are from larger, residential loads that are expected to penetrate systems in the future, such as vehicle battery chargers and variable speed heat pumps. Dan agreed to work on a section in the IEEE document to address system design.

    From the general discussion in the meeting, there is still a strong debate as to how soon harmonic equipment limits need to be implemented in industry. Several pointed out that that harmonic distortion has not increased as quickly as some (including EPRI) have predicted. However, research shows that distortion is gradually increasing and it is expected to continue to do so.

  4. Update on Standards Related Work - Arshad Mansoor briefly mentioned some recent developments with work in Canada. The work translates IEC 1000-3-2 limits to a recommended Canadian standard using source impedance and frequency more indicative of Canadian electrical systems. Copies of two related papers are included with the minutes.

    5.  

  5. Harmonic Limits Discussion - The task force discussed how harmonic limits should be structured. It was generally agreed that individual frequency limits must be included not just THD. It was also suggested that limits may be most effective if they address actual harmonic ampere injection rather than just percent distortion. Many favor listing injection limits in amperes per watt.

    6. Past history of limiting harmonic distortion was also discussed. A specific example of how California utilities influenced electronic ballast distortion was given. Generally a 20 % THD range was chosen for DSM rebates because they provided a better improvement in energy savings than those in the 30% range without creating any significant additional operating problems. Another example of how industry is influencing distortion limits can be seen with the Electric Vehicle Infrastructure Working Council (IWC). The IWC is developing specifications for vehicle battery chargers. These specs include recommendations for energy efficiency, power factor, disturbance susceptibility and harmonic distortion.

  6. Source Impedance and Testing Protocol Discussion - Choosing a consensus value for source impedance was briefly discussed. Alex Emanuel has contributed a section on source impedance and a suggested test protocol for equipment. There is little debate that a uniform source impedance value for testing equipment is needed. Most agree that because of system design differences, this value will differ from European standards.
  7. Web Access - Jim Howell reported that this spring, the Task Force will begin using the IEEE web site to post minutes, notices and sections of the Standards Document. Members will be notified of the details and as future postings are added.
  8. Panel Session - The Task Force agreed to request a panel session for the Summer Power Meeting in San Diego. The format for the session will be discussions from industry on the impact of single-phase harmonic limits. Manufacturers and utilities will be represented.

    9.  

     

  9. Action Items - The following action items were identified:

 

  1. Spring Meeting Announcement - The next meeting on the Task Force will be held at Summer Power Meeting in San Diego, July 12-16, 1998.

XI. Adjourn

 

 

 

Action Item Update 4/24/98