More to It Than at First Glance

A significant portion of the standard-making process goes beyond just rules and requirements. It is especially true for the standards developed by the Institute of Electrical and Electronic Engineers’ (IEEE) Power Quality Subcommittee, which produced a roadmap in 2006 to identify gaps or outdated information. The following are some of those documents that are worth reading.

IEEE Std 1159 2009, IEEE Recommended Practice for Monitoring Electric Power Quality, states, “An understanding of how power quality events impact the power system and end-use equipment is required in order to make monitoring useful … [and to] assist users as well as equipment and software manufacturers and vendors by describing techniques for defining, measuring, quantifying, and interpreting electromagnetic disturbances on the power system.” It’s a comprehensive standard, covering power quality definitions, detailed descriptions of power quality phenomena, monitoring objectives, various types of instruments used to measure and monitor power quality phenomena and insight on how to interpret the data captured.

IEEE Std 1250 2011, Guide for Identifying and Improving Voltage Quality in Power Systems, is quite useful “to assist power delivery system designers and operators in delivering power with voltage quality that is compatible with electrical end-use equipment … [and] to point utility system customers toward power quality solutions that may exist in the power utilization system and equipment.” It provides information on how a typical power system operates; benchmark values for the different phenomena described in IEEE 1159, along with what type of equipment is often susceptible to such phenomena; and mitigation techniques and equipment to prevent process interruptions. The guide is also a gateway to other relevant standards.

The mitigation discussions are carried into much greater detail in IEEE Std 1409 2012, IEEE Guide for Application of Power Electronics for Power Quality Improvement on Distribution Systems Rated 1 kV Through 38 kV. This publication is the first from the committee on this particular subject. It defines the technology of custom power, which is “the employment of power electronic or static controllers in medium voltage distribution systems for the purpose of supplying a level of power quality that is needed by electric power customers that are sensitive to rms voltage variations. Custom power devices include static switches, converters, injection transformers, master control modules, and/or energy storage modules that have the ability to perform current interruption and voltage regulation functions in a distribution system to improve power quality.” For each of the major categories of power quality phenomena, the publication examines a number of possible mitigation devices, such as “for voltage sag, swell, and interruption mitigation, the following custom power controllers are examined: dynamic voltage restorer (DVR) devices, static voltage regulator (SVR) devices, backup stored energy system (BSES) devices, and transfer switch (TS) devices.” It also provides the reader with input/output criteria and how to measure performance of the device, including real case studies involving such devices.

IEEE Std 1453 2011 is an update to the flickermeter standard, which first adopted the IEC 61000-4-15:2010, Electromagnetic compatibility (EMC)—Testing and measurement techniques—Flickermeter—Functional and design specifications, in 2004, moving away from what is referred to as the “GE flicker curve” and using the parameters perceptibility short term (Pst) and perceptibility long term (Plt) to describe the eye-brain response to the flickering of a lighting source from voltage fluctuations. IEEE Std 1453.1 2012 takes it to the next level, adopting IEC/TR 61000-3-7:2008, Electromagnetic compatibility (EMC)—Limits—Assessment of emission limits for the connection of fluctuating installations to MV, HV and EHV power systems. Like 1453, this standard contains significant tutorial information in the annexes, including explanations and data on the difference of 230-volt (V) and 120V lighting, how to apply the Pst and Plt values at one part in the system to what is expected at other parts of the system, how to assess the results of a measurement study, and case studies on various types of equipment that often cause flicker.

Several other standards are either in or about to reach the balloting stage, including the long-awaited update to IEEE 519, Recommended Practices and Requirements for Harmonic Control in Electric Power Systems. The also long-awaited and new material in IEEE 519.1, Guide for Applying Harmonic Limits on Power Systems (which is written to educate technicians who have been misapplying IEEE 519), and IEEE 1564, Recommended Practice for the Establishment of Voltage Sag Indices, which should be published in 2012. Another document in the backpack is IEEE 1459 2010, IEEE Standard Definitions for the Measurement of Electrical Power Quantities Under Sinusoidal, Non-Sinusoidal, Balanced or Unbalanced Conditions. It was also recently revised, adding more definitions to the power parameter list, specifying the variations of the term “apparent power.”

So don’t let the term “standard” lead you to believe it is just about rules and regulation. There is plenty to be learned that can be readily applied to day-to-day power quality activities. Pick one up, and give it a good read.

BINGHAM, a contributing editor for power quality, can be reached at 732.287.3680.

About the Author

Richard P. Bingham

Power Quality Columnist
Richard P. Bingham, a contributing editor for power quality, can be reached at 732.287.3680.

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