In the past year, a group of volunteers working on IEEE Standards for the Power and Engineering Society, particularly those in the Power Quality Subcommittee, have published four standards. Considering one of the most well known PQ-related standards, IEEE 519, went 22 years without revision until its latest update in 2014, this most recent trend toward more frequent publication is remarkable and encouraging.
Among the standards most recently published were IEEE 1250, 1159, 1159.3 and 1889, Guide for Evaluating and Testing the Electrical Performance of Energy Saving Devices . The first three were revisions to existing standards, though substantial changes were incorporated. IEEE 1889 deserves special attention because not only is this a new standard, but it also takes on a challenging and difficult topic—how to tell if the energy-saving claims of vendors of energy-saving devices (ESD) really save energy, with the focus on electrical ESDs. Don’t confuse ESD of energy-savings devices with ESD of electrostatic discharge.
When the work began in 2013 after the project approval request was approved, early discussions raised legal questions about this matter, such as “what if someone sues us for putting them out of business when their unscientific claims are disproven?”
As stated in the Purpose of IEEE 1889, it was created “to provide instructions for the measurement protocol of the most relevant electrical parameters such as voltage, current, kilowatts, and kilovars that are needed in determining the energy consumption of energy saving devices (ESDs). This guide also provides guidance for measuring performance characteristics of various loads affected by the ESD, such as lumens, rotations per minute, torque, temperature, voltage, etc.”
While the guide’s description may not seem overly exciting, what is really being addressed are claims by ESD vendors about their devices saving energy for the user, which implies that it saves the user money on their energy bills. With the disclaimer up front that there are many reputable vendors that produce true ESDs with real savings, most consumers don’t have the ability to determine the validity of the claims and if the device will work with their electrical loads to actually save energy.
Despite the legal concerns, the group forged ahead to develop engineering-based methods to evaluate and test the electrical performance of ESD by “describing measurement methods that focus on monitoring the power absorbed or generated by the observed load or generator without the ESD connected and with the ESD energized.”
Established and proven scientific principles were incorporated at each stage in the “detailed protocols which describe step-by-step the testing circuits to be used, the type and accuracy of needed instrumentation, what particular measurements and in what order are to be taken. Special emphasis is given to sources of measurement errors due to incorrect connection of instrumentation, inadequate instrumentation, or incorrect interpretation of results.” Even practical examples of the physical mechanisms of phenomena that may cause errors are covered.
Defining what constitutes a single-phase versus three-phase ESD, or what is a parallel-connected ESD versus series-connected ESD, may seem trivial but are important in the test process when measuring energy parameters accurately with and without the ESD in the circuit. If the circuit is modified to test with or without the ESD, then the results may not be consistent or scientifically valid. The measurements of both scenarios must be recorded over time, not one snap-shot reading, with all other nonelectrical energy flows or variables held constant over the duration of both sets of tests. This is often a challenge when conducting the test in the field, versus a laboratory. The algorithms used to calculate the electrical parameters being measured must be traceable to standards, such as IEEE 1459, IEEE Standard Definition for Measurement of Electric Power Quantities Under Sinusoidal, Non-sinusoidal, Balanced, or Unbalanced Conditions . Using the displacement angle between the voltage and current waveforms in today’s harmonic-rich current environments isn’t a true measure of power factor. Those conducting the tests should be run by qualified personnel to set up the system, run the tests and compile the report.
The intent of the guide is to provide interested individuals with sufficient information to accurately and repeatably determine the power reduction as measured by the local utility meter (or the lab measuring devices) regardless of the technology being tested; how the technology interacts with the load; the customer being residential, commercial or industrial; and the vendor’s claims.
The bottom line is the ESD must provide real savings for any return on investment to be realized.