What has changed in IEEE 519 between 2014 and 2022 editions?
IEEE 519 is one of the most common standards regarding power quality and harmonic control. The 1992 edition was in place for over two decades until it was replaced by 2014 edition. Eight years later it was superseded by 2022 edition. The question is: what has changed between the last two editions?
Structure of IEEE 519-2014 and IEEE 519-2022
First look at both editions, June 2014 and August 2022, does not reveal any major difference. The standard is still issued by the IEEE Power and Energy Society. Both editions have similar length with regards to number of pages. The structure remains the same:
- 5 main chapters
- Annexes A, B, C and D
Formal changes
Among the formal changes is some wording. The IEEE 519 is not called a “recommended practice” anymore but a “standard”. Instead of “recommended values” the standard now defines “limits”.
In multiple sections the word should has been replaced with shall indicating mandatory requirements.
Numerical values of harmonic limits
Now let’s look at the numerical values of harmonic limits. Table 1 in the standard provides the voltage distortion limits. They are exactly identical in 2014 version and 2022 version. The change is that it is not explicitly stated that limits for individual harmonics apply up to and including 50th harmonic.
Current distortion limit also appear the same:
- Table 2 provides current harmonic limits for systems rated 120 V through 69 kV
- Table 3 provides current harmonic limits for systems rated above 69 kV through 161 kV
- Table 4 provides current harmonic limits for systems rated above 161 kV
Same structure, same numerical values. Or not?
The devil is often in the detail. In 2014 version (and also 1992) the Tables 2, 3 and 4 provide current distortion limits for individual odd harmonic orders. Even harmonics are limited to 25% of the odd harmonic limits.
In 2022 edition the Tables 2, 3 and 4 look almost identical. However, when reading carefully we notice the difference. The limits in the tables are valid for all individual harmonic orders, not only for odd harmonics. Only for orders h ≤ 6 the even harmonics are limited to 50% of the harmonic limits from the tables.
The 2022 edition of IEEE 519 highlights the intention to use current harmonic limits for the evaluation of installation containing nonlinear loads instead of evaluating an individual nonlinear load (this concept is still frequently misused or misunderstood).
Annex A dedicated to interharmonic voltage limits had undergone a major rework.
Summary
IEEE 519-2022 is very similar to its predecessor from 2014. The limits for voltage harmonics, crucial for power quality, remain exact same.
A change appears for current harmonics. While the individual limits for odd harmonics and total demand distortion (TDD) remain unchanged, the approach for even harmonics changed. Previously, the even harmonics were limited to 25% of the limits for odd harmonics. Lately, the even harmonics have same limits as the odd harmonics, with exception of orders 2, 4 and 6 that are limited to 50% of neighbouring odd harmonic.
While the voltage limits are completely identical, the new approach gives more freedom for the distribution of current harmonics. 2022 edition does not allow more distortion (voltage THD but also current TDD unchanged) but it does not penalize even harmonics that some modern converter topologies may inject.
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References
[1] How to understand the requirements of IEEE 519? MB Drive Services, January 2022, available online, https://mb-drive-services.com/how-to-understand-the-requirements-of-ieee-519/
[2] VFD compliance with voltage and current harmonic limits, MB Drive Services, October 2024, available online, https://mb-drive-services.com/vfd-compliance-with-voltage-and-current-harmonic-limits/
