IEC61000-4-30: Learn all about the standard

ABNT NBR IEC Standards

Imagine if, as if by magic, the constitution and laws simply disappeared. What would become of everything without rules? The answer is simple: Chaos. If you can't imagine it, watch any movie with a post-apocalyptic theme, they always address it.

The organization and rules that we are able to create and follow are some of the many things that make us different from other species. We don't know how to live any other way. We need laws and rules, otherwise it becomes a mess.

Now, returning to the world of engineering, the ABNT, NBR, IEC, NEMA standards, among others, are our “guides” in everything we develop and create. They guarantee the organization, quality, and standardization of everything.

We need to “dance to the music”, and these rules guarantee us a safe dance. It is our obligation to understand and interpret them. Have you ever seen how ugly it is when someone dances strangely? It becomes a meme. So “dance” with technique!

Now that we know that it is vitally important to fully understand the standards that affect our lives and work, and that failure to comply with them borders on amateurism and ridicule, let's talk about one in particular that helps us a lot when it comes to energy quality: IEC 61000-4-30.

IEC 61000 Definition

IEC 61000 is a series of 71 standards that address the following topic: Electromagnetic compatibility. It is divided into 6 parts, each covering in greater depth, namely: 

• Part 1 - Generalities: Here we have introductions, fundamental principles, definitions, terminologies, and the entire basis for the development of the subject;

• Part 2 – Environment: Here we have the description, classification and compatibility levels. As in any modeling, how can we define something without knowing what is in the test “location”. What are we subjecting the target of the analysis to? Are there frequencies here? Radiation? It is in this environment that it speaks, and goes into depth. These are the conditions under which the definition is valid: “This standard is valid under these conditions”;

• Part 3 – Limits: This involves defining the emission limits of a disturbance and immunity to it. Harmonics generated by equipment, for example;

• Part 4 – Testing and measurement techniques, here is our focus! But still, it is too broad, and we will narrow it down to a more specific application;

• Part 5 – Guidelines: Installation and mitigation methods and devices;  

• Part 6 – Generic standards: Applied to homes, industries, substations, etc.

In summary, ABNT NBR IEC 61000-4 defines the methods for measuring and interpreting the results of electrical power quality parameters in alternating current power supply systems at 50/60 Hz. 

And pay close attention! It presents measurement methods and appropriate performance requirements, but does not define limits, i.e., do not expect to see percentages or limits for the phenomena found in your studies and measurements. This standard ensures that your analyzing or measuring equipment performs properly, and that you are protected regarding the reliability of the information generated.

To assess limits, an accompanying standard or instruction will be required. Examples: 

• Prodist module 8 for analysis at the coupling point with the dealership;

• ANSI/IEEE 446 to see the CBEMA curve;

• NEMA MGI 14-34 for imbalances;

• ONS measurement campaigns, and so on.

IEC61000-4-30 Standard

So now we know what IEC 61000-4 is all about. We still need to know what the 30 is! So far we know that IEC 61000-4 deals with electromagnetic compatibility, in the field of measurement and testing techniques.

There are 34 variants of this section. The IEC61000-4-30 variant presents methods for measuring power quality aspects, which is the focus of the analyzing and measuring equipment involved in consultancy, studies and inspections. This is where we will focus our approach, but I will highlight some related ones, mainly for tests for approval and class certification. They are:

• IEC61000-4-7: General guide on harmonic and interharmonic measurement and instrumentation for power systems and equipment connected to them;

• IEC61000-4-15: Flickermeter – Functional and design specifications.

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IEC61000-4-30 defines the methods for measuring the following parameters:

• Electrical system frequency¹;

• Magnitude of supply voltage¹;

• Light flicker (Flicker¹);

• Voltage dips and surges¹;

• Voltage interruptions¹;

• Transient voltages;

• Voltage imbalance¹;

• voltage harmonics and interharmonics¹;

• Signals transmitted over the supply voltage;

• rapid voltage variations;

Note¹: PRODIST module 8 mentions these phenomena, and establishes limits, at the point of coupling with the concessionaire.

Equipment classes

For each parameter, three classes are defined, namely A, S and B. And here, you should ask yourself: Why in this order? At least I was curious. What changes between them? Well, let's look at the definitions.

CLASS A energy analyzer

• Excerpt from the standard: “This class is used where accurate measurements are required, for example for contractual applications that may require dispute resolution, verification of compliance with standards, etc.”

Now, look, read it again: Audits and more complex evidentiary situations!

• Excerpt from the standard: “Any measurement of a parameter performed with two different instruments that comply with Class A requirements, when measuring the same signals, produces equal results within the uncertainty specified for the parameter.”

Here's the trick. The crucial characteristic that defines the class: High precision, that is, accuracy at the limit of measurement uncertainty, and synchronization. As for the first characteristic, I tell you, these are equipment with greater added value, greater technology, etc. Don't expect to see equipment of this class at the same price as the others.

Next, the universal method for synchronization is GPS. And note that we are not talking about spatial coordinates, despite the screens on our equipment, but rather about clocks. If you have to measure a transient “equally” on the same line, note that 1 second of error is an eternity. So there is no way for a piece of equipment to meet the class without synchronization, and therefore without GPS. See below, the function on the RE8000 .

CLASS S energy analyzer

• Excerpt from the standard: “ This class is used for statistical applications, such as surveys or power quality assessments, possibly with a limited subset of parameters. Although they use equivalent measurement ranges as Class A, the processing requirements of Class S are lower.”

Here is the “S”: “S”earch, which translated means research. I understand. But I don’t comprehend. I, Lucas, would prefer a B and then a C, because it gives me a better idea of ​​order, but anyway, let’s continue. This class is subjected to the same tests as class A, however, with some changes in uncertainty, and of course, without the requirement of synchronization.

CLASS B Analyzer and Meter

• Excerpt from the standard: “Defined with the purpose of avoiding the continued manufacture of obsolete designs for many existing instruments”.

When reading this, I have the feeling that it is a class that is not recommended, and it is not just a feeling, see another excerpt: “NOTE – Class B methods are not recommended for new projects. It is warned that Class B may be removed in a future edition of this standard.”

Here is my first and only disagreement with this standard! Everything in “real life” engineering involves an analysis between cost and project result. Class A and S equipment obviously have higher acquisition values ​​than B. And if we take as a basis the parameters that the standard cites, in countless applications, there will be no concern with all of them.

I may want to monitor just one or two, with a more lenient precision requirement (Less demanding), just as an indicator, and based on them, use a higher class punctually as needed.

I consider it a mistake to eliminate it. And I even think that it could have more detailed tests to standardize the numerous products that we see on the market, with extremely dubious reliability. Just because a known error is accepted does not mean that any error can be omitted!

Here is my campaign: Save class B, it can have even more applications than the others in volume! End of my campaign. Let's get back to the subject at hand.

Access to the analyzer class

• Excerpt from the standard: “The instrument manufacturer should declare which parameters are measured, which class is used for each parameter, the Udin range (declared input voltage) for which each class meets, and all necessary requirements and accessories (synchronization, test leads, calibration period, temperature ranges, etc.) to meet each class.”

This section makes clear, in addition to the class, a small detail that was previously unheard of: “ the manufacturer of the instrument declares”. This standard applies to the measuring instrument, commonly called a power quality analyzer. It is the manufacturer’s responsibility to comply with and obtain approval in accordance with the standard.

For the user, the most important thing so far is to know about it, and to ensure that the instrument is being used, also observing its annexes that discuss the correct use for measurement. But be careful, being in compliance is not the same as being certified.

The next 20 or 30 pages of the standard, starting with the definition of class B, explain: How the equipment should measure, what the “rules” are, error percentages, what the methods are, etc., that is, design aspects of the instrument, aiming at tests that say, “ok! This equipment meets class A for measuring a “sag” (for example).

And note that I mentioned sag, because the standard deals with each quality parameter separately and in detail, that is, it has specific methods and tests for each energy quality parameter.

From here on, instead of describing the technique, I will address the test result, as it will give a reasonable idea of ​​compliance with the standard, based on the parameters analyzed.

Equipment certified by IEC 61000-4-30

The approval of a piece of equipment is described through a certification document with the results of all tests applied to determine compliance with the requirements, that is, the guarantee that a piece of equipment meets the class is proven by a document of at least 60 pages of results, issued by a competent body.

See below the compilation of uncertainty ranges, together with the classes. For each line of the table, a test and a certainty range are determined in detail (the part of the standard that I am ignoring, and that is not suitable for use, unless you are creating a piece of equipment and want to have it approved, or are curious about formulas and techniques). See:

Embrasul has certification of conformity and meets the measurement techniques of the complete IEC61000-4-30, which results in the following complete certificate:

See below the result of one of these tests in the video, in full:

It can be concluded from this table that this equipment is capable of measuring voltage in a steady state, within the established Udin range, with an error of less than 0.1% between 10 and 150% of the range.

The first page that summarizes and proves the approval:

If you wish, download the IEC supporting certificate document to analyze:

certificado-RE8000.pdf

Download PDF • 105KB

AAttention! Don't give up, we've reached 32 of the 63 pages of the standard! If you're tired, don't give up!

The first part of this article helps you choose a good piece of equipment, and how the IEC indicates a methodology and test to classify a piece of equipment. The second part explains how to use it to perform a measurement! Follow our blog for part 2: Click here!