Substation testing rests on five families of documents: the IEC and IEEE product standards, which set the factory tests; the IEEE field diagnostic guides; the NETA acceptance, maintenance and commissioning specifications; the CIGRE technical brochures, which capture good practice; and the local electrical code and the utility's grid code, which are mandatory. This guide sorts them by family and links to a detailed guide for each group of tests.
Why it pays to know which standard applies
A test protocol without a reference standard is just a list of measurements. The standard tells you what to measure, how, and, where one exists, the criterion for accepting the result. It also lets you compare against the factory tests and defend the result before the client, the owner’s engineer or the utility.
The problem is that a substation brings together standards from several bodies, with editions that change and documents that IEEE declares inactive. This series, part of the technical standards topic, sorts them into four guides:
- Standards for primary equipment testing
- Standards for protection testing and secondary injection
- Standards for commissioning, FAT and SAT
- Standards for communications and synchronization
The five document families
| Body | Type of document it publishes | Examples |
|---|---|---|
| IEC (International Electrotechnical Commission) | Product standards with type and routine tests; high-voltage test techniques; communication protocols | IEC 60076, IEC 62271, IEC 61869, IEC 60255, IEC 61850 |
| IEEE (Standards Association) | Product standards (C37 and C57 series), application guides and field diagnostic guides | IEEE C57.12.90, IEEE C57.152, IEEE C37.233, IEEE 400 |
| NETA (InterNational Electrical Testing Association) | Field test specifications by equipment type, with tables of reference values | ANSI/NETA ATS-2025, ANSI/NETA MTS-2023, ANSI/NETA ECS-2024 |
| CIGRE | Technical brochures with the experience of the working groups; they are not standards | TB 637, TB 760, TB 401 |
| Local code and utility | Mandatory national electrical codes and grid-code requirements of the utility or grid operator, which vary by country | Adopted by the authority having jurisdiction and by the utility |
How they relate to each other
Product standards define the factory tests. IEC 60076-1 or IEEE C57.12.00 say which routine, type and special tests a transformer receives, and IEC 62271-100 or IEEE C37.09 do the same for a circuit breaker. They are the basis of transformer factory tests and of the protocols the manufacturer delivers with the equipment.
Field guides steer on-site diagnostics. IEEE C57.152 (transformers), IEEE 400 (cables) or IEEE C37.233 (protection systems) explain how to test equipment already installed and how to read the result. They do not replace the product standard: they complement it.
NETA turns all of the above into field specifications. Its documents list, equipment by equipment, the visual and mechanical inspection, the electrical tests and the reference values, with three distinct uses: acceptance (ATS), maintenance (MTS) and systems commissioning (ECS). Many client specifications cite them.
CIGRE captures good practice. Its technical brochures are neither standards nor mandatory criteria, but they are useful for designing test strategies, especially in IEC 61850 substations.
The local code and the grid code are mandatory. The national electrical code applies to every installation in the country, and the utility or grid operator sets the requirements for connecting to its network, including protection tests before energizing a connection. These requirements vary by country and by utility, so we adapt the test scope to the local code and to the utility requirements the client provides.
Map by type of test
| Type of test | Main standards |
|---|---|
| Power transformer tests | IEC 60076-1, IEC 60076-3, IEEE C57.12.90, IEEE C57.152 |
| Power factor and tan delta | IEEE C57.152, IEC 60137 (bushings), ANSI/NETA ATS and MTS |
| Circuit breakers: timing and contact resistance | IEC 62271-100, IEC 62271-1, IEEE C37.09 |
| Current and voltage transformers | IEC 61869-2, IEC 61869-3, IEEE C57.13, IEEE C57.13.1 |
| Partial discharge | IEC 60270 |
| Insulating oil | IEC 60422, IEC 60599, IEEE C57.104 |
| Grounding | IEEE 81, IEEE 80 |
| Secondary injection to relays | IEC 60255 family, IEEE C37.233 |
| IEC 61850 and communications tests | IEC 61850-10, IEC 61850-6, IEC 61850-8-1, IEC 61850-9-2 |
| Commissioning before the utility | Local code, utility grid code and connection requirements |
Editions, withdrawals and inactive standards
Standards change, and citing a superseded edition can earn you an observation from the owner’s engineer. Three useful ideas:
- IEC publishes a stability date for each standard, up to which it foresees no changes. When a new edition comes out, the previous one is replaced. For example, IEC 61869-1:2023 cancelled and replaced IEC 61869-6:2016, and the IEC 61869 series replaced the old IEC 60044.
- IEEE marks each standard as Active, Superseded (replaced by another), Inactive-Reserved (no longer maintained, but still available) or Inactive-Withdrawn (withdrawn). IEEE C37.118.1-2011, for example, was replaced by IEC/IEEE 60255-118-1:2018, and IEEE 80-2013 is listed as inactive-reserved while its revision moves forward.
- NETA publishes complete editions with the year in the name: ANSI/NETA ATS-2025, MTS-2023 and ECS-2024 are currently in force.
In each guide of the series we state the current edition only when we have confirmed it on the body’s official site, and we flag superseded or inactive standards.
Which standard governs when there are several
In practice, the order applied on a project is this:
- The electrical code and the regulations in force where the installation is built, which cannot be contradicted.
- The client’s technical specification or the contract, which chooses between IEC, IEEE or NETA and sets the acceptance criteria.
- The product standard the equipment was manufactured to, which defines its guaranteed values.
- The manual and the factory protocol, which give the reference values to compare against in the field.
If the contract does not define the standard, the sensible course is to agree on it in writing before the first test. Mixing IEC and IEEE criteria in the same protocol usually ends in arguments over which value was the acceptable one.
Testing to a standard, on site
At Tiza Group we perform primary equipment tests, secondary injection tests and FAT and SAT tests to the standard your contract requires, from medium voltage up to extra-high voltage. Field testing is done in Colombia, or elsewhere on request. Write to us and we will help you define the scope.
Related guides
- Transformer factory tests: routine, type and special
- Substation primary equipment tests: guide by equipment
- Power factor and tan delta: what the test is
- Circuit breaker operating time test: what it measures
- CT excitation test and knee point with CPC 100
- Partial discharge test: what it is and where it applies
- Dielectric oil analysis: tests, DGA and furans
- Ground resistance: what the test measures and IEEE 81
- Protective relays: types, functions and maintenance
- IEC 61850: what it is, parts of the standard and data model
Frequently asked questions
Which standard governs on-site tests of a power transformer?
There is no single one. Factory tests are set by IEC 60076-1 or IEEE C57.12.00 and C57.12.90; field diagnostics are guided by IEEE C57.152; and the ANSI/NETA ATS and MTS specifications give the acceptance and maintenance tests. The contract must say which one governs.
Can an inactive IEEE standard still be used?
Yes, as a technical reference, provided the contract accepts it. «Inactive-Reserved» means IEEE no longer maintains it, not that its content is wrong. If a newer edition or a revision project exists, it is best to cite the current one or note it in the test protocol.
Are IEC, IEEE and NETA standards mandatory?
On their own they are voluntary. A standard becomes binding when a code, a regulation, the utility's requirements or a contract cites it. What is mandatory for an installation is the electrical code in force where it is built and, to connect to the grid, the utility's or grid operator's requirements. We adapt the test scope to the local code and to the utility requirements the client provides.