How to Check a Solar Inverter's Grid-Code Compliance: Which Standard, Which Test Report, Which Certificate

Short answer. "Grid-code compliant" is not a property of an inverter; it is a statement that a named unit, with a named parameter set, passed the tests of a named standard edition. Four kinds of document get confused: the system-connection standard that says what the plant must do at the point of connection; the product standard that says what the inverter must be able to do; the test specification that says how to prove it; and the safety standard, which is about shock and fire, not grid behaviour. This guide maps the Chinese, IEEE and IEC documents to those four kinds, from the standards bodies' own pages and the NEA's 2025 rules, and ends with a matching checklist. It does not state what any specific inverter complies with.

Kind 1: system-connection standards (what the plant must do)

China splits connection requirements by voltage level and plant type. GB/T 19964-2024 "Technical requirements for connecting photovoltaic power station to power system" was issued and implemented on 15 March 2024 and is administered by the China Electricity Council. GB/T 29319-2024 "Technical requirements for connecting photovoltaic power system to distribution network" was issued and implemented on the same date under the same administration. GB/T 33593-2017 "Technical requirements for grid connection of distributed resources" was issued 12 May 2017 and implemented 1 December 2017, also administered by the China Electricity Council.

The edition matters: both 2024 texts were issued and implemented on the same day, 15 March 2024, so a report should be checked for the edition year it cites.

In North America the equivalent is IEEE 1547-2018 (board-approved 15 February 2018, published 6 April 2018, superseding 1547-2003, amended by 1547a-2020), whose focus is the technical specifications for, and testing of, interconnection and interoperability between utility EPSs and DERs, including general requirements, response to abnormal conditions, power quality, islanding and test specifications; it applies to all DER technologies at typical primary and/or secondary distribution voltages and is written for a 60 Hz source. IEEE 1547a-2020 revises the allowable trip clearing-time settings in Table 13 for abnormal-operating-performance category III DERs to allow wider ranges. A report that cites "IEEE 1547" without the year is ambiguous between a 2003 and a 2018 standard that differ in kind.

Kind 2: the inverter product standard (what the unit must be able to do)

GB/T 37408-2019 "Technical requirements for photovoltaic grid-connected inverter" (光伏发电并网逆变器技术要求) was issued 10 May 2019 and implemented 1 December 2019; it is in force, administered by the China Electricity Council, and an English version is listed. This is the document a Chinese inverter datasheet should cite for its grid functions; the connection standards above describe plant-level behaviour, and the product standard translates it into what the inverter must be capable of.

Kind 3: the test specification (how to prove it)

GB/T 37409-2019 "Testing specification for photovoltaic grid-connected inverter" is the companion test standard, issued and implemented on the same dates as GB/T 37408 and administered by the same body. For a project to which GB/T 37409 applies, ask for the corresponding GB/T 37409 test report; in other markets, check the claim against the connection standard and test method that apply there.

The IEEE pair works the same way: IEEE 1547.1-2020 (board-approved 5 March 2020, published 21 May 2020, superseding 1547.1-2005) specifies the type, production, commissioning and periodic tests and evaluations that confirm equipment conforms to IEEE 1547. Note the four test classes — type, production, commissioning, periodic. A type-test certificate on a sample is not a commissioning test on the delivered unit.

For anti-islanding specifically, IEC 62116:2014 (edition 2.0, published 26 February 2014) provides a test procedure for islanding-prevention measures of utility-interconnected PV inverters, single- or multi-phase; its criteria are minimum requirements allowing repeatability, and the main changes from the previous edition concern the DC power source and test conditions. IEC 62116 is a test procedure for one function, not a grid code; a certificate that lists it alone covers islanding and nothing else.

Kind 4: safety standards (not grid behaviour)

IEC 62109-1:2010 (edition 1.0, published 28 April 2010) applies to power conversion equipment for PV systems and defines minimum design and manufacturing requirements for protection against electric shock, energy, fire, mechanical and other hazards. It is a product-safety standard. A CE or CB certificate built on IEC 62109 says the inverter is safe to touch and will not start a fire under the tested conditions; it says nothing about ride-through, frequency response or reactive-power capability. Buyers who receive a safety certificate in answer to a grid-code question have been given the wrong kind of paper.

What the NEA's 2025 rules require

For distributed PV, the NEA's 2025 measures set the procedural frame: grid-interface equipment must meet national and industry grid-interface standards, be tested and certified by nationally recognised testing and certification bodies, and once certified the grid company may not demand repeat testing; after completion the grid company reviews the inverter and other key equipment test reports and performs the grid-connection inspection before commissioning. The same measures forbid grid companies from imposing technical requirements above national and industry standards on compliant facilities, except what is necessary for safe grid and equipment operation.

Two practical readings. First, the certification body's recognition status is part of the evidence: "tested" by an unrecognised laboratory does not satisfy the clause. Second, the grid company's review is of the reports, so the reports must exist for the exact models installed; the no-repeat-testing protection only applies to equipment that has already been certified.

Matching the paper to the unit

Common mismatches

• Edition drift. A report that cites a connection standard without the 2024 edition year.
• Wrong kind. IEC 62109 offered as grid-code evidence.
• Partial function. IEC 62116 offered as the whole grid-code package.
• Sample vs unit. IEEE 1547.1 names type, production, commissioning and periodic tests as distinct classes; a type test alone is not a commissioning test.
• Extra requirements. A grid company asking for tests above the standard; the 2025 measures limit this to safety necessities.

Scope limits

No standard full text was read; clause-level requirements such as voltage and frequency ride-through windows are not quoted. UL 1741 was not retrievable (HTTP 403). Industry (NB/T) standards and grid companies' own specifications are not cited. Certification-body databases were not queried. This guide describes what to ask for, not what any product has.