IEC 62116 is the test procedure used to evaluate whether a grid-connected PV inverter has adequate anti-islanding protection. Its full title is “Utility-interconnected photovoltaic inverters – Test procedure of islanding prevention measures.”

In plain English, that means it sets out how to test an inverter’s ability to detect a grid outage and automatically disconnect.

Let’s say we’re working on a solar PV installation in Sydney. The inverter needs to shut off quickly if the power goes out—otherwise, it could continue energising the lines connected to it. That could expose utility line workers to dangerous voltages. IEC 62116 helps prevent that by providing a repeatable method for testing whether the inverter can detect and react to this situation.

Why Islanding Is a Serious Risk

To explain islanding, let’s use an example. Imagine a small warehouse in Brisbane with a 30 kW rooftop solar PV system. It’s a sunny day, and the warehouse is consuming almost exactly the same amount of electricity as the solar PV system is generating.

Suddenly, the power from the grid goes out—but the inverter doesn’t notice. Because the local load (the warehouse’s machinery) matches the generation, there’s no obvious drop in voltage or frequency. The system keeps running. The inverter is now powering the warehouse independently of the grid—this is islanding.

If a worker from Energex shows up thinking the area is de-energised, they could be seriously hurt. Or the inverter might suddenly see the grid return and cause damage to electrical equipment due to a mismatch in voltage or phase. This is why automatic and rapid disconnection is critical.

What the Standard Actually Tests

IEC 62116 focuses on the worst-case scenario: when the load and the inverter output are perfectly balanced. This is the hardest condition for an inverter to detect.

Let’s say you’re testing a 5 kW single-phase inverter. You connect it to a load bank that’s drawing exactly 5 kW of real power. The reactive power is adjusted so that the inverter sees the same kind of load it would see in a real home or small business.

Then, without warning, you disconnect the simulated grid. The inverter must detect that something’s wrong and shut off. If it keeps operating, even for more than a few seconds, it fails the test.

The standard allows up to 2 seconds for disconnection. Any longer and the inverter is deemed unsafe for grid use.

Application in the Australian Context

Here in Australia, we already follow our own inverter connection standard: AS/NZS 4777.2. But this standard doesn’t exist in isolation—it references global IEC standards like 62116 when it comes to specific test procedures.

If we’re installing a new solar PV system in Perth or Adelaide and submitting an application to the local DNSP (like Western Power or SA Power Networks), we’ll likely be asked to confirm that the inverter complies with IEC 62116 for anti-islanding. This is especially true for medium-sized systems between 30 kW and 100 kW, where detailed protection settings and test certifications are reviewed.

An example of this in practice: a solar PV installer working on a 99 kW system for a commercial building in Melbourne was required by Powercor to provide an anti-islanding test certificate. The inverter manufacturer had pre-certified the unit to IEC 62116, which made the approval process smoother and avoided the need for additional site-specific testing.

How the Test Works in Practice

Let’s walk through a simplified version of how the test is done in a certified lab:

The inverter is connected to a simulated AC grid using a controllable power source. The DC side is fed by a programmable solar simulator.

A variable load bank is connected to the AC output side. The load is adjusted so the active and reactive power closely matches the inverter output—simulating perfect local balance.

The grid is suddenly disconnected, and high-speed measurement equipment captures the inverter’s response.

The disconnection time is recorded. If it exceeds 2 seconds, the inverter fails the test.

For example, a 3-phase 20 kW inverter may be tested with balanced loads on all phases. The test might be repeated across multiple load conditions and inverter output levels to ensure it performs consistently.

Active vs Passive Anti-Islanding

IEC 62116 is specifically designed to test active anti-islanding methods.

Let’s say a homeowner in Newcastle is using a modern hybrid inverter that employs active detection. This might involve slightly shifting the inverter’s output frequency and checking how the grid responds. If the grid is no longer there, the response will be different, and the inverter disconnects.

On the other hand, passive detection simply watches for voltage or frequency changes. That can work, but it’s often not reliable under those balanced-load conditions we discussed earlier.

Because Australia’s networks are increasingly complex and dynamic, active detection is now considered essential—and IEC 62116 is how we test whether it works.

Who Should Care About IEC 62116?

If you’re a system designer, engineer, or installer, this standard matters to you. For example:

If you’re specifying inverters for a new solar carport at a university in Canberra, you’ll need to check if the units are IEC 62116-certified.

If you’re preparing protection settings for an embedded generator in regional Queensland, you’ll want to ensure compliance to avoid project delays.

If you’re selling inverters into the Australian market, having that IEC 62116 certificate removes a major barrier to approval by DNSPs.

Even homeowners benefit indirectly. Knowing their system has passed stringent tests gives peace of mind that the system will behave safely in all situations.

Latest Version and What It Adds

The current version, IEC 62116:2014 (Ed. 2.0), includes several improvements over the original 2008 edition:

It expands test coverage to include 3-phase systems.

It includes clearer instructions for setting up repeatable tests.

It improves the modelling of DC sources and load characteristics.

If you’re sourcing equipment or reviewing test certificates, make sure this is the version being used.