Evoenergy Inverter Settings & AS/NZS 4777.2 Guide for ACT Solar Systems

Key Takeaways

• If your solar inverter in the ACT is frequently switching off or reducing output, it is likely responding to voltage changes on the grid.
• Your first step should be to contact your solar installer or electrician to verify that your inverter settings comply with Evoenergy's mandatory requirements.
• Systems found to be non-compliant with Evoenergy's requirements or Australian Standards may be disconnected from the network for safety and protection.
• If your inverter continues to trip after settings verification, you may need to complete a Solar Connection Investigation Form for Evoenergy to investigate.

Why does my solar inverter keep switching off or reducing output in the ACT?

If your solar inverter in the ACT keeps switching off or reducing its power output, it indicates that your system is responding to changes in grid voltage. This behaviour is a safety and grid stability feature, not necessarily a fault. The voltage fluctuations can be influenced by factors such as the amount of solar generation in your local area, broader network conditions, weather, and your household's energy usage.

Evoenergy, as the distribution network service provider for the ACT, sets specific requirements for how solar systems connect and operate on its network. These requirements are designed to maintain power quality and network stability for all customers.

What is actually going on

Solar inverters are designed to interact with the electricity grid, converting the direct current (DC) from your solar panels into alternating current (AC) for your home and for export to the network. To ensure grid stability and safety, inverters must operate within specific voltage and frequency limits. When these limits are exceeded, the inverter will either reduce its output or disconnect from the grid entirely. This is a protective measure to prevent damage to equipment and maintain the integrity of the network.

In Australia, the standard AS/NZS 4777.2 sets the technical requirements for grid-connected inverters. Evoenergy specifies additional mandatory settings for inverters connected to its network in the ACT, particularly concerning how they respond to voltage variations. These include:

• Volt-Watt Response Mode: This function enables the inverter to automatically reduce its active power output as the grid voltage rises. By lowering the amount of power injected into the grid, the inverter helps to mitigate further voltage increases, contributing to overall network stability. Evoenergy requires this mode to be enabled.
• Volt-VAr Response Mode: This mode allows the inverter to inject or absorb reactive power (VArs) to help manage voltage levels. While the specific curve parameters are not publicly detailed, Evoenergy requires this mode to be enabled to support power quality.
• Voltage Disconnection Thresholds: These are critical safety limits. If the grid voltage goes too high, the inverter must disconnect from the network to protect itself and the grid. Evoenergy specifies precise voltage levels and response times for these disconnections.

These settings are crucial for managing the increasing amount of distributed energy resources, like solar, on the network. They help Evoenergy operate the grid more efficiently and prepare for potential disruptions.

Evoenergy's Mandatory Inverter Settings for ACT

Evoenergy mandates specific settings for solar inverters connected to its network in the ACT to ensure power quality and network stability. These settings are based on the AS/NZS 4777.2:2020 standard. Your solar installer is responsible for configuring your inverter to meet these requirements.

What you can check yourself, and what you cannot

As a homeowner, you can observe your inverter's behaviour, such as frequent tripping or reduced output. If you notice these issues, your first action should be to contact your accredited solar installer or electrician. They can verify that your inverter's settings comply with Evoenergy's mandatory requirements.

What you can check:

• Inverter Display: Note any messages or codes displayed on your inverter.
• System Performance: Monitor if your system is consistently underperforming or frequently shutting down, especially during peak solar generation times.

What you cannot do:

• Change Inverter Settings: Grid-protection settings are configured by an accredited installer and changing them yourself can breach your connection agreement with Evoenergy and potentially compromise grid stability and safety.
• Diagnose Network Issues: While your inverter's behaviour might be a symptom of a network issue, only Evoenergy can investigate and confirm network conditions.

If your inverter continues to trip after your installer has verified the settings, you should complete the Solar Connection Investigation Form and email it to CustomerResolutions@evoenergy.com.au. Evoenergy's power quality investigations typically take 3-4 weeks and may involve monitoring voltage levels at your premises for 7 days. If your system is found to be non-compliant, Evoenergy will provide information on how to rectify it, to be shared with your solar installer or electrician. Systems found non-compliant may be disconnected from the network for safety reasons.

What the published sources do not tell you

While Evoenergy provides clear mandatory settings and connection requirements, there are aspects that are not publicly detailed:

• AS/NZS 4777.2 Standard: The full AS/NZS 4777.2 standard, which forms the basis for these requirements, is a paid document and not publicly available. This means specific technical details beyond the high-level requirements are not accessible without purchasing the standard.
• Specific Volt-VAr Curve Parameters: While Evoenergy states that Volt-VAr power quality response mode must be enabled, the precise parameters of this response curve (e.g., Q/P ratio, specific voltage thresholds for reactive power injection or absorption) are not published.
• Secondary Protection Thresholds: network documentation details voltage disconnection thresholds but does not specify other secondary protection thresholds, such as those for under/over frequency or rate of change of frequency (ROCOF) settings, which are also part of AS/NZS 4777.2.
• "Solar Connection Investigation Form" Details: The document mentions completing a "Solar Connection Investigation Form" but does not provide a direct link to this form or instructions on how to obtain it.
• Application Fee Schedules: For complex embedded generation applications (residential with battery, export limit, or additional capacity) and all commercial applications, fees apply. However, the "Schedule of charges" detailing these fees is not publicly available.
• "Model Standing Offer" and "Non-Standard Connection Agreement" Details: For systems 30kVA or less, approval is in line with Evoenergy's "model standing offer," and larger systems receive a "Non-Standard Connection Agreement." The specific terms and conditions of these documents are not published.
• Periodic Anti-Islanding Testing Requirements: Systems must complete "periodic anti-islanding testing," but the frequency or specific requirements for this testing are not detailed.