Congestion Management, Curtailment and Interruption for Distributed Generation

Centralines network is primarily designed and established for electricity flows in one direction. Increasing number of distributed generation could introduce bi-directional electricity flow on the network. This may lead to congestion of its low voltage and high voltage networks.

Network congestion occurs if an additional unit of electricity injected into the network would cause a component in the network (for example,. a circuit or a transformer) to operate beyond its rated maximum capacity or give rise to an unacceptably high level of voltage at the point of connection to the network.

Centralines manages its network congestion by:

• ensuring distributed generation connection is in unconstrained areas or accompanied by appropriate network upgrade, and
• implementing real-time operational curtailment rules and arrangement on case-by-case basis.

The network congestion measure will be dependent on the extent of congestion, technical and operational characteristics, and connection terms and conditions. In some cases, distributed generation may add to an existing network congestion that requires network reinforcement in the near future. Centralines will assess the incremental cost to relieve this constraint and allocate a pro-rata share of the network reinforcement cost consistent with its capital contribution policy.

Inverter settings and solar exports

To help manage voltage on the electricity network, solar inverters automatically adjust their output when local network conditions require it. During periods of high solar generation and low electricity demand, this may result in temporary reductions in the amount of electricity exported to the network.

From September 2026, low-voltage distributed generation systems must use the Australia A inverter settings specified in AS/NZS 4777.2:2020. These settings are designed to better align with New Zealand's permitted voltage range and can help reduce unnecessary solar export curtailment while continuing to support the safe operation of the electricity network.

If you are experiencing reduced solar exports, contact your installer to confirm your inverter is configured with the required Australia A settings before requesting further investigation.

Interruption

In the event of any fault on a distribution network, any distribution generator must through their own protection systems be automatically disconnected from the network. The customer has sole responsibility for the safety of their generating plant and equipment under such conditions.

Centralines DG Congestion Policy published in accordance with the Electricity Industry Participation Code 2010, Part 6, Sec. 6.3(d).