2016 AS/NZS 4777.2
Kristin Gillies, September 15, 2016
15 Sept 2016 AS/NZS 4777.2
Two weeks ago we released a clarification on the status of AS/NZS4777.2 (2015) for inverters. This replaces the previous AS4777.2 (2005) and AS4777.3 (2005).
We received a number of requests from members asking what are the differences in the new standard.
The major differences are:
- Country wide voltage/frequency settings
- High voltage limit is 248V over a 10 minute average
- Soft start – will take 6 minutes to reach full power on startup or re-connection
- Ride through for short grid events (low/high volts, low/high frequency of less than 1s)
- Requirements for Multimode inverters (ie inverters that have storage)
- Requirement for inverters to be certified to IEC62109.2
- Requirements for single phase inverters in a multiphase installation to be phase balanced (not to exceed 21.7A phase imbalance)
- Requirements for multiple inverters on an installation to all shutdown if any inverter detects an island grid situation
Optional features:
- Adjustable power factor – fixed, voltage or power dependent
- Adjustable volt/watt response – power turn down as voltage rises
- External interface (Demand Response Modes – DRM) in the inverter to allow the Lines Companies (or Aggregator etc) to:
- Disconnect the inverter (this is compulsory)
- Decrease the output power (50%, 75% rated)
- Increase generation (eg from storage)
- Decrease battery charging (50%,75% rated
- Increase battery charge
This requires an external interface device (DRED), which could be a ripple controlled, smart meter or network device
The optional features are generally to reduce the effect of high penetration of inverters on the distribution network – eg voltage rise.
The optional features may be requested by a Lines Company for specific installations.
