Impact and Management of Harmonics for Renewable Generators

An ARENA funded project in partnership with Edify Energy, ElectraNet, Essential Energy, Neoen Australia, RES Australia, Endeavour Energy, Transgrid, Vestas.

The Australian Power Quality and Reliability Centre (APQRC) is leading an ARENA funded project investigating the impact and management of harmonic distortion for large renewable generators. Our project partners include renewable energy generators and equipment manufacturers as well as distribution and transmission network service providers. The project commenced in March 2020 and concluded in May 2022 with publication of the report “Harmonic Study – Large Renewable Energy Generators”. A public workshop with over 125 attendees was also held in October 2022.

Project Outcomes

Key outcomes of the project include:

With respect to the impact of increasing penetration of REG on harmonic distortion in electricity networks and review of Australian and international literature on this subject indicates that the impact is highly varied with harmonic distortion in some networks increasing as the number of REG plants increase while in other network distortion levels appear to be decreasing as the number of REG plants increases.

An assessment of a range of the most common methodologies for determining an emissions allocation for harmonic distortion has shown that while subject to a range of limitations that require addressing, the IEC methodology appears to remain the most valid approach for Australian networks, although challenges have been investigated with its application in networks with long feeders and high levels of REG penetration and uncertainty.

A case study has indicated that diversity exists for all harmonic orders between the harmonic emissions from identical inverters within a wind farm. This challenges the conservative approach of arithmetically summating emissions which is presently applied with important consequences for preconnection compliance assessment.

Outcomes of modelling undertaken to investigate the impact of increasing REG penetration into a proposed renewable energy zone challenges the efficiency and efficacy of the present methods of assessing impact and implementing mitigation. These preliminary studies indicate that an approach which is network focussed as opposed to plant focussed will be better able to detect areas where harmonic distortion levels are problematic and also provide more efficient and targeted mitigation.

A preliminary assessment of the challenges related to pre- and post-connection compliance assessment has identified that significant work is required to develop prescriptive and technically robust methodologies for network and plant modelling as well as assessment of compliance through the use of field measurements.