Challenges of integrating Large Scale Solar projects into the NEM

Large scale solar energy is one of the fastest growing power generation modes in Australia as they are clean and environmentally friendly. In addition, governments set considerable high renewable energy penetration targets to reduce the carbon emission globally. There are increasing challenges to power system engineers to incorporate these large scale solar farms in to the National Electricity Market (NEM) due to lack of network data, errors or non- compliance of the inverter and power plant controller dynamic models, stability issues due to low short circuit ratios, stability issues related to higher export power on feeders, AEMO rule changes etc. This report aims to investigate the challenges to integrate large scale solar farms into the Australian NEM. To achieve this, past and current projects with sizes varying from 15MW to 300MW that involve different inverters are investigated.

Simulating the distribution network can prove difficult if the generator is connected to the distribution network. Most of the current inverters models don’t fully comply with present National Electricity Rules (NER); the proposed Rule changes add more hurdles to achieving connection approval from the Network Service Providers (NSP) and AEMO. Sizing of the solar farm critical infrastructure to comply with NER rules is challenging as some developers are not fully aware of the technical nature of the selection of active, reactive and apparent power of the inverters.

A number of criteria have been set during the connection studies for identifying correct plant sizes, dynamic model settings, network data etc. to address the challengers and to minimize the cost involves with these studies. It is believed that findings of this paper help power system engineers to carry out connection studies more accurately and efficiently.

Key Words: Australian Energy Market Operator (AEMO), National Electricity Market (NEM),