The Australian Energy Regulator (AER) has today released its sixth compliance bulletin. This compliance bulletin relates to instrument transformer testing.
The National Electricity Rules (Electricity Rules) require instrument transformers to be tested every 10 years for accuracy, unless an alternate test plan has been approved by the Australian Energy Market Operator (AEMO). In 2011, the AER was made aware of a failure by industry to test instrument transformers in accordance with the Electricity Rules. The AER was also notified by AEMO that industry had formed a Current Transformer Testing working group (CTTWG) to identify an acceptable sample testing approach.
The AER is concerned by the potential harm untested instruments transformers may have on the National Electricity Market (NEM). If an instrument transformer is inaccurate, this can affect the overall accuracy of the metering installation. However, given the work of the CTTWG and the current lack of industry guidance on testing methodologies, the AER has chosen to issue a compliance bulletin. The AER is seeking that industry demonstrate a willingness to comply by testing a sample of their instrument transformers over 12 months.