Addressing Barriers to Efficient Renewable Integration Milestone 2

This technical report presents the details and findings for the project ”Addressing Barriers to Efficient Integration of Renewables”, for the period 05 Jan 2019 to 15 Jul 2019. The specific topics discussed in this report include:

• Task 1: Bench testing of 17 commonly used PV inverters in Australia. Five of the selected PV inverters comply with AS 4777.2:2005 and twelve comply with AS 4777.2:2015. The basis of the testing procedure is the application of various voltage and frequency disturbances, the most important being summarized below:
  – response to rapid (100 ms) voltage sags
  – response to phase-angle-jumps (PAJs)
  – response to high rate of change of frequency (RoCoF) with frequency boundary within the limits of AS 4777.2:2005 (45 Hz < g < 55Hz) and AS 4777.2:2015 (47 Hz < f < 52 Hz).
  – response to frequency deviation within the limits of both versions of AS4777.2
• Task 2: The AS4777.2015 standard mandates PV inverters to ride-through short-duration volt- age sags, but our results in D.1.1 indicate otherwise. At present, there is no testing procedure that accredits PV inverters to short-duration voltage sags. Therefore, based on a comparison between the Australian standard and other international standards, such as the one in Germany and the USA, the need of a testing procedure to improve the accreditation of PV inverters to short-duration voltage sags is highlighted. The final objective is to enhance the accreditation process to guarantee that the majority of PV inverters in Australia comply what is mandated in the standard.
• Task 3: Development of the WECC Composite Load Model (WECC-CMLD) using a hybrid component-based and measurement-based approach. The component-based approach aggregates the distribution of loads according to standard load classes and the load components of each class to derive the parameters of the aggregate composite load model. On the other hand, the measurement-based approach uses high-sampling-frequency measurements collected at different substations in Australia to derive the most influential parameters of the model (the load composition and the under-voltage protection parameters). The first release of a computational tool to estimate the values of these parameters was developed. The ultimate goal is to minimize the error between the WECC-CMLD output and the collected measurements using state-of-the- art nonlinear optimization solvers. We refer the reader to Section 2 and Section 3 for a thorough description of composite load model and the developed parameter calibration approach.