This technical report presents the details and findings for the project “Addressing Barriers to Efficient Integration of Renewables”, for the period 2 Jul 2018 to 5 Jan 2019.
The specific topics discussed in this report include:
- Task 1 Bench tests of common PV inverters with a wide range of voltage and frequency disturbances based on AS4777.2-2015
- Task 2 Collect and analyse measured data for different frequency and voltage disturbances to serve as a basis for the DER as well as composite load modelling
- Task 3 Development of DER model, including tuning and model validation of the DER_A parameters based on the findings from Task 1 and Task 2.
The main findings and conclusions from the work completed are as follows:
- The PV inverters bench testing demonstrated that inverters’ responses to the same disturbance are diverse and different from a system dynamic point of view. This difference can, consequently, impact the modelling and aggregation of DERs for bulk power system (BPS) studies, and also have a detrimental effect on the grid by causing large reductions in the generation as a result of the inverter responses. This is shown in Chapter 2.
- A set of voltage and frequency disturbances has been analysed using PMU and high speed PQM data. Possible DER trip events have been observed, which can be confirmed after obtaining more information from the monitored feeders, e.g., load composition, voltage control strategy, etc. One of the main challenges is to discern between the voltage and frequency dependency of the traditional loads and the response of DERs to voltage and frequency disturbances. Hence, in addition to the DER modelling, it is very important to present dynamics of the load accurately by considering correct load composition. See Chapter 3 for details.
- This subtask utilises the DER_A model that was recently developed by the Western Electricity Coordinating Council (WECC) to represent dynamics of DER for BPS studies. This model mimics the aggregated behaviour of inverter-based DERs on a load bus for voltage and frequency disturbances. The model is generic and can be parameterised for different DERs’ settings. Based on the findings from Task 1 and Task 2, as well as the requirements set at AS4777.3-2005 and AS4777.2-2015, the parameters are tuned for voltage and frequency disturbance. See Chapter 4 for more details.