Meeting AEMO requirements for model acceptance testing

The Australian Energy Market Operator (AEMO) has published a new guideline document that imposes important new obligations on energy project developers in the National Electricity Market.

This AEMO document codifies the requirements for acceptance tests on PSCAD simulation models for generation projects. While project developers have been required to furnish PSCAD models to AEMO and NSPs for some years now, the pre-qualification requirements on these models have been sporadic and limited to informal checks against the AEMO Model Guidelines and limited benchmarking against hardware tests or PSS/E model results. There has not been a formal acceptance test specification similar to that which exists for PSS/E models. Today that gap has been closed.

The PSCAD Dynamic Model Acceptance Guideline (DMAG) establishes new test requirements to be satisfied for pre-qualification of electrical plant models before connection studies are undertaken — further extending the time and effort required at the due diligence and planning stage of all new projects.

The acceptance tests required by the DMAG will involve over 400 simulation cases in PSCAD software for a single generator model. For battery energy storage system technologies (BESS), these tests must be repeated for charge and discharge scenarios. Where a project is a hybrid of multiple technologies, it is required that the full suite of tests be performed for each model individually, and then again for the combined system. This will result in hundreds, if not thousands, of tests for a new connection. For example, a wind farm with battery storage requires over 2000 PSCAD tests to be performed.

Further, the requirement for PSCAD test results to be benchmarked against PSS/E results has been extended to include all balanced fault scenarios, and all changes in control system setpoints for voltage, reactive power, active power and frequency.

As project developers will appreciate, this number of PSCAD test scenarios will require substantial time and effort to complete and document.

Vysus Group, formerly the energy business of Lloyd’s Register, has been anticipating these requirements for PSCAD acceptance tests, and as a result has developed a fully automated PSCAD test suite that it says is capable of handling all the tests within the PSCAD DMAG just published.

Vysus says its automation tools provide speed and accuracy, including the capability for 24-hour execution through a combination of hands-off automation and expert review by Vysus engineers. Vysus use optimised parallel processing within the PSCAD architecture to cut back on simulation time. The benchmarking of the PSCAD results against PSS/E model results is also fully automated, and able to create and run hundreds of PSS/E simulations in minutes against the PSCAD results. Automatic visual presentation of results in overlay plots is included to validate the results against all relevant AEMO guidelines.

The Vysus Australia Grid Team is part of Vysus Group, a worldwide consultancy business providing specialised engineering services across the global energy sector.

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