Electromagnetic Transient Models: Importance of Performance Testing and Validation

Electromagnetic transient (EMT) models are becoming vital for understanding the power systems performance with growing penetrations of inverter-based resources (IBR). However, without appropriate model testing and validation, the accuracy of the power system analysis is far from guaranteed. A thorough model examination process that utilizes a combination of approaches to ensure model accuracy, robustness, and usability provides confidence in the EMT models and the outcome of the power system assessment using these models. Model testing ensures that the model is of good quality, numerically robust and has ability to appropriately represent plant's response to various operating conditions. During the model testing phase, a large number of simulation tests are applied to the model to check its usability, quality, performance, and consistency. While model testing provides confidence in the usability of the model, the accuracy of the model can be achieved through model validation process. There are various stages of model life cycle where model validation can be carried out using various approaches. Each stage of model validation has its own advantages and disadvantages. These approaches are generally divided in three categories: validating a single plant in a single-machine infinite-bus configuration, validating the full-scale system model consisting of many plants, and validating either a single plant or a group of plants using hardware-in-the-loop setup. When evaluating EMT models and validation outcomes, it is important to apply engineering judgment along with other metrics such as error tolerances and accuracy bands. Both model acceptance testing and validation are not straightforward and require time and resources, however, adequate and accurate models provide confidence to power system planners and operators to develop the power system operating envelope.