The Gaspésie network is a regional part of Hydro-Québec’s grid that feeds a small amount of load over a vast region. The grid is radially connected to the main 735 kV backbone and is known for its presence of series compensated lines, back-to-back line commutated converters (LCC), small load, weak grid and high IBR penetration. With more IBR’s planned to be added to the region, Hydro-Quebec benchmarked operational limits obtained through PDT simulations with EMT to ensure reliable operation of the grid. This article aims to share our experience doing operational transfer limits studies using EMT, both in terms of phenomena observed as well as issues encountered and solutions.

Firstly, a direct comparison of PDT and EMT simulation results has been done for the same system contingencies using comparable initial conditions in both software. The objective was to validate and compare power transfer capabilities obtained with PDT and EMT simulations. The limits were obtained simulating high impact single contingencies in various grid operating conditions and topologies. While the PDT transfer capability was limited by long-term voltage collapse, the EMT transfer capability was governed by the loss of generation and short-term voltage instability. The distinct power system and IBR dynamics between PDT and EMT simulations in weak grid like the Gaspésie region highlights the importance of benchmarking PDT with EMT simulations to ensure reliable grid operation.

Secondly, results obtained by this study emphasized that while different, each software complements the other. The PDT software while lacking accurate representation of IBR control loops and power electronics can study long-term voltage stability with enough accuracy without excessive computational burden. It also enables after some preprocessing of PDT simulation data and through playback methods in EMT to assess local stability of IBR’s while the rest of the power grid undergoes severe contingencies.

Thirdly, the article discusses some issues with the use of black-box dynamic models for wind power plants. The major issues were mostly tied with the nature of black-box models as well as being flexible enough to enable the studying of multiple grid topologies and power flows. Legacy models were developed to be simulated at the nominal active power at the wind farm. This was the requirement at the time where grid voltage stability studies weren’t the focus for these models, particularly in EMT simulations. With the growing need to study the voltage stability of the certain areas of the grid with IBR, model validation and accuracy in all operating conditions is becoming critical. This reinforces the need for field testing and a thorough commissioning process to ensure models represent the actual behaviour of the wind power plant.