What is an EMT control-interaction study, and when do I need one?
It looks at how the fast controls of converters (batteries, solar, wind, HVDC) interact with each other and with the network, at time scales below one cycle. You need one when RMS models can't show the effect: on weak grids, where several converters sit close together, or where equipment from different vendors meets. We run it in PSCAD with the vendors' own control models.
How do you screen for subsynchronous oscillation?
We scan the plant and network impedance across frequency and check stability with the Nyquist criterion. If the scan shows a risk, we confirm it with an EMT run in the time domain, then test the fix.
When should a project move from RMS to EMT?
RMS is fine for load flow, steady state and slower dynamics. Move to EMT when the answer depends on fast converter controls, harmonics, oscillations, ride-through or fast fault current. Most projects use RMS for breadth and EMT for the few cases that decide the result.
How do you work with TSOs and DNOs?
We build and validate models to the operator's requirements, record every assumption and scenario, and present the evidence in the form their reviewer expects. We can also handle the questions that come back from the operator.
What does a study deliver?
Validated model files, the method, the scenarios and operating points, result plots and a written report with recommendations. The exact set depends on the study and on what the operator asks for.
