- The snapshot feature is available through the HYPERSIM ribbon, in the simulation subset. It is only available during simulation.
- The goal of this feature is to save the state of the simulation to be able to force it onto the running simulation later on.
- Snapshot is an image of the simulation at a specific simulation step. It saves the voltage and current value at all nodes as well has historical values for components necessitating them such as lines and UCM.
- It's often used to force steady-state conditions after some events destabilized the systems or to study some transient behavior that is more complicated or longer to reproduce such as the starting sequence of a machine. It is thus very practical to facilitate manual testing and essential to automate testing.
- As an example, we'll use the example model Transmission & Distribution/HVAC_735k_38Bus, found in the examples provided with HYPERSIM, as it requires a bit of time to stabilize at the beginning of the simulation.
Running real-time simulation also makes it easier to demonstrate the behavior of the snapshot, as with non real-time simulation the acquisition is generally too fast to have the time to apply the snapshot during the acquisition.
- To better illustrate the feature, change the Trip breaker component (at the bottom of the model) and remove its second Timing, so that there is only one trigger event.
- Open ScopeView, and load the template for this model, and start the simulation. Let the system stabilize. Take acquisitions regularly without triggers to watch it stabilize.
ScopeView parameters :
- 5.0 seconds acquisition
- 20k sampling rate
- Sync. checked
- Terminal voltage Y-axis range : 0.99 - 1.01 pu
- Once the system is stable, click the Take snapshot button in the simulation subset of the HYPERSIM ribbon. The ScopeView graph should look like this (the other graphs aren't needed for the purpose of this example).
- Now, click the trigger checkbox in ScopeView controls, and take another acquisition. The acquisition should look like this.
- Now to observe the application of the snapshot, take an acquisition and quickly click on the Load snapshot button in the simulation subset of the HYPERSIM ribbon. The acquisition should look like this. This means that the event was triggered at 0.2 s as planned in the Trip component and destabilized the system. At 1.55s, loading the snapshot forced the state of the simulation when the snapshot was taken.