Design QuasiDynamicACPF Scenario Events

In SAInt, events are used to change default values, settings, and controls at specified times during the scenario time window. Scenario profiles can be assigned to an event to model time-dependent changes. This step will focus on designing scenario events to create different operating conditions of the network. The objective is to understand how to define scenario events to influence the behavior of your model.

1. Create demand events

We will start by defining the electrical demand on the system. For this, we will add one PSET event, which sets the active power of an object at a given time step. By using multiple PSET events or assigning a profile to the PSET event, you can change the power set point modeling the dynamic behavior of an object parameter.

1.1. Add an event via the model explorer

Create the PSET event on the demand object using the model explorer. Find the EDEM.DEMAND1 by going to Nodes NODE2 EDEM.DEMAND1, then right-click on the demand object and select Scenario Event Active power set point (PSET) (Figure 1). This will automatically create the event and prompt the event property editor window.

Figure 1. Adding a new event from the model explorer.

1.2. Define event properties

In the event property editor window, go to the profile category to assign a profile to the event. In the ProfileName (Profile) property, select PRF_DEM from the drop-down menu. In the setting category, define the Value of the event as 1. This value will be used to scale the profile data points at each time step. Then, change the StartTime under the time category to 01/01/2023 01:00. Close the editor window, and you will notice that the model explorer has been updated with a new scenario event under Scenario Events.

Profiles will only show in the ProfileName (Profile) property of the event if they have been previously created. Therefore, to avoid any issues, remember profiles must be created or inputted into the scenario file before assigning them to an event.
The ProfileStartTime (PrfStartTime) is used to define the start time of the profile when it differs from the event StartTime. Notice that in our case, once the StartTime was changed, the PrfStartTime also changed automatically. This is because the PrfStartTime cannot be set before the event StartTime. Additionally, the event StartTime must also be within the scenario time window. An error message will be prompted if any of these rules are not respected.

Why did we change the StartTime to 01:00 instead of keeping it at 00:00?

In SAInt, we have "transient" and "state" events. A transient event defines the change in an object parameter over a given time interval base on the scenario time step, such as the active power of an object. In contrast, a state event defines the operational state or level of an object parameter at a specific time step, such as the commitment of a generator or state of charge of an energy storage unit.

Due to this difference, all transient events during a simulation must be shifted by the scenario time step because in SAInt the time step indicates the period from 00:00 to 01:00. In this specific case, the demand event (PSET) represents the energy consumed from 00:00 to 01:00.

2. Create wind generator events

In an AC power flow simulation, the power output from non-dispatchable generators, such as wind generators, can be modeled as a time-varying quantity using a predefined power output profile that reflects their variable nature of generation. In this section, we will define the predefined production of the XGEN.WIND_GEN3 with a PSET event that is associated with a fixed profile. Additionally, a QSET event will be defined to set the reactive power.

2.1. Add new events via the node bar

We will continue by creating the PSET and QSET events using the node bar in the map window. The node bar is used to see all the objects (branches and externals) connected to a selected node. Open the node bar by clicking on the Node Bar tab on the right side of the map window. Click on the top right corner to dock or undock the node bar. Select NODE4 to view the XGEN.WIND_GEN3 in the node bar. Right-click on the XGEN.WIND_GEN3 and create PSET and QSET events sequentially.

2.2. Define event properties

In the event property editor window for the PSET event, go to the profile category to assign a profile to the event. In the ProfileName (Profile) property select the PRF_WIND from the drop-down menu. In the setting category, define the Value of the event as 1. Then, change the StartTime under the time category to 01/01/2023 01:00. Close the property editor window for both PSET and QSET events.

We did not change any properties for the QSET event because in SAInt, an event has a default value of 0. Since we want to model a wind generator with a unit power factor, its reactive power should be set to 0.

3. Create generic generator events

In this section, we will simultaneously define the scheduled production of the generic generators with PSET events associated to fixed profiles. In In the model explorer, select both generic generators by holding Ctrl, under Externals GenericGenerators. Right-click on one of them and select Scenario Event Active power set point (PSET). Close the multi-edit window for events as we will later use the event table to define the StartTime, Profile, and Value properties.

3.1. Additional events for generic generators

In addition to fixing the output of the generic generators with PSET events, we aim to set their active power compensation proportional to the scheduled power. To accomplish this, create the PFSET events for both generators simultaneously using the model explorer. Close the multi-edit window for events, as we will define the StartTime, Profile, and Value properties for PFSET events using the event table.

3.2. Edit event properties in the event table

The event table can be used to review, filter, and edit scenario events. Open the event table by going to the scenario tab and clicking on EEVT. To view the Profile (or any other) property in the event table, right-click on the top-left corner of the table window and select the Show Column Chooser option. Search for the required properties and drag and drop the columns to add it to the table. At this point, the event table should contain the following events as in Figure 2.

Figure 2. Scenario event table before filling in the data for the XGEN generators.

Next, use Table 1 to fill in the StartTime, Profile, and Value properties for generic generator events, directly in the event table.

Click here to view the event properties for generic generators.

Table 1. Properties for generic generator events.
StartTime	ID	Parameter	Profile	Value
1/01/2023 1:00	XGEN.NG_GEN2.PSET	PSET	PRF_NG_GEN2	1
1/01/2023 1:00	XGEN.NG_GEN1.PSET	PSET	PRF_NG_GEN1	1
1/01/2023 1:00	XGEN.NG_GEN2.PFSET	PFSET	PRF_NG_GEN2	1
1/01/2023 1:00	XGEN.NG_GEN1.PFSET	PFSET	PRF_NG_GEN1	1

Assigning the scheduled power profiles to PFSET events sets the active power compensation proportional to the scheduled power for NG_GEN1 and NG_GEN2.

4. Review the scenario file

Save the scenario file to add the seven scenario events to the scenario file. Spend some time reviewing the scenario events and profiles to ensure all the data was correctly inserted.