Constraint scenarios

Overview 

In PVcase Prospect, you can easily view the limiting grid constraints for any bus, giving you all the necessary information from the start.

The Constraint scenario tables detail the necessary upgrades for interconnection at a specific bus, organized by the chosen Capacity layer. Within each Capacity layer, the required upgrades are shown for progressively higher levels of power injection or withdrawal. All markets include the N-0 base-case scenario, and some also incorporate the N-1 scenario, which involves contingency analysis of the grid.

View Constraint scenarios for a given bus 

1. Toggle on the desired Capacity bus layer in the Layer Catalog (or via the Add Grid workflow sidebar option).
2. Click on the target bus in the layer

• Injection –  Use these for siting solar, wind, or any other project that generates and injects power onto the grid
• Withdrawal –  Use these for siting standalone battery storage, hybrid storage + generation projects, or data centers (or any project that withdraws power from the grid).

3. In the bus pop-up, click the Constraint Scenarios button to open the constraints table.

This will show you limiting constraints at different injection levels for N-1 and N-0 scenarios.

If there are multiple buses where you clicked, then multiple results will appear in the pop up. Scroll down on the pop up to locate the desired bus.

Filter constraints based on injection or withdrawal level

You can filter the constraint list for a given POI by any of the attributes available.

1. Click the Filter button at the top left or far right of the table.
2. Filter off any attribute in the table (or multiple)

e.g. Scenario (N-1 or N-0); Distribution Factor %, Pre-Existing Limiting Element, etc.

How are constraints modeled?

For the N-1 scenario, contingency analysis is applied. The following is a high-level description:

Contingency Analysis

• 'What if' scenario simulator that evaluates, provides and prioritizes the impacts on an electric power system when problems occur. A contingency is a provision for an unforeseen event or circumstance:
  - Loss or failure of a small part of the power system (e.g. a transmission line)
  - Loss or failure of individual equipment such as a generator or transformer
• Computer application that uses a simulated model of the power system 
  - Evaluates the effects of an outage event
  - Calculates any overloads that may result

This is referred to as maintaining system security
 

(Source: https://www.pjm.com/) 

In both scenarios, upgrades may be required to reach the desired injection or withdrawal amount. This table will list those upgrades and the injection/withdrawal amounts those upgrades make possible.