{
  "$schema": "https://ps-wiki.github.io/schema/v1/term.schema.json",
  "id": "short-circuit-ratio-with-interaction-factors",
  "title": "Short-Circuit Ratio with Interaction Factors",
  "description": "SCRIF. The ratio between short circuit apparent power from a 3LG fault at a given location in the power system to the rating of the location.",
  "language": "en",
  "tags": [
    "reliability",
    "nerc"
  ],
  "related": [
    "grid-strength",
    "reliability",
    "short-circuit-ratio",
    "weighted-short-circuit-ratio",
    "composite-short-circuit-ratio"
  ],
  "breaking": false,
  "dates": {
    "created": "2025-11-29",
    "last_modified": "2025-11-29"
  },
  "authors": [
    {
      "name": "Jinning Wang",
      "url": "https://jinningwang.github.io"
    }
  ],
  "content": {
    "sections": [
      {
        "order": 1,
        "id": "definition-by-nerc",
        "title": "Definition by NERC",
        "type": "definition",
        "source_keys": [
          "nerc2017integrating"
        ],
        "page": "p3",
        "body_md": "> SCR with Interaction Factors (SCRIF) has been proposed to capture the change in bus voltage at one bus corresponding resulting from a change in bus voltage at another bus. Electrically close inverter-based resource buses will have a relatively higher Interaction Factor (IF) than inverter-based resource buses that are electrically separated. When multiple inverter-based resources are located very close to each other, they share the grid strength and short circuit level; hence, the grid strength is actually much lower than the overall short circuit level calculated at that bus or buses. SCRIF captures the voltage sensitivity between inverter-based resources as a screening tool for potential controls issues by using inverter-based resource interaction factors, as follows:\n>\n> $SCRIF_{i} = \\frac{S_{i}}{P_{i} + \\sum_{j} (IF_{ji} \\cdot P_{j})}$\n>\n> Where $IF$ is the change in bus voltage at bus $i$ ($\\Delta V_{i}$) for a change in bus voltage at bus $j$ ($\\Delta V_{j}$), as follows:\n>\n> $IF_{ij} = \\frac{\\Delta V_{i}}{\\Delta V_{j}}$\n>\n> An advantage of the use of SCRIF is that it can be readily amended to cater for any conceivable configuration for connection of multiple inverter-based resources.\n"
      }
    ]
  }
}