{
  "language": "en",
  "interfaceLanguage": "ar",
  "url": "https://voltformer.com/ar/news/eirgrid-soni-enforce-1hz-per-second-rocof-grid-code-substation-standard",
  "slug": "eirgrid-soni-enforce-1hz-per-second-rocof-grid-code-substation-standard",
  "category": "policy-standards",
  "publishDate": "2026-10-01",
  "sourceName": "EirGrid Group & SONI System Operations",
  "sourceUrl": "https://www.eirgridgroup.com/newsroom/press-releases/2026/all-island-grid-code-update-1hz-rocof-compliance-substations-october-2026",
  "readingTimeMinutes": 5,
  "tags": [
    "EirGrid",
    "SONI",
    "All-Island Grid Code",
    "RoCoF",
    "SNSP 85%",
    "Ireland Grid",
    "Frequency Stability",
    "Transformer Protection"
  ],
  "content": {
    "title": "EirGrid and SONI Enforce Mandatory 1.0 Hz/s RoCoF Grid Code Standard Across All Island Substation Protection Relays",
    "summary": "Irish transmission operators EirGrid and SONI have legally enacted the updated All-Island Grid Code requiring all generator step-up transformers, transmission substations, and BESS installations to withstand a Rate of Change of Frequency (RoCoF) of 1.0 Hz/s over a 500 ms rolling window, paving the way to an 85% System Non-Synchronous Penetration (SNSP) cap.",
    "sections": [
      {
        "heading": "Pioneering Extreme Low-Inertia Island Grid Operations",
        "paragraphs": [
          "Effective October 1, 2026, EirGrid (Ireland) and SONI (Northern Ireland) finalized the operational transition requiring 100% compliance with the 1.0 Hz/s RoCoF withstand standard. In small synchronous island systems dominated by offshore wind and solar, the sudden tripping of a major interconnector or power unit causes frequency to plunge far more rapidly than in mainland continental grids.",
          "The mandatory standard prevents the cascade tripping of generator step-up transformers, loss-of-mains anti-islanding relays, and renewable feeder circuit breakers during high-RoCoF events."
        ]
      },
      {
        "heading": "Substation Protection Relay and Transformer Upgrades",
        "paragraphs": [
          "Transmission asset owners invested over €140 million across 350 substations to reprogram digital numerical relays, recalibrate vector shift and frequency rate settings, and perform dynamic short-circuit mechanical stress simulations on aging power transformers.",
          "With the standard fully enforced, EirGrid confirmed trial operations to lift the System Non-Synchronous Penetration (SNSP) limit from 75% to 85%, cementing Ireland’s global leadership in running an electricity grid on variable renewables."
        ]
      }
    ]
  },
  "companies": []
}