{
  "$schema": "https://ps-wiki.github.io/schema/v1/term.schema.json",
  "id": "secondary-control",
  "title": "Secondary Control",
  "description": "Balancing services deployed in the minutes time frame.",
  "language": "en",
  "tags": [
    "frequency-control",
    "generation",
    "nerc"
  ],
  "related": [
    "fast-frequency-response",
    "primary-control",
    "tertiary-control",
    "frequency-regulation",
    "automatic-generation-control",
    "frequency-stability"
  ],
  "breaking": false,
  "dates": {
    "created": "2025-03-15",
    "last_modified": "2025-06-22"
  },
  "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": [
          "nerc2021balancing"
        ],
        "page": null,
        "body_md": "> Typically includes the balancing services deployed in the “minutes” time frame. Some resources, such as hydroelectric generation, can respond faster in many cases.\n> This control is accomplished using the Balancing Authority’s control computer (terms most often associated with this are **“Load-Frequency Control”** or [**“Automatic Generation Control”**](/wiki/automatic-generation-control/)) and the manual actions taken by the dispatcher to provide additional adjustments. Secondary Control also includes initial reserve deployment for disturbances.\n>\n> In short, Secondary Control maintains the minute-to-minute balance throughout the day and is used to restore frequency to its scheduled value, usually 60 Hz, following a disturbance.\n> Secondary Control is provided by both [**Spinning**](/wiki/spinning-reserve) and [**Non-Spinning Reserves**](/wiki/non-spinning-reserve).\n",
        "figures": [
          {
            "path": "/assets/img/pswiki/frequency_trend.png",
            "caption_md": "Typical Frequency Trend for the Loss of a Generating Resource (from <d-cite key=\"nerc2021balancing\"></d-cite>).",
            "alt": "Typical Frequency Trend for the Loss of a Generating Resource.",
            "zoomable": true,
            "source_keys": [
              "nerc2021balancing"
            ]
          }
        ]
      }
    ]
  }
}