# Grid reconnection

> How a Voltmasters microgrid returns to the grid: releasing the reconnection in the platform or the app, the interruption it causes and the eight steps of the procedure.

Source: https://voltmasters.io/en/docs/microgrid/grid-reconnection/

Reconnecting an island to the grid briefly cuts the power: the controller first makes the site's bus dead, then closes the grid breaker. That is why, by default, the controller does not reconnect on its own but waits for a **release**.

## When the grid is back

As soon as the grid has been stable long enough, the site enters **Grid back, waiting for release** and keeps running as an island. At the same time:

-   the incident **Reconnection to the grid awaits release** opens;
-   users who may release get a push notification **Grid is back, release needed** in the mobile app;
-   a **Grid is back** banner appears at the top of the project's **Overview**.

![Voltmasters EMS: banner Grid is back with the message that the site keeps running as an island until the reconnection is released, and the Release reconnection button](https://voltmasters.io/assets/docs/microgrid-reconnect-bar-pending.webp)

*The banner shows since when the grid is back and holds the Release reconnection button.*

## Who may release

Voltmasters administrators and users with the **Installer** role on the project. Other users see the banner with the message that an administrator of the project has to release the reconnection.

## Releasing the reconnection

1. **Click Release reconnection**
   
   In the banner on the **Overview**, or on the microgrid screen of the mobile app. Choose a moment when a short interruption does no harm.
2. **Confirm**
   
   The confirmation window states how long the site may be without power. Click **Release reconnection** to start, or **Cancel**.
   
   ![Voltmasters EMS: confirmation window Release the reconnection to the grid, stating the site loses power for up to 2 minutes](https://voltmasters.io/assets/docs/microgrid-reconnect-confirm.webp)
   
   *When the battery forms the island, the site loses power for at most two minutes.*
3. **Follow the procedure**
   
   The banner and the procedure panel show which step is running. When the site is back on the grid, the banner says so and the incident closes.

## How long the interruption lasts

| Situation | Interruption |
| --- | --- |
| The battery forms the island | At most 2 minutes. |
| The battery forms the island, a generator runs alongside | The generator first runs down, which can take up to 10 minutes before the interruption starts. The interruption itself stays within 2 minutes. |
| The generator forms the island | The site is without power until the generator has cooled down and stopped and the site is back on the grid: at most about 12 minutes. |

## The eight steps

The procedure panel ticks off the eight steps of a reconnection, each with what the controller waits for.

![Voltmasters EMS, procedure panel of a reconnection. Checking the grid and preconditions](https://voltmasters.io/assets/docs/microgrid-reconnect-step-1.webp)

*Step 1 of 8: Checking the grid and preconditions*

![Voltmasters EMS, procedure panel of a reconnection. Stopping the generator](https://voltmasters.io/assets/docs/microgrid-reconnect-step-2.webp)

*Step 2 of 8: Stopping the generator*

![Voltmasters EMS, procedure panel of a reconnection. Switching off the battery converters](https://voltmasters.io/assets/docs/microgrid-reconnect-step-3.webp)

*Step 3 of 8: Switching off the battery converters*

![Voltmasters EMS, procedure panel of a reconnection. Disconnecting the PV](https://voltmasters.io/assets/docs/microgrid-reconnect-step-4.webp)

*Step 4 of 8: Disconnecting the PV*

![Voltmasters EMS, procedure panel of a reconnection. Confirming the bus is dead](https://voltmasters.io/assets/docs/microgrid-reconnect-step-5.webp)

*Step 5 of 8: Confirming the bus is dead*

![Voltmasters EMS, procedure panel of a reconnection. Closing the grid breaker](https://voltmasters.io/assets/docs/microgrid-reconnect-step-6.webp)

*Step 6 of 8: Closing the grid breaker*

![Voltmasters EMS, procedure panel of a reconnection. Starting the battery converters on the grid](https://voltmasters.io/assets/docs/microgrid-reconnect-step-7.webp)

*Step 7 of 8: Starting the battery converters on the grid*

![Voltmasters EMS, procedure panel of a reconnection. Releasing the generator for the grid](https://voltmasters.io/assets/docs/microgrid-reconnect-step-8.webp)

*Step 8 of 8: Releasing the generator for the grid*

1.  **Checking the grid and preconditions**
2.  **Stopping the generator**, if one runs (cool-down included).
3.  **Switching off the battery converters**
4.  **Disconnecting the PV**
5.  **Confirming the bus is dead**
6.  **Closing the grid breaker**
7.  **Starting the battery converters on the grid**
8.  **Releasing the generator for the grid**

## When it does not succeed

-   **The controller stops the reconnection**: the site keeps running as an island, the incident **Reconnection to the grid was aborted** opens, and the banner shows at which step and why. You can release again.
-   **The controller does not report back in time**: check the project's incidents and the live diagram before releasing again.

## Automatic reconnection

With **Reconnection** set to **Automatic** in the [microgrid settings](https://voltmasters.io/en/docs/microgrid/configuration/#reconnection), the controller reconnects on its own once the grid is stable and the **Automatic reconnection delay** (60 s) has passed. Choose this only when an unannounced short interruption is acceptable on the site.

> **Note**
>
> Every release is recorded in the project's [activity log](https://voltmasters.io/en/docs/voltmasters-platform/project-settings/activity/), with the user who gave it and the outcome.