Solar O&M Reference · No. 03 / 05 · Grid

Grid
Overvoltage

When the whole neighbourhood exports solar at noon, the local voltage rises. Your inverter pauses to protect itself, then resumes — usually within seconds.

244 V EMA ceiling The top of the allowed band. Above this, the inverter steps back.
242 V What SP already supplies Nominal supply sits close to the ceiling before your solar adds anything.
Seconds Typical pause The grid self-adjusts and the inverter resumes on its own. No action needed.
§ A · Cause Neighbourhood-wide
Move the slider

Why the voltage rises at noon

Between 11am and 3pm most homes are empty, so hardly anyone is using power — yet every rooftop is exporting at once. All that electricity pushes back into the same local grid node, and the voltage there climbs. Drag to add more exporting neighbours.

Local grid node

Few exportingWhole street
242.6 V
Voltage at your grid node
Within band · exporting normally

Midday sun, empty housesPeak generation lands exactly when household demand is at its lowest.

11am–3pm

Everyone exports at onceMany systems push power back into the same local node together.

2 of 8 homes

Node voltage climbsSP already supplies near 242 V. The extra export pushes it higher still.

242.6 V

244 V breached → inverter pausesIt protects itself, waits for the voltage to settle, then resumes.

Generating
§ B · Envelope ±6% of 230 V
The allowed range

The EMA voltage band

Floor 216 V
Nominal 230 V
Ceiling 244 V
216 V223 V230 V237 V244 V
The white marker follows the slider above

SP supplies at a nominal 242 V, already near the top of the band. When your solar system exports, the local node voltage rises a little further and can breach 244 V. The inverter pauses, the voltage settles, the inverter resumes.

§ C · Three factors combining

Why this happens

  1. Many PV systems in the area

    They all generate hard during the same hot, sunny hours.

  2. Most homes are empty

    Daytime household consumption is low, so little of it is used on site.

  3. Excess export floods the local grid

    Node voltage rises above 244 V and the inverter steps back.

§ D · FOMO response

Inverter tuning we can do

  1. Derating

    Reduce output gradually instead of cutting off completely, so the system keeps generating at lower capacity.

  2. Q-U curve

    The inverter absorbs reactive power as voltage rises, suppressing the rise locally.

  3. Threshold adjust

    Raise the overvoltage trip point. Requires power-operator consent.

§ E · Quick answers

Common questions

Should I worry about overvoltage alarms?

No. It is normal in solar-dense areas, especially between 11am and 3pm. The grid self-adjusts and most trips last seconds. No action needed.

Why does the inverter stop generating?

It hits its voltage limit and pauses to protect itself. That is a safety feature, not a fault. It resumes as soon as the grid recovers.

Will frequent trips damage the inverter?

No. The halt-and-recover cycle is exactly what the hardware is designed for. No components are stressed.

Who is responsible for fixing the grid?

SP Powergrid, regulated by EMA — not FOMO. We are in active discussion with EMA, and persistent issues can be escalated to SP Powergrid.

FOMO Energy reference sheet: Grid Overvoltage
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The one-page reference sheet

Everything on this page, condensed into a single sheet you can save or forward. Prepared by the FOMO Energy Solar O&M team.

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Seeing overvoltage outside midday?

Pauses at night or in dull weather are worth a look. Send us the date and time, and our O&M team will check it against the inverter logs.