Voltage dip
ms – sVoltage drops without reaching zero. Electronic equipment interprets it as a fault and disconnects.
AffectsDrives, PLC power supplies, contactors
Uninterrupted backup (STS)
A micro-outage lasts milliseconds. Restarting takes hours.
Drives, PLCs, servers and furnaces won't wait for the generator to start. With a BK battery and static switching, the critical load switches to battery within milliseconds and never notices the outage.
Uninterrupted back-up
- Static transfer switching with STS
- milliseconds
- Power Pro BK112H switchover to island mode
- < 20 ms
- Monitoring from our control centre
- 24/7
The problem
Your process can't tell a blackout from a micro-outage. Both stop it.
Most stoppages aren't caused by a long blackout, but by disturbances lasting tenths of a second that nobody sees and that bring the line down.
- A micro-outage lasting tenths of a second doesn't switch off the lights, but it trips drives, PLCs and contactors. The line stops all the same.
- Restarting a continuous process (extrusion, furnaces, refrigeration, chemicals) costs hours of production and scrapped material.
- A generator protects against long outages, but takes seconds to pick up the load: by then the process has already gone down.
- A conventional UPS covers minutes, only part of the load, and adds nothing for the rest of the year.
- The blackout on the Iberian peninsula proved that a total grid failure is not theoretical.
- 28/04/2025
- is one grid cycle at 50 Hz. A dip of a few cycles is enough to trip contactors and drives.
- 20ms
- for a typical generator to start and pick up load.
- ~10s
- Operating procedure requiring generation to stay connected during voltage dips.
- PO 12.3
Supply interrupted for hours across Spain and Portugal.
Enough to protect against a long outage; too late for a continuous process.
How a BK BESS solves it
The load switches to battery before it notices the outage.
The static transfer switch (STS) monitors the grid continuously. When it detects an outage or a dip, it isolates the site and the BK battery, with its inverter forming the grid, picks up the load within milliseconds.
- 01
Normal operation
The grid supplies the loads and the battery stays charged. Meanwhile, it can shave peaks or shift consumption to cheap hours.
- 02
Detection and switchover
The STS detects the outage or dip and isolates the site from the grid within milliseconds. Static switching, no moving parts.
- 03
Island mode
The bidirectional inverter forms the grid: it sets voltage and frequency and supplies the critical load from the battery.
- 04
Smooth return to the grid
When the grid is stable again, BK EMS resynchronises and the load returns to the grid. If the outage drags on, the generator starts and the battery bridges the gap.
- Grid
- Battery (island mode)
- Generator (optional)
Illustrative diagram; time scale not to proportion. The generator needs seconds to start and pick up load; static switching does it in milliseconds.
Dip, micro-outage, outage
Three different disturbances. One response.
Micro-outage
< 1 sVoltage disappears for tenths of a second. The lights barely flicker; the production line stops.
AffectsContinuous processes, servers, refrigeration
Outage
min – hNo supply for minutes or hours. Without back-up, everything stops until the grid returns.
AffectsEverything without back-up
With BESS + STS, all three are solved the same way: the critical load switches to battery within milliseconds and returns to the grid once the grid is stable.
Comparison
UPS, generator or battery with STS.
| Criterion | Conventional UPS | Generator | BK BESS + STS |
|---|---|---|---|
| Response time | Immediate (online) | ~10 s: start-up and load pick-up | Milliseconds |
| Autonomy | Minutes | Hours, depending on fuel | From minutes to hours depending on kWh; unlimited with a generator |
| What it covers | IT and control | The whole plant | The critical loads you choose, from 100 kWh to several MWh |
| Use for the rest of the year | None | None | Peak shaving, arbitrage and self-consumption |
| Operation | Batteries requiring periodic replacement | Fuel, start-up tests, noise and emissions | LFP, 24/7 monitoring with BK EMS |
Indicative comparison. The three systems can be combined: a battery with STS doesn't mean removing the generator or the UPS.
Where it matters
Sites that can't afford to stop.
Data centres and telecoms
Full availability without relying on generators alone. Long-duration LFP back-up with 24/7 remote management.
Process industry
Extrusion, injection moulding, furnaces, chemicals or food: wherever a few seconds' stoppage costs hours of production.
Pumping and irrigation
Irrigation communities and pumping stations that can't afford to stop halfway through the season.
Power quality
Voltage support during dips and disturbances, and help complying with PO 12.3 in generation facilities.
Recommended products
What we solve it with.
Hybrid and STS
Switchover in msBidirectional inverters, island mode and static switching to transfer the load to battery without interruption.
View productPower Pro
112–522 kWhOutdoor all-in-one. The BK112H switches to island operation in under 20 ms.
View productCabinets
241–418 kWhModular cabinets to size the exact autonomy your critical loads need.
View productPowerbolt
up to 6.25 MWhLarge-scale back-up for industrial plants and data centres.
View productReferences
We have already done it.
BESS for an irrigation community
Jaén
522kWh
250 kW · STS
Your installation
We tell you which system you need and how it performs in your case.
We also work on large-scale energy storage projects as back-up for major industrial groups in Spain.
Frequently asked questions
What people ask us before deciding.
Does it replace my UPS?
In many cases yes, for most of the load. If any equipment can't tolerate even a millisecond, we keep a small online UPS just for it and the BK battery provides the long autonomy.
How long can it carry the load?
Autonomy is the battery's energy divided by the power of the critical loads. For example, 522 kWh supplies 250 kW for about 2 hours (slightly less, allowing for reserve and losses). With a back-up generator, as long as needed.
Which loads do I connect to the back-up?
Only the critical ones, grouped on a dedicated switchboard behind the STS: control, servers, process lines, refrigeration. That way the battery isn't sized for the whole plant.
Can I use the battery to save money when there are no outages?
Yes. BK EMS reserves the energy needed for back-up and uses the rest to shave peaks or shift consumption to cheap hours. The back-up partly pays for itself.
Does it work with my generator?
Yes. The battery bridges the gap while the generator starts and, once it's running, keeps it working at an efficient load point.
What does PO 12.3 have to do with it?
PO 12.3 sets out how generation facilities must respond to voltage dips: stay connected and support the grid. A battery with fast power electronics helps sustain voltage; we include it in our O&M service as regulatory adaptation.
How much does a stoppage cost you?
Tell us which loads can't go down and how long you need to cover. We'll propose the battery, the STS and the integration with your generator or UPS.