UGS Grid Stabilizer

The UGS Ultracapacitor Grid Stabilizer combines the STATCOM capabilities of an IGBT-Power Converter with active power support based on high-power Maxwell Ultracapacitors. Compared to standard Li-Ion batteries the Ultracapacitors have a much higher power density (but a lower energy density), in combination with ultra-fast power electronics this makes them the ideal device for short-term grid stabilisation. Another advantage of Ultracapacitors is the high cycle-life with life-expectancy of up to 1.000.000 charge-discharge cycles. The UGS can provide voltage and frequency stabilisation in transmission or distribution networks with high renewable penetration. Another application is the stabilisation of electricity supply in the manufacturing industry to avoid downtime of machinery.

The FREQCON NGC Power Converter is a MW-scale IGBT-based power converter that was originally developed for renewable energy applications, with more than 18 GW installed in the field. Based on this experience new models for new applications such as STATCOM converters or battery-to-grid converters have been developed, with the UGS Ultracapacitor Grid Stabilizer being the latest application for our NGC power converter.


Dynamic Reactive Response (DDR)

The ability to deliver ultra-fast reactive current response to compensate voltage dips


The ability to deliver active power to compensate frequency dips within 5ms

Fast Frequency Response (FFR)

FFR supplements any inherent inertial response and delivers active power in the time frame 2 to 10 seconds to stabilise frequency

Primary Operating Reserve

Active power provision up to 15 seconds to stabilise frequency

Harmonic Filtering

Active filtering of harmonics based on ultra-fast IGBT-switching

UPS Capability

Providing transition power until a longer-term back-up source like diesel genset is up and running


Reference Project Kilpaddoge, Ireland

The Irish grid operator EirGrid has introduced new grid support services (DS3 Programme) in order to achieve 40% renewable electricity by 2020 without compromising on grid stability. One of the first projects qualifying for DS3 is the 2MW Kilpaddoge Power Park Module. The system combines 2MW of diesel generators for ramping services with 2MW of Ultracapacitors for Fast Frequency Response. The Freqcon solution integrates diesel gensets and Ultracaps by providing a Multi-Source-Converter with common DC-Link. This allows grid-code compliant and seamless delivery of several system services, from ultra-fast frequency response to longer-term ramping margin.