Keeping cool under pressure: Improving power quality at a cold storage facility

Merus^® A2 Active Harmonic Filters helped Constellation Cold Logistics address changing power factor correction requirements and reduce harmonic distortion at its solar-powered cold storage facility in northern England.

Customer background

Constellation Cold Logistics operates cold storage warehouse facilities in England. The company had recently installed a solar photovoltaic (PV) system to power and sufficiently cool its warehouse buildings, with the aim of running the cooling systems solely on solar power during the day.

SR Electrical, an electrical wholesaler based in northern England, was involved in addressing the facility’s changing electrical requirements following the addition of solar generation.

Challenges at the customer’s site

There was significant underlying harmonic voltage distortion (THDu) across the site, caused by the accumulation of inverter loads, including Variable Frequency Drives (VFDs), soft starters, office equipment, and battery chargers. While no single transformer generated sufficient harmonic currents to push harmonic voltage distortion beyond acceptable limits, the cumulative effect across the site did exactly that.

During the initial investigation, Merus Power’s local partner, Power Capacitors, attended the site and took electrical readings from distribution board meters and power factor correction (PFC) relays, along with detailed installation notes.

Solar generation had been added to all but one transformer, significantly changing the facility’s power factor correction requirements. As a result, the system needed fast response times, small and accurate compensation steps, and the ability to handle periods of leading power factor and large changes in reactive power demand.

Our Merus^® Solution

Power Capacitors proposed replacing the existing traditional power factor correction equipment where required with Merus^® A2 Active Harmonic Filters. The filters were configured primarily for dynamic power factor correction, responding to changing reactive power demands caused by the addition of solar generation. At the same time, their harmonic filtering capability reduced harmonic currents at individual transformers, helping lower overall THDu across the site.

Power Capacitors utilized the existing PFC switches to install the Merus^® A2 filters. The filters’ suitable IP protection options allowed the team to reuse existing PFC cabinets or mount the filters directly onto walls, depending on the installation environment. This flexibility helped reduce installation costs.

The installation team fitted and commissioned three Merus^® A2 units, each with a different installation design. The team completed all three installations on time and within budget.

Two additional filter cubicles were also planned for installation by a third party, pending separate modifications to the new electrical distribution boards.