Mitigating harmonics and lowering noise pollution in a Finnish greenhouse

A lot of energy is needed in year-round greenhouse production because in the winter months, greenhouses are heated and plants are given additional light. Particular challenges in greenhouses are energy-efficient and environmentally sustainable production. In what way could climate emissions from greenhouses be most effectively reduced while increasing production efficiency? Our greenhouse customer was looking for a solution to improve energy efficiency in Närpiö, Finland. Greenhouse lighting appeared as a source of high current harmonics that caused overheating of light bulbs, wires, and other components.

Challenges in the customer’s greenhouse

The greenhouse lights, a total of 22MW, are a source of high harmonic currents. Especially the 3rd harmonic was causing high current in the neutral wire which resulted in overheating of the wires and other power system components, for example, the transformer.

The customer had explored different solutions, in which the noise level and the footprint remained as issues. Furthering the challenge, the solution could not be implemented in the main distribution panel to lower the noise level, as the neutral currents would significantly strain the network, and in the main distribution board power quality solutions would cause resonance with capacitance in the system.

Our Merus^® Solution

Due to the customer’s need to solve this issue, they had measurements done by a third party, which led to Merus Power being recommended as the supplier. Merus Power suggested Merus^® A2-series Active Harmonic Filters as a solution that was supplied through a third party. Merus^® A2-Series filters have a small footprint and low audible noise level, thanks to the modern 3-level topology.

The solution consisted of 24 pieces of Merus^® A2-series 100A Active Harmonic Filters, installed in cubicles and parallel to the loads in the distribution boards. The silence solution was needed because the distribution boards are located in the greenhouse space where the cucumbers are grown and the gardeners work.