JANUARY 08, 2021
Dlaboratory Sweden AB's power quality analysis leads to reliable wind energy
With more and more power electronics being connected to the grid, the question of power quality has grown in importance in recent years . Power electronics can add more current harmonics, and be more sensitive for harmonics from other sources, such as fast chargers for vehicles (especially smart chargers where connected vehicles are acting as battery storage and supply energy to the grid on demand), battery storage power stations and solar power plants.
As of today, there are no prevalent issues concerning the general power quality in the Swedish grid. But the impending changes ahead demand connecting more sensitive equipment to the grid; equipment that might be sensitive to a lower level of power quality, while itself lowering the power quality levels. Also, more micro production (such as solar power panels on single houses) will be connected to the power grid. Therefore, power quality will be an increasingly important matter in the time to come.
In some wind power plants, monitoring power quality parameters is essential to appraise the plant’s performance and to understand how the power grid surrounding the plant affects its operations. The TSOs and DSOs are responsible for the power quality to reach standard levels. However, since the harmonics mostly come from connected consumers and production sources, collaboration between producers, distributors and consumers is required. Having a monitoring system of your own plant will ease the dialogue with the other parties.
There are multiple reasons why wind power production tends to come into the limelight when discussing power quality in the grid. One reason is that a wind power plant, and even a single turbine, has a significant amount of power, and thus a capacity to influence the power grid locally. Another reason has to do with harmonics; today’s wind power plants have inverters with power electronics, which produce harmonics in the grid. Also, wind power plants are power production sources, and as such, they influence the reactive power flows and voltage stability in the grid, as well as how the plants react to faults in the supplying grid.
Finally, there is a historic connection between flicker (fast voltage variations visible in a classic light bulb) and wind power. Wind power turbines of an older model have been known to produce flicker. But as new technology has taken over, and inverters have been introduced, the flicker problems have significantly diminished, while the association of flicker and wind power lingers on.
Qualitative measuring and analysis are needed in all kinds of situations connected to optimized operations: monitoring the power quality; controlling wind power plant operations when feeding lines have disturbances; or detecting and repairing minor faults in a wind farm’s internal grid before they turn into power failures and production loss. Dlab has the solutions to keep high power quality in the future grid, consisting of sustainable power and micro production, decentralized energy storage and smart load control.
Victor Bagge, systems engineer, Dlaboratory Sweden AB