Transformers for Solar and Wind Power Generation Industry: Part One

The adoption of renewable energy is gaining paramount importance, considering the increasing carbon emissions and climate change. The power generation industry is also looking forward to catering to the generation and the supply of renewable energy in the consumable form by judiciously harnessing these resources. 

The International Energy Association states that solar will become the world’s single largest source of electricity by 2050, supplying nearly 30% of the total demand. (Source: https://www.apollopowersystems.com/blog/9-amazing-fun-facts-about-solar-energy-you-probably-didnt-know/). Most power generation companies look to solar and wind energy for generating energy. The transmission and distribution of solar and wind power are as complicated as the generation of solar and wind power. Therefore, the right type and construct of the transformers are necessary for efficient conversions and distribution, as per the final power requirements. To cater to these distinct setup conditions, transformer manufacturers fabricate solar and wind power transformers. 

Are these transformers similar to the other category of transformers? Is there construction, design, insulation, harmonics, etc. get the same importance? No. The transformer installation at wind energy and solar power units is an entirely different matter. The transformers are exposed to endure extreme weather conditions, uneven production or supply of energy, and immediate hyper functioning of the setups. Therefore, the solar transformer and wind transformer manufacturers must carefully work on the construction and design of these transformers. 

Further in the blog, let’s learn about solar and wind transformers. 

Solar Transformers

The solar power transformers convert the DC electricity generated by the solar panels to the AC electricity used by the electricity grids. Traditionally the transformers were performing the step-up or step-down functions for the setups. But, for modern structures, one can find different types of solar transformers in solar energy generation - station, sub-station, pad mounted, grounded, and distribution. Every solar transformer has distinct design requirements and faces different issues regarding the factors affecting it. For instance, harmonics, fault ride through, inverters, transformer range, etc. Every transformer works on various variables, and thus, the manufacturing must be distinct to produce the best results. 



 

Factors of consideration while working on the design of a solar transformer: 

Non-symmetrical loads and voltage, the existence of direct current in the winding, Windings, waveforms of inverter output, efficiency and loss of a transformer, Inrush current considerations, thermal design, short-circuit considerations, High frequency switching transients, standards of IEEE, certain practices for installation, and operations, Quick rising pulse waveform of LV windings, etc. 

Wind Turbine Transformers

Wind turbine transformers installed at the wind farms connect the wind turbines and the distribution grid. The wind speed is not constant throughout the day, hence, fluctuating the output of the turbines. The transformer converts the low output voltage of the turbines to the medium or higher output voltage (collector voltage). Notwithstanding the transformers are termed as the weak links for the wind farms. Owing to their incapability to withstand the dynamic circumstances and factors at the wind farms. These include mechanical, electrical, and corrosion-related aspects. Moreover, the fluctuating output generation due to fluctuating wind speeds can lead to transformer failure. Therefore, the transformer manufacturer must focus on attributing these factors to ensure the efficient performance of the transformers.

The transformers for this industry can be categorized on a different basis - type, application, and output. The liquid-type and dry-type transformers fall under the categorical division by type. The transformers are segregated as onshore and offshore based on their application. Based on the output the category has a low-voltage output (up to 10kV), medium-voltage output (up to10kV - 35kV), high-voltage output (36kV - 100kV), and ultra-high-voltage output (above 100kV)

Unique factors of consideration for improving the reliability and performance of wind transformers:

Harmonics, Non-sinusoidal loads, variable loading, low-voltage (LV) fault ride, transformer size, variations in voltage, step-up duty, switching surges, fire behavior and protection, transient over-voltages, loss evaluating, and gassing. 

Undoubtedly solar and wind power generation will dominate the source of electric power and the electricity generation industry. Moreover, the industry needs strong infrastructural support to leap forward. Their demand for transformers' design and attributes is distinct from that of the regular transformers. The industry has categorized the transformers but now needs to develop intelligent transformers incorporating all the necessary features for streamlining with the evolving smart grids. Collaborative teamwork in the transformer industry will aid in meeting future challenges smoothly.