Sunshine is free of charge! That makes it a great fuel for power generation. The value of this free energy and generated power depends on demand and available alternative sources. In other words, it’s a case of simple supply and demand.
The question is how to harvest this energy effectively and generate high quality power to the grid. Solar intensity, cloudiness and available land conditions vary in different locations and parts of the world. Besides that, it comes down to a proper system design and selection of optimal components.
Optimized utility solar system design
Solar panels come in a variety of powers and with a range of electrical parameters. Open Circuit Voltage (Voc) can be anywhere from less than 40 V to over 80 V. A system engineer will build an array of numerous parallel strings consisting of series connected solar panels. Achievable power and revenue generation depend on the available land and solar irradiation conditions.
Each megawatt of output grid power may have close to 5,000 panels configured to optimize output with minimum installation cost and losses. It is generally optimal to have longer strings of panels producing the required power at a higher voltage with lower current. Lower current means a lower cost for cabling, combiner boxes and everything else. The voltage limit is set by the selected system components and applicable standards.
Higher voltage limit leads to lower costs
The Switch solar inverter’s Voc and maximum power point tracking (MPPT) limit is 1000 V, the highest among low-voltage inverters on the market.
This voltage limit is defined by the availability of standard low-voltage equipment, such as breakers and other components. The higher allowable voltage provides system benefits in several ways. You can add four more panels per string than what would be possible for inverters with the common 820 V voltage limit. This reduces the current by 18% with a corresponding reduction in cable cost. Further, the longer strings mean that fewer panels are required in parallel. This means that fewer combiner boxes are needed, resulting in a simpler cable routing, fewer cables and less installation work.
All in all, the higher voltage provides a considerable overall saving – less material and less work.
Benny Nyberg
Key Account Manager/Business Development
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