For investors invested in solar systems, no matter for Rooftop On Grid Solar System Or Ground On Grid Solar System , Agrivoltaic System or Solar Caport System, the income comes from every single kwh power generated from the solar system, to ensure the solar system working optimally all the time becomes all-time topic. The power generation of a solar system will be affected by many factors, such as: solar panels, solar inverters, solar cable quality, solar panel installation inclination, shadows, solar panel and inverter DC oversizing ratio, and grid power quality, etc.
Shades On Solar Panels Impact On The Power Generation
Among the many factors that affect the power generation of solar systems, shades on solar panel is a relatively common one, especially for Rooftop On Grid Solar System. Common shades mainly come from electric poles, chimneys, trees, guardrails, bird manure, dust, and front and rear rows of solar panels.
During the construction of many solar systems, it is often impossible to avoid shades. Many people think that the shades area will not cause a great impact as long as the shades area is not too big. In fact, some solar panels or a single solar panel being shaded, and the entire solar panel string will be affected. This is the barrel effect of the series circuit. In a serial connected solar panels string, the current of the string is determined by the lowest current output solar panel. So as long as a single solar panel is shaded, the whole string power output will be limited, power lose could be 20% to 30%. It will also possible to trigger the hot spot effect, reduce the solar system power production and the lifespan of the solar panel, and even potentially to cause fire. Therefore, it is necessary to avoid shades on solar panel during the design phase of the solar system, but also essential for future maintenance, and regularly cleaning on the solar panel surface.
The Effect Of The System Capacity Ratio On Power Generation
The capacity ratio refers to the ratio of the installed capacity of the solar panel to the rated capacity of the inverter. If the solar system is designed according to a 1:1 capacity ratio, the capacity of the inverter will be wasted when the output power of the solar panels does not reach the nominal power which happens all the time. Most solar system performance ratio less than 90%, some rooftop solar system performance ration even lower than 80%.
System oversizing design is often used to improve the comprehensive utilization rate of solar system, to oversize the system by 10% to 20%, some even allows the oversizing by 50%, to make fully use of the inverter, to make every penny count, to reduce the initial investment cost and the kwh cost of the system. Rooftop On Grid Solar System due to rooftop limited condition has more oversizing than Ground On Grid Solar System. However, that does not mean that the capacity ratio can be set randomly or at any figure, a reasonable design of the system capacity ratio is conducive to improving the economy of the solar system. In different types of resource areas, due to the different conditions of solar energy resources, regional temperature, and solar system design details other characteristics, it is necessary to calculate according to the specific local conditions, to consider all possible factors.
The Impact Of Improper Solar Cable Selection On Power Generation.
If the inverter is compared to the brain of the solar system, the cable is the nervous system of the solar system, connecting the solar panels, inverters, combiner boxes, grid-connected cabinets and other equipment into a whole. Therefore, the right cable selection is crucial for the entire solar system.
When doing the cable design and selection, the appropriate wire diameter should be considered, especially for large scale solar system, which cover a large area and have a long transmission route, if the AC cable diameter is too small, it will lead to cable overload and heating, also with voltage dropping during the transmission which will not only affect the power generation, but also have potential safety hazards such as short circuit and fire.
Another point to note is that the cross-sectional area of aluminum cables is much larger than that of copper cables for the same current-carrying cable, so it is necessary to consider whether the AC end of the inverter can fit when considering aluminum cables. The AC output side of the inverter is designed according to the copper wire standard, and it is recommended to use copper core cables. However, the use of aluminum core cables will save a certain investment cost compared to copper core cables, so, many installers will use aluminum core cables. However, it is necessary to use the copper-aluminum wiring transition terminal that meets the requirements of the standard, because the copper-aluminum joint is prone to electrochemical corrosion, which causes poor contact between copper and aluminum, increases the resistance, and affects the efficiency of the entire solar system. Long time operation will cause the temperature of the joint part to rise, accelerate corrosion, and even burn out.
Choosing the right cable type, specification, and cable with right load capacity, weather resistance and durability can minimize power loss, improve power generation efficiency, and ensure the operation of solar system and maximize power generation.
The Influence Of Power Quality Of the Power Grid
The power quality of the power grid includes: voltage deviation, current deviation, frequency deviation, voltage fluctuation or flicker, three-phase unbalance, temporary or transient overvoltage, waveform distortion, voltage sag and so on.
The voltage and frequency of the grid are not constant, but will change with the change of load and power flow, while the output voltage of the inverter follows the grid voltage. However, after the grid voltage and frequency fluctuation exceed a certain range, the inverter will stop working.
Voltage fluctuations, flicker and harmonics in some mechanical processing plants, there are cranes, electric welding machines, gantry milling machines and other high-power equipment, and some electric arc furnace factories, between the start and shutdown of the equipment, the power change is very drastic, accompanied by a large number of harmonics, the existence of harmonics and unbalanced negative sequence components in the power grid will lead to the output of the solar system active power fluctuations, and the higher the grid voltage distortion rate, the smaller the output of the solar system active power; And the higher the distortion rate of the grid voltage, the greater the output current THD of the solar system. When the grid voltage fluctuates violently, the inverter's adjustment ability is limited, which may cause the PV inverter to restart frequently, and in serious cases, it may cause the power device in the inverter to overvoltage and the electrolytic capacitor to burst overcurrent.
From the above points, solar systems can be in many forms, no matter for Rooftop On Grid Solar System Or Ground On Grid Solar System , Agrivoltaic System or Solar Caport System, the power generation of the solar not only depends on the power generation performance of the solar system itself, but also closely related to the later operation and maintenance, and the correct and timely maintenance can not only improve the power generation, but also improve the service life of the whole system.
