When considering to install a on grid solar power system, most householders are suggested to make the PV array capacity bigger than the capacity of solar inverter. For example,in a system with 6kW solar panels,usually it would be configured with a 5kW solar inverter.
Oversizing a PV array, also referred to as undersizing a PV inverter, It can be a valuable tool for system designers seeking to deliver a maximum amount of energy at a lowest possible specific cost.
The below following 5 reasons tell you why solar designers and householders prefer to oversizing Solar Array
1.Smaller delivered energy than rated output power
Not all DC array output is translated into useful AC energy. There are several losses along the way such as cable losses, inverter efficiency losses, etc.
2.Falling cost of solar panels
Solar panels’s prices have fallen drastically, therefore the incremental cost of the DC side of the system has significantly decreased. This way, one can allow clipping of power at peak generation time in order to maximize generation during non-peak hours.
3.Rated module capacity against actual capacity
Solar panels often operate below the nominal rated power. Nominal rated power is the output of the module, however, these conditions are not always met under standard test conditions. Inverter efficiency is low when it operates at low power levels, so you might be better suited with a smaller inverter. Also because the output of the solar panels will decrease slightly over the lifetime of the panels, the smaller inverter will operate more efficiently than a large one once the panel output begins to decrease
Modules are rated at STC conditions, which rarely occur in actual on-site conditions. Secondly, modules are sensitive to temperature and soiling. Both these factors tend to decrease module output. There may be very few instances when the modules are operating at their peak power output. This results in gross under-utilization of the inverter’s capacity. Modules also tend to degrade over time – which means that the peak power levels may never be attained after a few years of operation. In such cases, it would make sense to increase the energy production by oversizing the inverters.
Oversizing inverters can increase production of energy during non-clipping (non-peak) times. This results in a greater yield – and therefore greater revenues. What’s more, and ‘Time of Day’ incentives may skew economics towards production during non-peak times and designers may want to make best use of this.
5.Achieve favourable energy output when installing inverters in limited space
Inverters sometimes need to be installed in specific locations, either due to constraints from the owner or local electrical regulations. This may mean it would not be possible to install as many inverters at a site as would be desired for a perfectly sized system. However by oversizing PV arrays, it may be possible to achieve almost the same annual energy output with fewer installed inverters.