Why is the output power of solar inverter not up to the rated power of the module

The output power of solar inverters, and generally it is difficult to reach the standard components of power, this is because the components in the weather conditions are very good, is the power of components also under the condition of low temperature test, normal weather is can not meet the conditions, not necessarily all acceptable to solar photovoltaic components, because all has not in the best Angle.Moreover, the photovoltaic system has losses: dust, shielding, shadow, etc. on the components, cable, switch, joint and other line losses;Inverter, transformer, distribution cabinet and other equipment loss.In general large power stations, the highest output power of the system may only be about 85-90% of the rated power of components.In a small distributed power plant, the maximum output power of the system may only be about 90%-95% of the rated power of the components.

1. Solar irradiance factor
We often say 3000W pv module, the maximum power Pmax/W, means its peak power is 3000W in the standard test environment.The output power of photovoltaic modules is “nominal power” (3000W) only under standard test conditions (irradiance is 1000W/m2, and the battery temperature is 25℃). The power of solar inverter will also change when irradiance and temperature change.

2. System loss factor
The key factors influencing the capacity is the system efficiency and system efficiency main factor: component dust and shadows shade caused by low efficiency, the component temperature reduction caused by power, the impedance matching loss caused by dc cable, components in series voltage and the inverter voltage does not match the produce efficiency is lower, the inverter MPPT loss to follow-up, the power loss of inverter itself, communication cables, transformers, power loss of power loss, and other factors.
System loss is the loss of integrated power generation, the value of which varies according to conditions.The factors that affect the maximum power output are components and DC cables. In order to increase the output power, various losses must be minimized.After the location of photovoltaic installation is determined, it is difficult to change the installation Angle, component temperature, inverter loss, MPPT tracking efficiency and other factors.However, dc cable loss, DC cable impedance matching, components and inverter voltage matching factors can be controlled.

1) to minimize the length of the dc cable, from components to inverter, want to use dc cable, the influence of the length of the cable on the system capacity is very large, on the one hand is the wastage of the dc cable itself, on the other hand is the impedance matching, inverter as far as possible close to the component, dc cable control at 20 meters, each of the MPPT dc cable as far as possible.

2) The working voltage after series of components is as close as possible to the rated voltage of the inverter to reduce the loss of the inverter.
So how do you tell if a photovoltaic system is generating electricity normally?First look at the output power of inverter, when the weather is very good, if you can reach more than 90% of the power components, the design of the system do not have what problem, also calculate electricity, check the local hours daily output, use hours multiplied by 365, take the system efficiency is the average annual output, average system efficiency is 0.8, if electricity in this range, system design and installation of all no problem.