The editor believes that equipment factors are the main reason affecting the efficiency of photovoltaic systems, which mainly includes: the matching degree of photovoltaic modules, the efficiency of inverters and transformers, DC line loss, AC line loss, and equipment failure.
Matching degree of photovoltaic modules:
The nominal deviation is an important parameter of photovoltaic modules, generally acceptable within ±3%. This indicates that even though the nominal parameters of the modules are the same, the output characteristic curves vary, leading to efficiency reductions when multiple modules are connected in series due to inconsistent currents.
Efficiency of inverters and transformers:
Although the European efficiency in the inverter technical specifications reflects a weighted conversion efficiency considering different load rates, rarely do inverters achieve the commonly used 98.5%. Achieving a weighted efficiency of 97.5% during the AC conversion is considered good.
Different inverters exhibit varying MPPT tracking effects. For instance, when the maximum power point voltage changes with irradiance, the inverter needs to continuously adjust the voltage to identify the maximum power point voltage, and the lag in tracking may lead to energy loss. Additionally, a 500kW inverter must track around 100 strings of MPPT, and variations among these strings can affect tracking accuracy. Some inverter manufacturers now utilize multiple MPPTs to minimize these losses.
In the DC input voltage range, maximizing the number of series-connected modules to increase voltage while reducing current can improve the inverter’s conversion efficiency and simultaneously lower line losses.
Transformers inevitably incur energy losses during the voltage boosting process, which is determined by the transformer parameters, generally around 1.5%.
DC line loss, AC line loss:
An area of about 3.5 to 4 hectares is needed for 1MW units. To transmit electricity generated by photovoltaic modules over such a large area requires long DC lines. There are two ways to reduce line losses: using high-quality cables and raising the voltage. Generally, DC line losses can be estimated at around 2 to 3%.
AC lines are shorter, resulting in relatively lower line losses, which can typically be estimated at around 1%.
Equipment failure:
Equipment failures and maintenance are significant reasons for low efficiency in photovoltaic power generation systems.
Professional photovoltaic manufacturers create high-quality power generation systems with a professional attitude and offer specialized after-sales services to address your concerns.
