Rooftop and ground-mounted solar power plants both play critical roles in capturing solar energy, which is a growingly popular and environmentally friendly form of electricity. According to IEA Solar photovoltaic (PV) energy production reached a record 270 TWh in 2022, up 26% from 2021. 4.5% of the world’s total electricity is produced by solar photovoltaics. The direct current (DC) produced by solar panels in these systems is converted into alternating current (AC) for usage in houses and the grid by inverters, which are an essential component. Here we are going to let you know what is a solar inverter and many types of solar inverters used in both rooftop and ground-mounted solar power plants.
Introduction to Solar Inverters
Solar inverters are essential parts of solar power systems because they transform the DC energy from solar panels into the AC electricity required for home appliances and grid integration. Optimizing energy output, keeping track of system performance, and maintaining safety are all crucial tasks that inverters are crucial for.
Ground-Mounted Solar Power Plants
Solar panels are placed on open land, sometimes in isolated locations, in large-scale systems called ground-mounted solar power plants. These systems frequently employ microinverters, string inverters, and central inverters.
Rooftop Solar Power Plants
Smaller-scale solar power plants called rooftop solar power plants are erected on the roofs of industrial, commercial, and residential structures. Typically, they use microinverters and string inverters.
Types of Solar Inverters for Ground Mount and Rooftop
1. Central Inverters
A frequent component of ground-mounted solar power systems is a central inverter, usually referred to as a string inverter. In most cases, they are positioned in a central area, and parallel strings of solar panels are attached to them. Key characteristics and benefits of central inverters are as follows:
· High Efficiency: Because of their ideal conversion efficiency, central inverters are popular for use in large-scale systems. The conversion efficiency of central inverters is relatively high, ranging from 95% to 98% 3.
· Cost-Effective: For projects utilizing a large number of solar panels, these are cost-effective.
· Ease of Maintenance: The centralized position of central inverters makes it simple to access them for maintenance and repairs.
However, there are certain limitations to central inverters as well3:
· Partial Shading: The efficiency of the entire system may suffer if any of the solar panels are partially shadowed.
· Single Point of Failure: The output of the entire system may be impacted if the main inverter fails.
2. String Inverters
A sort of central inverter called a string inverter is intended for smaller installations, such as rooftop solar power plants. There are many different ways of connecting a string of solar panels. A typical solar array can consist of around 15 solar panels of each 250Wp 4. They provide greater design freedom for the system since they are linked to several parallel strings of solar panels. The following are some essential traits and benefits of string inverters:
· Moderate Efficiency: For medium-sized installations, string inverters are useful because of their high efficiency. String inverters are more effective than microinverters. They have better efficiency than microinverters and can convert DC energy into AC energy at a rate of up to 98%3.
· Enhanced Shade Tolerance: Compared to central inverters, they operate more effectively when partial shadowing occurs.
· Cost-Effective: For projects with moderately large arrays, string inverters are a cost-effective option.
However, string inverters have certain disadvantages with central inverters when it comes to a single point of failure.
3. Microinverters
Microinverters are tiny inverters that are permanently attached to both ground-mounted and rooftop solar power plants. PV systems produce DC from sunlight, which is then converted to AC via an inverter. Each solar panel may create AC through microinverters. To convert DC into AC, each micro-inverter operates separately, removing shade and orientation concerns on a different panel 6. Here are some essential characteristics and benefits of microinverters:
· Enhanced Shade Tolerance: They are very effective in shaded settings because of microinverters, which individually improve the performance of each panel.
· Monitoring and Maintenance: They provide comprehensive panel-level monitoring, making it possible to spot problems quickly.
· Increased System Reliability: Microinverters reduce the impact of a single panel or inverter failure on the entire system.
However, compared to central and string inverters, microinverters are often more costly and need more complicated wiring during installation.
Difference Between Ground-Mounted Solar Inverter vs Rooftop Solar Inverter
A comparative diagram outlining the primary variations between solar power systems that are rooftop and ground-mounted is provided below:
| Ground-Mounted Solar Inverter | Rooftop Solar Inverter | |
| Location of Installation | Installed in a dedicated inverter room or enclosure, typically near the solar array. | Installed near the rooftop solar panels or in a dedicated inverter room if applicable. |
| Cooling and Ventilation | Larger inverters may require additional cooling systems due to higher power capacity. | Smaller inverters are less likely to require specialized cooling systems. |
| Inverter Type | String inverters or central inverters are commonly used for large-scale ground-mounted systems. | String inverters are frequently used due to their scalability and ease of installation. Microinverters may also be used for certain rooftop installations. |
| DC Input Voltage Range | Typically higher voltage ranges to accommodate longer DC cable runs from panels. | Typically lower voltage ranges due to shorter DC cable distances. |
| Maximum DC Power | Higher maximum DC power handling capacity to accommodate larger arrays. | Lower maximum DC power capacity compared to ground-mounted inverters. |
| Efficiency | High efficiency is crucial for large-scale systems to maximize energy harvest. | Similar or slightly lower efficiency requirements compared to ground-mounted inverters. |
| MPPT (Maximum Power Point Tracking) | Advanced MPPT algorithms for optimizing energy production. | Similar MPPT technology to track the maximum power point of solar panels. |
| Monitoring and Communication | Advanced monitoring systems with remote access and data logging capabilities. | Similar monitoring capabilities with options for remote access and reporting. |
| Grid Integration | Must comply with utility-scale grid requirements and may include grid-support functions. | Must meet local grid codes and requirements for distributed generation. |
| Protection Features | Comprehensive protection against overvoltage, overcurrent, short circuit, and other faults. interconnection | Similar protection features to ensure safety and prevent system damage. |
| Maintenance | Ground-mounted inverters may be larger and require more intensive maintenance procedures. | Rooftop inverters are typically smaller and may require less frequent maintenance. |
| Physical Environment | Designed for outdoor use and must withstand environmental factors such as dust, moisture, and temperature variations. | Designed for indoor or outdoor use, depending on installation location, with similar environmental protections. |
| Space Requirements | May require a dedicated inverter room or enclosure near the solar array. | Smaller physical footprint, potentially installed near the rooftop panels or in a dedicated room. |
Here is a table comparing smart features typical in rooftop and ground-mounted solar power inverters:
| Smart Feature | Ground-Mounted Solar Inverters | Rooftop Solar Inverters |
| Monitoring Software | Typically equipped with advanced monitoring software for real-time data tracking and analysis. | Equipped with monitoring software for remote monitoring and performance analysis. |
| Communication Protocols | Supports various communication protocols such as Modbus, RS485, Ethernet, and potentially wireless options. | Supports communication protocols like Modbus, RS485, Ethernet, and potentially wireless options. |
| Data Logging | Extensive data logging capabilities for historical performance tracking and reporting. | Provides data logging features for historical performance tracking and reporting. |
| Remote Monitoring | Enables remote monitoring and control through web-based interfaces or dedicated apps. | Allows for remote monitoring and control through web-based interfaces or dedicated apps. |
| Mobile App Integration | Many models offer mobile app integration for convenient monitoring and control on smartphones and tablets. | Mobile app integration for convenient monitoring and control on smartphones and tablets. |
| Predictive Maintenance | Some models offer predictive maintenance features, using data analytics to anticipate and prevent potential issues. | May offer predictive maintenance features, using data analytics to anticipate and prevent potential issues. |
| Fault Detection | Advanced models may include fault detection algorithms for identifying and addressing issues proactively. | May include fault detection algorithms for identifying and addressing issues proactively. |
| Grid Interaction Control | Capable of providing grid support services like voltage regulation, frequency control, and reactive power injection. | Capable of providing grid support services like voltage regulation, frequency control, and reactive power injection. |
| Weather Forecast Integration | Some models integrate weather forecast data to optimize energy production and grid interactions. | May integrate weather forecast data to optimize energy production and grid interactions. |
| Energy Management System | Can be integrated into broader energy management systems for optimized energy usage within the facility. | Can be integrated into broader energy management systems for optimized energy usage within the facility. |
| Cyber security Measures | May have advanced cyber security measures to protect against cyber threats and unauthorized access. | May have cyber security measures to protect against cyber threats and unauthorized access. |
Inverter technology in ground-mounted and rooftop solar power plants is dependent on a variety of variables, including system size, shading circumstances, cost, and maintenance preferences. In bigger systems, central inverters and string inverters are frequently utilized, however, microinverters are preferred for smaller installations where shading and monitoring are crucial considerations. The efficiency and dependability of solar power systems are being further improved as a result of the development of new inverter types and hybrid solutions, making them a more alluring alternative for the generation of sustainable energy.
