Power Quality Challenges in Rooftop Solar PV Systems

Power quality issues are becoming increasingly common as rooftop solar photovoltaic (PV) systems integrate with low-voltage (LV) distribution networks. While these systems provide a Sustainable Energy source, they also introduce several power quality challenges.

Common issues include voltage fluctuations, Harmonic distortions, unbalanced voltage, and DC injection. These problems can affect not only the solar systems themselves but the entire electrical grid, leading to equipment damage, energy inefficiency, and grid instability.

Voltage Flicker: A Common Issue in Solar PV Systems

Voltage flicker is one of the most noticeable power quality issues in solar PV systems. This happens when the output of solar inverters fluctuates, often due to changes in sunlight intensity, cloud cover, or shading. These rapid voltage changes can cause visible flickering in lights, discomfort for consumers, and even damage sensitive electrical equipment.

For rooftop solar installations connected to the LV distribution network, voltage flicker can worsen due to the variable nature of solar power generation. Solar panels produce different amounts of electricity throughout the day, depending on weather, time of day, and environmental factors. Without proper regulation, this can lead to large voltage fluctuations. This issue can be worse when multiple rooftop solar systems are located near each other, amplifying the fluctuations.

Voltage Unbalance and Solar Systems

Voltage unbalance is another common problem caused by rooftop solar systems. Many solar systems are single-phase, which means they only deliver power to one phase of the three-phase distribution network. When many single-phase solar systems are connected to the LV grid, they can cause voltage imbalances across the phases. This can result in overheating, equipment damage, reduced efficiency, and even system failures.

Voltage unbalance is especially common in areas with high solar adoption. It stresses transformers, shortening their lifespan and leading to possible unplanned shutdowns. These issues are a concern for both residential and industrial users.

Harmonics and DC Injection

The operation of solar inverters can introduce harmonics into the grid. Harmonics are high-frequency currents that distort the smooth, sinusoidal waveform of the power grid, causing harmonic distortion. These distortions occur due to the switching operations of the inverters' power electronics. Harmonics can disrupt sensitive electrical equipment, reduce grid efficiency, and increase wear and tear on components like transformers and motors.

DC injection is another potential problem. Some solar inverters, especially those without isolation transformers, can inject DC power into the grid. This DC injection can lead to significant issues, such as overheating transformers and damaging grid infrastructure. DC current in an AC system can cause transformers to become saturated, reducing efficiency and causing eventual failure.

Solutions for Power Quality Problems in Solar PV Systems

To address these power quality issues, it is essential to use solutions that minimize the negative effects of rooftop solar systems on the grid. Below are some common methods:

Active Harmonic Filters (AHF) and Static Var Generators (SVG)

One effective solution for voltage flicker, voltage unbalance, and harmonic distortion is the use of Active Harmonic Filters (AHF) and Static Var Generators (SVG). Intone Power offers both of these advanced technologies.

• Active Harmonic Filters (AHF): AHFs are designed to filter out harmonic currents and keep the grid stable and free from harmful distortions. AHFs work in real-time, adjusting dynamically to changes in harmonic current levels. This makes them ideal for systems with multiple solar PV installations that generate significant harmonic distortion.
• Static Var Generators (SVG): SVGs regulate voltage by providing or absorbing reactive power. This helps manage voltage fluctuations and imbalances caused by the variable nature of solar power. SVGs ensure a stable, reliable power supply and improve the performance of solar systems, particularly in areas with high solar penetration.

Grid Infrastructure Improvements

Another solution to power quality issues is enhancing the grid infrastructure to handle the unpredictable nature of solar power. This includes upgrading transformers, adding compensators, and implementing smarter grid technologies that respond to real-time changes. A more robust infrastructure makes the grid more resilient to fluctuations caused by rooftop solar systems.

Inverter Technology Improvements

Modern inverters also play a role in addressing these power quality issues. Many newer inverters come equipped with features like power factor correction, harmonic filtering, and grid support capabilities. These inverters help reduce issues like voltage flicker and harmonics before they even reach the grid. Ensuring that solar inverters comply with international grid codes can also minimize their impact on the electrical grid.

DC Injection Prevention

To prevent DC injection, it is important to use inverters with isolation transformers. These transformers block DC power from entering the grid, ensuring only AC power is fed into the system. Inverters with proper isolation help protect transformers and other grid equipment from damage.

The Role of Intone Power in Power Quality Management

Intone Power offers solutions that play a crucial role in addressing the power quality challenges associated with rooftop solar systems. With more than 15 years of experience in the field of power quality, Intone Power provides products like Active Harmonic Filters (AHF) and Static Var Generators (SVG), which enhance the stability and reliability of both residential and industrial electrical systems.

Intone Power’s AHF and SVG products are engineered to handle high levels of harmonic distortion, voltage flicker, and reactive power compensation. These solutions ensure that solar systems operate efficiently without compromising grid stability. Intone Power also provides training and support to help engineers and on-site personnel manage the system and resolve issues as they arise.

Conclusion

Rooftop solar systems present a great opportunity for sustainable energy generation but also bring power quality challenges. Voltage flicker, harmonic distortion, voltage unbalance, and DC injection can disrupt the grid and affect the performance of both solar systems and electrical infrastructure.

These issues can be effectively managed by using solutions like Active Harmonic Filters (AHF) and Static Var Generators (SVG). Intone Power’s expertise and products offer reliable and efficient solutions for improving the power quality in solar PV systems.

Contact us for expert guidance:

For more information on how our Active Harmonic Filter and Static Var Generator can improve power quality: sales@intonepower.com

keywords: generate electrical, solar energy, power quality analyzers, high quality, photovoltaic cell

clean energy, large scale, pv technologies, power measurements, power source, sine wave, pv cells

solar cells, voltage drops, converting sunlight, semiconductor material