Let's delve into the intricate world of harmonics in electrical systems—where subtle voltage and current distortions resonate at multiples of the fundamental frequency. This phenomenon is central to the realm of power electronics, which is dedicated to the efficient control and conversion of electrical power. In this blog, we’ll explore the critical importance of understanding and managing harmonics. Effective harmonic management not only safeguards equipment but also optimises power system performance and ensures compliance with international standards. Join us as we uncover how these seemingly minor disturbances have major impacts across various industries. 

The discovery  

The concept of harmonics in mathematics and physical sciences was pioneered by Joseph Fourier in the early 19th century. Fourier introduced the idea that any periodic function could be represented as a sum of sine and cosine functions, each at different frequencies, which he described in his seminal work, "Théorie analytique de la chaleur" published in 1822. This mathematical insight was crucial for understanding harmonics in various physical systems, including electrical circuits. Over time, as electrical engineering developed, the practical implications of Fourier's theories became evident, leading to deeper investigations into the effects of harmonics in electrical power systems. 

Understanding the Origins and Impacts of Harmonics in Modern Power Systems 

Harmonics in electrical systems are primarily caused by non-linear loads, which draw power in a way that disrupts the normal, smooth flow of electricity. Non-linear loads are common in many modern devices and equipment such as variable speed drives, energy-saving light bulbs, and computers. These devices frequently turn their power usage on and off very quickly to control how much energy they use. This rapid switching disrupts the regular wave pattern of the electrical current, leading to the creation of harmonics. These are additional frequencies that ride along with the main frequency (typically 50 Hz in India or 60 Hz in the US) and can accumulate, causing disturbances. 

The situation can be worsened by how the electrical system itself is set up. For instance, the inherent characteristics of the power system, such as its impedance (a measure of resistance to current when voltage is applied), can interact with these harmonic currents, enhancing their effect in what is known as resonance. Moreover, the way power cables are arranged and their length can also influence how severe the harmonics are across the network.  

As the electrical grid continues to incorporate more devices that contribute to non-linear loading, managing harmonics becomes increasingly crucial for maintaining power quality and system efficiency. This highlights the need for careful planning and application of specific techniques to mitigate the impact of harmonics in electrical systems. 

Effects of Voltage Harmonics 

Voltage harmonics in electrical systems are essentially distortions in the supply voltage waveform. These distortions occur when harmonic currents, generated by non-linear loads, flow through the system's impedance. As these harmonic currents interact with the inherent resistance to current (impedance), they induce a voltage drop across these impedances. This process distorts the original voltage waveform, creating what we refer to as voltage harmonics. 

The severity of voltage harmonics is commonly measured by Total Harmonic Distortion (VTHD). On the low-tension side of a transformer, a VTHD value exceeding 5% is considered high, indicating significant distortion, and values above 8% are viewed as very high. These high levels of VTHD can lead to various issues, including decreased efficiency, increased operational costs, and potential damage to electrical components. Understanding and managing these harmonics is critical to maintain the integrity and performance of power systems. 

Interconnected Impacts — how Harmonics in One Industry Affect Others 

In a power grid that connects multiple industries, the harmonics produced by one sector can have a ripple effect on the entire network. When industries with large non-linear loads, such as those using heavy machinery or extensive electronic equipment, generate significant current harmonics, these disturbances do not remain isolated. Due to the interconnected nature of the grid, these current harmonics can travel through the system's transformers and other impedance paths, spreading to other parts of the network. 

Nearby industries, even those with minimal or no non-linear loads, are particularly vulnerable. They can experience high levels of voltage harmonics primarily due to the harmonics generated by their neighbors. This occurs because the current harmonics induced by one industry's non-linear loads increase the total harmonic distortion across the grid's shared transformer impedance. Consequently, industries that might not directly contribute to harmonic pollution can still suffer from its effects, such as equipment inefficiencies, increased operational costs, and potential damage to sensitive electronic devices. This interdependency highlights the need for comprehensive grid management strategies that account for the collective impact of harmonics across various industries. 

Strategic Mitigation—Using Capacitors to Control Harmonics 

Capacitors are widely used in industries to manage voltage harmonics effectively because they present low impedance to harmonic currents. By integrating capacitor banks for power factor correction, industries can significantly reduce the impact of both internally generated harmonics and those from the grid. These capacitors act as sinks, absorbing the harmonics and thereby stabilising the voltage levels within the facility. 

However, while capacitors are beneficial for mitigating voltage harmonics, their use can introduce other challenges. Specifically, the harmonic currents drawn to the capacitors can increase the stress on the Automatic Power Factor Correction (APFC) panels. This elevated stress can lead to high current harmonics within the panels, potentially causing overheating and premature failure of the capacitors if not properly managed. Therefore, while capacitors serve as a crucial component in harmonic mitigation strategies, it’s important for industries to monitor and manage the load on their APFC panels to ensure long-term reliability and efficiency. 

Advanced Technology for Harmonic Mitigation 

Lauritz Knudsen Electrical and Automation is at the forefront of addressing the challenges posed by voltage harmonics in industrial systems with the development of the High V-THD reactor. This technology utilises advanced mechanisms to maintain operational temperatures within safe limits, thereby preventing the common issue of system overheating due to high harmonic distortion levels. Designed to enhance system efficiency and reduce noise, the High V-THD reactor also effectively controls current harmonic amplification and resonance, crucial for protecting system components from undue stress and extending their operational lifespan. 

The Role of Active Harmonic Filters (AHF) 

Explore Lauritz Knudsen Electrical and Automation's cutting-edge solution for high voltage harmonics: the High V-THD reactor. This advanced technology operates at safer temperatures, effectively eliminating the risk of overheating associated with high V-THD percentages. It features lower power losses and operates without any humming noise, ensuring both efficient and quiet performance. The High V-THD reactor not only mitigates significant current harmonic amplification and resonance but also prevents capacitor overloading. Additionally, the AHF rating can be optimized to deliver peak performance, making it a reliable and effective solution designed to tackle high voltage harmonics and ensure optimal operational efficiency. 

Active Harmonic Filters provide a robust solution to mitigate issues such as current harmonic amplification and resonance, avoid capacitor overloading, and optimize AHF ratings. In conclusion, understanding the origins, impacts, and implementing effective mitigation measures like capacitor banks and active harmonic filters is crucial for maintaining the reliability and efficiency of industrial facilities.  

Lauritz Knudsen Electrical and Automation's High V-THD reactor is at the forefront of technology, offering a precise and sustainable approach to managing high voltage harmonics in complex industrial environments. 

To conclude  

As industries evolve and integrate more sophisticated technologies, the challenge of managing harmonics becomes increasingly complex. The pioneering solutions provided by Lauritz Knudsen Electrical and Automation, particularly the High V-THD reactor, represent a significant leap forward in mitigating these disruptive effects. By addressing harmonic distortions at their source and refining the technology used in active harmonic filters, Lauritz Knudsen not only enhances the operational efficiency of industrial systems but also contributes to a more stable and reliable power grid. 

Understanding and implementing these advanced harmonic mitigation strategies is not merely a technical necessity; it's a strategic investment in the longevity and health of electrical infrastructure worldwide. With harmonics poised to play a pivotal role in the functionality of modern industries, solutions like the High V-THD reactor are essential. They ensure that businesses can operate at peak efficiency without the risk of downtime or damage due to poor power quality. As we continue to push the boundaries of what is possible in power management, embracing these innovations will be key to sustaining growth and advancing industrial capabilities in a world driven by technology.