# Disturbances Generated by Lighting Systems with LED Lamps and the Reduction in Their Impacts
## 2 The Impact of Higher Harmonics in Electrical Circuits
Problems related to signal distortions become more and more complicated, as the above-mentioned technically advanced devices (e.g., LED lamps), on the one hand, are a source of higher harmonics, and on the other hand, on many occasions, they are systems which are strongly sensitive to the impacts of voltage and current higher harmonics. Electroluminescent light sources are capacitive loads, and they draw current in which the signal is significantly distorted from the sinusoid. The nature of the load and the current waveform are significantly affected by control and supply systems built using DC-DC converters. As a consequence of this, the power factor declines, high reactive power is consumed, and higher harmonics of current are generated affecting voltage distortion in the power mains. This follows from the fact that LEDs, which are the main components of LED lamps, are non-linear elements. The systems that manage their operation (drivers) are also characterised by strong nonlinearities. Each non-linear element incorporated in the electrical circuit causes current waveform distortion in the system. In analyses of distorted signals, using the Fourier transform, this translates into the occurrence of a frequency spectrum in which, in addition to the fundamental frequency (compliant with the distorted signal frequency), intensive components with frequencies that are a multiple of the fundamental frequency appear, i.e., higher harmonics [26; 27; 28; 29; 30; 31; 32]. In driver circuits, power factor correction (PFC) circuits, which work to reduce current distortions, i.e., to reduce the occurrence of higher harmonics, are integrated. The degree of reduction in the impact of the harmonics depends on the quality and technical advancement of these circuits. However, this is related to the price of these circuits. In the market economy, the price of products is often the factor that has a decisive impact on the choice of structural solutions for products. Therefore, cheap elements with disadvantageous technical parameters, which are not directly important for the user, appear on the market. The results of their application, however, are the irrational management of energy and an adverse impact on other devices that operate in the same electrical system. The issue of the deterioration of the electrical parameters in lighting systems is particularly important in the case of connecting compact LED luminaires, which are substitutes for traditional light sources in the already existing installations of facilities. Because of the limited dimensions of such lamps, the application of extended current distortion correction circuits inside them is difficult. The negative aspects of the use of electroluminescent light sources have been discussed on many occasions by the authors of this article in numerous publications and during conferences [20; 21; 22; 23; 28; 29; 30]. This is, by no means, just a local or national problem. It concerns all countries because electrical lighting is commonly used everywhere. Complex lighting systems may consist of hundreds or even thousands of light sources. If the number of LED lamps connected to electrical systems constitutes a significant part of all of the electrical light sources in a facility, then, because of the level of power consumed, problems with the impact of higher harmonics in such mains occur. In many scientific centres from all over the world, research related to the quality of the electricity in the power systems of LED lamps is conducted [13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23]. At the same time, different solutions aimed at the improvement of the electricity quality parameters in these systems are proposed [33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46]. The problem may turn out to be very serious in a very near future. The number of LED lamps connected to the electricity network is increasing rapidly. They are widely used in domestic and office lighting, in public utility places, as street and industrial lighting, and in recent years, even as lighting in cars [47].