The journey towards sustainable transportation has significantly increased the grid penetration of electric vehicles (EV) around the world. The connection of EVs to the power grid poses a series of new challenges for network operators, such as network loading, voltage profile perturbation, voltage unbalance, and other power quality issues. This paper presents a coalescence of knowledge on the impact that electro-mobility can impose on the grid, and identifies gaps for further research. Further, the study investigates the impact of electric vehicle charging on the medium-voltage network and low-voltage distribution network, keeping in mind the role of network operators, utilities, and customers. From this, the impacts, challenges, and recommendations are summarized. This paper will be a valuable resource to research entities, industry professionals, and network operators, as a ready reference of all possible power quality challenges posed by electro-mobility on the distribution network.

Occurrence of high frequency emission due to increasing use of power electronic based equipment challenges the functioning of equipment, e.g., malfunctions of equipment, audible noise or performance/lifetime degradation of dc-link capacitor. When subjected to a high frequency voltage distortion, an AC-DC converter draws intermittent current of the same frequency, this is referred to as 'intermittent conduction'. In this paper, a link between intermittent conduction and dc-link capacitor current has, for the first time, been constituted through a mathematical expression. Based on this, a model that can quantify the impacts on dc-link capacitor and calculate maximum allowed voltage in the frequency range of 2-150 kHz, so called 'supraharmonics' (SHs), has been proposed for avoiding degradations. Besides modelling, a testing technique is implemented where maximum allowed voltage can be identified for an equipment under test (EUT). The result shows that dc-link capacitor's stress can be managed under the SHs if maximum SH voltages are respected. The proposed model gives a better understanding of SH impacts on dc-link capacitor and the mechanisms behind. The study has been limited to equipment that draws input current lower than 16 A as they exhibit more non-linear characteristic and longer zero-crossing which results in intermittent conduction.

More and more devices connected to low voltage networks inject currents in the frequency range above 2 kHz up to 150 kHz, so called supraharmonics. Supraharmonics can appear as synchronized or nonsynchronized to the power system frequency. A device exposed to a fixed supraharmonic frequency are here shown to generate interharmonics when the power system frequency deviates from the ideal 50/60 Hz. Resulting interharmonic frequency and magnitude are determined by three factors, the frequency at which a supraharmonic component exist, the voltage magnitude of that component, and the deviation from 50/60 Hz of the power system frequency. Formation of interharmonics is confirmed in a functional model and validated through the measurements and numerical simulations.

The function of electrical and electronic equipment is challenged by the high frequency emission originated from the more use of switching-based power electronic equipment and Power line communication (PLC) signaling. Investigations have shown that interferences occur in the frequency range between 2 kHz and 150 kHz, e.g., error in smart meter reading, audible noises, performance degradation and even malfunction of the equipment. This study aims to model and analyze the interference mechanism and gain the knowledge of equipment behavior/immunity under voltage disturbance from 2 kHz up to 150 kHz, so called “Supraharmonics.”

Experimental studies were conducted on different type of AC-DC converters, LED drivers, computer power supplies, Active Power Factor Correction (APFC) circuits (pre-regulator), single stage and double stage converters such as flyback and buck topologies. AC-DC converters were exposed to Supraharmonics (SHs) according to IEC 61000-4-19. Interferences, that occur in the input voltage/current and dc-link, were observed and analyzed through a mathematical model of converter circuit. 

When the AC-DC converter is exposed to SHs, three phenomena occur that 1) the conduction and blocking time of the diodes, in the bridge rectifier circuit, are deviated, 2) intermittent conduction takes places in the beginning and of diodes conduction, 3) reverse-recovery of the diodes happen that impact the dc-link voltage of the converter. Those behaviors are verified in a functional model and validated through the experiments. It is also shown that dc-link voltage metrics, peak-to-peak and average value, are impacted when SHs are present at the terminal of the converter. Further, it is revealed that if the SHs are nonsynchronized to the power system frequency, the converter due to uneven deformation of the diode conduction /blocking time generates interharmonic currents. The generated interharmonic frequency can be precisely determined by using frequency modulation equation. Result shows that generated interharmonic magnitudes are negligible if the applied SH frequency is above 16 kHz. 

In order to quantify the impact of SHs on dc-link capacitor, an immunity model that links the intermittent conduction and the dc-link capacitor current is established, analytically. By this means, it is ensured to avoid the degradation of the dc-link capacitor’s lifetime by defining the SHs voltage limits.

The analysis and modelling studies proves that SHs at the AC-DC converter terminal can cause deviations in the function of equipment both in short term and long term., e.g., increased light intensity in LED drivers, reduced peak-to-peak voltage in dc-link, interharmonic injection and reduced estimated lifetime of the dc-link capacitor. Those impacts originates from the reaction of the diodes and non-linear circuit configuration. Functional models presented in this study are able to express the reasoning and occurrence of the impacts. Established immunity model analytically gives guidance on how immune converters can be achieved in the design stage of power electronic circuits. This study provides deep insight on how AC-DC converters behaves under SH emission. Standard committees and converter manufacturer, to achieve immune and reliable power system and equipment for the future’s systems, can use this knowledge. 

Photovoltaic (PV) systems, Electric vehicles (EV) and LED lamps have gained significant popularity in our current society. It is therefore common to find customer installations with all three operating together. PV and EV are known sources of voltage variations on the grid. The impact of these voltage variations on LED lamps situated in close proximity to PV or EV in a low voltage installation, in terms of overvoltage, undervoltage, and rapid voltage changes is systematically studied in a laboratory environment in this paper. Such variations can cause malfunctioning of the lamp based on its immunity and tolerance level or be disturbing to the end-user based on the intensity of variations and rate of recurrence of being subjected to such variations. In this work, the observed impacts on LED lamps are illustrated as 15 different cases. The scope of this work is to identify the possible impacts due to voltage variations induced by PV and EV systems on LED lamps and the potential problems that could happen long term due to recurrent subjection of such voltage variations.

There is an ongoing transition from high-pressure sodium lamps to LED street lamps that offer higher efficiency, cost saving and better photometric performance. This transition could lead to unintended consequences such as light flicker and extinguishing in street lighting applications when they are exposed to voltage dips. The goal of this paper is to analyse the light intensity variation of various street lamps when they are exposed to voltage dips. Several performance metrics for quantifying immunity of lamps have been proposed. Values for these metrics are obtained by applying artificial voltage dips to lamps. For voltage dips with residual voltage above 38%, lamps are immune in terms of a short-term light flicker metric. For residual voltage above 25%, light intensity reduces but without extinguishing. Compared to an incandescent lamp and high-pressure sodium lamp, LED street lamps exhibit longer zero-light intensity duration. Most of the studied LED street lamps exhibit uncoordinated light intensity drops, i.e. longer or shifted, with respect to the applied voltage dip. Individual characteristics of LED street lamps require testing before installation to prevent unexpected consequences. Recommendations are given for standardisation committees to implement an assessment method for lighting equipment.

LED lamps are both potential victims and sources of electromagnetic disturbances in the frequency range between 2 kHz and 150 kHz (“supraharmonics”). Immunity tests for this frequency range are important due to possible performance degradation of light intensity with LED lamps. In this paper, the impact of supraharmonics (SHs) on light intensity from LED lamps has been analyzed. LED lamps have been exposed to supraharmonic test profiles based on IEC 61000-4-19. Three phenomena that impact light intensity metrics have been observed and explained by models: (1) earlier conduction/later blocking caused by supraharmonic voltage, (2) intermittent conduction depending on the supraharmonic impedance of the LED driver and (3) reverse-recovery current of the diodes at higher frequency. It is observed that impact on the light intensity metrics shows up around the beginning and end of the conduction period. The results reveal that the profile of the supraharmonic voltage could cause deviations in the modulation depth and the average light intensity. The immunity of LED lamps against SHs shall be further studied and discussed by research groups and standard committees.

An increasing application of LED street lamps brings out an important question regarding their immunity against power quality disturbances. The behaviour of commonly used lighting equipment such as incandescent lamps, compact fluorescent lamps (CFL), and gas-discharge lamps is known. However, knowledge on immunity of LED based lighting equipment is still limited, particularly in street lighting aspect. In this paper, immunity of LED street lamps is determined for voltage dips, short interruptions, voltage fluctuations and supraharmonics. A series of experiments has been performed with respect to test levels defined in IEC 61000-4-11, IEC 61000-4-15 and IEC 61000-4-19. Voltage dips and short interruptions cause higher short-term light flicker severity values that might lead to unintended consequences for car drivers and pedestrians. Interharmonics can result in light flicker, but the impact is very limited, only one lamp exceeds the limits. Supraharmonics impact the current but have minor impact on the visible light. The supraharmonic current can be 25 times nominal. This could decrease the lifetime of equipment

Measurements in electrical and thermal parameters of LED lamps over time have been studied. To get comparable results between lamps, for compliance testing and benchmarking, measurements after stabilization are recommended. Two cases have been tested in the lab: stabilization with sinusoidal voltage waveform and stabilization with distorted voltage waveform both with and without external cooling of the lamp, giving four tests for each LED lamp.

The parameters tested were illuminance, active power and temperature of the LED lamps. Based on the results for voltage variations, no significant difference of the parameters studied have been observed. On the other hand, according to the results about environmental thermal variations (emulated using forced ventilation) it is concluded that the illuminance increases with low temperatures, and in addition, in greater percentage than the active power consumed, since the low temperatures would decrease the temperatures of thermal stabilization of LED lamps.

ED lighting technology is the most efficient way oflighting service and its usage has increased rapidly. Although,LED lamps are potential victim and source of electromagneticinterference in the frequency range between 2 kHz and 150 kHz(“supraharmonics”). Therefore, immunity test for this frequencyrange is necessary to analyze its performance variations. In thisstudy, Test profiles described in IEC 61000-4-19 have beenapplied to LED lamps and the results have been analyzedaccording to implemented algorithm that uses the relative lightintensity variation index. The results show that bothsupraharmonics and modulation of the test profiles can reveallight flicker. In addition, some potential drawbacks of thestandard have been found that deviation of the mains’ frequencyis also another factor causes intermodulation/nonsynchronizationon the applied test signal, so this can be seen aslight flicker. This issue better be clarified with more details in theIEC 61000-4-19, particalulary for lighting equipment.