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Abstract:With the introduction of more non-linear loads, e.g., compact fluorescent lamps, electric vehicles, photovoltaics, etc., the need to determine the harmonic impact of the residential load is rising, illustrated by the many studies performed on their harmonic impact. Traditionally, these studies are performed for a single new device and single penetration level, neglecting the harmonic interaction between new types of devices, as well as giving little information at which moment in time possible problems may arise. A composite approach to access the impact of harmonic sources on the distribution network is therefore proposed. This method combines a bottom-up stochastic modeling of the residential load with harmonic measurement data and harmonic load-flows all based on a scenario analysis. The method is validated with measurement data and shows a good prediction of the current level of harmonics in a residential neighborhood for the current situation. To demonstrate the applicability of the proposed method, case studies are performed on the IEEE European Low Voltage Test Feeder. These case studies show a marked difference between applying individual device-based models and a composite modeling approach, demonstrating why the proposed approach is an adequate method for the determination of the impact of new devices on the harmonics.

Nowadays, more and more lamp types are being used. Since different lamp types have different working principles, they also have different flicker responses. This paper shows the measurement results of different flicker responses for various types of lamps. These results prove that the UIE/IEC flickermeter, which has been used widely around the world for many years, cannot be used to advise on the flicker level of all lamp types. This is because of the fact that this flickermeter is based on a 230 V, 60 W or 120 V, 60 W incandescent lamp and can be used as reference only for this type of lamp or as reference to the standard. The UIE/IEC (International Union for Electricity Applications/International Electrotechnical Committee) flickermeter and the existing standards are therefore insufficient for other lamp types. This paper describes a proposal to improve the UIE/IEC flickermeter.

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Voltage dip is considered as the PQ problem related to the highest financial losses for the customers. It occurs unpredictably mainly due to short-circuit faults in the networks. Network operators and customers want to know more about the occurrence and the potential impact of voltage dips. PQ monitoring is an essential tool for the assessment of voltage dips and it can ultimately contribute to the regulation of voltage dip events. In this paper, firstly the methods of voltage monitoring and voltage dips characterization are discussed. Voltage dip indices of six substations are presented in order to assess the occurrence, type and severity of dips that occur in typical Dutch MV networks. Finally, an approach, which is based on the disrupted loads because of a voltage dip event, is introduced and applied to the data at one substation in order to assess the quality of supply voltage and its implications for the end-users. Index Terms-assessment of voltage dips, dip monitoring, reporting dips, transfer of dips, voltages dip indices

SUMMARYVoltage flicker is an irritating problem especially for the low voltage (LV) customers. It is mainly caused by the loads having repetitive cycle of operation. During the past years, the network operators around the world have registered many complaints from the customers about flicker related problems. Presently, there is no common standard value for the flicker planning level available globally. Moreover, in some countries (for example, in the Netherlands), the existing networks are not even based on a specific planning level value for flicker. Therefore, it is necessary to discuss the flicker planning level values in different voltage levels to overcome flicker related problems. In this paper a typical LV network is simulated to analyze the flicker propagation behavior in the network. The effects of switching LV disturbing loads (such as elevator, welding machine, etc.) on flicker generation at different customer's installations are studied by using synchronized measurement technique. Also, the impacts of the background flicker pollution transferred from the upstream to the downstream networks are analyzed. The simulation results give an overview of the flicker pollution levels at the LV customer's installations in the presence of background flicker. This paper estimates the maximum value of flicker emission share at different customer's point of connections (POC), considering the impact of background flicker pollution. Finally, planning level values of flicker in different voltage levels are suggested that can be useful for the network operators in designing their future networks.