Power Quality Evaluation of a High-Power Residential Load: An Experimental Study

Chapter 24 - Power Quality – Harmonics in Power Systems

24 - Power Quality — Hamonics in Power Systems

Management of harmonic voltage levels can impose significant economic impacts for both electricity suppliers and customers. For the case where harmonic voltage levels are high, economic costs include damage to equipment and associated loss of production due to high voltage harmonic levels as well as the costs associated with mitigation of harmonic currents, for example, harmonic filters. In the alternate scenario, ie. the case where harmonic voltage levels are acceptable, considerable expense may be incurred mitigating harmonic currents unnecessarily due to lack of knowledge of harmonic levels and/or network capabilities. As such, there is considerable potential for industry to make large economic gains if harmonic voltage levels can be better understood. Using data collected as part of an ongoing long-term power quality monitoring project, this paper details the characteristics of voltage harmonic behaviour on Australia electricity distribution networks.

Management of harmonic voltage levels can impose significant economic impacts for both electricity suppliers and customers. For the case where harmonic voltage levels are high, economic costs include damage to equipment and associated loss of production due to high voltage harmonic levels as well as the costs associated with mitigation of harmonic currents, for example, harmonic filters. In the alternate scenario, ie. the case where harmonic voltage levels are acceptable, considerable expense may be incurred mitigating harmonic currents unnecessarily due to lack of knowledge of harmonic levels and/or network capabilities. As such, there is considerable potential for industry to make large economic gains if harmonic voltage levels can be better understood. Using data collected as part of an ongoing long-term power quality monitoring project, this paper details the characteristics of voltage harmonic behaviour on Australia electricity distribution networks.

Sustainability is a guiding principle for a responsible, future‐oriented 21st century lifestyle and this already begins in private households with the daily household tasks. Approximately 25% of an average household's electricity consumption is required to do the laundry and dishwashing – 5% alone is for washing clothes with a corresponding energy consumption of 6 billion kilowatt hours. In addition, 600 000 tonnes of detergent and 330 million cubic metres of water are used for textile care in Germany. These figures provide the rationale for the scientific study of current practices of using washing machines and for a resulting estimate of the latent energy‐saving potential in German households.In the context of the in‐home study presented here, 236 private households throughout Germany were studied with respect to their washing practices and existing knowledge about topics on the sustainable, energy‐saving use of their washing machines. Overall, across all households 2867 wash cycles were individually recorded and subsequently analysed over a 4‐week period.The results of this study show that washing machines tend to be underloaded, and therefore maximum loading of the machines could lead to a reduction of wash cycles per household. With respect to detergent dosage, it was determined that the consumer does not adjust the dosage to the textile type, load size, soil level and/or water hardness, and this can lead to under‐ or overdosing depending on prevailing conditions. Finally, the selection of the wash temperature showed a 90°C/95°C programme was only chosen in 2.3% of all recorded wash cycles, however, every fourth cycle was completed at 60°C. Therefore, adjusting the load size and detergent dosage as well as selecting the right wash temperature are key themes to be taken into account in future consumer communication about energy‐saving households.

This paper discusses the level of harmonic distortion in current power distribution system for laboratory and office building. These two places often house a significant number of equipment such as computers, air conditioners, etc which are significant nonlinear loads. The high number of these nonlinear loads affects the quality of the power system and energy at the linked grid. This is due to harmonics components in current that is resulted by the conversion and switching processes by the nonlinear loads. This case study is located at main operation buildings at School of Electrical System Engineering, Universiti Malaysia Perlis at Pauh Putra Campus. This case study is intended to study the severance level of harmonics in current distortions at the said power distribution system. The tool used for data mining and analysis is the Fluke 1750, which records the data for 30 days. The analysis includes the level of harmonics in current at the point of common coupling at the power distribution system. It is benchmarked against relevant standards related to harmonics in current and power quality in grid. It is found that the harmonic distortion level exceeded the maximum value set by standards. This highlighted that the quality of power at this grid is low and results in losses of energy

Poor power quality has a negative impact on electrical protection systems, rotating machines, transformers, control circuits, electronics, and power electronics equipment. The demand from industries to use power electronics equipment leads to more poor power quality issues – especially relating to harmonics. Determining the level of harmonics in an electrical network has become a necessity, as most electrical equipment are susceptible to harmonics. Previously, electrical networks on the customer side consisted mostly of direct current and induction motors, which resulted in simple networks that were easy to model using various types of simulation software. Today’s electrical network is considered complex due to power electronic equipment such as variable frequency drives (VFDs), uninterruptible power supplies (UPSs), switch mode power supplies (SMPSs) and other electronics equipment. Power electronic equipment are primary source of harmonics and are also susceptible to harmonics. To protect the electrical network infrastructure, it is very important to identify the level of harmonics content in an electrical network, so that solutions can be developed to minimise the harmonic level to acceptable limits – as determined by power quality or harmonics standards. This dissertation presents an analysis of the performance of an island electrical network for an offshore crude-oil drilling ship. A real-time digital simulator was used as a systematic analytical tool to study the level of harmonics in a reduced-scale electrical network model, used to represent the real drilling ship power network. The study objective was to evaluate the behaviour of the power network when direct on line (DOL) starters and variable frequency drives are used to run induction motors coupled with mechanical loads. The waveforms from a limited number of field measurements on the actual network are compared to those obtained from the reduced-scale real-time simulation model of the plant. The study reviews the theory and literature of power quality, generators, transformers, variable frequency drives, and induction machines, and focuses on poor power quality as contributed to by harmonics. The investigation was based on 12 pulse rectifiers for all variable speed drives, which are standard for drilling ships and other offshore installations – as they offer advantages in reducing the fifth and seventh harmonics. Both the field measurements and real-time simulation results in the dissertation indicate the presence of similar harmonic waveforms, and with comparable frequencies – but with different amplitudes. Unfortunately, the simulation results could not be closely matched to the field results, as most operating parameters that are needed for better representation of the plant in the simulation model, could not be obtained within the limited time available for field measurements. Nevertheless, the model developed could be used with a greater degree of accuracy to demonstrate the level of harmonics for an offshore drilling ship power network, provided all operating conditions’ parameters are available.

Hydrogen peroxide (H2O2) is used as bleaching agent in household appliances like washing machines. For the bleaching of laundry with H2O2, an alkaline environment is required in the washing machine, which is ensured by the use of an heavy-duty detergent. In powdered heavy-duty detergents for washing machines, H2O2 is provided in form of sodium percarbonate, which releases H2O2 as soon as it is dissolved in water. As long-term stability of H2O2 in liquids requires acidic environment, no sufficient amount of H2O2 based bleach can be stored in liquid heavy-duty detergents, resulting in a lower bleaching efficiency for laundry cleaning. However, liquid heavy-duty detergents can be dosed fully automatically in washing machines, which is convenient for the user and can reduce the detergent consumption by optimizing dosing amount [1]. To take advantage of a fully automatic dosing system and at the same time obtain an effective heavy-duty detergent with bleach capability, an additional in-situ bleach source is required. An attractive route for the in-situ production of H2O2 is the electrochemical reduction of oxygen (O2) at a carbon-based cathode in a flow cell. The use of a gas diffusion electrode (GDE) results in higher production rates by directly supplying gaseous O2 to the reaction site compared to a submerged cathode where O2 is dissolved in the electrolyte [2,3]. As evidenced by the lack of literature, this kind of a specific application-related flow cell design for the use in a washing machine has not yet been developed.Therefore, a compact and simple electrochemical flow cell was developed that can provide sufficient H2O2 quantities within the time scale of a washing cycle and can be installed in a washing machine. The novel cell consists of an electrolyte reservoir, which is integrated within the cell and is separated from the dimensionally stable anode (DSA) by a divided wall. The expanded metal design of the DSA allows a zero gap arrangement by allowing the separator to lie directly on the anode. Between separator and carbon-based GDE, the electrolyte can be pumped in a circuit via the reservoir. A three-way valve allows the electrolyte accumulated with H2O2 to be discharged to the washing machine. The GDE is supplied with atmospheric O2 from the non-anode-facing side. During operation, the cell is first filled with electrolyte via the filling hole. As soon as the anode chamber (between the anode and the divided wall) is completely filled, the liquid can flow over the divided wall and fill the reservoir. Subsequently, the circulation pump and the air supply of the GDE are started and the current is applied. During electrolysis, the H2O2 is produced in the GDE and accumulates in the circulated electrolyte. The divided wall and the separator prevent the direct oxidation of H2O2 at the anode. The O2 produced at the anode can escape via the gas vent. After a sufficient amount of H2O2 has been generated in the electrolyte, electrolysis is stopped and the H2O2-solution is pumped into the drum of the washing machine via the 3-way valve.The transient H2O2 faradaic efficiency and energy consumption were compared to literature data. The combination of in-situ H2O2 production with liquid heavy-duty detergent was compared to a solid heavy-duty detergent using a standard soiled cotton textiles test.[1] Smulders, E. (2001), Laundry Detergents, Wiley-VCH; 1. Edition.[2] Pérez, J. F., et al. (2016), Electroch. Com. 71, 65–68.[3] Muddemann, T., et al. (2021), Proc. 9, 1482. Figure 1

This paper presents the power quality problems of the power system and discusses the current situation of pow- er quality management. The various analytical methods and means of power quality are discussed in detail. Depending on the power system harmonic, reactive and negative sequence power quality indicators, this paper expounds power quality indicators treatment methods, and analyzes the prospects for the development of power quality control. Aiming at the shortcomings of the contemporary power quality management, and makes some corresponding countermeasures for im- proving power quality management level. Power quality management is under the responsibility of government, enterpris- es and users. Only the government, enterprises and users of the three joint efforts to further improve the power quality of the power system, in order to satisfy the requirements of national economic progress.

Even two level PWM sources with low harmonic voltage and current distortion characteristics can affect an industrial plant's power system in such a way that voltage sensitive electronic equipment is adversely affected. It is unwise to feed PWM sources and sensitive electronic equipment from the same substation transformer. The resulting voltage distortion is time consuming to trouble-shoot and expensive to fix. Additional filtering is needed to stop the unwanted harmonic frequencies that emanate from PWM sources from interfering with the operation of sensitive electronic equipment such as gas burner controls, robots and assembly line sensors typically used in the automotive industry. The paper describes the generation of voltage and current harmonics of two level PWM inverter sources. The level of these harmonics were measured before the application of a passive filter and serve as a guide as to the effectiveness of the passive filter in minimizing the level of voltage and current harmonics.

Electrical power quality (PQ) disturbance has become a prominent issue in Indonesia. On a distribution network, it is mainly caused by a nonlinear load. Due to the varying power produced, it is affected by a solar PV system as well. Therefore it is necessary to take a solar photovoltaic (PV) without battery storage into account on evaluating a PQ problem. This paper presents observation results of a rooftop PQ system interconnected to the distribution network which supplies nonlinear loads. In this paper, electrical PQ measurements and harmonic levels of rooftop solar PV integration are presented. The PQ measurements were set up on a distribution network which supplied a nonlinear load individually and whenever a PV system is interconnected with it. As is known, the level of harmonics depend on the performance of a PV system inverter. Since IEEE 1547-2003 standard applies to the measurement results, it is revealed that a PV system inverter is not meeting the standard. To prevent excessive levels of harmonic current injected by a solar PV system, risk mitigations are proposed. The risk mitigations cover redesigning a transaction energy meter, redesigning the interconnection code, and reviewing the standing operation procedure.

Candida and Fusarium species known as opportunistic human pathogens from customer-accessible parts of residential washing machines

Nonlinear loads are becoming a larger percentage of the total load in commercial facilities. Fluorescent lighting has always resulted in some harmonic generation. Now, single phase power electronic loads are a major portion of the load in many commercial facilities. They have become a problem for neutral conductors, transformer heating, and interference with other loads on the facility. Besides, single phase electronic equipment, many adjustable speed drives are now commonly applied for HVAC equipment. UPS equipment can have similar characteristics to the ASDs. The combination of these different nonlinear loads can also result in excessive injection of harmonic components from the customer facility onto the utility power system. Harmonic problems can be solved by controlling the harmonics in the loads themselves, through filtering (active or passive) on the electrical system, or by rating the system components to handle the harmonic levels. This paper discusses the expected harmonic levels in a facility as a function of the amount of nonlinear load of the different types. Alternatives for reducing harmonic distortion levels are discussed.

Washing laundry is one of the most widespread housework tasks in the world. Washing machines, performing this task already in many private households, are now responsible for about 2% of the global electricity consumption. Worldwide, more than 840 million domestic washing machines are in use, with an annual consumption exceeding 92 TWh of electricity and 19 billion m3 of water as well as causing emissions of more than 62 megatons CO2eq. In North America, Western Europe and Pacific OECD countries, most households own a washing machine. In these economies standard and label policy programs already addressed and reduced the specific electricity and water consumption of washing machines per wash cycle. Nevertheless, in other world regions, the level of ownership for washing machines is still well below saturation and high growth rates can be observed in developing and newly industrialising countries. As washing machines use water, electricity, chemical substances and process time as resources, also the absolute worldwide resource consumption and emissions of these appliances are still on the rise. Due to different washing habits and practices as well as types of washing machines in different world regions, the specific consumption of resources for doing the laundry is varying to a large extent. On that score, this paper presents an overview of the current situation worldwide as well as respective saving potentials. Bottom-up scenario calculations, carried out for the 11 world regions according to the Intergovernmental Panel on Climate Change classification, show that large energy, water and greenhouse gas savings are possible with the ‘Best Available Technologies’ today, and even higher savings will be possible with next generation ‘Best Not yet Available Technologies’. According to model results, these savings are usually also very cost-effective. Following these calculations, it is highly advisable for policymakers world-wide to pay even more attention to improvement options in order to implement ambitious and product-specific policy packages, including minimum performance standards and labelling schemes.

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