This paper discusses the sensitivity of adjustable speed drives (ASDs) to voltage sags and short interruptions on basis extensive test results. Existing standards previously published work are critically reviewed, a description procedures needed for appropriate assessment ASD is presented. The following tests were performed: rectangular three-phase, two-phase, single-phase with ideal nonideal supply characteristics, as well nonrectangular-balanced three-phase similar those caused by starting...

This paper discusses the sensitivity of personal computers (PCs) to voltage sags and short interruptions on basis extensive test results. Existing standards previously published works are reviewed, a description used testing procedure is presented. The following tests were performed: rectangular with ideal nonideal supply characteristics, caused by starting large motors. results obtained emphasize importance clear definition malfunction criteria for this equipment.

In this study, a heuristics-based optimisation methodology for day-ahead unit commitment (UC) model in microgrids is proposed. The aims to schedule the power among different microgrid units while minimising operating costs together with CO2 emissions produced. A storage device added where charge and discharge calculated according both objectives. addition, as part of demand side participation strategy, charging was determined electric vehicles (EV) order increase system security further...

High-resolution residential smart meter data play a pivotal role in numerous applications, ranging from assessing hosting capacity low-voltage grids to evaluating the economic viability of household-level solutions such as integration photovoltaic (PV) installations with battery energy storage systems (BESS). However, privacy concerns often restrict access large-scale datasets, leaving only synthetic load profiles available public, which generally represent averages individual data. In...

A workshop on power system harmonics was organized in Stockholm January 2014. On the agenda among others a discussion what are main issues at moment and near future. Some of discussed that presented this paper its companion paper. In following will be addressed: appearance emission higher frequencies (supraharmonics); need for new improved standards; measurement data analysis.

This paper presents an in-depth comparison of the benefits and limitations using a low-voltage DC (LVDC) microgrid versus AC with regard to integration low-carbon technologies. To this end, novel approach for charging electric vehicles (EVs) on distribution networks by utilizing LVDC backbone is discussed. The global aim conducted study investigate overall energy losses as well voltage stability problems microgrids. Both architectures are assessed compared each other performing power flow...

This paper describes what factors (i.e., load and supply) have an important effect on the neutral conductor current. It is shown that asymmetry up to 10/spl deg/ or unbalance of 10% in power supply has only a minor RMS value An conditions increases Harmonics voltage highly affect

The standard squirrel-cage induction machine has nearly reached its maximum efficiency. In order to further increase the energy efficiency of electrical machines, use permanent magnets in combination with robust design and line start capability is extensively investigated. Many experimental designs have been suggested literature, but recently, these line-start permanent-magnet machines (LSPMMs) become off-the-shelf products available a power range up 7.5 kW. magnet flux density function...

Low voltage distribution feeders are designed for unidirectional energy supply from transformer to consumer. However, the implementation of small-scale PV production units on local utilities may result in bidirectional flows. The simultaneous power injection at sunny moments cause a serious rise along feeder. These overvoltages not only damage critical loads but also switches inverters off causing loss green most productive moments. This paper presents method limit by introducing small...

A workshop on power system harmonics was organized in Stockholm January 2014. On the agenda among others a discussion what are main issues at moment and near future. The results of this summarized paper some discussed more detail its companion paper. This discusses emission from wind solar as well advantages disadvantages active passive filters.

The quantification of harmonic emission requires an accurate model the network impedances. A number techniques have been proposed for assessment impedances to be practical and noninvasive. This paper presents innovative application known based on pre posttriggered waveform capturing a rapid voltage change event. impedance values are derived each event, analyzed, statistical median results is used represent It enables online noninvasive tracking configuration validation simulated results.

The increased use of grid-tied converters (GTCs) leads to power conversion harmonics in low voltage networks supraharmonics range. effect using with switching rates that are non-integer multiples the grid frequency is studied. It observed both high (HF) and (LF) emissions increase more than what expected occur at many interharmonic frequencies, due a combination feedback mechanisms. When GTC switched multiple frequency, extra harmonic bands appear around main LF HF emitted from GTC....

AC/DC converters, controlled by pulse width modulation (PWM) and used as power factor correction (PFC), is considered one of the main contributors to emissions in range 2 kHz–150 kHz, recently known supraharmonic (SH) range. This study looks at impact SH grid distortion on LF (<2 kHz) HF (>2 emission an converter. The PFC boost converter a particular case for validation results. It observed that converters emit additional interharmonics subharmonics when voltage contains interharmonic...

Induction machines usually have a reduced efficiency when supplied with non linear currents. Most of the induction are not used at nominal loading, but 60% loading rate. In paper it will be shown that derating factors for motors fed nonlinear currents, like NEMA MG1 or IEC 60034-17, correct loading. At lower these can underestimate losses. The measurements in this indicate low percentages, phase angles harmonics significant influence on peak and therefore saturation level machine. For rates...

Condition Monitoring on rotating electrical machines has proven to be economically beneficial in the last decades, especially for industrial production processes. Vibration analysis already become a reliable and commercial tool perform condition monitoring or predictive maintenance. Stator current analysis, newer technology that is still being developed can possibly open new perspectives opportunities world of This also known as Motor Current Signature Analysis MCSA. In this paper advantages...

The increased utilisation of distributed renewable energy sources in low voltage grids leads to power quality problems such as overvoltages and unbalance. This imposes challenges the distribution system operators maintain their grids. To overcome these issues, storage systems could be integrated together with resources stored used when needed better improve achieve grid performance. However, integrating an introduces additional cost, therefore, determining right capacity is essential. In...

Companies active in distribution or transmission of electrical energy know the power losses their HV and MV cables. Users have no idea magnitude cable installations. Nevertheless can be a significant part (3%–5%) total consumption. Nonlinear loads (ASD, CLF, IT-equipment,…) are often installed with aim rational use. However, one is not aware increase due to nonlinear load. A software tool developed order enable companies simulate supply system present future installation an easy way,...

Similar to standard three phase direct on line induction motors are line-start permanent-magnet machines (LSPMMs) susceptible grid voltage distortion. Although straight forward adaptation of harmonic loss mechanisms for squirrel-cage LSPMMs seems appropriate, this study will indicate that calculations unsuitable give accurate or even reasonable estimations the influence supply distortion energy efficiency LSPMMs. This research specifically address interaction rotor-induced currents....