L. Sainz, L. Monjo, J. J. Mesas, J. Pedra, M. Cheah‐Mane
Traction system stability can be affected by the interaction between the traction load and resonances in the railway traction grid. This paper presents an electrical resonance instability study applied to traction systems. The influence of traction section length and converter time delay on traction system stability is analyzed with examples. An impedance-based representation of the traction system is used to identify the resonances and analyze stability problems. PSCAD/EMTDC time-domain simulations are also shown to validate the stability study.
{"title":"Electrical resonance instability study in traction systems","authors":"L. Sainz, L. Monjo, J. J. Mesas, J. Pedra, M. Cheah‐Mane","doi":"10.1109/PQ.2016.7724102","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724102","url":null,"abstract":"Traction system stability can be affected by the interaction between the traction load and resonances in the railway traction grid. This paper presents an electrical resonance instability study applied to traction systems. The influence of traction section length and converter time delay on traction system stability is analyzed with examples. An impedance-based representation of the traction system is used to identify the resonances and analyze stability problems. PSCAD/EMTDC time-domain simulations are also shown to validate the stability study.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"8 1","pages":"133-138"},"PeriodicalIF":0.0,"publicationDate":"2016-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90977140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper gives an insight to the importance of choosing one certain value in a range for the permanent magnets parameters given by manufacturers. The purpose of the research is to test the influence of chosen parameters values, which are given in a range and are used in computational modeling, on the devices main characteristics, as nowadays scientists and product developers are using more and more different simulation tools. Paper includes the electromagnetic field modeling, based on the finite element analysis and the electromagnetic measurements, obtaining the hysteresis loops of permanent magnets.
{"title":"Influence of choice of permanent magnet electromagnetic parameters in the research of electrical devices","authors":"B. Ose-Zaļā, A. Kallaste, T. Vaimann","doi":"10.1109/PQ.2016.7724117","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724117","url":null,"abstract":"The paper gives an insight to the importance of choosing one certain value in a range for the permanent magnets parameters given by manufacturers. The purpose of the research is to test the influence of chosen parameters values, which are given in a range and are used in computational modeling, on the devices main characteristics, as nowadays scientists and product developers are using more and more different simulation tools. Paper includes the electromagnetic field modeling, based on the finite element analysis and the electromagnetic measurements, obtaining the hysteresis loops of permanent magnets.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"45 1","pages":"225-228"},"PeriodicalIF":0.0,"publicationDate":"2016-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87048058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes the hardware and software to perform phasor measurements at busses of the power network. The advent of the Global Positioning System (GPS) absolute timing reference allows voltage phase angles to be measured, and referred to a common location in order to compute angle differences. The equipment to be described has accuracy dependent upon the microprocessor and represents a simple, low cost, method to synchronize phase measurements at remote points in a power grid. The software is code within simple stand-alone devices or can have an equivalent in Remote Terminal Units (RTU's). Power systems are dense with existing RTU's and with the method of this paper more PMU measurements can be available for State Estimation or coordinating machine swing transients.
{"title":"Measurement of power system phase differences by means of GPS timing","authors":"G. Kusic, William E. McGahey, M. Lehtonen","doi":"10.1109/PQ.2016.7724130","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724130","url":null,"abstract":"This paper describes the hardware and software to perform phasor measurements at busses of the power network. The advent of the Global Positioning System (GPS) absolute timing reference allows voltage phase angles to be measured, and referred to a common location in order to compute angle differences. The equipment to be described has accuracy dependent upon the microprocessor and represents a simple, low cost, method to synchronize phase measurements at remote points in a power grid. The software is code within simple stand-alone devices or can have an equivalent in Remote Terminal Units (RTU's). Power systems are dense with existing RTU's and with the method of this paper more PMU measurements can be available for State Estimation or coordinating machine swing transients.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"120 1","pages":"297-300"},"PeriodicalIF":0.0,"publicationDate":"2016-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91050228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Limited range of Electric Vehicle's (EV) battery in terms of number of miles per recharge, requires EV to recharge the battery at least once during the long trip. However, long charging durations are not acceptable in these cases, therefore fast charging of EV is needed. Fast charging of EV needs more charging power for relatively shorter period of time, which gives rise to overloading of the power network due to simultaneous charging of multiple EVs at the fast charging stations. This paper studies the power network requirements to meet the EV fast charging needs on highways. Different parameters are considered in the study, for instance, arrival order of EVs at the charging stations, number of charging slots per charging station, power rating of installed chargers, distance between charging stations, state of charge (SoC) of EVs arriving for charging, battery capacities, waiting time at charging stations and the duration of charging. Various scenarios are simulated using Monte Carlo Simulations (MCS) to see the impact of fast charging on the power network loading. The key finding is the peak load on individual fast charging stations with respect to different penetration levels of EVs on the road. A real highway case in Finland is considered in this study to show the rationality of the results.
电动汽车(EV)电池每次充电的续航里程有限，要求电动汽车在长途旅行中至少给电池充电一次。然而，在这些情况下，长时间的充电是不可接受的，因此需要对电动汽车进行快速充电。电动汽车快速充电需要更大的充电功率，充电时间相对较短，多辆电动汽车在快速充电站同时充电会导致电网过载。本文研究了满足高速公路电动汽车快速充电需求的电网要求。研究中考虑了不同的参数，如电动汽车到达充电站的顺序、每个充电站的充电槽数、安装的充电器的额定功率、充电站之间的距离、到达充电站的电动汽车的充电状态(SoC)、电池容量、充电站等待时间和充电持续时间。利用蒙特卡罗模拟(Monte Carlo Simulations, MCS)对不同场景进行了模拟，以了解快速充电对电网负载的影响。关键的发现是各个快速充电站的峰值负荷相对于不同的电动汽车在道路上的渗透水平。为了证明研究结果的合理性，本研究以芬兰高速公路的实际案例为例。
{"title":"Analysis of power network loading due to fast charging of Electric Vehicles on highways","authors":"Farhan H. Malik, M. Lehtonen","doi":"10.1109/PQ.2016.7724097","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724097","url":null,"abstract":"Limited range of Electric Vehicle's (EV) battery in terms of number of miles per recharge, requires EV to recharge the battery at least once during the long trip. However, long charging durations are not acceptable in these cases, therefore fast charging of EV is needed. Fast charging of EV needs more charging power for relatively shorter period of time, which gives rise to overloading of the power network due to simultaneous charging of multiple EVs at the fast charging stations. This paper studies the power network requirements to meet the EV fast charging needs on highways. Different parameters are considered in the study, for instance, arrival order of EVs at the charging stations, number of charging slots per charging station, power rating of installed chargers, distance between charging stations, state of charge (SoC) of EVs arriving for charging, battery capacities, waiting time at charging stations and the duration of charging. Various scenarios are simulated using Monte Carlo Simulations (MCS) to see the impact of fast charging on the power network loading. The key finding is the peak load on individual fast charging stations with respect to different penetration levels of EVs on the road. A real highway case in Finland is considered in this study to show the rationality of the results.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"23 1","pages":"101-106"},"PeriodicalIF":0.0,"publicationDate":"2016-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82662332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Melentjev, A. Belahcen, A. Kallaste, A. Rassõlkin, T. Vaimann
This paper presents a review of losses calculation and also loss reduction control methods of permanent magnet assisted synchronous reluctance drives. Reluctance machines as well as drive systems containing such machines are gaining popularity and hence need closer investigation and optimization. The paper introduces the topic, describes the possible drive system and loss types, addresses different control technologies in the perspective of losses in permanent magnet assisted reluctance machines and gives mathematical justifications on all the mentioned parts. Necessity of further study is also pointed out.
{"title":"Review of loss calculation reduction control methods of permanent magnet assisted reluctance drive","authors":"S. Melentjev, A. Belahcen, A. Kallaste, A. Rassõlkin, T. Vaimann","doi":"10.1109/PQ.2016.7724113","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724113","url":null,"abstract":"This paper presents a review of losses calculation and also loss reduction control methods of permanent magnet assisted synchronous reluctance drives. Reluctance machines as well as drive systems containing such machines are gaining popularity and hence need closer investigation and optimization. The paper introduces the topic, describes the possible drive system and loss types, addresses different control technologies in the perspective of losses in permanent magnet assisted reluctance machines and gives mathematical justifications on all the mentioned parts. Necessity of further study is also pointed out.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"19 1","pages":"199-206"},"PeriodicalIF":0.0,"publicationDate":"2016-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85083335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Bosovic, H. Renner, A. Abart, E. Traxler, Jan Meyer, M. Domagk, M. Music
Harmonic voltages are important voltage quality parameters defined in EN 50160. For harmonic voltage studies in electricity networks, harmonic emission of loads is often modelled as harmonic current source. In this paper harmonic current sources were parameterised on the basis of measure-ments of total harmonic current emission of several different low voltage networks. Measurements from low voltage net-works with different typical customer configurations were used: residential, offices and PV. A real medium voltage electricity distribution network of an Austrian distribution system operator, with significant consumption of residential and office customers, was chosen for this analysis. In order to automate the harmonic load flow calculations in DIgSILENT PowerFactory for every 10-minute interval of one week, a script in DIgSILENT Programming Language - DPL was developed. Harmonic voltage results from the harmonic load flow simulation are compared with the results of harmonic voltage measurements from power quality monitoring system installed in this network. The goal of this paper is to assess the suitability of the approach, where only background harmonics and key harmonic current sources are modelled. Since the approach provided good results, it can be used in future work as a basis for optimising the number and locations of power quality monitors in electricity distribution networks.
{"title":"Validation of aggregated harmonic current source models based on different customer type configurations","authors":"A. Bosovic, H. Renner, A. Abart, E. Traxler, Jan Meyer, M. Domagk, M. Music","doi":"10.1109/PQ.2016.7724093","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724093","url":null,"abstract":"Harmonic voltages are important voltage quality parameters defined in EN 50160. For harmonic voltage studies in electricity networks, harmonic emission of loads is often modelled as harmonic current source. In this paper harmonic current sources were parameterised on the basis of measure-ments of total harmonic current emission of several different low voltage networks. Measurements from low voltage net-works with different typical customer configurations were used: residential, offices and PV. A real medium voltage electricity distribution network of an Austrian distribution system operator, with significant consumption of residential and office customers, was chosen for this analysis. In order to automate the harmonic load flow calculations in DIgSILENT PowerFactory for every 10-minute interval of one week, a script in DIgSILENT Programming Language - DPL was developed. Harmonic voltage results from the harmonic load flow simulation are compared with the results of harmonic voltage measurements from power quality monitoring system installed in this network. The goal of this paper is to assess the suitability of the approach, where only background harmonics and key harmonic current sources are modelled. Since the approach provided good results, it can be used in future work as a basis for optimising the number and locations of power quality monitors in electricity distribution networks.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"47 1","pages":"77-84"},"PeriodicalIF":0.0,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78897486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The measurement of harmonic and interharmonic voltages up to 2.5 kHz is an inherent part of the Power Quality assessment in electrical networks. In the past the monitoring of harmonic voltages has been of minor importance for many transmission system operators (TSO). As the number of power electronics connected to the transmission grid (e.g. self-commutated HVDC stations or converters in large wind power plants) increases continuously, the concern of TSOs regarding the harmonic levels grows as well. This is also confirmed by the recent significant increase of installed Power Quality monitors in transmission grids [1]. In many cases the traditional voltage instrument transformers (VT), which are only designed to have a high accuracy at rated frequency, are used for voltage harmonic measurements. This questions the accuracy of the harmonic measurements and the reliability of any compliance assessment (e.g. against existing planning levels). The paper illustrates the challenges of harmonic voltage measurements from the viewpoint of a TSO. After a quick description of the initial situation the paper presents and discusses the measurements of the frequency response characteristic of different VTs and their impact on the accuracy of voltage harmonic measurements.
{"title":"Accuracy of voltage instrument transformers for harmonic measurements in elering's 330-kV-transmission network","authors":"Jan Meyer, R. Stiegler, J. Kilter","doi":"10.1109/PQ.2016.7724094","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724094","url":null,"abstract":"The measurement of harmonic and interharmonic voltages up to 2.5 kHz is an inherent part of the Power Quality assessment in electrical networks. In the past the monitoring of harmonic voltages has been of minor importance for many transmission system operators (TSO). As the number of power electronics connected to the transmission grid (e.g. self-commutated HVDC stations or converters in large wind power plants) increases continuously, the concern of TSOs regarding the harmonic levels grows as well. This is also confirmed by the recent significant increase of installed Power Quality monitors in transmission grids [1]. In many cases the traditional voltage instrument transformers (VT), which are only designed to have a high accuracy at rated frequency, are used for voltage harmonic measurements. This questions the accuracy of the harmonic measurements and the reliability of any compliance assessment (e.g. against existing planning levels). The paper illustrates the challenges of harmonic voltage measurements from the viewpoint of a TSO. After a quick description of the initial situation the paper presents and discusses the measurements of the frequency response characteristic of different VTs and their impact on the accuracy of voltage harmonic measurements.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"32 1","pages":"85-90"},"PeriodicalIF":0.0,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90717586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper presents the analysis of main reasons and consequences of the decrease of the efficiency for suppression of single phase-to-ground faults causing dangerous technological failures and faults in distribution networks. Advantages and disadvantages of main systems for partial or full compensation of a ground fault current used for minimizing losses are described. Comparative calculations on the emergency tripping probability due to the development of a single phase-to-ground fault into phase-to-phase short circuit in compensated and ungrounded networks are given. Based on the experience of manufacture and operation, technical requirements to arc suppression devices and their compensation automation systems are developed.
{"title":"Conditions for effective ground fault suppression in distribution networks with capacitive current compensation","authors":"A. Shirkovets, A. Telegin, D. Kochura","doi":"10.1109/PQ.2016.7724131","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724131","url":null,"abstract":"The paper presents the analysis of main reasons and consequences of the decrease of the efficiency for suppression of single phase-to-ground faults causing dangerous technological failures and faults in distribution networks. Advantages and disadvantages of main systems for partial or full compensation of a ground fault current used for minimizing losses are described. Comparative calculations on the emergency tripping probability due to the development of a single phase-to-ground fault into phase-to-phase short circuit in compensated and ungrounded networks are given. Based on the experience of manufacture and operation, technical requirements to arc suppression devices and their compensation automation systems are developed.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"14 1","pages":"301-307"},"PeriodicalIF":0.0,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89531085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grounding systems are considered as an essential part of power systems since they are designed to protect them against fault currents according to some safety and power quality standards. When lightning strikes a substation or a transmission tower near the substation, high current generated by the stroke would flow into the grounding system of the substation and dissipate into the soil. The transient response of the grounding system is a very important indicator to the safe and reliable operation of the power system. A model with lumped time-varying parameters is developed and is implemented into software tools (Matlab/Simulink) to calculate the transient behavior of the grounding systems during lightning strokes. The effects of different parameters especially soil resistivity and ionization of the soil around the electrode on the transient behavior of the grounding system subjected to lightning impulse current are analyzed.
{"title":"Transient response of grounding systems under impulse lightning current","authors":"Idir Djamel, F. Slaoui, S. Georges","doi":"10.1109/PQ.2016.7724092","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724092","url":null,"abstract":"Grounding systems are considered as an essential part of power systems since they are designed to protect them against fault currents according to some safety and power quality standards. When lightning strikes a substation or a transmission tower near the substation, high current generated by the stroke would flow into the grounding system of the substation and dissipate into the soil. The transient response of the grounding system is a very important indicator to the safe and reliable operation of the power system. A model with lumped time-varying parameters is developed and is implemented into software tools (Matlab/Simulink) to calculate the transient behavior of the grounding systems during lightning strokes. The effects of different parameters especially soil resistivity and ionization of the soil around the electrode on the transient behavior of the grounding system subjected to lightning impulse current are analyzed.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"9 1","pages":"71-75"},"PeriodicalIF":0.0,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87026945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The number of single phase connected devices (electric vehicle charger, photovoltaic inverters, etc.) with high electrical power and long periods of operation increases continuously and may lead to a significant increase in voltage unbalance. In order to perform a realistic simulation of voltage unbalance in public low voltage networks, the contribution of residential loads to unbalance has to be included. This paper presents a probabilistic model of household loads for unbalance studies. The model is based on a set of power measurements of households of different size in different networks. Based on these data an unbalanced load flow model for household loads is developed and validated. Both, simulation and measurement results are discussed and simplified equations to estimate unbalance and maximum power of a group of households are provided.
{"title":"Probabilistic household load model for unbalance studies based on measurements","authors":"F. Möller, Jan Meyer","doi":"10.1109/PQ.2016.7724098","DOIUrl":"https://doi.org/10.1109/PQ.2016.7724098","url":null,"abstract":"The number of single phase connected devices (electric vehicle charger, photovoltaic inverters, etc.) with high electrical power and long periods of operation increases continuously and may lead to a significant increase in voltage unbalance. In order to perform a realistic simulation of voltage unbalance in public low voltage networks, the contribution of residential loads to unbalance has to be included. This paper presents a probabilistic model of household loads for unbalance studies. The model is based on a set of power measurements of households of different size in different networks. Based on these data an unbalanced load flow model for household loads is developed and validated. Both, simulation and measurement results are discussed and simplified equations to estimate unbalance and maximum power of a group of households are provided.","PeriodicalId":6470,"journal":{"name":"2016 Electric Power Quality and Supply Reliability (PQ)","volume":"1 1","pages":"107-112"},"PeriodicalIF":0.0,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90362981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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