بررسي و مطالعه مشكلات كيفيت توان ناشي از سيستم هاي حمل و نقل الكتريكي روي شبكه توزيع و روش هاي اصلاح آن

چكيده انگليسي :

Analysis of power quality phenomena induced by electrical traction systems on distribution system and their mitigation methods Seyed Ebrahim Moeini moeini@ec iut ac ir Date of Submission 2009 07 4 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Mehdi Moallem moallem@cc iut ac ir Akbar Ebrahimi ebrahimi@cc iut ac irAbstract Electric Traction has been a popular transportation system for years and nowadays it is expanding moreand more in Iran These systems in comparison with other transportation systems introduce advantagessuch as low cost fast speed and low pollution on environment Although electric traction systems arespread around the world for years in Iran it is not widespread and several new projects are underdevelopment Due to this reason the importance of electric traction systems is evident Development ofelectric traction systems cause some disadvantages Electric traction load is one of the most polluting loadsfor electric distribution system and decreases the power quality due to high power electric drives fastchanging loads and proximity to domestic loads in the distribution system Due to these problems it isnecessary to study the power quality effects of electric traction system and design compensation methods toreduce the power quality effects The first step for studying the electric traction systems and their powerquality effects is to know these loads characteristics By knowing characteristics of these loads it is possibleto calculate needed power profile according to movement algorithms which is defined based on trafficrules After calculation of power profile of electric traction load it is necessary to connect this calculatedload to electric power distribution system and simulate the overall system that contains traction systemdrives electric substations and electric power distribution system The connection point between load andutility that is named PCC is the point that in it power quality effects should be investigated To do this power quality analyzers should be used to measure the power quality phenomena according to powerquality standards Power quality standards introduce limitations for power quality phenomena in the PCCand also introduce some mitigation methods It is necessary to restrict power quality effects to limits thatdefined in power quality standards Usual power quality effects in distribution feeders that are feeding theelectric traction systems are different for different electric traction systems DC or AC These are highvariable current and voltage harmonics voltage flicker unbalance in 3 phase systems low power factor andvoltage sag Usual power quality effects due to connection of DC electric traction systems to electric powerdistribution system are high variable voltage and current harmonics and over allowed voltage flicker ForAC electric traction systems it is usual to detect previously mentioned power quality effects and in additionto it other effects such as unbalance in three phase power feeding systems voltage sag and low powerfactor are usual Other thing that is very important in traction system is reliably of traction For this and insome contingency circumstances it may detect higher over allowed power quality effects due to connectionof AC and DC traction loads to same electric power feeders In this project electric traction loadcharacteristics and their effects on electric distribution system are studied and compensation methods areinvestigated For this purpose the information of an electric traction system is used and the power profile ofthis system is calculated The calculated power profile is connected to 13 bus IEEE test distribution system This system is simulated using PSCAD software and power quality phenomena are investigated and thenmitigation methods are examined to reduce power quality effects to the permitted level The results ofsimulation before and after mitigation are com

معيني، ابراهيم

بررسي و مطالعه مشكلات كيفيت توان ناشي از سيستم هاي حمل و نقل الكتريكي روي شبكه توزيع و روش هاي اصلاح آن

استانداردهاي كيفيت توان , روش هاي جبران