Study On Electrified Railway Power Quality Improvement Based Multiple Balance Transformers

With the deve lopme nt of high-speed and heavy load in electrified railwa y, thepower qua lity proble m of the power system is getting worse. Therefore, thegoverna nce issue of power quality is the key one in electrified railway research. Thepower qua lity has its own unique characteristics, such as the strong asymmetry, thehigh fluctuation of load, strong randomness, large treatment capacity. Choosing a kindof governa nce whic h can overcome the above comp lex condition has become ahotspot. When comparing the advanta ges and disadvanta ges of various methods tocontro l the arms, the paper research the governance method in the perspective of thetransformer comb ined power electronic devices. It can increase the syste m re liability,get better dyna mic governa nce performance and reduce system cost. For a variety ofelectrified railway power quality control issues, the paper studies the following:First of all, it gives an overview of the various features of arms compensationcontro l method to treat power qua lity in e lectrified ra ilway, the basic princ ip les ofevery method, advantages and d isadvantages. The n derived the essence of electrifiedrailway ne gativesequence, harmo nics,reactive power control and the distrib ution ofnegative-sequence load harmo nic components in each transformer wind ings withmathematica l princ ip les based on Star-delta connectio n bala nce transformer、YN/〉/－V connection ba lance trans former、 Y/>/connection ba lance trans former. Thefeatures of multi-purpose bala nced three-phase inverter trans former are beingresearched. And a new topology mana ge ment e lectrified railwa y power quality isproposed.Secondly, on the basis of previous research work, a detection method of negativesequence,harmonics and reactive is fo und. The compensation syste m is detected bythis method. And a control method of vo ltage and current double closed-loop wasapplied to three-phase bridge inverter.Accroding to the measured waveform of thewestern of Hunan province, a simulation model is made in the Matlab/Simulinksoftware to prove the effect o f the power quality co mprehens ive ma nage ment. Themodel compare the disadvanta ges and advanta ges between different topology anddifferent ma nage ment methodsWhich can provide some practical guidance for thistype of electrified railway power quality management.Fina lly, based on the e xisted sma ll capacity5KVA connection ba lance transformer in our laboratory, an experime nted model of the entire mana geme ntsystem is established. The various parts of the hardware of the entire system isdescribed.,whic h make a more perfect preparation for the next who le experime nt. Theexperiment verify the accuracy of the theory. It can achieve better guida nce value inengineering practice.