户内变电站通风性能的CFD数值模拟分析

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Sep．2013机 床 与 液 压Hydromechatronics Engineering Vo1
． 41 No．18DOI：10．3969／j．issn．1001—3881．2013．18．028The CFD Numerical Simulation on Ventilation of IndoorTransforml Substatiqer onxu Luwen ，WANG Guocha0 ，DING Jun ，CHEN SongElectric Power Science and Research Institute
， Chongqing E1ectric Power Corporation，Chongqing 401 123
，China；2-School of Mechanical Enginering，Chongqing University of Technology，Chongqing 400054
． Chinn1．IntroductionAbstract：This article examines the possible cause of power—off in Chongqing resulting from the o.

verheating of the main transformer in summer
， discusses a CFD (Computational Fluid Dynam.

ics)numerical model of the main transformer，and analyzes the results with FLUENT software
.

The optimum heat dissipation efect is produced and the optimum layout of the air inlet and outletare obtained by changing the positions of the air inlet and outlet
． Such layout not only optimizesthe ventilation and thermal dissipation of the transformer substation and reduces reconstructioncost but also guides the construction of the substation
.

Key words：Transformer substation
，
Ventilation and heat transfer
， CFD numerical simulation． In.

Iets and outletsThe rapid development of the Chinese economy
，the rapid expansion of power grids，and the use ofhigh voltage in urban areas have increased the re—quirement for city—network substations and for themore distribution points of transformer substation[1 j．The city—network electric．power substation indowntown bears a large electric power supply for theneighbor residents．In order to improve the eficiencyof use of land。coordinate with the construction styleof city buildings， and reduce the influence 0f thenoise of the electric power substation on the urbanenvironment necessitate，the application of a wholeindoor layout substation has so far been spread out indesigning city—network power substations[2-3].

The most significant difference between a citv.

network electric-power substation with a whole indoorlayout and a traditionally designed electric．powersubstation is that equipment in the former
， includingReceived：2013—04—09XU Luwen，Senior Engineer．E—mail：xuluwenl00### tom
． com the main transformer，is installed inside the staf0n
.

Installing power transfm-mers with high voltage andhigh capacity indoors reduces the heat they emit andventilates them if they yield the same rated output asthose in the outdoor layout[4 ]．Therefore，av0i.

ding substantial heat generation by normal loss duringthe operation of a transformer(as in the outdoor lay.

out)through the natural(rather than forced)ventila—tlon of the transformer room to ensure the normal op—eration of the transformer is a major function of theindoor city．network power substation
.

This article describes the fluid flow and heattransfer of the natural ventilation of an indoor trans—former，examines the heat dissipation of the indoortransformer as wel as the mutual relation between thetransformer structure and the area and location of theair inlet and outlet of the transformer room and theheight of the transformer room
，
and proposes require—ments for indoor transformer rooms for building andventilation professionals． Traditional reconstructi0nentails high cost and possibly unsatisfactory out—comes． Numerical simulation by FLUENT not onlvreduces cost but also achieves high accuracy and isthus an excellent approach to reconstruction
.

142 Hy(1 r(】mechaIr0nics Engineering2．NumericaI simulationThe geometry model of indoor substation with anlain transformer is created in 3 D software．as ilus—trate(j in Fig． 1．It shows the layouts of the originalair inlet and outlet of the transforlner substation ac—coMing to an actua1 indoor substation．with two inletsand two outlets located at the bottom and on the topof substation。respectively.

Fig．1 File geometD"model of indoor transformer substationThe tool of M ESHING in ANSYS software isused fol·meshing the model of indoor·substation withthe element type of tetrahedral grids enlployed to dis—ci’ete the nunlerioaI ulodel and the number ot’gridsnrore than 2．5 million．The steady．state simulationscheme and integral separation algorithm are em—ployed to numerically calculate the temperature distri—bution f0r a better convergence．The boundary condi.

tions for inlets are prescribed as the type of velocityarid for outlets as the type of flux『7]．The CFD sim.

ulation is performed in FLUENT software．and thentransferl‘ed in special software CFD·Post for postpro—eess『8 ．The mmlvsis fol·the results ot CFD of in—dool，su1)station focuses on the temperature distribu—ti(m on the main transformer since the temperature O1transformer Ol-in roonl is a key factor to evaluate theefficiencv of}mat exchange in indool’substation.

3．Results and discussionFog．2 shows the eontoui’map lot’temperature onthe main transfoITiqel·in iIldoor substation．It demon.

strates that the higher temperature centers Oil theurain trailsformer and that the values for temperaturearound iIr substation al·e far smaller than that of tern—pel’ature． The partial nlaximum temperature of themain body of the original transformer reaches about36l K r 88℃ .

Fig．2 The temperature distribution on the lnain h'ansforme!。

3．1．The optimization for distribution of inletsthe above conclusion suggests two optimum heatdissipation methods．With a constant area of the airinlet，varying the number and layout position of theinlet achieves the desired ventilation efect． Themodifed positions for two inlets are illustl，ate(1 as Fig.

3． the first dissipation method divides the originalinlet into four pieces．with the Iotal inlet al·ea un—changed．These pieces are placed on the four COrnersof the main trailsformer roon1．The second dissipationmethod divides the original inlet into eight inlets ofthe same area and shape． these inlets are installedOl1 the walls of the transf(Jrmer rooln heal·the ground.

Employing the numerical scheme mentione(1 a—I)ove．the nunlerieal simulation for two various casesf0r inlets have been conducted and the results fortemperature distribution on the main tl，ansformer aredemonstrate(1 in Fig．4(a)and(b)．It shows themaxj Ilium temperatures of the main transfn1-mer ac—cording to numerical simulation are 627 K (354 )and 357 K (84℃ )． Fhe ventilation et ct ofthe firstdissipation method does not reach the heat dissipationrequirement of the transformer．The ventilation efectof the second method is 1101·e significant than that ofthe first and stronger than that in the original layout.

However，the actual al’inlet in the project is dificuhto instal，extremely noisy，and very costly．There—fore．the new air inlet must be improved based on theadvantages of the origina1．i．e。as Fig．1.

(a)Inlets located at the bottom (b)Inlets distributed oil the wa[IsFig．3 The various positions for inlets in indoor substationXU Luwen，et al：Tile CFD Numerical Sinmlatiot1 on Ventilation of Indool’Transformer Substation 143(a)CaseforFig 3 (b)Casefol’Fig 3Fig．4 TIle temperature distribution 01 transformer forvarious inlets distributionBased on the foregoing，the position and shapeof the air inlet are changed and the cooling effect isoptimized，with minimum cost．The three other opti—mization scenarios are as folows as Fig．5．For sim—plieity，we do not geometrically show the specifcconfiguration for other three locations of inlets．Fig．5(a)shows the air inlet of the tl’ansfol。nler substationis placed under the cooling fin of the main transform—er，with the size and position of the air outlet un—changed．In this case，the maximum temperature ot’the main transfol’mer is calcnlate(I as 355 K f about82 qC)．Fig．5(b)shows a partial area from theside is added to the underside of the right}lead of themain transformel’．with the Iotal area of the air outletunchanged．In this ease，the lnaxinlulI1 tenlpel’atureof the main transformer is calculated as 355 K (abortt83℃ )．Fig．5(c)illustrates the at，ea of the air inletbelow the right llea(I of the mail transformer is COI1.

tinuously increase(1．with tile total area of the air out.

1et unchanged． the maxinlunl tempel’ature of themain transfornler is calculated as 360 K (about 87cc)．Heat dissipation in this scenal·io is not as satis.

factory as in the above two scenarios.

It Cal be conclude(I that the heat dissipation ofthe cooling fin should primarily be considered i n theventilation desigl1 of transforileI·substations 1)ecauseit significantly affects the tota1 Iteat dissipation of thetransfornlel’．Considering costs．Iavout difhcuhv．andall other factors，the location fo r’Fig．5(a)is tile op—tinml layout for substation air inlets． These inletsshoul(1})e enhanced according to these findings.

(a、Case for the air inlet ofthe trailsformersubstation tinder tbe cooling fia(b)Casefortile sideaddedtotheunderside ofthe right head(c)Case for tile air inlet below tile right headcomposed of tour piecesFig．5 TIle temperature distribution on main transfi)rmel’for thFee dift)l’elIt posilions of inlets3．2．The optimization for distribution of outletsFor tile sake of seal·thing fi)r a better solution toventilation and heat transfer generated by the maintransformer’，other attempt is transferred to change thedistribution of outlets．We considered two cases withthe area for outlets of two cases nnchanged． Olie isthat tile two air outlets are place(／on the top rightside of the cooling fin，while the other is that on tiletop right side of the transformer room．Fig．6(a)and(b)illustrates the temperature distribution on thenlain transfor-mer for the case of outlets on the rightside of the cooling fin an(1 for the case of outlets onthe top right side of the transfomter rooll，respective—lv.

(a)Case for outlets O11 the topright side ofcooling fan【b)Case ofoutletsonthetop righside oftransformer roomFig．6 The tenlpera|ure distribution oil the Ir,ail transformerIt shows the nlaximum tentperatut’e on the inaintratlsfomler is redt,eed fl-om 36 1 K (on the right topside of cooling fil1)to 355 K (on tile top right side ofrooin)，i．e．，from 88℃ to 82℃ ．a diference of144 Hydr0mechatr0nics Engineering6 oC．The optimized flow field more significantly en—hances the heat dissipation of the transfo13Tier than theflow field before optimization．The 1ayout of the newair inlet and outlet substantially facilitates airflOW andthe heat dissipation of the transformer and provides areference for optimum transformer design.

4．ConclusionsThe CFD simulations on ventilation and heat dis—sipation of indoor substation have been performed toimprove the eficiency of heat exchange and find theoptimum location for inlets and outlets． It can beconcluded that the best inlets should be located at theright bottom side of the cooling fin，not of main trans—fol~ner，and that the better location for outlets be onthe right top side of the cooling fin，not the center ofthe transformer rooIl1.

References：[1] s0NG Fuxiang，RUAN l,idong，SUN Quanhong．Afection and assessment of the environment around the trans—former station[J]．Safety and EMc，2005(2)：90—92.

[2] xu Luwen，LI Yongming，LIU Changsheng．Analysis onpower frequency electric and magnetic fields within5(x】KV substations in chongqing Area[J]．Power SystemTechnology，2008，32(2)：66—70.

[3] YANG Min，ZHONG Haoping，YAN Qing．et a1．Simu—lation and analysis of sound field in 220 KV urban indoorsubstations[J]．Journal of Southeast University，2010，40(6)：1226—1231.

1 4 l cHEN Qiu，LI Zhenhai．Research on noise eontrolscheme of electric transformer substation『J]．ElectricPower Environmcnta1 Protection，2006，22(3)：49—51.

[5] wANG Rongjie，CHEN Hongwei．Establishing and anal—ysis of the noise mode1 in the ventilation room『J 1．Jour—nal of Huaqiao University：Natural Science，2008，29(1)：】4—16.

[6][7][8]户内变电站通风性能的CFD数值模拟分析徐禄文h，王国超 ，丁 军 ，陈 松I．重庆市电力公司 电力科学研究院，重庆 401123；2．重庆理工大学 机械工程学院，重庆 400054JIN Lijnn．Analysis on convection exchange in transform—er Room[J]．Electric Power Construction，2000，8：19— 22.

ANSYS Inc，Fluent User’S Guide，Cavendish Court，Lebanon，Nn 03766，2010[S].

ANSYS Inc，CFD—Post User’S Guide，Cavendish Court，Lebanon，NH 03766，2010[S].

摘要：探讨了造成重庆市区居民断电的可能原 因是由于户 内变电站主变压器发热量过大的问题为了解决户内变电站的通风换热问题，建立了用于CFD分析的数值计算模型，并利用专业的流体分析软件 Fluent进行了三维CFD仿真模拟分析。在保证进风口和 出风13'面积不变的情况下，通过改变进风口和出风口的大小和位置分布，获得了最佳的进风 1：2和 出风口位置，有效地降低了主变压器的温度，提高了户内变电站的热交换率，为以后户内变电站的设计提供了参考。

关键词：变电站；通风换热；进 出风 13'；CFD数值模拟中图分类号：TH12