Impacts of Fe-Based Amorphous HB1 Core Transformers on Energy Efficiency and Environment Protection

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1 Impcts of Fe-Bsed Amorphous HB1 Core Trnsformers on Energy Efficiency nd Environment Protection Chng-Hung Hsu, b, Yeong-Hw Chng Electricl Engineering, Chng Gung University, To-Yun, Tiwn, R.O.C. b Electric Mchine, Fortune Electric Ltd, Co., To-Yun, Tiwn, R.O.C. E-mil: chshiu@fortune.com.tw Abstrct: - In this pper, the properties of the physicl nd chemicl mterils, such s low loss morphous HB1 core, high temperture resistnce winding nd insultion vegetble oil hve been developed for use in liquid-immersed power trnsformer. The mesured results of mgnetic properties with different ferromgnetic mterils core were obtined. Considering winding property for opertion bove 95 condition, the coil mnufcturing ws constructed with double lyer of Nomex insultion pper nd conductor. The effective het trnsfer nd stisfied electricl insultion property hs illustrted by lightning impulse test. For environment protection concept of field, prcticl using insultion vegetble oil cn be successfully incorported into power trnsformer by dissolved gs nlysis (DGA). To investigte the performnce of mgnetic properties, 3-phse liquid-immersed morphous-cored power trnsformer with cpcity 1MVA is fbricted. Experimentl results illustrte tht the proposed environment protection trnsformer cn provide better performnce of lower core loss, exciting power, noise nd low CO 2 gs dischrge thn the conventionl counterprt. Key-Words: - Amorphous Metl, SA1, HB1, FR3 Insultion Vegetble Oil, Trnsformer 1 Introduction Environment protection is n importnt issue in the light of reduction of CO 2 gs dischrge nd energy loss. One spect of the development is tht the trnsformer cn be fbricted by different component, such s low loss core, low CO 2 gs dischrge of insultion oil nd high temperture resistnce winding. Therefore, trnsformers cn be designed for specific pplictions. For ppliction viewpoint of core, there re mny reports tht trnsformer core with morphous lloy HB1 hs been presents. An Fe-bsed morphous lloy focus on energy sving problem becuse of their dvntge of extremely low loss property [1-3]. The Fe-bsed morphous lloy (HB1) hs been widely used s conventionl core type for distribution trnsformers. Therefore, the size nd the noise of n morphous distribution trnsformer re less thn those of corresponding conventionl SA1 lloy core unit. Becuse the sturtion induction nd noise level for HB1 lloy re lower thn tht for SA1 lloy. An morphous lloy HB1 with high sturtion induction is bout 1.64 (T), which is higher thn SA1 lloy. Consequently, the HB1 lloy hs bility decrese the noise of morphous distribution trnsformers. For the new concept of winding ppliction, becuse liquid immersed power trnsformers hve used n insultion mteril combining with conductor nd insultion oil more thn few decde. These mterils hve illustrted to be suitble nd economicl when pplied within the rnge of their technicl limittions. The generl technicl limittions for insultion fibers mterils hve been developed by chemicl nd physicl modifictions during the mnufcturing process. One of the principl limittions is the mximum temperture which the insultion mteril cn tolerte while still providing suitble operting condition. For industril liquid-immersed power trnsformer, the bsis high rted temperture limittion is bove 65 C to 95 C verged over 24 hour period. However, if it is necessry to operte bove these tempertures for specil long periods of time, the user must hve concern for the effect on the life of the insultion mteril. A superconducting motor combining of high temperture superconducting (HTS) rotor nd core sttor is present [4], where Nomex mteril pper ws used for electricl insultion. For insultion oil ppliction viewpoint, the electricl distribution trnsformers insultion oil re considered bsed on their totl duty life cycle cost from economicl, sfety nd environmentl protection. Due to nture qulity higher efficiency of distribution trnsformers with insultion vegetble oil is developed in industry [5-7]. It ws focused on fluids to improved environmentl sfety nd helth properties while mintining the fire-resistnt properties of stble flmmble oil. In this pper, the rest of this pper is orgnized s follows. In Section 2, the implementtions of ISSN: ISBN:

2 environment protection trnsformer re discussed. The experiment test nd results re ddressed in Section 3.The conclusion is given in Section 4. 2 Implementtion of Environment Protection Trnsformer 2.1 Comprison mterils mgnetiztion with ferromgnetic mterils In Fig. 1 is compres B-H curve for commercilly vilble morphous SA1 nd HB1 lloy. Both of HB1 nd SA1 lloy sturtion induction were chieve to 1.65 (T) nd 1.54 (T), respectively. And silicon steel mteril sturtion induction is bout 2.0 (T). In Fig. 1, the mesured results ws illustrted the following dvntgeous fetures of the morphous lloy: (1) coercivity Hc is lower thn the conventionl SA1 lloy, nd (2) the mgnetiztion towrd sturtion HB1 mteril is shrper thn the conventionl SA1 mteril, s the coercivity compred with sturtion induction rtio were indicted. (3) the permebility HB1 mteril is higher thn the conventionl SA1 mteril. Due to B-H curve (higher B r /B s rtio) indictes tht the HB1 mteril cn be excited closer to its sturtion thn the conventionl SA1 lloy. This leds to reduced udible noise of trnsformer bsed on the HB1 lloy compred with the one bsed on commercilly vilble SA1 lloy. Nomex Type 410 is insultion pper which offers high inherent dielectric strength, mechnicl toughness, flexibility nd resilience. And it is widely used in mjority of electricl equipment pplictions. The high temperture resistnce test with Nomex insultion mteril pper hs been developed for immersed insultion vegetble oil. This subject ws used to derive test dt on cellulose mteril oil. This mteril, the insultion pper (Nomex) is generlly known s n rmid. The moleculr structure of the mteril is prticulrly stble. These mterils hve proven to be relible nd economicl when pplied within the rnge of their technicl limittions. One of the principl limittions is the mximum temperture which the insultion system cn tolerte while still providing n cceptble operting life. For modem thermlly rising fiber, the bsis-of-rting temperture limittion for the hottest spot is 200 C verged over 24 hour period. If it is necessry to operte bove these high tempertures for prolonged periods of time, the user must hve concern for the effect on the life of the insultion system. The insultion pper mnufcturing nd testing is shown in Fig. 2. () (b) Fig.1 The ferromgnetic mteril B-H curves of the specimens 2.1 High temperture resistnce windings In industry ppliction, liquid-immersed power trnsformers hve utilized n insultion system consisting of nturl celllose-bsed mterils due to conductor ws rolling up with insultion pper. The insultion pper of the high temperture resistnce ppliction with trnsformer is importnt issues. The (c) (d) Fig.2. Mnufcturing winding nd testing () Conventionl insultion pper (b) Nomex insultion pper (c) Winging mnufcturing (d) Winding testing. 2.2 Insultion vegetble oil In Tble 1, it is lists severl physicl, chemicl, nd electricl properties of vegetble oil specificlly developed for trnsformer used. Comprison dt re used focused on high-temperture minerl oil nd silicone fluid used in trnsformers. For products of the decomposition property, when the vegetble oil ISSN: ISBN:

3 used in trnsformers, the experimenttion fluids dt therml nd electricl stress; therefore, it is importnt to determine the effect on these stresses. The mesured property of the gs genertion condition is esily understood. Consequently, it is meningful tht surveys the gs genertion fter geing in presence of copper for specific periods were obtined. It cn be seen tht the food-grde mterils possesses superior key chrcteristics in just bout ll ctegories. The results shows the nturl ester fluids hve the highest fire resistnce property. Its dielectric brekdown property is superior nother oil. The viscosity is closer to tht of conventionl minerl oil thn silicone one. On the negtive side, the nturl ester hs existing reltively high pour point, but it hs very good service record in trnsformers instlled in different with cold nd hot climtes. 2.3 Trnsformer ssembling This pper presents development nd testing of environment protection power trnsformer with cpcity of 1MVA operted in liquid-immersed insultion vegetble oil for rted primry nd secondry voltges of 11.4/22.8 kv nd 220V. This equipment of the power system ws composed with core, windings shell. Consequently, for improving high resistnce temperture of winding, it ws used Nomex insultion pper. For chieving concept of environment protection, the trnsformer ws used the insultion vegetble oil. () (c) (b) (d) Fig.3. Mnufcturing nd ssembling of 1MVA power trnsformer () Amorphous HB1 core (b) Nomex mteril winding (c) Trnsformer ssembling (d) FR3-Vgetble oil trnsformer. Tble 1 Comprison Insultion Oil of Trnsformer. Ctegories Vegetble Oil High Temperture Minerl Oil Silicon e 561 Fluid Physicl Appernce Colorle Light yellow Light yellow ss Specific Grvity t 25 C Kinemtic viscosity, cst 0 C C C C Pour point, C 15 to mx 50 mx. Interfcil Tension (IFT), dynes/cm Flsh point, C min. 300 min. Fire point, C Moisture content, ppm dry oil b (Wter solubility t 25 C) Therml constnts Het cpcity, cl/g. C Therml conductivity, 0.17 W/m.K Coefficient of expnsion, / C 4 Chemicl Chemicl type Ester Hydrocrbon Orgno -silicon Acidity, mg KOH/g Oxidtion stbility - ASTM D 2440 Pss Pss Pss Electricl Dielectric constnt t 25 C Volume resistivity t 25 C, Ohm.cm Brekdown voltge, kv ASTM D 1816, 60 2mmgp electrodes 74 Impulse brekdown voltge, kv (needle negtive) Dissiption fctor,% C mx C mx. Gssing tendency ASTM D to +20 N/A Biodegrdbilityc CEC-L-33 (21 dys) Very low Notes: : For BIOTEMP fluid, b: Vries with trnsformer rting c: See below. For reducing the core loss, the high sturtion induction of morphous HB1 core ws obtined. This mteril sturtion induction cn be chieved bout ISSN: ISBN:

4 1.64 (T). In this pper; considertion with noise level of the core ws setting design induction, 1.3(T). The core, winding nd trnsformer ssembling re show in Fig Experiment Test nd Results 3.1 Core loss nd mgnetic chrcteristics The mesured core loss relted to mgnetic induction is shown in Fig. 4, it cn be seen tht the core loss of HB1 core trnsformer is less thn the conventionl SA1 core trnsformer with ech mgnetic flux density, Bm 1.1~1.5(T). In ddition, for HB1 lloy, the mesured core loss is lower thn SA1 mteril respect to ech mgnetic induction, t lest reducing core loss up to 0.03W/kg. Beside, the mesured exciting power result of the morphous lloy respect to mgnetic flux density chrcteristic show s Fig. 5. Form the mesured results, the exciting power of HB1 mteril hve lower performnce thn tht SA1 lloy will be obtined. Especilly, when the specimen of the mgnetic sturtion induction hs been chieves induction Bm 1.5(T), for HB1 nd SA1 mteril, there is higher curve of the exciting power performnce thn mgnetic induction Bm 1.3(T). In nother word, when the induction Bm higher thn 1.5(T), the exciting power of the morphous lloy will soon surpss 1.5 times tht induction Bm1.3(T). According to Fig. 1, the mesured results both of the hysteresis loops nd sturtion induction for conventionl SA1 mteril is with Bs 1.56(T), nd HB1 mteril is with Bs 1.64(T), respectively. Becuse of morphous lloy chieves sturtion induction, HB1 nd SA1 lloy with B s 1.41(T) nd 1.38(T), the exciting power of the morphous mteril will rising up very fst. However, it is well to know the sturtion mgnetic flux density of the trditionl silicon steel mteril will be chieves to induction Bm 2.0(T). In nother word, becuse of the mgnetic flux density not chieves sturtion induction for silicon steel mteril, in which the exciting power is keeping stbility chrcteristic between Bm 1.1~1.6(T), nd lower thn 1.5(VA/kg). Due to the silicon steel mteril hs higher sturtion induction compred with morphous lloy. Therefore, it is notice tht the exciting power of morphous lloy mteril trnsformer is less thn tht of silicon steel trnsformer, HB1 with Bm 1.41(T) nd SA1 with Bm 1.38 (T), respectively. To chieve better efficiency by using the fbricted morphous lloy HB1 nd SA1 cores trnsformer, it is suggested to follow the observtion tht the mgnetic flux Fig.4. The mesured core losses of the HB1, SA1 nd silicon steel cores trnsformer. Fig.5. The mesured exciting power responses of the HB1, SA1 nd silicon steel cores trnsformer. Fig.6. The mesured noise level responses of the HB1, SA1 nd silicon steel cores trnsformer. density is less thn 1.41(T) nd 1.38 (T). Nerveless, the trnsformer efficiency will turn to be cost down becuse of the exciting power hs been existing rise very fst phenomenon. The mesured noise level ISSN: ISBN:

5 results of the morphous lloy nd silicon steel cores shown in Fig. 6. The silicon steel mteril shows the lower noise levels t ll mgnetic induction. In ddition, the mesured noise result of the HB1 core respect to ech mgnetic induction is ll of lower thn conventionl SA1 core, t lest more 5dB vlues. 3.2 Lighting impulse test Before performing the lightning impulse test, it is required with the secondry side shorted nd core grounded. According to the IEEE specifictions, the input test wves include full-wve voltge -150kV, reduced full-wve (50~70%) voltge. Experimentl results of morphous HB1 core re shown in Fig. 7, where () is reduced full-wve test one time, nd (b) is full-wve test one time, respectively. Obviously, there is no brekdown occurrence cused by impulse wves test, nd the IEEE stndrd is stisfied s well. 3.3 Vegetble oil testing The insultion vegetble oil test re list in Tble. 2. Considering winding property, ech of turn field coil ssemblies ws constructed with double lyer of Nomex insultion pper opertion hgiher thn 95. It is clerly tht trnsformer insultion oil ws operted bove generl working temperture, excess 30. The effective het trnsfer nd stisfied electricl insultion property before nd fter temperture rising test were illustrted by DGA. In this pper, The testing results ws shown the trnsformer insultiion vegetble oil stisfied under high temperture working. Tble 2 Trnsformer insultion oil testing results Ctegory Trnsformer temperture rising After Before O N CO CO H CH C2H C2H C2H 2 ND ND TDVG (PPM) V Results OK OK ASTM D3612 method A detection () 4 Conclusion To stisfy the chllenges proposed by environmentl protection concerns, such s low loss morphous HB1 core, high temperture resistnce winding nd insultion vegetble oil hve been developed for use in liquid-immersed power trnsformer with cpcity 1MVA. To investigte the performnce of mgnetic properties, the experimentl results illustrte tht the proposed environment protection trnsformer cn provide better performnce of lower core loss, exciting power, noise nd CO 2 gs dischrge thn the conventionl ferromgnetic mteril counterprt. (b) Fig.7. Lightning impulse tests for morphous lloy HB1 core () reduced full-wve test one time; (b) full-wve test one time, respectively. Reference [1] R. Hsegw, D. Azum, Impcts of morphous metl-bsed trnsformers on energy efficiency nd environment, Journl of Mgnetism nd Mgnnetic Mtereils, Vol. 320, 2008, pp [2] R. Hsegw, Advnces in morphous nd nnocrystlline mgnetic mterils, Journl of ISSN: ISBN:

6 Mgnetism nd Mgnnetic Mtereil,, Vol. 304, 2006, pp [3] Y. Ogw, M. Noe, Y. Yoshizw, R. Hsegw, Mgnetic properties of high Bs Fe-bsed morphous mteril, Journl of Mgnetism nd Mgnnetic Mtereils, Vol.304, 2006, pp. e675-e677. [4] M. H. Sohn, S. K. Bik, Y. S. Jo, E. Y. Lee, W. S. Kwon, Y. K. Kwon, T. S. Moon, Y. C. Kim, C. H. Cho nd I. Mut, Performnce of high temperture superconducting field coils for 100 HP motor, IEEE Trnstion on Applied Superconductivily, Vol.14, No.2, 2004, pp [5] V. Oommen, Vegetble oils for liquid-filled trnsformers, IEEE Electricl Insultion Mgzine, Vol.18, No , pp [6] C. P. McShne, Vegetble-oil-bsed dielectric coolnts, IEEE Industry Applictions Mgzine, Vol.8, No.3, 2002, pp [7] P. McShne, Reltive properties of the new combustion-resist vegetble-oil-bsed dielectric coolnts for distribution nd power trnsformers, IEEE Trnstion on Industry Applictions, Vol.37, No.4, 2001, pp ISSN: ISBN: