Extraction of Electrical Power Transformer Parameters

Transcription

1 nternational Journal Of Engineering nd Couter Science SSN: olue ue 1 Jan 013 Page No btract Extraction of Electrical Power Tranforer Paraeter Eia Bahier M. Tayeb 1,. Taifour li and M. lbager lkhir H. li 3 1, Sudan Univerity of Science &Technology - College of Engineering. 3 Technical Education Cororation 1 Eail:eiabahier@yahoo.co, yha_114@yahoo.co 3 Eail:bager333@yahoo.co n thi aer the SUL BSC language i ued to deign an interactive rogra that hel in undertanding of tranforer theory, a well a deontrating it internal contruction, getting it oerating characteritic and the uivalent circuit eleent. The rogra hel in iniizing the coutational tie eecially in cae of colicated hand calculation and facilitate an eay way for exlaining extracting the tranforer araeter. Keyword: Power Tranforer, Tranforer Paraeter, virtual Lab. 1. ntroduction The huge lea in the cience and technology ruled that innovation odern ethod and for of teaching roce, acceibility of the inforation in hortet oible tie and intereting. Thee odern ethod are to exloit the oibilitie of couter rograing to build virtualized environent that hel to aiilating the baic eleent of the curriculu with eae away fro the criling colexity. lo to introduce the irit of the coure that are characterized by a kind of iobility, need ability to a large iagine and colex calculation to analyze large aount of variable and to draw concluion on the. For rograing uch function the high level language uch a BSC, SUL BSC, C, C+, C++... etc were ued.. deal Tranforer and oltage Ratio ower tranforer norally conit of a air of winding the et of winding connected to the ource ide of the tranforer are called riary winding, and thoe connected to the load are naed econdary winding. They are linked by a agnetic circuit or core. When an alternating voltage i alied to the riary winding, a current will flow which et u an alternating agneto-otive force (..f). Hence an alternating flux i develoed in the core, which in turn induce electroagnetic force (e..f) in both winding. n the riary winding thi i the back e..f. and, if the tranforer were erfect, it would ooe the riary alied voltage to the extent that no current would flow. n reality, the current which flow i the tranforer (agnetizing current). n the econdary winding the induced e..f. i the econdary oen-circuit voltage. f a load i connected to the econdary winding which erit the flow of econdary current, then thi current create a deagnetizing..f. thu detroying the balance between riary alied voltage and back e..f. To retore the balance an increaed riary current ut be drawn fro the uly to rovide an exactly uivalent..f. o that uilibriu i once again etablihed. Since there i no difference between the voltage induced in the riary or the econdary winding, then the total voltage induced in each of the winding by the coon flux ut be roortional to the nuber of turn. Thu the well known relationhi i etablihed that: [1] E E = N N. (1)

2 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) The ratio of the aere-turn balance; N = N () The relationhi between the induced voltage (e) and the flux ( Φ ) i given by reference to Faraday law which tate that it agnitude i roortional to the rate of change of flux linkage, and Lenz law which i norally exreed in the for; [, 3] dφ e = N( ). (3) dt But for ractical tranforer, it can be hown that the voltage induced er turn i, E = KNΦ f = 4. 44NΦ f.. (4) Where K = = 4.44; for inuoidal voltage. For deign calculation the deigner i ore intereted in volt er turn and flux denity in the core rather than total flux, o the exreion i; E N = 4.44B f..... (5) For ractical deign B et by the core aterial and the oerating condition for the tranforer, a elected fro a range of cro-ection related to the tandard range of core ize, whilt fruency f i dictated by the cutoer yte. t i then an eay atter to deterine the nuber of turn in each winding fro the ecified voltage of the winding []. Tranforer loe ay be divided into two ain tye. The loe which vary with load current and that vary with the core flux. Since the load current i not contant during noral oeration the winding R loe will vary. Under noral condition, the core flux will reain aroxiately contant, o the loe which vary with the core flux will be aroxiately contant indeendent of the load. Thee loe include tray loe due to e..f induced by tray field in adjacent conductor. Thee will be a lo due to the reitance of each winding, o the total winding lo i: ' Pc = R + R = ( R + R ).... (7) The core loe are divided into two art, the hyteri lo (P h ) and eddy current loe (P e ) [, 3]. The teel ecien i ubjected to an alternating flux; the hyteri lo er cycle i roortional to the area of the loo and therefore, the hyteri lo i: h h n P = K fb w/ 3. (8) n = coefficient eirically found in the range 1.6 to. The eddy current lo i due to flow of eddy current in core then high reitance laination effectively reduce the eddy current lo to all oeration. The eddy current lo i roortional to the uence of the fruency. The total core lo Pi i: P + n i = Ph + e = K h fb K e f B. (9) Provided that B and f are contant the core loe hould be contant. For B to be contant; the agnetizing current and the alied voltage ut be contant [3]. 3. Deterination of Tranforer Paraeter For the uroe here we concentrate on the tet ethod and the exeriental et-u of the traditionally acceted electrical uivalent circuit for a ower tranforer in teady-tate hown in Page188

3 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) Fig.1. Thi articular uivalent circuit araeter are referred to riary ide. The haor diagra of ilified uivalent circuit of tranforer i hown in fig., [,3,4,5]. Fig.1: Power Tranforer Steady-tate Equivalent Circuit Fig. : Phaor Diagra of Silified Equivalent Circuit of Tranforer t i iortant to note that for a tyical ower tranforer the ratio of the arallel cobination of the coon leg iedance to the total iedance of either winding will exceed 00.. The oen circuit and hort circuit tet The oen-circuit tet run at rated voltage and yield the following quantitie: The R loe on oen circuit ay be neglected, the no load inut i the noral core lo then the value of R c and X in the arallel exciting circuit a in fig.1 can be calculated. R C = = P Oh (10) The reactance X can be found by deterining the reactive art of the tet quantitie. Thu, the ower factor i: Q f = (1 1) P = S P (1 ) = in(co 1 f ).. (13) Where; i the agnetization current of the tranforer in aere. Page189

4 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) X Where X ; i the agnetization reactance. = = Oh..... (14) Q n the hort circuit tet; one winding i hort circuited and the voltage alied to other i gradually raied fro zero until full load current flow. Thi run at rated current and rovide the value of the alied voltage, nut hort-circuit current and the inut ower; the uivalent iedance een a: ' ' Z = R + R + j( X + X ) = R + X = SC SC (15) Since the arallel cobination of the coon leg iedance i very large, the ajority of the inut hort-circuit current ae through only the winding iedance. Therefore, the core loe are negligible and the following i true []. P R = (16) SC SC X = Z R.... (17) R R 1, R = and X1, X = (18) n the abence of ore definitive inforation, the coonent of R and X are lit ually between the two ide of the tranforer. Thi colete the develoent neceary to derive the teady-tate uivalent circuit fro the tet data.. Tranforer Efficiency and Regulation The erforance of the device can be checked by coaring the outut with reect to the inut. OututPower Efficiency, η = *100% nutpower X P out coθ = *100% = *100% Pout + Ploe coθ + P c + P cu... (19) η ( fulload ) Where: coθ = coθ + P + P c cu *100% n coθ η ( loadn) = *100%.. (0) n coθ + P + n P c cu f ½ load, hence η = ½, ¼ load, η = ¼, 90% of full load, η =0.9. n thi cae, P cu = P c & Pc = P oc. Equivalent Circuit Regulation ethod i ued. n which, the araeter are referred to riary or econdary.. R = f referred to riary ide 1 [ R coθ ± X inθ ] 01. f f 100%.. (1) Page190

5 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ). R = 4. The Prooed Progra [ R coθ ± X inθ ] 0. f 0. f 100%.. () Microoft iual Baic 6.0 ha been ued to deign a all ize rogra for deigning laboratory iulator unit of tranforer. Thi rogra i develoed three Multile Docuent nterface (MD) for. Two of the are oen and hort circuit tet, and the uivalent circuit araeter of tranforer [6, 7, 8, 9, 10].. Running Siulator Progra Siulator For, run to derive the uivalent circuit tye of tranforer. Fig 4 how the uivalent circuit of ingle hae referred to riary, uivalent circuit referred to econdary. Siulator B For, which contain oen circuit and hort circuit tet and tranforer erforance, including the loe, efficiency and voltage regulation. Thi accolihed through a hort circuit and oen circuit tet. The inut i the baic inforation for tranforer a voltage rating (econdary and riary), aarent ower and ower factor in the baic inforation recorded in rogra. Through the oen and hort circuit button in tet-circuit frae the araeter can be calculated. For ecified tranforer erforance the loe, efficiency and voltage regulation data can be given a a reort or rinted forat. Fig.4.a llutrate Equivalent circuit Referred to Priary. Fig.4.b llutrate Equivalent Circuit Referred to Secondary. Page191

6 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) Start Satrt (Tet Tye) / Data Error Meage Not Nuber Data /P Tet Colete? Error Data Not Colete No Ye No Data nteger? Ye Procee End Fig.5 Flow Chart llutrate Calculation of Paraeter in Siulator B.. Progra erification Fig.6. Window for Calculating the Tranforer Paraeter Thi ection coare the calculated uivalent circuit araeter with obtained by iulation rogra. The tranforer ued for thi exerient are rated ( k, 1000k). Thi tranforer anufactured by Sudanee Egytian Electrical ndutrie SUDTRF. Page19

7 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) Ue the 433 and the 631 voltage range etting for the oen circuit and hort circuit tet reectively. For oen circuit tet; the econdary ut be diconnected for the oen circuit-tet, while alying rated voltage, 433, fro the Single-Phae C ource to the riary ide of the tranforer. Record of ower, current and voltage are hown in table 4.1. Table (1) value of oen circuit tet. Power Current oltage 1.50 KW For hort circuit tet; the hort-circuit tet i run with the econdary juer connected. by SLOWLY increaing the ingle-hae C ource fro the zero etting until a 53 reading i achieved. llow a little tie for the yte to tabilize, and then record of ower, current, and voltage are in table. Table () value of hort circuit tet Power Current oltage 9.910KW Table (3) Equivalent Circuit alue (in oh) a calculated anually: alue referred to Priary Secondary Serie Reitance (R 1, ) Serie Reactance (X 1, ) Shunt Magnetizing (X ) Shunt Core Lo(R c ) The rogra ha ability to analyze data of oen and hort circuit tet of tranforer; which i a ain target of the rogra. well a, oibility of giving excitation current, agnetizing current and core-loe.. Siulation rogra Reort Page193

8 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) 5. Dicuion and Concluion For the araeter of tranforer (R C, X, X 1, X, R 1, R ) the iulation and anual reort reult how all deviation fro each other. Thi due to the fact that the iulation i alway conidered being the ideal ituation, while the ractical reult include oe uneen inor effect. n thi aer, the concet of the generating agnetic flux theory, tranition and (oen/hort) circuit tet all are eaily deontrated through interactive SUL BSC rograing. The rogra ha the ability to link between atheatical uation to infer the characteritic of tranforer and deriving uivalent circuit along with the oibility of giving the reort on the electrical eleent of the tranforer. The rogra develoed when coared with anually calculated araeter of tranforer, it varie in error fro 0.05 for hunt core lo reitance of the econdary ide to axiu error of 96 for the hunt agnetizing reactance of the riary ide. Reference: [1] Martin J. Heathcote, The J & P Tranforer Book ractical Technology of the Power Tranforer- Welfth edition Reed Educational and Profeional Publihing Ltd [] Del Toro, incent. Electroechanical Device for Energy Converion and Control Syte, Prentice- Hall, nc [3] Jae H. Harlow, Electric ower tranforer engineering CRC Pre LLC, 004. [4] htt://fullnet.co/~tog/gootee.ht; Modeling a Power Tranforer Directly fro Meaureent. [5] ivek Pahwa nd Dr. K. S. Sandhu; Modelling and Siulation of Single-hae Tranforer ncluding the Flux Saturation Effect; NSC 008, Deceber 17-19, 008; (81-85). [6] Byron.Gottfried, Ph.D. Schau Outline of Theory and Proble of Prograing with SUL BSC McGraw-Hill Coanie; 001. [7] Michael Halvoeon, Microoft SUL BSC008, 008. [8] Steven Holzner, iual Baic 6 Black Book, Corioli Grou; [9] Lou Tylee, Learn iual Baic 6.0, KDware [10]Luc ouligny; Power Tranforer Siulation Laboratory for Proactive Maintenance. OSoft ; Uedr Conference 01. Page194

9 Eia Bahier M. Tayeb, nternational Journal Of Engineering nd Couter Science :1 Jan 013( ) Lit of Sybol ued: f B P oc SC SC P SC R C X R P, X P R S, X S P, S E P, E S c, 1, 1 o Q P S N, N 1 The axiu value of total flux linking the turn The uly fruency Maxiu value of flux denity in the core Nett cro-ectional area of the core Exciting current a read by aeter of oen circuit tet lied voltage a read by volteter of oen circuit tet Power a eaured with watteter of oen circuit tet lied voltage a read by volteter of hort circuit tet nut hort-circuit current a read by aeter of hort circuit tet nut ower a read by watteter of hort circuit tet Core reitance. Magneti reactance Priary winding reitance and leakage reactance. nd winding reitance & leakage reactance Priary uly & nd (load) voltage Priary & Secondary winding voltage... Core current & Magnetizing current.. Priary & nd winding current.. Priary winding current.. No load current.... Reactive ower of oen tet in ctive ower in... arent ower in.. Turn Nuber of riary& econd winding Weber (Hz) Tela W W Oh Oh Oh Oh KR kw k turn Page195