Forecasting of Load Model Based On Typical Daily Load Profile and BP Neural Network

Transcription

1 2012 Intenational Confeence on Syte Engineeing and Modeling (ICSEM 2012) IPCSIT ol. 34 (2012) (2012) IACSIT Pe, Singapoe Foecating of Load Model Baed On Typical Daily Load Pofile and BP Neual Netwok Rongen Zhang a, Guigang Qi b, Canbing Li c, Long Li d, Yiping Bao e and Yuheng Zhu f College of electical and infoation engineeing, Hunan Unieity, Changha, Hunan, China, z0125@126.co a, loeqi2009@163.co b, licanbing@gail.co c lilong_1688@163.co d, baoyiping0304@163.co e, oyzhu2011@163.co f Abtact. Load odeling i ecognized a a difficult iue in field of powe yte digital iulation. The eliability of the iulation eult depend on the eacity of the load odel which will futhe affect powe yte planning and aid deciion aking. In ode to inceae the accuacy of the load odel, the copoite load of powe conuing-indutie wee claified by thei induty attibute and the coponent of the wee alo analyzed in thi pape. Then, the atheatical odel of load copoition i etablihed on the baic of typical daily load pofile and the identification algoith deeloped by C language i ued to identify the paaete of copoite load by chooing the data collected duing the coeponding chaacteitic tie peiod of the typical day. Baed on the odel ecto achine theoy and the paaete identified, the paaete of copoite load odel of powe conuing-indutie can be calculated by uing the way of leat quae appoxiation. And the BP neual netwok wa ued to foecat the paaete of copoite load of powe conuing-indutie. Finally, an exaple how the alidity of the popoed chee. Keywod: load odel foecating; BP neual netwok; typical daily load pofile; load of powe conuing-indutie; odel ecto achine theoy 1. Intoduction Load odeling, cauing widepead concen in engineeing and acadeic doain of powe yte, i of challenge and eeach alue in the field of powe yte digital iulation and odeling [1-3]. Lage-cale blackout, uch a the blackout of WSCC in 1996 [4] etc, occued in the pat yea need load odel of high accuacy to iulate the pactical unning ituation of powe yte at that ey tie which can poide expeience fo futhe anageent and tudy. The way of load odeling can be claified into two categoie: the tatitical ynthei ethod and the oeall eauing-identification ethod. The load odel baed on the tatitical ynthei ethod i eident in phyical ignificance and eay to undetand. At the ae tie, though the analyi of the coponent of the load, the baic eaon that caue the chaacteitic diffeence of the copoite load can be tudied. Refeence[5] took adantage of fuzzy clute ethod to categoize geneic load and elect the typical powe conuing-indutie, then the coeponding tatitical ynthei load odel i etablihed. Howee, thee ae oe liteatue which ue the oeall eauing-identification ethod fo load odeling. Voltea eie odel and atificial intelligence algoith wee adopted to tudy the quick on-line identification of pecentage of dynaic load coponent epectiely in Refeence[6,7]. On the othe hand, ethod of load foecating baed on iila day theoy, waelet analyi and neual netwok wee popoed epectiely in Refeence[8-10]. Theefoe, uing the thought of load foecating a the efeence, the way of foecating load ode i popoed by cobining the poweful ability in nonlinea apped of BP neual netwok with the chaacteitic of copoite load of powe conuing-indutie. The copoite load of powe conuing-indutie wee claified by thei induty attibute and the coponent [11] of the wee alo analyzed in thi pape fitly. And then the odel of load copoition i etablihed on the baic of typical daily load pofile. Baed on the odel ecto achine theoy and the paaete identified, the paaete of copoite load odel of powe conuing-indutie can be calculated by uing the way of leat quae appoxiation. Then the paaete of copoite load of powe conuing-indutie can be calculated by uing the leat quae appoxiation. Finally, the ideal pediction alue will be obtained afte the taining of 38

2 the BP neual netwok. An exaple how the alidity of the popoed chee. 2. Analyi Of Chaacteitic And Coponent Of Copoite Load Of Powe Conuing-Indutie The claification of load will hae diffeent eult accoding to diffeent claification citeia. Baed on thei induty attibute, The claification of load can be diided into fou categoie: indutial load, agicultual load, coecial load and load of unicipal goenent and houehold. The atio of indutial load i high and high pecentage of inductie load et the indutial load apat fo the othe thee. The agicultual load ae conit of the load of the at ual aea which ae highly affected by the cliatic facto copaing with the indutial load. Conit of lighting load, ai conditioning load and utility equipent load of coecial depatent and coeing a big aea, the coecial load ae alo affected by the cliatic facto with it electicity conuption of i gowing teady. The load of unicipal goenent and houehold, including the load of eidential aea, utility depatent and goenent depatent, ae cloely elated to the daily life and wok egulation of people with a upwad tend yea afte yea. 3. The Etablihent Of The Matheatical Model Of Load Copoition Baed On Typical Daily Load Pofile 3.1 The Diiion Of The Chaacteitic Tie Peiod A analyzed aboe, the etablihent of the odel of load copoition hould take the eaonal facto into conideation. Howee, the typical daily load pofile of diffeent eaon hae iila ule: two peak load tie peiod, a alley load tie peiod and a flat tie peiod in a day. Theefoe, the diiion tandad of the chaacteitic tie peiod i gien a follow: alley load tie peiod 1:00~8:00, and 4:00~8:00 i the chaacteitic tie peiod of alley load tie peiod, peak load tie peiod in oning 9:00~13:00, with 10:30~12:30 a the chaacteitic tie peiod, flat tie peiod 14:00~17:00, with the whole tie peiod a the chaacteitic tie peiod, and peak load tie peiod in eening 18:00~24:00, with 20:00~22:00 a the chaacteitic tie peiod. 3.2 Etablihent Of The Matheatical Model Of Load Copoition The atio of the load of diffeent powe conuing-indutie will change duing diffeent chaacteitic tie peiod which tun out to be nonlinea, tie-aying and ando on the whole. Theefoe, the atheatical odel of load copoition wa popoed a follow: ki, jp( i, j) = P( j) (1) i= 1, j= 1 The intege paaete i ( i =1,2,3,4 ) epeent the fou tyle of the load entioned aboe; Siilaly, the intege paaete j ( j = 1,2,3,4 ) epeent the fou chaacteitic tie peiod entioned aboe; P( j) epeent the aeage alue of load of powe conuing-indutie duing the chaacteitic tie peiod of j in the coeponding eaon; k i, j P ( i, j ) epeent the total aount of powe load of the i kind of i = 1, j = 1 powe conuing-indutie duing the chaacteitic tie peiod of j ;The intege paaete i j epeent the eaon chaacteitic alue of the i kind of the load of powe conuing-indutie duing the chaacteitic tie peiod of j, and it pecific alue ae in table 1. k i, j ue winte Sping&autun Tabel1 alue of tie-aying aiable i j unde diffeent cicutance 3.3 Model Vecto Machine Theoy Accoding to the atheatical odel of load copoition elated aboe, the popotion of load of powe conuing-indutie at diffeent chaacteitic tie peiod can be calculated. Theefoe, the k, 39

3 atheatical expeion of odel ecto achine wa popoed a follow: a11 a12 a1 h1 p1 a21 a22 a2 h2 = p2 (2) an1 an2 an h pn Fo hot, it can be expeed a follow: AH = P (3) The eleent in atix A epeent the coeponding popotion of load of powe aij conuing-indutie h i. Howee, eey ow ecto h epeent the odel paaete of load of powe i conuing-indutie to be obtained though calculation. The data of atix A can be obtained by uing the atheatical odel of load copoition. Matix P epeent the ecto paaete of the odel ecto achine. And the data of Matix P wa obtained by uing the eal-tie data of powe gid with the optiizing of identification algoith which wa dicued in detail in the next ection The Paaete Identification Of The Copoite Load Model A i known, the odel of the copoite load i conit of the dynaic odel and tatic load odel. And the thee-ode odel of induction oto wa ued a the equialent odel of the dynaic odel. The powe function odel i equialent to the tatic load odel. The identification of odel paaete i an optiization poble with etictie condition. The paaete identified in thi pape i a follow: [ p, q, R, X, X, R, X, H, A, B, K b ] 1. And paaete b epeent the pecentage of dynaic load, =. d coponent. The definition of it i: b P ( P + P ) P and P epeent the actie powe of dynaic load d odel and oeall actie powe of copoite load. The flow-poce diaga of identification algoith 2 wa hown a aboe in Figue 1. Data Acquiition of Chaacteitic Tie Peiod Calculate the Initial Dynaic&Static Repone of Copoite Load and Contant Ipedance Initial Value Fo The Repectie Independent Paaete To Be Identified Calculate the object function the Nube of Iteation i Condition et? Calculate The Initial Value of State Vaiable NO i=i+1 output YES END Fig1. The Opeational Flow Chat of Paaete identification of Copoite Load Model 1 The eaning of the identified paaete ( p, q, R, X, X, R, X, H, A, B, K, b )ae a follow: p and q epeent the index of actie and eactie powe of powe function odel which i the equialent odel of the tatic load odel, and the ange of the both ae fo 0 to 1. The et paaete ae fo the thee-ode odel of induction oto epeenting the dynaic load odel and the alue of the ae baed on the pe-unit alue. R and X epeent the inductance and eitance of the geneato tato. X epeent the excitation inductance. R and X epeent the inductance and eitance of the geneato oto. H epeent inetial tie contant of the equialent geneato. A and B epeent the index of echanical toque baed on the quae of the oto peed and lineaity with the oto peed. K epeent the initial atio of induction oto. b epeent the pecentage of dynaic load coponent in the powe yte copoite load. 2 The identification algoith wa deeloped by C language and eay to ue. Uing the eal tie data collected at the coeponding chaacteitic tie peiod and typed in the pecibed foat, the paaete of copoite load can be identified. 40

4 4. Foecating Of Load Model Of Powe Conuing-Indutied 4.1 Model Of BP Neual Netwok Conited of input laye with 12 node, hidden laye with 31 node and output laye with 22 node, and no feedback between the laye, the BP neual netwok odel in thi pape ue the paaete of copoite load of powe conuing-indutie, pecentage of dynaic load coponent in the powe yte copoite load and weathe facto a the data of the input laye. The expected eult will be obtained though taining. The odel of BP neual netwok i foulated in MATLAB and pat of the code i a follow: net=newff(thehold,[31,12],{'tanig','logig'},'tainl');net.tainpaa.epoch=1000;net.tainpaa.goa 1=0.01; 4.2Cae Study 8500 Seen typical ue daily load pofile of a city in Noth China Gid LOAD/MW TYPICAL DAY 1 TYPICAL DAY 2 TYPICAL DAY 3 TYPICAL DAY 4 TYPICAL DAY 5 TYPICAL DAY 6 TYPICAL DAY 7 Fig2. Seen typical ue daily load pofile A i hown in Figue 2, een typical ue daily load data of wee choen a data fo cae tudy. Accoding to the atheatical odel of load copoition, the paaete of copoite load ay with tie changing. The popotion of load of powe conuing-indutie i hown in table 2 accoding to the atheatical odel of load copoition. Tabel2 popotion of load of powe conuing-indutie Load type Typical day indutial load agicultual load coecial load load of unicipal goenent and houehold On the othe hand, the chaacteitic tie peiod choen fo identification of paaete i alley load tie peiod of ue fo typical day 1 to typical day 7. The identification eult 3 of typical day 1i hown in table 3 by uing the identification algoith, and the analytical pocedue and calculation to othe typical day i the ae. Table3 Paaete identification of Copoite Load Model(typical day 1 at alley load tie peiod) p q TIME/Hou R X X R X H A B K b 3 The identification eult of each typical day at diffeent chaacteitic tie peiod will be diffeent. And een tie point wa choen in the alley load tie peiod to indentify the paaete. Fo typical day 2 to typical day 7, the poce of paaete identification i the ae. 41

5 So the atix H i calculated though atheatical expeion (6) by uing the way of the leat quae appoxiation, the eult i hown a follow: = H So the paaete of the fou kind of load wee calculated, fo typical day 2 to typical day 7, which i the ae by chooing the coeponding chaacteitic tie peiod. Due to patial data of load paaete exceed the thehold etiction of tanfe function connecting hidden laye of BP neual netwok. Noalized data poceing technique ae ued. Finally, the foecating eult and eo of load odel baed on BP neual netwok and typical load pofile i hown in figue3. VALUE OF MODEL PARAMETERS Concluion Fig3.load odel foecating of indutial load at alley load tie peiod Load odeling i ecognized a a difficult iue in field of powe yte digital iulation which need to conide any facto uch a tie-aying, non-linea coplexity and dieity of load. The coeponding chaacteitic tie peiod of typical day 1 to typical day 7wee choen to identify the paaete i to educe the bad effect of tie-aying chaacteitic of load. The poweful ability in nonlinea apped of BP neual netwok wa ued to educe to eo of foecating. The eult how the alidity of the popoed chee which can poide accuate load odel fo the powe yte tability iulation and analyi and efeence fo eaonable aangeent of the cheduling and ealuation fo the coing day. 6. Refeence load odel foecating of indutial load at alley load tie peiod MEASURED VALUE PREDICTIVE VALUE ERROR P q R X X R X H A B K b MODEL PARAMETERS [1] Xinan Li; Lide Wang; Peiqiang Li. The tudy on copoite load odel tuctue of atificial neual netwok [C]. Electic Utility Deegulation and Retuctuing and Powe Technologie, DRPT Thid Intenational Confeence on. [2] Shi, J.H. ; He Renu. Meaueent-baed load odeling-odel tuctue [C]. Powe Tech Confeence Poceeding, 2003 IEEE Bologna. [3] Beipohl, A.M. ; Lee, F.N. ; Zhai, D. ; Adapa, R. A Gau-Mako load odel fo application in ik ealuation and poduction iulation[j]. Powe Syte, IEEE Tanaction on. Vol. 7, No. 4, Noebe [4] Rifaat, R.M.. Independent powe poduce (IPP) pepectie and expeience with WSCC equieent fo 42

6 geneato odel alidation tet[j]. IEEE Tanaction on induty application, VOL. 37, NO. 4, JULY/AUGUST [5] Li Pei-qiang, Li Xin-an, TANG Wai-wen,e tc. Conue Choice fo an Induty in Statitical Synthei Method Baed Load Modeling[J]. Autoation of Electic Powe Syte. 2005,29(14): [6] WANG Cheng-han,CHAI Hua,XIE Xiao-ong,e tc. Online Identification of Pecentage of Dynaic Coponent in Copoite Load Model[J].Poceeding of the CSU EPSA. 2008,20(3). [7] Shi Jing-hai, He Ren-u. Paaete Identification of Dynaic Load Model Uing Multi-Cue Fiting Method[J].Autoation of Electic Powe Syte. 2003,27(24): [8] S. Baghinia, S.Kaankeh, N. Mahdai, A. H. Vahabie, A. A. Goji. A Cobination Method fo Shot Te Load Foecating Ued in Ian Electicity Maket by NeuoFuzzy, Bayeian and Finding Siila Day Method [C]. Electicity Maket, EEM th Intenational Confeence on Euopean. [9] Zhang Xiaoyun, Wu Ying. Load Foecating Baed on Waelet Analyi Cobined with the Fuzzy Suppot Vecto Kenel Regeion Method [J]. Electic Infoation and Contol Engineeing (ICEICE), 2011 Intenational Confeence on Apil [10] Valeo, S. ; Apaicio, J. ; Senabe, C. ; Otiz, M. ; Sancho, J. ; Gabaldon, A.. Copaatie analyi of elf oganizing ap. ultilaye pecepton neual netwok fo hot-te load foecating [C]. Moden Electic Powe Syte (MEPS), 2010 Poceeding of the Intenational Sypoiu Sept [11] DAI Qi. Load Modeling of Powe Syte Baed on Load Copoition[D]. Hehai Unieity. Jiangu. China Biogaphie Rongen Zhang wa bon in Hunan Poince, China in He eceied the B.Eng degee fo Nanhua Unieity, Hengyang, China in And he i cuently puuing M.Eng Degee in Hunan Unieity. Guigang Qi wa bon in Jiangu Poince, China in He eceied the B.Eng degee fo Huaiyin Intitute of Technology, Huaian, China in And he i cuently puuing M.Eng Degee in Hunan Unieity. Canbing Li (M 06) wa bon in Hunan Poince, China in He eceied BS degee in Electical Engineeing fo Tinghua Unieity in 2001 and eceied PhD degee fo Tinghua Unieity in Hi cuent poition i aociate pofeo of Hunan Unieity. Long Li wa bon in Hunan Poince, China in He eceied the PhD degee fo Hunan Unieity, Changha, China in And he i cuently doing eeach in Dotund Unieity. Yiping Bao wa bon in Hunan Poince, China in He eceied the B.Eng degee fo Notheat Dianli Unieity, Jilin, China in And he i cuently puuing M.Eng Degee in Hunan Unieity. Yuheng Zhu wa bon in Hunan Poince, China in He eceied the B.Eng degee fo xiangtan Unieity, xiangtan, China in And he i cuently puuing M.Eng Degee in Hunan Unieity. 43