220kV變電所電氣一次系統(tǒng)設(shè)計1,kv,變電所,電氣,一次,系統(tǒng),設(shè)計 2004 lntematlonal Conference on Power System Technology POWERCON 2004 Slngapore 21 24 November 2004 I Unschctnsformer unit The capacity of the equivalent transformer unit is determined by the reserve margin and the tie line capacity constraint Besides the corresponding probability of the equivalent unit is obtained by the forced outage rate of the existing transformer units By considering the transfer capability of neighboring reserve margin the timing to commit new transformer to maintain the service reliability can be delayed and the loading factors of all main transformen can be improved A Mod ed expansion planning of Fengshan service area To investigate the impact of transformer reserve margin of interconnected areas to the LOLE of Fengshan service area two neighboring service areas of Renwu and Siaogang are included in the simulation The total existing capacity of main transformer units of Renwu and Siaogang areas are 200MVA and 460MVA respectively By summing the capacity of tie lines between Fengshan and the other mas the reserve capacity which can be provided by Renwu and Siaogang is 25 MVA each By including the equivalent transformer capacity and considering the corresponding probability of the neighboring service area the loss of load expectation of Fengshan service area has been modified as illustrated in Fig 4 and table WI To maintain the same service reliability with LOLE as 0 001 daydyear with peak loading forecast the new transformer unit of 60MVA has to be committed far years of 2009 2 1 12 2 1 17 and 2 12 1 respectively By comparing Fig 4 to Fig 2 it is found that the investment of new main transformers can be postponed if the capacity reserves of neighboring service areas are considered in the evaluation of system reliability 1 0 1 1 E 2 1 8 1E 5 1 E6 t E 1 E4 159 300 350 400 450 500 550 600 6 annual peak loading Mw Fig 4 Modified LOLE of Fengshan area for dlfkent MTR capacity 10 61 OoooO5577 Ow001155 000600017 0 oooooobb 0 0000oooo 000118612 0 00022273 0 00000324 OM o xIS 0 000 M00 0 00387wci 0 00086863 O oooO2367 0 00000MO 0 00000001 400 0 02129481 0 00492490 O wO16757 O ooOW551 0 0000W15 Fig 5 shows the revised LOLE of Fengshan service mea after taking into account the capacity reserve of SOMVA provided by the neighboring areas To serve the peak loading of 425MW with the existing 450MVA main transformer capacity the LOLE has been solved as 1 5246 daydyear as shown in table VI On the other hand the LOLE has been reduced to be 0 11 3 ldaydyear if the 50 MVA capacity reserve is included in the reliability analysis I owooooo00 0 010Mx10000 0 0001000o0o 0 0000010000 o ooooooo1oo 0 1 150 200 250 300 350 400 450 500 Peak load MW Fig 5 LOLE of Fengshan V CONCLUSIONS been derived According to the forced outage rate of main transformers the loss of load expectation has been evaluated The expansion planning of main transformers to maintain system service reliability is obtained To further enhance the cost benefit of main transformers expansion planning the transformer reserve capacity of neighboring areas is considered and represented as an equivalent transformer unit with the corresponding outage probability The service reliability of distribution system cil l be improved effectively with the reserve capacity supported by the neighboring areas Besides the commitment of new transformers can be postponed and the loading factors of existing transformen can be improved by the proposed expansion strategy W RE FERENCES I 2 131 4 0 5 Luo Service reliability of dishibutiou system Taiwan Power Company training center 1987 Dishibution annual reports Taiwan Power Company 2002 Roy Billinton and Ronald N Man Retiability Evaluation of Power Systems Second Edition 1996 EEX Recommended Practice for the Design of Reliable Indastrial and ConmKrrial Power Systems IEEE Standard 493 1997 Vn BIOGRAPHIES C S Chen received the B S degree hnm National Taiwan University in 1976 and the M S PhD gm in Eldcal Enginaaing from the University of Texas at Arlington in 1981 and 1984 respectively From 1984 to 1994 he was a professor of Electrical Engintcring department at National Sun Yat Sen University From 1989 to 1990 he was ou sabbatical at Empros Systems International Since Oct 1994 he woks as the depuly director general of Dcpamncnt of Kaohsiuug Mass Rapid Transit From Feb 1997 to July 1998 he wag with the National Taiwan University of Science and Technology a a professor Fmm August 1998 he is with the National Sun Yat Sen University a full professor His majors are wmputa control of power systems electrical and mechanical system integration of mass rapid transit systems M Y Huang received the M S degree in Electrical Engineering mm National Chtng Kung University in 1993 He is currently pursujng Ph D degree in Electrical Engincuing of National Sun Yat Sen University C C Chen received the B S dege hm National Taiwan Institute of Tffihnology in 1989 M S degree fium National Suu Yat Sen University in 2003 He is presently an enginscr at Taipower To achieve the optimal expansion planning of main transformer capacity with the load growth of distribution system the historical peak load demands of service areas have been collected By performing the regression analysis the time series model for load forecasting of service areas has 62