Thdng tin khoa hpc cdng nghe md THIET Bf AN TOAN TIA LUA KS LE VAN HAI KS PHAM VAN HIEU KS VU TUAN ANH Vien Khoa hpc Cdng nghe Md TKV Increasing coal productivity in parallel with ensuring working saf[.]
Thdng tin khoa hpc cdng nghe md vdi nhau, phai dupe thidt kd de giam thieu dien dp hd mach va ddng dien ngan mach den mdc KS LE VAN HAI tdi thieu, khdng gay sU bdc KS PHAM VAN HIEU KS VU TUAN ANH chay cho hon hpp khf nd, bang Vien Khoa hpc Cdng nghe Md - TKV each lam hd mach hoac ngan mach, tiep dat, hoac bang each Increasing coal productivity in parallel with ensuring working safety nung ndng cae phan is one of the key targets in the automation process of the coal mach sector For these purposes, the application of the intrinsic spark safe dien (de giam nang lupng phat ngoai) equipment to the mining activities is essentiaL The paper introduces some fundamental principles about the spark safety Mach thuan trd la mach ehi ed phan trd khang, cae NhCimg nam gan day nao tdi hon hpp khf nd (vd phan phan khang, cam cac md than ham Id Viet Nam phdng nd) khang va dung khang khdng da dua vdo dp dung eac thidt + Cach ly ngudn gay nd vdi ed hoac nhd khdng dang ke bj vd he thdng ludng dieu hon hpp khf nd khien tu ddng ed tfnh an toan + Han chd nguon nang Nang lupng dien phat tU cao, dd ed cae thidt bj va lupng phat tU cac thiet bj dudi mach phu thude vao he thd'ng an toan tia Ida nhu mUe ed kha ndng gay nd hdn ngudn dien V va ddng dien Isc he thdng quan trac khf metan, hpp khf nd (an toan tia Idfa) bj gidi han bdi dien trd R Khd he thdng thdng tin lien lac, Ta't ca cae phUdng phap ap cd the xac djnh dupe tUdng dieu khien tu ddng, tU xa, he dung cho cac thiet bj chd'ng quan giu'a nang lupng bdc Ida thd'ng kiem soat nhan su chay nd deu phai tuan theo tieu tdi thieu vdi mach phat tia Id Tuy nhien, sU hieu biet ve chuan qud'c gia hoac qud'c te Ida Cac phep thd da 6ugc thifc thiet bj an toan ndi chung va Cae tieu chuan qui djnh each hien va cho tha'y kha nang bdc thidt bj an todn tia Ida ndi rieng thiet ke va lap dat thiet bj cho Ida hdn hpp khf nd cdia tia Ida cdn han chd Bai viet gidi cac nha san xua't va ngudi sd phu thude vao dien dp hd thieu ve nguyen tac an todn tia dung Tuy nhien, eac thiet bj mach (Voc=V) va ddng ngan Ida cdia thiet bi dang sdr dung d phai 6ugc cdc ed quan ed tham mach (lsc=V/R) Dudng dac cac md hien quyen chap nhan va cap chdng tfnh bdc Ida cua mach thuan Cac nguyen tac cd ban ehi Trong ta't ca eac phUdng trd the hien tren hinh ve an toan tia lilira phap chdng chay nd, phUdng Hinh the hien dudng dac Thiet bj dien lap ddt phdp ddn gian, hieu qua nha't tfnh bdc Ida ed quan he vdi vung ed nguy ed ehdy nd cd dp dung cho eac thiet bj dien, nhdm hon hpp khf nd da dupc the phdt hd quang, tia Ida dien td, la phUdng phdp an toan phan loai theo tieu chuan dien hodc sinh nhiet lUpng tia Ida (Ex i) Dudng dac tfnh cho thay vdi cao ed the gay bdc ehdy hon Nguyen tac ed ban eda dien dp hd mach thap hdn, thi hpp chat ehdy nd mdi phUdng phdp an toan tia Ida Id edng suat ngudn 6ugc sd dung trudng xung quanh nd han chd tinh trang sU ed, dat tinh an todn se Idn hdn Ode diem PhUPng phdp dam bao an trang sU cd dudi mUc binh cho thay cdc thiet bj ed todn de trdnh sU ed ehdy nd Id thudng vd bidt tnJdc kha ndng sU dien dp cap ngudn tU 20-30y ngdn chan sU xuat hien ddng cd ed the xay Tdt Id, tia Ida, difdc sd dung hieu qua nhat thdi eda hon hpp khf nd va cae hd quang hoac nhiet dp be mat cdc thiet bj an toan tia Ida ngudn ed the gay ndng eda mach dien lap dat Ndng lupng ddnh Ida tdi lupng Idm bdc chay hdn hpp vung ed nguy ed ehdy nd 6ugc thieu (MIE) Id khac do] do, bao gdm: gidi han tdi mdd khdng dd de lam vdi tCfng loai nhien lieu, the + ChUa thiet bj ed kha ndng bdc Ida hon hpp khf nd Cae thiet hien bang ti le eda nhien lieu gay bdc Ida vdo khdng gian bj dien lap ddt vung ed CO khdng khf, ma d ti le het sifc chac chan, dam bao nguy cd ehdy nd, cung nhU cae dd hon hpp nhien lieu vd khdng gdy bdt ky nguy hai kdt ndi ve dien gi&a eac thiet bj khdng khf rat dd bj bdc Ida THIET Bf AN TOAN TIA LUA KHCNM sd 4/2010* CO DifiN - T U D O N G HdA MO Thdng tin khoa hpc cdng nghe mo 2000 1000 inA \\\ M i l l U l l U m ,pry,ttno CUrXCIltS applicable to electrical a p p a n t t u s -with c a d m i i u n ziiic m a g n e s i u m or alununutli V 500 Clas s i Lip D 200 100 Grt up C \ 50 C'Llss I Oroups 4.& B 20 10 10 20 50 100 200 Hinh a) Dudng ddc tinh bdc Ida tdi thieu theo nhdm cho thiet bi dien dung khai thac md (nhdm I) b) Dudng ddc tinh gidi h^n ndcao vd gidi han ndthap cua tdng loai Cdn eU theo nang lupng Neu ndng lupng danh Ida thap hdn mUe MIE, thi nd bdc Ida tdi thieu, khf ehdy khdng the lam bdc Ida d bat ky 6\jgc chia cdc nhdm, ndng dp hon hpp nao Ndng dp theo dd, thiet bj dien an todn hdn hpp khf chay nd giam dan 6\jgc chia hai nhdm: cho den mdt gia trj ngUdng ma Nhdm la cac thiet bj dien sd tai dd ndng lUpng bdc Ida dung yung md cd khf khdng the lam bdc Ida hon hpp clidy nd va nhdm II Id cac thidt ndng dp qua tha'p, gpi la gidi bj sd dung cac vung han nd dudi eda hdn hdp khf, kf khdc ed nguy hiem ehdy nd hieu Id LEL (low explosive Cac nhdm khf chay nd va thiet limit) Ndng dp hon hdp khf bj dien eac nhdm I va II chay nd tdng dan cho den mpt lai tiep tue 6ugc phdn nhdm gia tri ngudng ma tai dd nang nhd hdn cac phan nhdm lupng bdc Ida khdng the lam A, B, C, Cdc thiet bj an toan bdc Ida hon hpp (do qua ft d- tia Ida dung md ham Id xy), gpi Id gidi han nd cao eda thudng Id cap bao ve Ex iai hdn hpp khf, ky hieu Id DEL Ex ibi va Ex id, dd cap (upper explosive limit) (bang 1) Ex iaI Id cao nhat vd ed the sd dung khu vuc cd nguy Bang Gidt han ndthap vd gidi han nd cao eiia mdt sd cd cao nha't (bang 2) chatkhi Mpt sd Ipi the eda phUdng Chat Gidi ^ Gidi phap an toan tia Ida ma cac chay han nd han nd phUdng phap khac khdng cd: thap(%) cao(%) + Sd dung 6ugc b hau het /^celylenoe 2,3 ioo(ti; vung nguy hiem (vung nguy gian nd) hiem nhat) Ethylene 2,4 32,6 + Bao tri va cdn chinh thiet Methane 4,4 17 bj dudi hien trudng, cd the Propane 10,8 1,7 thuc hien ca khu vuc Hydrogen 4,0 77,0 san xuat dang hoat ddng va KHCNM s d 4/2010* CO DI£N - TUDdNG HdA Md tham chf ca mach thiet bj dang hoat ddng Mach ed dien dp thap nen an todn cho eon ngudi + Khdng can phai cd bien phap bao ve dac biet cho day dien d hien trudng, ed the sd dung ddy cap dien eda thiet bj thdng thudng Trong eac Cfng dung an toan tia Ida, cd ba phan chfnh phai 6ugc xem xet: (1) Thidt bj an todn tia Ida (2) Hang rao an todn tia Ida (mach each ly an todn): la phan ket ndi giCJfia vung an todn vd vdng cd nguy ed ehdy nd (3) Day ndi lien ket - Thiet bj an toan tia Ida Cdc thiet bj an toan tia Ida nhu bp chuyen ddi dau khf gid nhiet dp, vd bat ky mdt thiet bj ndo "luu gid nang lupng" deu phai 6ugc cap chdmg chi thidt bj an toan tia Idtei sd dung mdi trudng cd nguy cd ehdy nd - Hang rao an toan tia Ida (thiet bj an toan tia Ida td hap) Thdng tin khoa hpc cdng nghe m d Bang Cap bao vp an todn tia Ida Mdta Cap bao ve Mach khdng cd kha ndng gay bdc lifa Exia dieu kien hoat dpng binh thudng vd mdt hoac hai sif cd xay Mach khdng cd kha ndng gdy bdc Ida Exib didu kidn hoat ddng binh thudng hoac mot sU cd xay Mach khdng c6 kha ndng gay bdc iCfa Exic dieu kien hoat dpng binh thudng Didm phdn gidi giOa thiet bj dudi hien trudng vdi thiet bj phdng dieu khien gpi Id "hdng rdo an toan tia Ida" Hang rdo cd tdc dung bao ve cdc mach dien vung cd khf nd bang each gidi han dien dp vd ddng dien Idm viec, cung nhu dien dp va ddng dien sU ed eda thidt bj d mdc an todn (an todn tia Ida) di qua nd Cd hai kieu each ly an todn Id "cdeh ly an todn bang di-dt zener" vd "each ly dien" Hai kieu cdeh ly khdc ve each gidi han nang lupng gay nguy hiem tU cdc thidt bj phdng dieu khien den vung ed nguy ed ehdy nd Hang rdo an toan tia Ida phai dupe thidt kd va 6\jgc cap chdng ehi phu hpp cho tdng thiet bj an todn td hdp (he thdng cdc thidt bj ndi vdi nhau) de kdt ndi vdi cdc thiet bj an todn tia Ida khdc vung ed nguy ed ehdy nd Cdc thidt bj an todn tia Ida td hdp Id nhCmg thdnh phan chfnh eda bat ky mdt he thdng an todn tia Ida ndo bdi vi nd quyet dvnh cdc thdng sd an todn tdi da cho phep de ket ndi cae thidt bj vdi mdt he thdng an todn tia Ida - Kdt ndi cdp didn hd thdng an todn tia Ida Dien dp va ddng dien trdng cdc mach an toan tia Ida Id nhd, dd nd cho phep cd the Vfdu Sd dung di-6t zener dd bao ve qua ap, neu c6 sif cd lam di-dt zener tidng thi di-dt zener thQ vin hoat dong binh thudng Sif dung di-dt zener de bao ve qua ap, neu c6 SLf cd lam di-dt zener hong thi di-dt zener thU van hoat dong binh thudng sd dung cdp dien eda cdc thiet bj thdng thudng khdc vdi dieu kien la cam khdng (dien cam) va dung khdng (dien dung) eda cap nam gidi han an todn cho phep eda he thdng an toan tia Ida Thdng sd eda cdp thudng la ddng nhat tai mpi diem, dd ed the de dang tfnh 6\sgc cam khang va dung khdng Cfng vdi chieu dai cap eu the Rao chan an toan tia lua Rao chan an toan la thiet bj kdt nd'i cdc thiet bj giua vung an todn vd vung nguy hiem vdi (chay den mUc tdi thieu nd), muc dfeh Id gidi han ndng lupng nguy hiem tU vung an todn di vao vung nguy hiem khdng the lam bdc Ida 6ugc hon hpp khf ehdy nd Ndng lupng dien vupt qud eac mach dien cd sU cd d vung an todn ed the 6ugc ngdn chdn bang cdeh: dua ndng lUdng vupt qua vd dat (tidp dja); chdn ddng ndng lupng sU cd bang cdc phan td each ly Nhu vdy, xay su cd, mdc dien dp vd ddng dien vdng nguy hiem dupc han che tdi mdc an toan - Rdo chan an todn tia lua dung zener lis lau rdo chan an todn bang zener da dupe sd dung rdng rai lam thiet bj an todn trung gian ddp Cfng nhu cau Idn sd dung thiet bj dien KHCNM s d 4/2010* CO DlfeN - TV »dNG HdA Md vung ed nguy ed ehdy nd cao Khi lam viec binh thudng rdo chan cho phep truyen tin hieu dien theo ca hai hUdng vd khdng can trd chdng Khi xay SLf ed tdng dien dp (dp Idn tdi da 250V) d phfa vung an toan tdi, thi dan den xua't hien mdt ddng Idn chay qua eau chi, qua di-dt zener vd xud'ng dat Cau ehi ndy cd td'c dp chay rat nhanh de dam bao an toan sU ed di-dt zener xay (di-dt zener bj ddt se din den nguy ed ndng lupng dien nguy hiem vupt qua dupc hang rao vdo vung ed khf nd), eau ehi bj chay se cdeh ly vd dien gida vung nguy hiem (trong Id) vd vung an todn (mdt bang) Theo tieu chuan an todn, cau chi khdng dupc phep thay the de trdnh Idm suy ydu kha ndng bao ve an toan cho hang rdo chan, mdt cau chi bj ehdy thi thay mdi ca hang rdo cdeh ly Khi xay sU cd, dien dp hd mach (Voc) d phfa eau dau nd'i xudng vung nguy hiem eda rdo chan an todn, 6ugc ghim bang dien dp ghim eda didt zener, vd ddng ngan mach tai eau dau ndy 6[Sgc gidi han bdi dien trd gidi han Rlim Gid trj eda dien dp hd mach Uoe vd ddng ngan mach Ise se quyet djnh cam khdng vd dung khdng tdi da cho phep eda cdc thiet bj (ke ca cam khdng vd Thdng tin khoa hpc cdng nghe mo dung khang eda dUdng day) vung nguy hiem dUdc phep nd'i vao rao chan an toan, dieu de dam bao ndng lUpng eda Uoe va Ise khdng the lam bdc Ida hon hpp khf chay nd vung nguy hiem Tuy nhien, hieu qua bao ve eda rao chan an toan phu thupc vao viec ket ndi tiep dja cd tdt khdng Vi theo nguyen ly' bao ve nay, ndng lUpng eda dien dp va ddng dien 6ugc han che bang each tra nang lUpng thUa ve da't eda vung an toan thdng qua dUdng tidp dja rieng Dien trd tiep dat eda rdo chan an toan phai dam bao nhd hdn 1Q, tUdng Cfng vdi kfch thude day tdi thieu 4mm^ Rao chan an toan tia Ida sd dung didt zener ddn gian, hieu qua va re tien, song, ed mpt sd han che: + Phai dam bao tiep dja tdt + Cac thiet bj cap trudng phai 6ugc each ly vdi da't + Dien dp rdi tren rao chan ed the gay anh hudng den hoat dpng eda thiet bj + Viec ket nd'i khdng ddng hoac cd dien dp dang cao se lam ddt cau chi + Kha ndng loai trU nhidu kem, nhieu thiet bj cd ket ndi vdi se gay nhieu dien dp cho nhau, cd ca nhidu td hudng tiep dja tdi - Rao chan an todn tia Ida dung cac phan tur cdeh ly dien So vdi dung zener nguyen ly khac biet d chd tao su each ly vd dien gida vdng an toan va vung nguy hiem bang each sd dung eac phan td each ly nhu bien dp rdle ghep quang (opto coupler) Ta't nhien cae thidt bj theo dang cung phai tuan theo tieu chuan an toan quy djnh va phai 6\Sgc cap chCimg ehi Neu 6ugc thiet ke ddng thi "hang rao an toan tia Ida dung phan td each ly" se dam bao dien dp dau phfa ndi tdi vdng nguy hiem ludn d mUc gidi han an toan cho dd dien dp dau vao rat cao Hang rao each ly kieu cho phep mach thidt bj khdng can phai tiep dja an toan danh rieng va viec tiep dja cho mach de ddng eau chi bao ve la khdng can thidt nda Cae thdng sd an toan eda dien dp hd mach Voc va ddng ngan mach Ise 6\jgc xdc djnh tUdng tu nhu d "hang rao an toan dung didt zener" NhCJrng Ipi the chfnh eda phUdng phap cdeh ly: + Viec ket ndi tiep dja danh rieng dam bao chac chan khdng can thiet va cac thiet bj cap trudng ed the ndi tiep dja true tiep xudng dat + Cae thiet bj cap tafdng hoat dpng d cap dien dp tdi da, vi khdng cd dien dp rdi trung gian (khdng ke rdi tren day) hda viec lap dat thiet bj vd tang cUdng an toan * Cac thdng sd an todn eda thiet bj an toan tia Ida ket ndi vdi can dam bao theo nguyen tac sau (chi dp dung vdi he thdng ddn ngudn hoac nhieu ngudn nhung tuyen tfnh): Ui < Uo li < lo, Pi < Po, Co ^ C i + Cc^p, Lo ^ Lj + Leap Trong dd: Ui: Dien ap vao cue dai UQ: Dien ap cue dai li : Ddng dien vao cue dai lo: Ddng dien cue dai P,: Cdng suat vao cifc dai Po: Cdng suat cue dai Co: Oien dung ngodi cue dai (dien dung cho phep) Q: Dien dung cue dai (tdng dien dung tUdng dUdng eda thiet bj) Ce^p: Dien dung dudng ddy LQ: Oien cam ngoai cue dai(dien cam cho phep) L; Oien cam cue dai (tdng dien cam tUdng dUdng eda thiet bj) Lc4p: Oien cam dudng ddy Mot so he thd'ng thiet bj an toan tia Ida dupc dua vao sijf dung cdc md ham Id Viet Nam + Mach tfn hieu va mach bao ve an toan cd the tfch hdp vao edng mdt thiet bj + Lap ddt ddn gian, dUa thiet bj vao hoat ddng ma khdng can mach tiep dja a) He thdng canh bao tu ddng metan an todn tia lua Ba Lan san xuat: + Kha ndng loai trU nhilu dien dp tdt (do dau nhieu thiet bj ed ngudn mdt chung) - Rdo chdn an toan tia lua tdhpp Trong cac he thdng an toan tia Ida hien thudng sd dung ca hai phUdng phdp tren de tan dung ldi the eda ca hai phUdng phdp dd ddn gian Hau het cdc md than ham Id vdng Quang Ninh da dUde dau tu lap ddt he thdng tu ddng quan trac KSP-2C KSG-10 hang va Carboautomatika (Ba Lan) san xuat, cac tin hieu dien vd thiet bj eda he thdng phan ham Id la dang an toan tia Ida (hinh 2) KHCNM s d 4/2010* CO DifeN - Tl/DdNG HdA MO Thdng tin khoa hpc cdng nghe m o Vi giao tiep Oaudo CH4, i Mach giao 0l£ tiep BAI 220/50 VAC CO, gio Mach clach ly quang 220VAC Vi giao tiep Dau CH„ CO, gio Mach giao tiep d.do Mach each ly May tfnh RS232 H H Trong ham 16 Phong Giam sat tap trung Khdi mach vi XLf ly trung tam Hinh 2.- So dd khdi ciia he thdng tu ddng cCia Ba Lan Sd dd hinh cho thay: - He thdng ed nhieu kenh do, mdi kenh giao tidp vdi mpt dau thdng qua vi giao tidp each ly an todn tia Ida Cae dau ed the la dau CH4, CO, gid, nhiet dp - Cdc kenh eda he thdng each ly hodn todn ve dien, sd dung cdc phan t d bien dp cdeh ly vd phan t d ghep quang (opto coupler) - Mach vi xd 1^ trung tam eCia he thdng truyen nhdn dd lieu vdi eac dau thdng qua vi mach giao tiep vd each ly vdi vi ndy bang cdc phan t d cdeh ly quang Do dd mach cd the kdt ndi true tidp vdi mdy tfnh vd vdi ngudn dien khdng each ly Nhu vdy, SLf an todn tia Ida eda he thdng dUdc quyet djnh bdi bidn dp each ly (BACL50/33/12), vi giao tiep, dau ket ndi vdi vi giao tiep va dudng day a) Phan tich an toan tia Ida cho mdt kdnh Cach kenh eda he thdng la gidng het vd hoan toan each ly dien vdi nhau, dd de hieu rd 6\jgc su an toan tia Ida eda he thdng ta chi can phdn tfch sU an todn tia Ida eda mdt kenh Sd 66 khdi eda mdt kenh ed the dupe bieu dien nhu sau (hinh 3): Mach kenh cdeh ly vdi mach VXL trung tdm bang cae phan td cdeh ly quang (optocoupler) vdi khoang each an BACL BA1 220VAC todn dam bao theo tieu chuan TCVN7079, nen mach khdng cd lien he gi ve dien vdi mach VXL, dd qua trinh tfnh toan mach gidi han ndng lupng cap tdi dau 6ugc dam bao an todn tia Ida se khdng xet den mach VXL vd mach each ly quang Ngudn 220VAC dUpe xudng 33V thdng qua hai bien dp each ly B A I , BACL va cau chinh luu de cap ngudn cho "vi giao tidp", ludi each ly cdia hai Ciu di-it T 220/50VAC 50/33VAC 100uF M9Ch h-Mschjchuyin , , deh ail tin I I ly an j hi0u H to^" r X M^chcich ly quang Mach VIglio flip Mach VXL tnjng Hinh 3-Sodd khdi mdt kenh (390+150)12 150n Ph6ng€)DTT Dirdih^mlb Hinh 4-Sddd tuong duong mdt kenh KHCNM S6 4/2010* CO DrtN - TU DdNG HdA Md Thdng tin khoa hpc cdng nghe m o bien dp dam bao dien dp each ly tdi 500V han che nang lupng dien d mdc an toan hoat ddng binh thudng cung nhu cd sif cd tang dp tU ngudn 220VAC cd the bang qua hai bien ap each ly tdi vi giao tiep kenh Tdi vi giao tiep, ngudn dien dupe chuyen qua mach han che ddng dien va dien dp (mach each ly an todn tia Ida) de cap tdi dau dudi ham Id, ndng lupng dien sau mach each ly an toan dam bao an toan tia Ida Nhin tU gdc dp an toan tia Ida, sd 66 he thdng eda mpt kenh ed the dua ve dang tUdng dUdng nhu hinh Dien dp hd mach Uco 6itgc khdng che bdi didt zener 33V, va ddng dien ngan mach Ise 6\sgc khdng che bdi dien trd 690Q Tfnh toan hai thdng sd nhu sau: Ddng ngan mach (bao gdm he sd an toan) lse= 1,5x[33/(390+150+150)] «72mA (lo) Dien dp hd mach (bao gdm he sd an toan) Uco = 1,5x33 « 50V(Uo) Tra dudng ddc tfnh ddnh Ida tdi thieu U=f(C) vdi dien trd (390+150+150)=690Q, xac djnh dien dung cho phep khoang 200uF(Co) Trong dd tdng dien dung mach khoang 150uF(Ci), nhU vay dien dung tdi da cho phep eda dudng day vd eda dau ket ndi vao kenh la 200150=50uF Thue te tdng dien dung cdia dudng day va eda cae thiet bj da'u vao kenh rat nhd, ehi cd vai uF(Ci +Ccip+ Ci TB kh4c) vay dam bao an toan tia Ida theo dien dung Vdi ddng ngan mach lse=72mA tra dudng dac tfnh danh Ida tdi thieu L=f(l) xdc dinh dUdc dien cam tdi da cho phep Id O.'lH (Lo=100mH) Trong dd tdng dien cam mach chfnh la cudn day eda bien dp each ly (Li nhd hdn lOOuH) cdng vdi dien cam dudng day vd dien cam dau (Lo^p+U aiudo) khoang lOmH ed trj sd nhd hdn nhieu so vdi dien cam cho phep, nen mach an toan dien cam Cdc phan td va dUdng mach in mach each ly an toan (trong vi giao tidp) dam bao khoang each so vdi cdc phan td hodc dudng mach in ndi bd mach va so vdi cac mach khdc xung quanh theo tidu chuan TCVN7079, khoang each tdi thieu Id 6mm b) Phan tich an toan tia ICfa cho dau khimdtan CPC-2 Mach dien eda dau CPC-2 la dang an toan tia Ida, mach tUdng ddi nhieu linh kien Tuy nhien, vi xet d gde dp an toan tia Ida, nen mach dupc dUa ve dang tUdng dUdng va ehi xem xet ky cac phan td can phai khdng che 6e mach trd an todn tia Ida Trong mach gdm ed mpt sd bd phan lifU trd va phdt sinh ndng lupng can dUdc khdng che: bp ae quy, mach tao ngudn chuan cho sensor va mach bao edi, dd, bd ae quy ddng vai trd ca'p ngudn cho toan bp mach vd nd 6ugc nap de bu dap lai ndng lUdng bj hao hut tU may tram tren phdng GSTT TU ac quy cd the chia nhanh cap ngudn chfnh khac can phai xem xet ve mdt an toan, cd nhanh cd chUa KHCNM s d 4/2010* CO DifiN - Tl/ DdNG HdA Md cdc phan td dao ddng can phai khdng che dien dp, ddng dien vao va eda hai nhdnh do, cdn cae nhanh khdc ehi xet dien trd tUdng dUdng, dien dung tUdng dUdng va dien cam tUdng dUdng TU tram trung tam, dau 6iigc cap ngudn va ddng thdi cung la dudng tfn hieu truyen gida may tram va dau Ngudn tU may tram di qua didt vao mach dau do, theo tieu chuan trd khdng cdia dau dupc coi la rat Idn, dd dung khang va cam khdng gan nhU bang khdng - Xet khdi mach ae-quy: Mach ae quy cap ngudn cho toan bp mach dau vd nhan ngudn ndng lupng bd sung tu may tram Ddng dien su ed mach 6ugc khdng chd bdi eau ehi eat nhanh 0,25A va dien trd 3,3Q, dien dp hd mach 6ugc khdng chd bdi hai didt zener 12V Vdi dien dp hd mach eda mach ae quy la 1,5x12V= 18V (tfnh ea he sd an toan), xdc djnh dudng ddc tfnh U(c) thi dien dung cho phep(Co) mach Id rat Idn (tren lO.OOOuF), dd tdng dien dung tUdng dUdng eda toan bp mach nhd hPn nhieu so vdi gia trj cho phep, dd mach dam bao an todn ve dien dung Cau chi 0.25A ehi cho phep ddng sU cd Id 1.7x0.25 = 0.425A (sU ed cao nhat) vdi ddng su cd thi dien cam tdi da cho phep mach Id 6mH, dd tdng dien cam mach rat nhd (khoang 300uH) nen mach an toan ve dien cam Oien dp va ddng dien cap cho dau eda khdi mach ae quy dam bao an toan tia Id^ Thdng tin khoa hpc cdng nghe m o Tuy nhien ndu ndi bd khdi mach ae quy xay su cd chap mach thi tia Ida sinh se rat nguy hiem dd toan bd khdi mach 6ugc 66 day bang chat cdeh dien de loai trd SLf ed Cdc trj sd dien dung, dien cam vd ddng tai eda todn bp mach dam bao khdp vdi thdng sd an todn tia Ida eda ngudn ae quy Tuy nhien, mach cdn mdt sd mach cue bd can phai xem xet, vi cdc mach ed kha ndng thay ddi thdng sd ddng dien vd dien dp cue bd cd the gdy mat an toan tia Ida Dd Id cdc khdi mach: mach cdp ngudn chuan cho sensor, mach edi bao ddng - Mach cap nguon chuan cho sensor Dien dp hd mach dau cOa mach ndy 6ugc khdng chd bdi didt zener 5,6V, gid tri dien dp hd mach tdi da Id (tfnh ea he sd an todn): Us-eo = 1,5x5,6 = 8,4V Tra dUdng ddc tfnh U(e) xdc djnh 6\jgc dien dung tdi da cho phep eda mach Id khoang 5000uF dd dien dung mach chi Id IIOuF do mach an todn tia Ida theo dien dung Ddng dien tdi da xay dau sau hai di-dt zener bj chap mach Tuy nhien ddng dien ndy bj khdng chd bdi cau chi eat nhanh 125mA dd ddng ngan mach chi dat tdi da Id Is-sc = 1.7x0.125 = 0,2125A tra dudng ddc tfnh bdc Ida tdi thidu L = f(l) xac djnh dupe dien cam tdi da cho phep Id 1H, dien cSm mach la lOOuH, dd mach an todn theo dien cam Cdc tin hieu dien dp vd ddng dien dau vao va dau dam bao an toan tia Ida, nhifng ndu xay chap mach ndi bd mach thi cd the phat sinh tia Ida nguy hiem ed kha ndng lam bdc Ida hdn hpp khf chay nd Do dd, de loai trU sU cd thi toan bd mach 6itgc " 66 day" bang chat each dien (hinh 5) - /Wac/7 phat chudng bao ddng: Mach cung gan gidng nhu mach cap ngudn sensor, nhien mach chi cd phan cam khang Ddng ngan mach cua mach cung dupc khdng chd bdi cau chi 125mA, ddng ngan mach la 0,2125A, tra dudng dac tfnh bdc Ida tdi thieu mach dam bao an toan (vi cam khang eda mach Id rat nhd) Ddng dien phan khdng eda cudn ddy mach ed the sinh ddng phan khdng ed gia trj Idn cd the gay huy hiem, nhung nd bj triet tieu bdi di-dt mac song song, dd tfn hieu dao ddng cap cdi dam bao an todn tia Ida Cung gid'ng nhu mach tren, todn bd khdi mach 6ugc "66 day" chat cdeh dien de trdnh sU cd chap mach ndi bd mach - Mach CPU: Ddng ngan mach (tfnh ca he sd an todn 1,5): lepu-sc = 1.5x9.6V/(3.3+150)n = 94mA Tra dudng ddc tfnh ddnh Ida tdi thieu L = f(l) xdc djnh 6\sgc KHCNM s d 4/2010* CO DI$N - TV DdNG HdA Md dien cam tdi da cho phep la 120mH Trong dd dien cam eda mach CPU ehi khoang 200uH, dd mach dam bao an todn tia Ida theo dien cam Vdi dien dp hd mach tdi da tai dau eda mach ae quy la 1,5x12V = 18V(dUpe han che bdi cac di-dt zener 12V), xac djnh dudng dac tfnh U(c) thi dien dung cho phep mach la rat Idn (tren lO.OOOuF), dd mach dam bao an todn ve dien dung b) He thdng canh bao Nhat Ban san xuat He thd'ng kiem soat khf tu dpng cLia Nhdt Ban (da lap dat d Mao Khe) dp dung ddng thdi tieu chuan thidt bj vd phdng nd vd tieu chuan thiet bj an todn tia Ida He thd'ng cd ca'u true phdn tdn, tram trung tdm Id he thdng cdc mdy tfnh vd truyen thdng vdi cdc may tram cue bd dudi Id Cdc mdy tram Id cd kdt eau dang vd phdng nd (Exd), kdt nd'i vdi cdc dau dudi dang tfn hieu an toan tia Ida He thdng sd dung mang truyen thdng ndi tidp, tram gidm sdt tap trung (GSTT) tren mdt bang ehi kdt ndi cdp quang vdi tram cue bd dau tien qua kdt eau phdng nd, tidp dd tfn hieu truyen thdng ndi tdi eac tram cue bd phfa sau bang cdp dien vd tfn hieu dien Id an todn tia Ida Ngodi hai dang cdng an todn tia Ida ndy, cdn cd cdng kdt ndi dau vdo vd dang on/off sd dung cdc phan td cdeh ly quang Thdng tin khoa hpc cdng nghe m o PRDMTER Phong giam sat' May khach Cap dien(cap xoan doi) Hinh 5-Sodd khdi he thdng Moi tram sd dung bien dp each ly dien dp tU 127V (380V) xud'ng 24V, sau dd dUdc chinh luu va ca'p cho mach CPU, va cac mach kenh (8 kenh do) Mach CPU va cac mach ca'p ngudn kenh sd dung cac bp chuyen ddi ngudn each ly DC/DC de each ly ngudn vdi va vdi ngudn chfnh, dien dp each ly eda cac phan td la 2,5kV Cae bp phan eda may tram each ly ve dien vdi vdi dien dp each ly Idn, dd ta cd the tien hanh phan tfch sU an toan tia Ida eda tdng khdi ddc lap Khoang each eda cdc bp phan mach each ly dam bao theo tieu chuan TCVN7079 (hinh 6) Isc =J8V/24n = 0.75A (^ ddng ngan mach) - Mach cap nguon cho dau do: ed mach, moi mach cap ngudn cho mdt dau do, vd eac mach dpc lap vdi nhd bd chuyen ddi ngudn Tra dudng ddc tfnh bdc Ida tdi thieu vdi dien trd ndi tiep 24Q xdc djnh dUde dien dung cho phep la rat Idn (Uo tren 3000uF) va dien cam cho each ly DC/DC, dien dp sau caehIyla12VDC (hinh7) Oien dp 12V sau bd each ly DC/DC se chay qua mach han che dien dp va ddng dien (mach an toan tia Ida), dien dp va ddng dien sau mach la an toan tia Ida va dupc ndi den mpt khoang cau dau rieng (khoang cau da'u an toan tia Ida) Khoang eau da'u cd the md may tram dang hoat dpng de ket ndi tdi dau vi dien dp va ddng dien khoang la dam bao an todn tia Ida Cdc thdng sd mach: Uco = 1.5x12V = 18V (Uo dien dp hd mach tdi da) KHCNM s d 4/2010* CO DI$N - TIT DdNG HdA Md phep tdi da 150mH (Lo) Tong dien cam va dien dung mach dudng day va mach dau la rat nhd (U^p+Li aa=100uH C^p+Ci ad=10uF) nen mach dam bao an toan tia Ida Hdn nda nguyen ly' mach rat an todn neu xay sU ed qua dp (tdc la didt zener lam viec) thi cac bdng trudng se lam ngan mach trudc dien trd han ddng 12Q d dau vd ddng dien la 12V/12Q = 1A se lam ddt cau ehi 0.5A vd cdeh ly ngudn dien vdi mach an toan tia Ida Cac mach ndy khdng can cha't "do day", vi nd dupc bao ve bang vd phdng nd dang Exd nhifng khoang cdeh cdc phan tu mach vdn phai dam bao theo tieu chuan an toan tia Ida Vdi nguyen ly mach thi eac linh kien mach cd dp ben rat cao neu cd su cd thi thudng ehi can thay eau chi de phuc hdi lai -K/jd7fT?ac/jCPL'(hinh8): Mach CPU thu thap dd lieu tu cae dau va gdi thdng tin ve trung tdm gidm sdt thdng qua mang truyen thdng RS485 Cac dau gdi tfn hieu ndng dp khf dang tfn hieu ddng dien tUdng tU ve CPU thdng qua cae mach cdeh ly an toan tUdng tU nhU mach cap ngudn nhung cdc tin hieu rat nhd va disgc han che qua cac dien trd cd trj sd Idn nen cam khang va dung khang anh hudng den mach CPU gan nhu khdng dang ke Thdng tin khoa hpc cdng nghe m d Mdi CPU cd mdt dja chi rieng biet vd nhat he thdng, ed yeu cau se gdi dd lieu tra Idi ve may tram Nhu vdy, mach CPU se ed cap ddy de kdt ndi vao mang truyen thdng eda he thdng, va cdc dudng truyen thdng deu dupe bd sung cac mach an todn tia Ida Cdc cap dUdng ddy ndy tUdng t u nhau, nen chi can xet mpt dudng Dien dp hd mach eda dudng truyen tiidng 6ugc khdng chd bdi ba didt zener 5,1V, vdi he sd an todn 1,5 thi dien dp Id 1,5x(5,1+0,7) = 7,7V, tra dudng ddc tfnh bdc Ida tdi thieu vdi dien trd nd'i tidp la 66Q thi dien dung cho phep Id rat Idn (tam Id'y Id lO.OOOuF) Vdi tdng dien dung tUdng dUdng mach CPU khoang 150uF thi dien dung tUdng dUdng eda mdt eda truyen thdng Id 3,7uF Trong he thdng ed tdi da 15 mdy tram, dd tdng dien dung tdi da tren dudng truyen thdng la 15x3,7uF = 55,5uF, tdng dien dung cdia dudng day tdi da ed khoang 4,2uF (200pF/m x 14x1500m) Nhu vdy tdng dien dung cdia ca he thdng ed tren dau eda mdt eda truyen thdng Id 55,5 + 4,2 = 59,7uF , nhd hdn nhieu so vdi dien dung cho phep, nen mach dam bao an todn ve dien dung DC/DC l±i_—^ lr9m pttias sau ''^y phia\nr 127VAC CM Madi Ulu •0) , 127/12VAC Hinh 6-Sodd khdi may tram dudi gdc dd an toan tia ilia 0,5A 12n/5w 12n/5w I 3^ n n ?I A —f 12/12V f- s: Mach aliu ^ Cach ly DC/DC Mciy tram I Hinh 7- So dd khdi mdt kenh may tram lOOmA' M n Cdeh ly DC/DC -^ 12V/5V Khoi mgch CPU 150uF -^ T "•CffOniA" "33n 100mA 33n TTI^ 33„ y " Tai may trgm phia sau 33n , •'=>n' I I l^^v Tx 33n JM ' ' ' * ' "^^^ '^'"^ HZD-y phia tru'dc Rx Hinh 8-Sodd khdi mach CPU may tram mdc cho phep, nen mach an toan ve dien cam Can lifU y, cdc dien trd han ddng, didt zener gidi han dien dp hd mach, didt triet tieu ddng phan khdng la cdc phan td chju tai chfnh ed sU ed, do can phai dupe tfnh todn edng Ddng ngan mach 5V/66n = suat tUdng dng vdi ddng dien 76mA vdi he sd an toan la hodc dien dp xay sU ed 114mA, tra dudng ddc tfnh bdc cao nhat, vd nhdn vdi he sd an Ida tdi thieu cam khdng cho toan 1,5 Ndu khdng dupc tfnh phep Id khoang 300mH Tdng dien cam tdi da cd t h i eda todn ddng thi nhiet dp be mdt dudng day vd eda mach CPU Id eda cac phan td ndy sinh ed t h i rat cao vd gdy nguy hiem vi (14x1500mx1uH+15x100uH) = 36mH nhd hdn nhilu so vdi nd phSi chju qua tai./ KHCNM Sd 4/2010* CO DI$N - TV DdNG HdA Md Tdi lieu tham khao: Practice Electrical Equipment and Installations in Hazardous Areas Geoffrey Bottrill Derek Cheyne G Vijayaraghavan Steve Mackay Tieu chuan TCVN70790/11, lEC 60079-11 Tai lieu vS he thdng quan trie KSG10, KSP-2C cOa Hang Carboautomatika (Ba Lan) Tai lieu v6 hd thdng quan trie Nhdt Ban Ky thuat an todn cac him Id than vd didp thach, TCN-14-06-2006 4/2007 ... mach han che dien dp va ddng dien (mach an toan tia Ida), dien dp va ddng dien sau mach la an toan tia Ida va dupc ndi den mpt khoang cau dau rieng (khoang cau da''u an toan tia Ida) Khoang eau... thdng an toan tia Ida Thdng sd eda cdp thudng la ddng nhat tai mpi diem, dd ed the de dang tfnh 6\sgc cam khang va dung khdng Cfng vdi chieu dai cap eu the Rao chan an toan tia lua Rao chan an toan... cac mach khdc xung quanh theo tidu chuan TCVN7079, khoang each tdi thieu Id 6mm b) Phan tich an toan tia ICfa cho dau khimdtan CPC-2 Mach dien eda dau CPC-2 la dang an toan tia Ida, mach tUdng