CHỈÅNG IV TÊNH TOẠN NGÀÕN MẢCH Ngàõn mảch l tçnh trảng sỉû cäú nghiãm trng thỉåìng xy ra trong hãû thäúng âiãûn. Vç váûy cạc khê củ âiãûn phi âỉûåc tênh toạn v lỉûa chn sao cho khäng nhỉỵng lm viãûc åí chãú âäü bçnh thỉåìng m cn cọ thãø chëu âỉûng âỉåüc khi xày ra sỉû cäú ngàõn mảch. Âãø kiãøm tra cạc pháưn tỉí trong hãû thäúng âiãûn âm bo äøn âënh âäüng v äøn âënh nhiãût, chụng ta phi dỉû bạo cạc tçnh trảng ngàõn mảch cọ thãø xày ra v xạc âënh dng ngàõn mảch tênh toạn tỉång ỉïng. Cạc säú liãûu vãư dng ngàõn mảch l càn cỉï quan trng âãø thiãút kãú hãû thäúng bo vãû råle v âënh phỉång hỉåïng váûn hnh hãû thäúng. Do tênh toạn ngàõn mảch l pháưn khäng thãø thiãúu trong thiãút kãú nh mạy âiãûn v hãû thäúng âiãûn, phỉång phạp tênh toạn åí âáy l dng phỉång phạp dng âỉåìng cong tênh toạn. IV.1. TÊNH TOẠN NGÀÕN MẢCH CHO PHỈÅNG ẠN 1: IV.1.1. Âiãøm ngàõn mảch tênh toạn: Hçnh IV.1.1 Hçnh IV.1.1 - Âiãøm N 1 : dng âãø chn khê củ âiãûn phêa cao ạp 220kV. Tçnh trảng så âäư trỉåïc lục ngàõn mảch l cạc thiãút bë váûn hnh bçnh thỉåìng, ngưn cung cáúp l táút c mạy phạt v hãû thäúng. SVTH: Mai Hải An Trang21 110kV ~ F 1 ~ F 2 ~ F 3 ~ F 4 B 1 B 2 B 3 B 4 220kV ~ H TD TD TD TD 1 N 2 N 7 N 8 N ' 7 N 3 N ' 3 N 4 N 5 N 6 N ' 5 N - ióứm N 2 : duỡng õóứ choỹn khờ cuỷ õióỷn phờa trung aùp 110kV. Tỗnh traỷng sồ õọử trổồùc khi ngừn maỷch laỡ tỏỳt caớ caùc thióỳt bở õang vỏỷn haỡnh bỗnh thổồỡng, nguọửn cung cỏỳp laỡ tỏỳt caớ maùy phaùt vaỡ hóỷ thọỳng. - ióứm N 3, N 3 ' : duỡng õóứ choỹn khờ cuỷ õióỷn phờa haỷ aùp maùy bióỳn aùp lión laỷc. Tỗnh traỷng sồ õọử trổồùc khi ngừn maỷch laỡ tỏỳt caớ thióỳt bở vỏỷn haỡnh bỗnh thổồỡng, nguọửn cung cỏỳp cho N 3 giaớ thióỳt chố coù F 2 laỡm vióỷc, nguọửn cung cỏỳp N 3 ' laỡ ỡ tỏỳt caớ maùy phaùt vaỡ hóỷ thọỳng trổỡ maùy phaùt F 2 . - ióứm ngừn maỷch N 5 ,N 5 ' , N 7 , N 7 ' : duỡng õóứ choỹn khờ cuỷ õióỷn maỷch haỷ aùp maùy bióỳn aùp nọỳi bọỹ. Tỗnh traỷng sồ õọử trổồùc luùc ngừn maỷch laỡ tỏỳt caớ caùc thióỳt bở vỏỷn haỡnh bỗnh thổồỡng, nguọửn cung cỏỳp cho N 5 giaớ thióỳt chố coù F 4 laỡm vióỷc, nguọửn cỏỳp cho N 7 giaớ thióỳt chố coù F 1 laỡm vióỷc, nguọửn cung cỏỳp N 5 ' laỡ ỡ tỏỳt caớ maùy phaùt vaỡ hóỷ thọỳng trổỡ maùy phaùt F 4 , nguọửn cỏỳp N 7 ' laỡỡ tỏỳt caớ maùy phaùt vaỡ hóỷ thọỳng trổỡ maùy phaùt F 1. - ióứm ngừn maỷch N 4 , N 6 N 8 : duỡng õóứ choỹn khờ cuỷ õióỷn cho maỷch tổỷ duỡng. Tỗnh traỷng sồ õọử trổồùc luùc ngừn maỷch laỡ tỏỳt caớ thióỳt bở vỏỷn haỡnh bỗnh thổồỡng, nguọửn cung cỏỳp laỡ tỏỳt caớ maùy phaùt vaỡ hóỷ thọỳng. Dổỷa vaỡo sồ õọ HỗnhVI.1 ta coù: 3N 3N4N ' III += ; 5N 5N6N ' III += ; 7N 7N8N ' III += . IV.1.2. Lỏỷp sồ õọử tờnh toaùn vaỡ xaùc õởnh caùc õaỷi lổồỹng tờnh toaùn: a.Sồ õọử thay thóỳ : Hỗnh IV.1.2 Hinh IV.1.2 b. Xaùc õởnh õaỷi lổồỹng tờnh toaùn: + Choỹn caùc õaỷi lổồỹng cồ baớn: óứ õồn giaớn trong vióỷc tờnh toaùn, choỹn caùc õaỷi lổồỹng cồ baớn sau: SVTH: Mai Haỷi An Trang22 1 E 2 E 3 E 4 E H 1 X 2 X 4 X 3 X 5 X 6 X 7 X 8 X 11 X 10 X 13 X 14 X 9 X 12 X S cb = 100MVA U cb = U tb : nghộa laỡ : U cbIII =230 kV, U cbII = 115kV, U cbI = 10,5kV + Doỡng õióỷn cồ baớn: Cỏỳp 220kV: 251,0 230.3 100 U.3 S I cbIII cb cbIII === (kA) Cỏỳp 110kV: 502,0 115.3 100 U.3 S I cbII cb cbII === (kA) Cỏỳp 10,5kV: 499,5 5,10.3 100 U.3 S I cbI cb cbI === (kA) Giaù trở õióỷn khaùng cuớa caùc phỏửn tổớ trong sồ õọử: - ióỷn khaùng cuớa caùc maùy phaùt nhióỷt õióỷn: 179,0 75,68 100 123,0 S S XXXXX õmF cb d4321 == ==== - ióỷn khaùng cuớa maùy bióỳn aùp 3 pha 2 cuọỹn dỏy B 4 , B 1 : 131,0 80 100 100 5,10 S S 100 %U X 4õmB cbN 5 === 138,0 80 100 100 11 S S 100 %U X 1õmB cbN 6 === - ióỷn khaùng cuớa maùy bióỳn aùp tổỷ ngỏựu lión laỷc B 2 , B 3 : õmB cb TCN cl HTN cl HCN H107 S S %U K %U K %U 200 1 XXX +=== 291,0 160 100 11 5,0 20 5,0 32 200 1 XXX H107 = +=== õmB cb cl HCN cl HTN TCNT118 S S K %U K %U %U 200 1 XXX +=== 028,0 160 100 5,0 30 5,0 20 11 200 1 XXX T118 = +=== õmB cb cl HTN cl HCN TCNC129 S S K %U K %U %U 200 1 XXX === 097,0 160 100 5,0 20 5,0 30 11 200 1 XXX C129 = +=== - ióỷn khaùng cuớa õổồỡng dỏy lión laỷc vồùi hóỷ thọỳng: 04,0 230 100 .100.42,0.5,0 U S lX 2 1 X 22 cbIII cb 013 === SVTH: Mai Haỷi An Trang23 - ióỷn khaùng cuớa hóỷ thọỳng: 009,0 3000 100 27,0 S S XX õmHT cb HT14 === IV.1.3. Tờnh doỡng ngừn maỷch taỷi caùc õióứm. a. ióứm ngừn maỷch N 1 : Sồ õọử thay thóỳ :Hỗnh IV.1.3 Hỗnh IV.1.3 317,0XXX 6115 =+= 47,0XXX 7216 =+= 47,0XXX 10317 =+= 31,0XXX 5418 =+= 049,0XXX 141319 =+= 0485,0 2 097,0 X//XX 12920 === 235,0 2 47,0 X//XX 171621 === 1337,0 31,0235,0 31,0235,0 X//XX 182122 = + == 1822,0XXX 202223 =+= 118,0 1822,0317,0 1822,0317,0 X//XX 231524 = + == Tờnh doỡng ngừn maỷch: - Doỡng ngừn maỷch do caùc maùy phaùt cung cỏỳp: SVTH: Mai Haỷi An Trang24 1 E 2 E 3 E 4 E H 179,0 1 X 179,0 2 X 179,0 4 X 179,0 3 X 131,0 5 X 138,0 6 X 0 8 X 0 9 X 291,0 10 X 097,0 12 X 009,0 14 X 04,0 13 X 291,0 7 X 097,0 9 X 1 N H 1 E 2 E 4 E 3 E 049,0 19 X 317,0 15 X 47,0 16 X 31,0 18 X 47,0 17 X 097,0 9 X 097,0 12 X 1 N H 1 N 049,0 19 X 317,0 15 X 235,0 21 X 0485,0 20 X 31,0 18 X 1 E 23 E 4 E H 1234 E 049,0 19 X 118,0 24 X 1 N 3245,0 100 275 118,0 S S XX cb õmB 24tt === Tra baớng õổồỡng cong tờnh toaùn xaùc õởnh õổồỹc bọỹi sọỳ thaỡnh phỏửn chu kyỡ cuớa doỡng ngừn maỷch: I ckt o = 3,1; I ckt = 2,2. cbIII õmF cktcktF U3 S IIII == -Doỡng ngừn maỷch do hóỷ thọỳng cung cỏỳp: 122,5 049,0 251.0 I X 1 I cbIII 19 NH === (kA) - Doỡng ngừn maỷch 3 pha taỷi N 1 : 262,7122,5 2303 275 1,3I U3 S II NH cbIII õmF 0ckt1N =+ =+ = (kA) 641,6122,5 2303 275 2,2I U3 S II NH cbIII õmF ckt1N =+ =+ = (kA) - Doỡng ngừn maỷch xung kờch: 486,18262,7.8,1.2IK2i 1Nxkxk == = (kA) ( ) 038,11262,7.52,1I1K21I.qI 1N 2 xk1Nxk == += = (kA) b. ióứm ngừn maỷch N 2 : Sồ õọử thay thóỳ : Hỗnh IV.1.4 Hỗnh IV.1.4 317,0XXX 6115 =+= 47,0XXX 7216 =+= SVTH: Mai Haỷi An Trang25 1 E 2 E 3 E 4 E H 179,0 1 X 179,0 2 X 179,0 4 X 179,0 3 X 131,0 5 X 138,0 6 X 0 8 X 0 9 X 291,0 10 X 097,0 12 X 009,0 14 X 04,0 13 X 291,0 7 X 097,0 9 X 2 N H 1 E 2 E 4 E 3 E 049,0 19 X 317,0 15 X 47,0 16 X 31,0 18 X 47,0 17 X 097,0 9 X 097,0 12 X 2 N 1 E 2 E 3 E 4 E H 179,0 1 X 179,0 2 X 179,0 4 X 179,0 3 X 131,0 5 X 138,0 6 X 0 8 X 0 9 X 291,0 10 X 097,0 12 X 009,0 14 X 04,0 13 X 291,0 7 X 097,0 9 X 2 N 47,0XXX 10317 =+= 31,0XXX 5418 =+= 049,0XXX 141319 =+= 0485,0 2 097,0 X//XX 12920 === 235,0 2 47,0 X//XX 171621 === - Bióỳn õọứi Y( X 15 , X 19 , X 20 ) sang ( X 25 , X 26 ) 015,0 317,0 0485,0.049,0 0485,0049,0 X XX XXX 15 2019 201925 =++= ++= 679,0 049,0 0485,0.317,0 0485,0317,0 X XX XXX 19 2015 201526 =++= ++= 1117,0 1337,0679,0 1337,0.679,0 X//XX 222627 = + == Tờnh doỡng ngừn maỷch: - Doỡng ngừn maỷch do caùc maùy phaùt cung cỏỳp: 302,0 100 275 1117,0 S S XX cb õmB 27tt === Tra baớng õổồỡng cong tờnh toaùn xaùc õởnh õổồỹc bọỹi sọỳ thaỡnh phỏửn chu kyỡ cuớa doỡng ngừn maỷch: I ckt o = 3,3; I ckt = 2,25. cbII õmF cktcktF U3 S IIII == -Doỡng ngừn maỷch do hóỷ thọỳng cung cỏỳp: 467,33 015,0 502.0 I X 1 I cbII 25 NH === (kA) - Doỡng ngừn maỷch 3 pha taỷi N 2 : SVTH: Mai Haỷi An Trang26 H 2 N 049,0 19 X 317,0 15 X 235,0 21 X 0485,0 20 X 31,0 18 X 1 E 23 E 4 E H 1234 E 015,0 25 X 1117,0 27 X 2 N 015,0 25 X 679,0 26 X 2 N H 234 E 1 E 13370 22 , X 023,38467,33 1153 275 3,3I U3 S II NH cbII õmF 0ckt2N =+ =+ = (kA) 573,36467,33 1153 275 25,2I U3 S II NH cbII õmF ckt2N =+ =+ = (kA) - Doỡng ngừn maỷch xung kờch: 791,96023,38.8,1.2IK2i 2Nxkxk == = (kA) ( ) 795,57023,38.52,1I1K21I.qI 2N 2 xk2Nxk == += = (kA) c. ióứm ngừn maỷch N 3 , N 5 , N 7 . Giaớ thióỳt nguọửn chố coù 1 maùy phaùt cung cỏỳp + Sồ õọử thay thóỳ : Hỗnh IV.1.5 Tờnh doỡng ngừn maỷch: - Doỡng ngừn maỷch do caùc maùy phaùt cung cỏỳp cuợng chờnh laỡ doỡng ngừn maỷch 3 pha taỷi N 3 : 123,0 100 75,68 179,0 S S XX cb õmB 2tt === Tra baớng õổồỡng cong tờnh toaùn xaùc õởnh õổồỹc bọỹi sọỳ thaỡnh phỏửn chu kyỡ cuớa doỡng ngừn maỷch: I ckt o =8; I ckt = 2,8. cbI õmF cktcktF U3 S IIII == - Doỡng ngừn maỷch 3 pha taỷi N 3 : 242,30 5,103 75,68 8 U3 S II cbI õmF 0ckt3N = = = (kA) 585,10 5,103 75,68 8,2 U3 S II cbI õmF ckt3N = = = (kA) - Doỡng ngừn maỷch xung kờch: 688,81242,30.91,1.2IK2i 3Nxkxk == = (kA) ( ) 294,49242,30.63,1I1K21I.qI 3N 2 xk3Nxk == += = (kA) Tổồng tổỷ õọỳi vồùi N 5 , N 7 : SVTH: Mai Haỷi An Trang27 2 E 179,0 2 X 3 N 242,30III 3N7N5N = = = (kA) 585,10III 3N7N5N === (kA) ( ) ( ) ( ) 688,81iii 3Nxk7Nxk5Nxk === (kA) ( ) ( ) ( ) 294,49III 3Nxk7Nxk5Nxk === (kA) d. ióứm ngừn maỷch 3 N . Sồ õọử thay thóỳ: Hỗnh IV.6 Hỗnh IV.1.6 317,0XXX 6115 =+= 47,0XXX 10317 =+= 31,0XXX 5418 =+= 049,0XXX 141319 =+= 0485,0 2 097,0 X//XX 12920 === - Bióỳn õọứi Y( X 15 , X 19 , X 20 ) sang ( X 25 , X 26 ) 015,0 317,0 0485,0.049,0 0485,0049,0 X XX XXX 15 2019 201925 =++= ++= 679,0 049,0 0485,0.317,0 0485,0317,0 X XX XXX 19 2015 201526 =++= ++= 1868,0 47,031,0 47,0.31,0 X//XX 171828 = + == SVTH: Mai Haỷi An Trang28 097,0 12 X 009,0 14 X 04,0 13 X 1 E 3 E 4 E 179,0 1 X 179,0 4 X 179,0 3 X 131,0 5 X 138,0 6 X 0 8 X 0 9 X 291,0 10 X 291,0 7 X 097,0 9 X ' 3 N H ' 3 N 015,0 25 X 679,0 26 X 291,0 7 X 1868,0 28 X 1 E 34 E 015,0 25 X 291,0 X 7 ' 3 N H 134 E 1465,0 29 X 049,0 19 X H 1 E 4 E 3 E 317,0 15 X 291,0 7 X 31,0 18 X 47,0 17 X ' 3 N 0485,0 20 X 1465,0 1868,0679,0 01868.679,0 X//XX 282629 = + == - Bióỳn õọứi Y( X 7 , X 25 , X 29 ) sang ( X 30 , X 31 ) 3357,0 1465,0 015,0.291,0 015,0291,0 X XX XXX 29 257 25730 =++= ++= 2796,3 015,0 1465,0.291,0 1465,0291,0 X XX XXX 25 297 29731 =++= ++= Tờnh doỡng ngừn maỷch: - Doỡng ngừn maỷch do caùc maùy phaùt cung cỏỳp: 764,6 100 75,683 2796,3 S S XX cb õmB 31tt = == X tt = 6,764 > 3 nón khọng duỡng phổồng phaùp õổồỡng cong tờnh toaùn 6766,1 5,103 75,683 764,6 1 U3 S X 1 X I I cbI õmF tttt F = = == - Doỡng ngừn maỷch do hóỷ thọỳng cung cỏỳp: 381,16 3357,0 499,5 I X 1 I cbI 30 NH === (kA) - Doỡng ngừn maỷch 3 pha taỷi 3 N : 0576,18381,166766,1III NHF3N =+=+= (kA) 0576,18381,166766,1III NHF 3N =+=+= (kA) - Doỡng ngừn maỷch xung kờch: 967,450576,18.8,1.2IK2i 3Nxkxk == = (kA) ( ) 447,270576,18.52,1I1K21I.qI 3N 2 xk3Nxk == += = (kA) e. ióứm ngừn maỷch N 5 ' . Sồ õọử thay thóỳ Hỗnh IV.1.7 SVTH: Mai Haỷi An Trang29 H 134 E 2796,3 31 X ' 3 N 3357,0 30 X 1 E 2 E 3 E H 179,0 1 X 179,0 2 X 179,0 3 X 131,0 5 X 138,0 6 X 0 8 X 0 9 X 291,0 10 X 097,0 12 X 009,0 14 X 04,0 13 X 291,0 7 X 097,0 9 X ' 5 N Hỗnh IV.1.7 317,0XXX 6115 =+= 47,0XXX 7216 =+= 47,0XXX 10317 =+= 049,0XXX 141319 =+= 0485,0 2 097,0 X//XX 12920 === 235,0 2 47,0 X//XX 171621 === - Bióỳn õọứi Y( X 15 , X 19 , X 20 ) sang ( X 25 , X 26 ) 015,0 317,0 0485,0.049,0 0485,0049,0 X XX XXX 15 2019 201925 =++= ++= 679,0 049,0 0485,0.317,0 0485,0317,0 X XX XXX 19 2015 201526 =++= ++= 1757,0 679,0235,0 679,0.235,0 X//XX 262132 = + == - Bióỳn õọứi Y( X 5 , X 25 , X 32 ) sang ( X 33 , X 34 ) 157,0 1757,0 015,0.131,0 015,0131,0 X XX XXX 32 255 25533 =++= ++= SVTH: Mai Haỷi An Trang30 H ' 5 N 015,0 25 X 679,0 26 X 235,0 21 X 131,0 5 X 1 E 23 E H 1 E 3 E 049,0 19 X 317,0 15 X 131,0 5 X 47,0 17 X ' 5 N 0485,0 20 X 2 E 47,0 16 X 131,0 5 X 015,0 25 X 1757,0 32 X H 123 E