BL20A0501 Electricity distribution technology. Introduction Jarmo Partanen

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2 BL20A0501 Electricity distribution technology Introduction Jarmo Partanen

3 Introduction to ED Prof. Jarmo Partanen, D.Sc Jukka Lassila Topics of lectures Introduction to Electricity Distribution, ( ), 6426 Methods for electrical, economic and reliability calculations, ( ), 6426 Strategic planning of electricity distribution network, 3.11 ( ), 6426 Planning of primary substations and medium voltage networks 4.11 ( ), 6311 Structures and planning of distribution substations and low voltage networks, ( ), 6311 Short circuit and earth fault protection of distribution networks ( ), 6311 Operation of distribution systems ( ), 6426 Electricity distribution automation, 1.12 ( ), 6426 Smart Grids, 2.12 ( ), 6311

4 Introduction to ED Local 110 kv networks Primary substations 110/20 kv (110/10 kv) Medium voltage networks 20 kv (10 kv) Distribution substations 20/0,4 kv Low voltage networks 1.0, 0.4 kv Industrial networks 20, 10, 6, 3, 0,6, 0,5, 0,4 kv Electricity distribution network radially operated a lot of lines and nodes low prices of components (compared to transmission level) a lot of similar design and construction tasks well analysed cases principles huge amount of input data for calculations including uncertainty 4

5 Background 400 V 110/20 kv Primary substation ( MVA) 20 kv Network structure in rural areas: Mostly overhead lines (400 V, 20 kv, 110 kv), 3-phase system at all voltage levels Feeders, in Finland: Total km of distribution lines: 20 kv 400 V 400 V low voltage (62 %) and 20 kv medium voltage (38 %) lines MV (20 kv): km/feeder LV (400 V): 116 m/customer 5

6 Medium voltage networks (20 kv) 1) City company customers km 20 kv - Peak power 45 MW - Cabling rate 72 % MARTINKYLÄ 110/20 kv 2) Rural area company customers km of 20 kv network - Peak power 50 MW - Cabling rate 12 % 20/0.4 kv distribution substation ( kva) 110/20 kv MASSBY 110/20 kv 20/0.4 kv distribution substation ( kva) KALLBÄCK kv underground cable Finnish distribution companies 110/20 kv LANDBO Number of customers (total number 91) 1) 2) 10 miles 20 kv overhead line 6

7 110/20 kv Electricity Distribution in Rural Area 20/0.4 kv 110/20 kv primary substation 20/0.4 kv distribution substation 20 kv Road 500 m = 0.3 miles Avg km/feeder (20 30 miles/feeder) % inside forests 20 kv overhead line 7

8 Medium voltage networks (20 kv) 110/20 kv Control room automation (SCADA, GIS, automatic fault location and separation ) Substation automation (110/20 kv) Manual 20 kv disconnector Remotecontrolled 20 kv disconnector NEED FOR.. 20 kv feeder (65 km) - several branch lines - some rings yet radially operated 2 miles Pole-mounted switchgear (reclosers) 8

9 Low voltage networks (400 V, 3-phase) 110/20 kv = 20/0.4 kv distribution substation MARTINKYLÄ 20 kv 20 kv MASSBY 400 V 400 V KALLBÄCK LANDBO 20 kv 400 V 20 kv medium voltage network 400 V 1 mile (1.6 km) 9

10 Electricity Distribution in Rural Area 20/0.4 kv distribution substation ( kva) 400 V 400 V ABC line (3-phase system) AMR 400 V 150 feet Road 20 kv 400 V underground cable Lappeenranta University of (3~) Technology 10

11 Ownership of distribution companies Elenia Fortum E.ON 85 companies 10 biggest, customers: Fortum Sähkönjakelu Oy Helsingin Energia Vattenfall Siirto Oy Espoon Sähkö Oyj Tampereen Sähkölaitos Uudenmaan Sähköverkko Oy Savon Voima Oyj Järvi-Suomen Energia Oy Vantaan Energia Oy Pohjois-Karjalan Sähkö Oy

12 Introduction to ED - 110/20 kv primary subsstation 110 kv components (circuit-breaker, voltage transformer (VT), current transformer (CT) ) Main transformers, 1-3 units, S n = MVA, voltage regulation 20 kv busbar 1-busbar system 1½-busbar system 2-busbar system double-busbar system 20 kv feeder shells circuit breaker disconnectors CT; load current, protection, zero current coils protection relays; short circuit, earth fault, recloser, voltage measurement cell busbar voltage measurement earth fault protection, neutral voltage, open delta connection Auxiliary supply DC-system, batteries 12

13 Introduction busbar systems K1 K2 PM1 25 MVA PM2 16 MVA Teknikum 2 MW Nybacka 1 MW Myllynummi 2.0 MW Koff 4.5 MW Sorsakorpi 1.5 MW Nissilä 2.5 MW Omakäyttö SA1_22 Alikerava II Koff SA1_20 Kilta SA1_18 Alikerava I Jäspilänpiha SA1_16 SA1_14 Lapila SA1_12 Varayhteys uudelle asemalle SA1_10 Varayhteys uudelle asemalle SA1_8 SA1_4 Syöttö uudelta asemalta I SA1_2 SA1_21 SA1_19 SA1_17 SA1_15 SA1_13 SA1_11 SA1_9 SA1_7 SA1_5 SA1_3 Syöttö uudelta asemalta II Peltomäenkatu Keskusta Sompio Kannisto Sampola Savio Ifi/Stowe Voimala 13

14 Introduction to ED medium voltage networks 3-phase system, 20 kv, 10 kv open loops, radially operated disconnectors in open points between feeders, partly remotely controlled backup routes neutral isolated or system earthed via arc-suppression coil (centralized or distributed) protection by relays and circuit-breakers typical transmission capacity some megawatts and km (in Lapland areas even 100 km) 14

15 Introduction to ED medium voltage networks Overhead lines ACSR conductors mm 2 price k /km Covered over head lines (PAS-lines) thin isolation not full touch safety more narrow line route, double and triple lines lower fault rate % more expensive than overhead line High voltage overhead cable SAXKA used when special environment requirements Underground cables full isolation, plastics cross-sections mm 2 price k /km based on digging environment 15

16 Introduction to ED distribution substations Disconnector between 20 kv line and transformer Substation + transformer pole mounted substations in overhead networks bad mounted or building substations in cable networks Low voltage substation simple fuse-box in pole mounted substations real swicthboard in pad-mounted substations Body of transformer is grounded (connected to earth, protection against touch voltages) 16

17 Introduction to ED low voltage networks 3-phase system, neutral (neutral conductor) earthed Radial network, rarely backup connections AMKA-conductors (aerial bundled cable) in rural areas mm 2, k /km Plastic underground cables in urban networks ploughing when possible mm 2, k /km swicthing boxes Protection by fuses; overload, short circuit, touch voltages Protective and neutral groundings are connected to each other 17

18 North-American distribution system Primary substation (HV/MV) HV/MV transfomer Neutral conductor Switchgear/ Circuit breaker MV branch line MV trunk line, e.g. 11 kv Fuses Sectionaliser, recloser Distribution substation (MV/LV) Automated disconnector Distribution transformer KJ MV-lines Trunk line: 3 phases + neutral Branch line: 1, 2 or 3 phases + neutral LV LV (127 V)

19 Sockets in different market areas a) b) c) a) Europa b) USA ja Japan c) Great Britain

20 MV-lines in Canada, 11 kv 1-phase 11 kv line

21 MV-lines in Canada, 11 kv Fuse 1-phase transformer Neutral conductor

22 MV-lines in Canada, 11 kv Fuses 3-phase transformer

23 Introduction to ED design of lines Main constraints voltage drop long 20 kv and 0.4 kv over head lines losses main 20 kv overhead lines thermal capacity main 20 kv and 0,4 kv lines in cable networks short-circuit current conductors of 20 kv branch lines near to feeding point (110/20 kv primary substation) quick operation of fuses (short circuit current vs. fuse size) long distance 0.4 kv lines having low loads reliability medium voltage networks and primary substations economy always important 23