Presentation to CIGRE Next Generation Network Visit of Seine substation Projet Seine 30 août 2012
Contents 0. Presentation of RTE 1. Power supply of «Ile-de-France» and Paris 2. 225 kv Paris substations - Civil Works characteristics 3. Seine substation : The Gas Insulated Substation 4. Introduction to underground lines design 2
0. Presentation of RTE 3
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KEY FIGURES ABOUT RTE TRANSMISSION LINES about 100 000 km of circuits 46 cross-border lines 400 kv Network CIRCUIT LENGTH IN OPERATION (km) 400 kv 21 093 225 kv 26 322 150, 90, 63 et 45 kv 52 759 6
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REVENUE SOURCES 2010 /
COST STRUCTURE 2010 /
A REGIONAL COMPANY 7 regional systems covering France Normandy-Paris, North-East, East, West, South-West, South-East, Rhône-Alpes Auvergne Power System units Regional network dispatching Regional network development Electricity Transmission units Network operation and maintenance Network development engineering /
1. Power supply of «Ile-de-France» and Paris 11
Part of the French 400 kv network 12
Ile-de-France power supply : a specific case in France A 400 kv loop diameter of 60 km A 225 kv loop diameter of 15 km 13
225 kv cable 225/20 kv substations A 225 kv radial cable feeds up to 3 substations 225/20 kv, forming 3 crowns 14
36 substations (225/20 kv) feed the 20 kv underground network 15
225 kv cables 100 MVA 20 kv 220/20 kv substation with 1x100 MVA transformer 16
225 kv cables 70 MVA 20 kv 70 MVA 220/20 kv substation with 2x70 MVA transformers partially guaranteed 17
Artère 1 Artère 2 Artère 3 Artère 4 Two 220/20 kv substations are connected by 4 MV arteries Each artery has 6 MV cables in // 18
220/20 kv substations 20 kv arteries Normal scheme of operation 19
Re feeding arteries after a loss of a 220/20 kv substation 20
Re feeding arteries after a loss of a 220/20 kv substation 21
On going evolutions to secure the 220/20 kv substations 22
2. 225 kv Paris substations Civil Works characteristics 23
Example of three 225kV Substations 24
Gambetta 225kV Urban Substation 25
La Muette 225kV Urban Substation 26
Seine 225kV Building Substation 27
1. Fire protection: Urban substation: key concerns Objective: limit the effect of a fire in the substation building (explosion of power transformer) to protect the neighborhood Mitigation technique: use of very specific fire protection devices (on-site water tank, temperature/pressure sensors, fire-resistant walls ) 2. Noice cancellation: Objective: limit the sound emitted by the substation (cooling of power transformer) that troubles neighbours Mitigation technique: use of sound trap and antivibration plots 3. ElectroMagnetic Field: Objective: do not exceed the legal limit of 100 µt (High current circulating in the MV cables) outside the building Mitigation technique: move away those cables in the layout, use of reduced EMF laying 28
Usual urban substation layout longitudinal section Oil tank Oil Radiator Power transformer Ground level water water Fire protection 225kV metal-clad busbars (SF 6 insulated)
1. Detection loop Fire protection Pneumatic circuit (no electrical supply required due to reliability requirement) Quartz bulbs (burst when temperature increases) 225kV and 20kV breakers tripped off 2. First sprinkling circuit Water pushed by CO 2 tanks 3 spray rings Water tank of 12 m 3 Sprinkling for 2 min 3. Second sprinkling circuit Water pushed by CO 2 tanks 2 spray rings Water tank of 20 m 3 Sprinkling for 10 min
Transformer cooling and noise cancellation
Transformer cooling and noise cancellation
Seine 225kV transformer building 33
Seine 225kV transformer building Ground level 34
3. Seine substation: Gas Insulated Susbstation 35
SEINE substation : a key component of the Nord of Ile-de-France power supply An area of influence on the 225 kv loop surrounding Paris: 600 000 inhabitants of Seine Saint Denis region and Paris (1st, 2nd, 9th et 18th arr.) Stade de France SNCF (TGV Nord, North suburbs ) Seine substation RATP (1/4 of subways and RER) Global cost of the projet : 75 M 36
The evolution of an area From an industrial past to an urban environment L Ile StSt-Denis Villeneuve-Villeneuve La--Garenne La Autoroute A86 Poste Seine Saint--Denis Saint To remove To buld 37 Saint--Ouen Saint Poste Ampère à 225 kv Project of ecological river quarter Project of Cité du Cinéma
Plan of Seine substation Transformers Towers GIS x Control Command Site actuel Projet Cité du Cinéma 38
Seine substation : Gas Insulated Substation The Gas Insulated Substation technology (GIS) RTE owns approx. 120 GIS (20 new S/S in the next 5 years). The first S/Ss built in 1969 are still in service The substation surface area is significantly reduced (1/10 of the equivalent AIS) SEINE was manufactured by SIEMENS Grenoble in 2009/2010 Equipped with digital SF6 monitoring 39
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Radial cable : SEINE - CAULAINCOURT - PYRAMIDES SEINE Caulaincourt 2 4 3 1 PYRAMIDES TR 611 TR 612
Caulincourt Plessis Gassot 2 Revest 1 Tr 631 Plessis Gassot 4 La courneuve Plessis Gassot 3 Tr 632 Couplage Ampère Tr 613 Revest 2 St Ouen 2 Plessis Gassot 1 Ampère Tr 612 St Ouen 1 42
Feeder bay Disconnector 1 Circuit breaker Current transformer Earthing switch Cable box 43
Other types of gas compartments Busbar earthing switch Maintenance disconnector Voltage transformer Line disconnector Voltage measurement on 1 phase Double cable box 44
Buffer compartments to increase availability during maintenance works and testing 45
Accessibility for the time-based maintenance Adding of a catwalk Mobile platform 46
Transformers The Power Transformers Installation 2 power transformers : Rated Power Sr : 100 MVA / 100 MVA / 65 MVA, Rated Voltage Ur : 225/64,5/21 kv - YNd11d11, cooling: ODAF. 2 shunt reactors connected to the LV winding (21 kv) of the power transformers: Réactive power: Q : 64 Mvar; cooling : ONAN, Rated Voltage Ur : 21 kv - Y. 2 neutral grounding transformers connected to the 63 kv network: Rated Power Sr : 500 kva; cooling : ONAN, Rated Voltage Ur : 68,5 / 11 kv - YNd11. 2 auxiliary transformers connected to the LV winding (11kV) of the grounding transformers: Rated Power Sr : 250 kva; cooling : ONAN The only one transformer of that kind in France Rated Voltage Ur : 10,5 kv / 400 V YNzn11. 47
Transformers and reactors The main alternatives 1. Two standard 100 MVA + 2 x 80 MVAr / 225 kv reactors (standard specification) 2. Two specific 100 MVA with a 65 MVA tertiary + 2 x 64 MVAr / 20 kv reactors The second solution was 25 % cheaper than the second one Main specifications Same Short circuit impedance and turn ratio as standard 100 MVA transformers Same overload capabilities as standard 100 MVA transformers Voltage dip < 3% on the 63 kv network when switching on the 64 MVAr reactor specific design 13,0 % MV HV - 1 % 15,1 % LV 64 MVAr LV HV MV 48
4. Introduction to underground lines design 49
Underground cable Outer semi-conductive layers (sheath test after laying) Outer and inner semiconductive layers (avoid point effect in the electric field) Outer sheath (PE) Metal screen (short-circuit current) Insulation (XLPE) Core conductor (current flow) 50
Cable laying Cables laid in plastic pipes to reduce disturbances from the civil works Cables laid: in PEHD pipes in the ground (on the left) or in PVC pipes embedded in concrete (on the right) Challenge: -Fault containment -Heat dissipation -Magnetic field 51
Cable design When current flows through the core conductor, losses lead to temperature rise in the cable. The limitation comes from the XLPE insulation which can withstand a maximum 60 C. Losses are due to: Joule losses in the core conductor (current flow) Dielectric losses in the insulation (not an ideal insulation) Joule losses in the metal screen (in case of induced current) The underground line rating comes from the capacity of the cable and its environment to dissipate heat. As a result it becomes paramount to take also into consideration the ground drying out, which affects the ground heat conductivity and can lead to cable fault. 52
Heat dissipation Joules losses in the metal screen Dielectric losses Joules losses in the core conductor Heat dissipation through the ground 53
Main factors for thermal design of the cable Core conductor size. Ground characteristics. Current circulation in the metal screen. Laying method (distance between cables, laying depth, ). Weather conditions. Heat sources in the ground. 54
Cable bonding When current flows through the core conductor, it induces voltage in the metal screen. This induced voltage must be controlled in order to protect people and equipments. First solution: direct grounding at both cable ends. Core Sheath Termination Direct grounding Problem: current circulation reduces the cable rating. This solution is adapted for low rating lines (under 600A). 55
Cable bonding Second solution: single point grounding (at one end or middle point). Result: no current in the screen but voltage build-up at one cable end. Surge arresters to protect the cable sheath Parafoudres de gaine Conducteur de terre isolé Insulated ground cable Problem: voltage limited to 400V in normal operation, thus limited to short lines (a few kilometres only). 56
Cable bonding Third solution: cross-bonding. Result: similar to direct grounding, but the screen cross-bonding erases the current circulation in the metal screen. Screeninterruption Sheath Core Surge arresters X-bonding pits Problem: more expensive (need for screen interruption joints protected by surge arresters). 57
Cable bonding Third solution: cross-bonding. Induced voltage in the metal screens. A B L U 0 L 2L 3L The maximum length L is defined according to the voltage withstand by the screen interruption joints. 58
GIS cable terminations 59
GIS cable terminations 60
Underground lines at Seine station Name Voltage (kv) Section (mm²) Core Screen Supplier Length (km) Grounding Ampère Seine 1 225 1200 Cu Al Silec 0.46 Single side in Seine Ampère Seine 1 (TR631) 63 1200 Cu Al Silec 0.78 Single side in Seine Ampère Seine 2 225 630 Al Al Nexans 0.44 Single side in Seine Ampère Seine 2 (TR632) 63 1200 Cu Al Silec 0.63 Single side in Seine Plessis Gassot Seine 1 225 1600 Cu Al Prysmian 0.19 Single side in Seine Plessis Gassot Seine 2 225 1600 Cu Al Prysmian 0.14 Single side in Seine Plessis Gassot Seine 3 A&B 225 2x1600 Cu Al Prysmian 0.14 Single side in Seine Plessis Gassot Seine 4 A&B 225 2x1600 Cu Al Prysmian 0.12 Single side in Seine Revest-Seine 1 & 2 630 / Prysmian 2.36 / 225 Al Al (SNCF 2 phases) 400 / Silec 2.33 Single side in Seine LS TR631 225 630 Al Al Prysmian 0.12 Single side in Seine LS TR632 225 630 Al Al Prysmian 0.05 Single side in Seine Caulaincourt - Seine 225 1200 / 1000 Cu Al Silec 4.55 Direct grounding Courneuve - Seine 225 1200 Cu Al Silec 7.67 Cross-bonding UG line between TR631 and its Neutral Point 63 630 Al Al Nexans UG line between TR632 and its Neutral Point 63 630 Al Al Nexans Seine St Ouen 1&2 225 1200 Al Al Nexans 4.63 Middle point grounding 61