8.67 One‐line diagram for two parts of the 69 kV GIS, simplified draw...Figure 8.68 Side elevation of the GIS with SF6 gas‐to‐air bushing, simplifie...Figure 8.69 Plan view of the 69 kV GIS substation, simplified drawingFigure 8.70 Side elevation of the 69 kV GIS with underground cable interface...Figure 8.71 Side elevation of the 69 kV GIS bay with circuit breaker and und...Figure 8.72 Compact design of the 69 kV GISFigure 8.73 Underground substation for 69 kV below a city parkFigure 8.74 Electrical single‐line scheme of the 69 kV underground GISFigure 8.75 Top view of the 69 kV underground GISFigure 8.76 Side view of the cable bayFigure 8.77 Entrance to the underground substationFigure 8.78 Emergency exit of the underground substation in the parkFigure 8.79 Outside view of the lightweight GIS buildingFigure 8.80 Inside view of the 8 bays GIS during erection. Front sideFigure 8.81 Inside view of the 8 bays GIS during erection. Rear sideFigure 8.82 View to vertical circuit breaker enclosures with connected groun...Figure 8.83 View to outgoing three phase bus lines. Rear sideFigure 8.84 History of BergenFigure 8.85 Conclusion of the site evaluationFigure 8.86 Electrical layout of the substationFigure 8.87 Physical layout of the substationFigure 8.88 Camera system for disconnects and grounding switchesFigure 8.89 Gas density monitoring systemFigure 8.90 UHF partial discharge monitoring systemsFigure 8.91 Providing the foundationFigure 8.92 Erection of the GIS buildingFigure 8.93 GIS under constructionFigure 8.94 GIS installation completed (left) and walkway in GIS bays (right...Figure 8.95 Bergen switching station, 230 kV, 80 kA with gantry supportsFigure 8.96 Gas‐insulated bus section to connect the GIS in the building to ...Figure 8.97 Bergen switching station aerial viewFigure 8.98 Left: top view of city center, right: possible route of electric...Figure 8.99 Left: GIL laid in an open trench, Right: GIL laid under a concre...Figure 8.100 Left: GIL laid in a concrete tunnel, Right: GIL laid directly i...Figure 8.101 GIL laid in a squared tunnel of 2.4 m width and 2.6 m height...Figure 8.102 Overview Street House ConceptFigure 8.103 Upper: cross‐section Street House Concept, lower: detail concre...Figure 8.104 Left: Street House Concept with tall office towers, right: Stre...Figure 8.105 Cross‐section of Street House at junction point with parking se...Figure 8.106 Left: access roads and integration of building complex to stree...Figure 8.107 Safe electric power transmission lines using GIL below office b...Figure 8.108 Impression of street house complex with electric power transmis...Figure 8.109 City Junction North Line, black line: existing overhead line, o...Figure 8.110 Infrastructure at City Junction North LineFigure 8.111 Principal design of 245 kV XLPE power cableFigure 8.112 Principal design of 550 kV GIL laid in a tunnel [7, 8, 10]Figure 8.113 Example of 2 three‐phase circuits 550 kV in a tunnel with reser...Figure 8.114 Top view of City Junction North, solid lineFigure 8.115 Overview of routing obstacles along City Junction North LineFigure 8.116 Connecting point overhead line (OHL) to GIL in a tunnelFigure 8.117 Upper part: example of highway crossing tunnel between two shaf...Figure 8.118 Example of height deviation level between residential area and ...Figure 8.119 Example of narrow space between residential area and highway...Figure 8.120 Example of bridge above high junction street sectionFigure 8.121 Example of underground tunnel section at access road to highway...Figure 8.122 Example of large tunnel with four segments for 550 kV GIL and 2...Figure 8.123 Example of tunnel boring machineFigure 8.124 Principal laying process of GIL in a tunnel through access shaf...Figure 8.125 Upper part: example of ventilation of four GIL circuits in two ...Figure 8.126 Ventilation shaft to segmented tunnel and minimized visual impa...Figure 8.127 Ventilation and access shaft of GIL or cable tunnel integrated ...Figure 8.128 Assembly of GIL through tunnel shaft and pull into tunnelFigure 8.129 Lifting GIL segments to positions at tunnel steel structures...Figure 8.130 Containerized substation, 123 kVFigure 8.131 Containerized substation, 123 kV – extension is in extremely co...Figure 8.132 Single‐line substation layout of a 72.5 kV GIS mounted on a tru...Figure 8.133 Substation layout of a 72.5 kV GIS mounted on a truck trailer –...Figure 8.134 Mobile 420 kV GIS mounted on a truckFigure 8.135 Mobile 420 kV GIS connected in the substationFigure 8.136 Mobile high‐ and medium‐voltage substationFigure 8.137 Mobile high‐voltage GIS mounted on a truck trailer – electrical...Figure 8.138 Mobile high‐voltage GIS mounted on a truck trailer – T‐connecti...Figure 8.139 Mobile medium‐voltage GIS mounted on a truck trailer – cable co...Figure 8.140 Mobile high‐ and medium‐voltage GIS substation – multibay confi...Figure 8.141 Mobile 72.5 kV voltage GIS – 15 bays double bus bar configurati...Figure 8.142 Overview of a typical design of mixed technology switchgear (MT...Figure 8.143 Space requirement comparison of AIS, GIS, and MTS circuit break...Figure 8.144 MTS module 420/550 kV with CB/SW/CT combinationFigure 8.145 MTS 550 kV bay module with CB/SW/CT combination and vertical bu...Figure 8.146 MTS 145 kV double circuit breaker with circuit breaker, disconn...Figure 8.147 Compact substation – double outdoor cable bay of 145 kV, 31.5 k...Figure 8.148 Compact substation – double bay on the roof of a substation bui...Figure 8.149 Compact substation – single‐phase insulated bay of 230 kV, 50 k...Figure 8.150 Compact substation – three‐phase insulated outdoor bay of 132 k...Figure 8.151 Three‐phase insulated outdoor bay to connect a wind farm of 145...Figure 8.152 Single‐phase insulated outdoor bay used to sectionalize an air‐...Figure 8.153 Progress in size reduction, example of the 145 kV GISFigure 8.154 Construction of a Rogowski coilFigure 8.155 Principle of the Rogowski coilFigure 8.156 Application of a Rogowski coilFigure 8.157 Construction of a capacitive dividerFigure 8.158 Principle of a capacitive dividerFigure 8.159 Groundwater treatment, upper part: water level at underground b...Figure 8.160 High‐temperature fire of burning oil of transformerFigure 8.161 Separated ventilation for transformer and buildingFigure 8.162 Sprinkler system on the ceiling (left), water drainage system o...Figure 8.163 On the left photo, the fire protection control system is shown,...Figure 8.164 Fresh air outlet and dust cleaner, left: under the transformer,...Figure 8.165 Left: transformer‐encapsulated termination with XLPE at 110 kV,...Figure 8.166 Left: substation ventilation shaft from the basement of the bui...Figure 8.167 Reduced air exchange by using air conditioning, left: switchgea...Figure 8.168 Typical air conditioner system to compensate the heat released ...Figure 8.169 Heating exchanger from transformer oil to the building heater...Figure 8.170 Left: sound absorbing cover on the ceiling, right: sound absorb...Figure 8.171 Acoustic solutions for underground substation ventilationFigure 8.172 Use of surge arresters to protect from lightning strokes (left)...Figure 8.173 Substation control room next to the high‐voltage switchgear of ...Figure 8.174 Vicinity of people and public, left: at underground substations...Figure 8.175 Left: 145 kV and 3150 A high‐voltage GIS, right: 11 kV and 2000...Figure 8.176 Completely underground substation with a public park on the top...Figure 8.177 Semi‐underground substation in a sloop between street, public p...Figure 8.178 Underground substation with a public park on the topFigure 8.179 Substation building above ground in a city centerFigure 8.180 Substation in an exhibition area installed undergroundFigure 8.181 Substation under a park or green field in the city centerFigure 8.182 Substation under a square or plaza in the city centerFigure 8.183 Architectural solutions for substation in the city center, left...Figure 8.184 City center development, left: city view in 1980s, right: city ...Figure 8.185 City development with three new underground substationsFigure 8.186 Substation integrated at the convention centerFigure 8.187 Substation integrated in Financial District (left) and city cen...Figure 8.188 420 kV GIS substation for industrial aestheticsFigure 8.189 Example of a project execution schedule of an underground subst...Figure 8.190 Left 110/10 kV GIS Substation in the basement of a building com...Figure 8.191 Access shaft for 110/10 kV transformer 40 MVA at underground le...Figure 8.192 Access shaft for 110/10 kV transformer 40 MVA at underground le...Figure 8.193 330/132 kV Downtown Business District substation, left: locatio...Figure 8.194 330/132 kV Downtown Business District substation, left: four ba...Figure 8.195 Hydropower plant, left: Damn in a mountain valley, right: acces...Figure 8.196 Hydropower plant, left: Seven bays of 420 kV GIS, double busbar...Figure 8.197 Hydropower plant, dam overview in a remote mountainous area dif...Figure 8.198 Hydropower storage plant, left: connection to 245 kV power grid...Figure 8.199 Hydropower storage plant, left: entering the cavern through a t...Figure 8.200 Substation building at desert conditions 132/11 kV, left: subst...Figure 8.201 Residential area city substation 132/11 kV, left: overview of s...Figure 8.202 Three‐voltage‐level substation 1 of 11/66/220 kV, left: substat...Figure 8.203 Three‐voltage‐level substation 2 building of 11/66/220 kV inclu...Figure 8.204 Stadium substation left: stadium overview, with 110/10 kV GIS b...Figure 8.205 Prefabricated concrete slab under the grass floorFigure 8.206 Monument Park substation of 132 kV GIS, left: access to substat...Figure 8.207 City center transmission voltage substation 245 kV GIS, left: s...Figure