The GAS-INSULATED SWITCHGEAR HALL (GIS Hall)
is the heart of TMSR500 electrical operations
The GAS-INSULATED SWITCHGEAR HALL (GIS Hall) is the heart of TMSR500 electrical operations. The expertly arranged electrical equipment, immersed in exceptional insulating gas, guarantees smooth and efficient electrical operations within the power system. The GIS hall structure exhibits similarities to the turbine hall.
- Main Transformers
With a weight of approximately 100 tons, three single-phase transformers are located at the forward end of the GIS hall and are accessible through hatches. Big conservatively designed transformers are known for their reliability, but it is worth noting that their level of reliability is significantly lower than that of other major, long-lead time components in the plant. Consequently, ThorCon has implemented a strategy of storing a spare transformer in the port aft corner of the turbine hall, allowing for quick and efficient replacement of a transformer without the need for outside assistance.
- Low Voltage Side
The 21 to 26 kV power will be transmitted through bus ducts from the main generator aft to a 25000 amp Generator Circuit Breaker located just aft of the TG on the center line, and then to the delta-wired low voltage side.
- High Voltage Side
The wye-connected high voltage side facilitates the flow of power from the transformers to the gas insulated circuit breaker. If the Isle is situated close to the shore, the power will be transmitted ashore via conventional, air-insulated transmission lines. For offshore locations, subsea cables will be utilized for the transmission of power.
- Auxiliary Transformer
The auxiliary transformer is a 15 MVA, three-phase device that reduces the grid voltage to 6.6 kV. This power is then transported from the GIS hall on either side of the turbine hall to the port and starboard PMOD support areas. The 6.6 kV bus is powered by the sentry turbine generator and the black start generators. The auxiliary transformer is capable of functioning in both directions.
- House Load Cabling
The cables running from the aft end of the GIS hall to the VFC room are well protected along their entire route. ThorCon has made ample provision for the cables and is willing to invest in additional protective measures if necessary.
- Inner Bottom Level
This area contains water reserves that can be used to extend the grace period during an extreme emergency event, as well as diesel oil tanks that have sufficient capacity for four cold start operations.
- Space for HVDC
ThorCon has set aside ample space for high-voltage direct current (HVDC) rectification. In instances where the Isle is more than 50 km offshore or the grid calls for DC, this area will house the VSC AC to DC valves and their accompanying equipment. With Voltage Source Commutation (VSC) technology, ThorCon can confidently provide the reactive power required by the grid without reliance on high-quality AC power, and can also flexibly produce reactive power to meet the grid’s evolving needs.
- Black Start Generators
The black start generators are the sole source of power during the tow. They provide a crucial “black start” capability by supplying initial power to the auxiliary boiler and sentry turbine. In addition, they are used to power the ballast pumps during ballasting and deballasting, and provide backup power for the firefighting and deluge system. In the event of a station blackout, they can also provide lighting, instrumentation, and hotel services.
- Other GIS Hall Equipment
The GIS Hall will also be equipped with sewage treatment plant, aircon plant, step down transformers for smaller in-house loads, and store cranes.