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5 achievement(s) found In order to accompany the nuclear fusion research activities of the ITER project, it has proved necessary to improve the Japanese JT60 fusion reactor (tokamak). Capsim has participated in the design of the project by modelling all of the electrical supply infrastructure and by simulating the current draw necessary for a plasma shot.
The objective was to evaluate the impact in terms of the active power, reactive power, frequency and voltage of the network, and to verify the correct sizing of the equipment that makes up the system. [...]ITER is a very large-scale international scientific experiment for demonstrating the scientific and technological feasibility of electricity production using energy from nuclear fusion and leading to its industrial and commercial production.
CAPSIM is undertaking a project to assist its customer, ITER ORGANIZATION, in the selection of architecture and in sizing the HVA and HVB electrical power grids.
The study includes performing the initial sizing of electrical equipment that will in future be used for the grid to auxiliary systems of the ITER facility.
This grid, known as the Steady State Electrical Power Network (SSEPN), is connected to a double circuit 400 kV line. It is able to supply the ITER auxiliary systems, i.e. cooling, cryogenics and pumping systems, etc.
The total power of the installed loads is 160 MW and 80% have medium voltage induction motors.
The network contains high/medium voltage transformers supplying the principal busbars. At each start up, the required electrical power is distributed to the various production and generation sectors via the circuit breakers, cables and step-down transformers. [...]This study involved determining the influence of the tolerances applied to the various parameters of a motor driven pump and its power supply system, on its capacity to change from a low speed regime to a high-speed regime. This equipment delivers a cooling function for a nuclear application. [...]ITER is a very large-scale international scientific project for demonstrating the scientific and technological feasibility of electricity production using energy from nuclear fusion and leading to its industrial and commercial production.
With this goal, a magnetic plasma confinement system called a tokamak has been constructed using superconducting coils. These coils are supplied on a 66 kV and 22 kV distribution grid via AC/DC thyristor converters (12 pulses). This grid is supplied by three 3-winding transformers, 400kV/66kV/22kV, allowing it to be connected to the RTD grid on a dedicated 400 kV line.
The power consumption of the coils fluctuates greatly during a plasma shot and, in particular, during its initiation and extinction. The impact of these power fluctuations on the grid needed to be estimated in order to validate adherence to the connection constraints of the ITER grid to the supplier distribution grid including limits for active power, reactive power and voltage levels of the various buses.
Hence, the requirement expressed by ITER was to obtain a tool which could simulate the voltage plan of the grid and the power flows throughout the duration of a plasma shot scenario. [...] The Transient Recovery Voltage (TRV) is the voltage which appears across electrical equipment shortly after a current interruption. The waveform of the recovery voltage actually depends on the circuit configuration (inductive or capacitive nature). For example, a circuit breaker should be able to interrupt a given current for any recovery voltage provided that this value does not exceed its assigned TRV value (this TRV value is specified in the 61071 IEC standards).
The replacement of a HV circuit breaker, particularly in the case of replacement of SF6 circuit breakers by vacuum ones, requires the TRV calculations to be rechecked.
It is necessary to check that the generated overvoltages respect both the insulation levels of the present network equipment and the IEC assigned values of the breaking device. If the overvoltage levels are too high, then the installation overvoltage protection equipment should be considered (for example capacitors which reduce the rising edge steepness of overvoltages, RC circuits, surge arresters...). [...] | 
