TRU's.  Limiting factors for the adoption of this  strategy, however, are cable inductances and impedances presenting resonant behaviour at the elevated frequencies. Five SACs outputs are parallel connected to provide a high power dc input to the Primary Up Converter (PUC) for power conversion. The implications of paralleling the outputs of 100'10kW power converters is challenging, and requires consideration of converter topology (Voltage sourced Inverters (VSIs) don't readily parallel, for instance), particularly with the availability of each being dependant on insolation, manufacturing tolerances and converter health. Here, power distribution is at the primary level, and is transmitted to the Primary Down Converter(s) (PDCs) located at the central distribution and load control unit located in, or directly above, the main pressure vessel (cabin). The four primary transmission systems are sized such that in the event of a single failure, full power can be supported by the remaining 3 systems i.e each distribution system is rated at 1.5MW (1.33MW +12.5%). This is achieved by allowing the SAC's to cross connect between the PUC's. The electrolyser(s) are considered as load(s) on the secondary distribution system for the purposes of architecture design. The merits of this architecture are that power can be transmitted at high potential, reducing the copper (or aluminium) requirements -- at the expense of increased converter mass. High frequency, 20kHz, ac [20kHz] transmission is being considered to facilitate the application of relatively low mass power transformers for the purposes converting power down to dc using TRU's.  Limiting factors for the adoption