Remote controlled switching of supply to premises - lowers the value of fusing at times of unacceptable high current demand

摘要

The supply authority is able to switch off user's drawing current in excess of the declared requirement at times of system actual or incipient overload. Between the incoming supply cable (2) and the user's distribution board (3) is a sealed control unit (5). It contains a signal receiver and processor (6) operated by power line carrier system impulses. The processor controls two switches (7,8) which connect the power supply (2) to the distribution board (3). In series with each switch is a fuse (9,10). The fuse values are chosen such that in normal service operation (7 closed) the associated fuse (9) is rated for fault current protection. At times of overload on the whole supply system the supply authority automatically changes over (7 open, 8 closed) to insert a fuse (10) rated to carry the declared load only. Any individual user overload thus results in a loss of supply. The system can be adapted to cover shedding selected loads inside the consumer's premises.