Access BPL is technology that carries broadband Internet traffic over medium voltage power lines.
In Access BPL systems, three components of the electric power distribution network are directly involved. The first is the medium voltage line, carrying typically 1000 to 40,000 volts, over which an electric utility brings power from a substation to a residential neighborhood. The second component is the bypass of the low-voltage transformer in the residential neighborhood that steps down the line voltage to the 220/110 volts for residential use. The third component of the existing power distribution system is the low voltage distribution from the transformer to residential electrical outlets, including the exterior service cable, circuit breaker panel, and interior wiring.
Access BPL systems carry high-speed data and voice signals outdoors over the medium voltage line from a point where there is a connection to a telecommunications network. This point of connection may be at a power substation or at an intermediate point between substations, depending on the network topology. Near the distribution point to a residential neighborhood, a coupler or bridge circuit module is installed to enable the transfer of high-frequency digital signals across the low-voltage distribution transformer. Finally, the high-speed communication signals are brought to the home over the exterior service power cable from the bridge across the distribution transformer, either directly, or via an Access BPL adaptor module.
Access BPL systems can be used to provide high-speed Internet access and other broadband services to homes as well as providing electric utility companies with a means to more effectively manage their electric power distribution operations. Given that Access BPL can be made available in conjunction with the delivery of electric power, it may provide an effective means for “last mile” delivery of broadband services and may offer a competitive alternative to digital subscriber line (DSL), cable modem services and other high-speed Internet technologies.
- There are limits on the effective operating length of the service cable between the transformer and a residence, such that in the United States, a single low-voltage transformer serves on average six to eight residential units. A single transformer may serve more residences in urban and multi-dwelling settings and fewer in rural settings.