Abstract: A single-phase, 3-wire watthour meter which can measure power consumption, alter a contract capacity, control the stop/start of power supply/distribution, and easily update programs from a higher-level control apparatus by providing a central processing unit, a storing means, a communicating means and various interfaces, can measure, for example, every 0.2 sec, a currents (ia and ib) running through 100V T-phase and R-phase, voltages (v1 and v2) between T-N and between R-N and a current (i3) and a voltage (v3) under a 200V load, determine a 100V power consumption by W100=(ia?i3)·v1+(ib?i3)·v2 and a 200V power consumption by W200=i3·v3, and measure the detailed behavior of a power consumption by totaling a power consumption every 30 min, interlocks with a gas leakage detector and a fire alarm, can control the opening/closing of rain doors and shutters and the operation/stop of Internet home electric appliances, and enables low-cost communication by means of dynamic IP Address-based communication.

Abstract: There is provided a power system for an area containing a set of power consumers which can be applied to a collective housing consisting of a single or more buildings and can prevent power supply stop of a supply line having a higher priority. The system includes: means for cutting off each of the power supply lines in a single power consumer section from a remote management section by remote operation; means for setting the power consumption limit amount within the maximum power that can be supplied to the single power consumption section via the Internet; and means for setting the power supply priority for the power supply lines in advance and outputting an instruction to cut off power in the power supply line having the lowest power supply priority by the remote out-off means when the remote measurement value of the total power consumption amount exceeds the set value of the power consumption limit amount.