To provide an electric power monitoring system which stores the history of accumulated electric energy of a load for a long term and store monthly history of the accumulated electric energy of a load preferentially for a long term.
The electric power measuring apparatus 1 includes a control section 11 which stores accumulated electric energy determined by a calculation section 10 for determining accumulated electric energy supplied to the load 5 within a predetermined term using an instantaneous voltage value and an instantaneous current value measured by a measuring means and the present date and time measured by a time measuring section 12 in association with each other in a storage section 13 as a history and deletes a history of which the term from its storage to the present time has exceeded a predetermined term from the storage section 13. The storage section 13 includes a first storage section 13a for storing the history of daily accumulated electric energy by unit and a second storage section 13b for storing the history of monthly accumulated electric energy by unit, where the second storage section 13b has a longer history storage term than that of the first storage section 13a.
MIZUNO YOJI
YUASA HIROAKI
NISHIKAWA MAKOTO
| JPH11225438A | 1999-08-17 | |||
| JP2002296307A | 2002-10-09 | |||
| JP2004170310A | 2004-06-17 |
Atsuo Mori