| 摘要 |
PURPOSE: To avoid operational interruption of power system or replacement or repair of a relay upon detection of a partial defect in a nonvolatile RAM employed in a digital relay by avoiding the use of the defective part. CONSTITUTION: The sum of a plurality of settled values determining the characteristics of a digital relay is operated and stored sequentially in a buffer RAM 3 along with the ' values. The stored data is then transferred collectively to a nonvolatile RAM 5 and each settled value data is read out therefrom a specified moment in time. Subsequently, the sum of the settled values is operated and compared with the sum value stored in the nonvolatile RAM 5 thus performing sum check. If they do not match each other, the data stored in the butter RAM 3 is transferred back to a blank area in the nonvolatile RAM 5 thus avoiding operational interruption of power system or replacement or repair of a digital relay. |
