Protective control method and apparatus
US4774621A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 30, 1985 |
| Grant date | Sep 27, 1988 |
| Priority date | — |
| Expiry date | Jul 30, 2005 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2075/027
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In an apparatus for producing data concerning a fault in an AC electric power system, an AC electric quantity is sampled at a frequency which is a multiple of the rated frequency of the AC electric quantity, and is stored, for later use as predicted values, and an arithmetic operation is performed on the sample values to produce a data concerning a fault in the power system. The predicted values are determined by the following equation: ##EQU1## where l and m represent natural numbers; PA1 n represents a natural number; PA1 Y.sub.m represents the predicted value for a specific time point; PA1 S.sub.o represents a sample value in advance of the specific time point by m/2 times the rated period; PA1 S.sub.l represents a value equal to (-1).sup.l times the sample value at a time point in advance of the specific time point by l/2 times the rated period; and PA1 K.sub.o and K.sub.l represent constants satisfying the following relationship: ##EQU2## where .epsilon. represents the permissible range of error for the predicted value which may occur when the power system is operating at the rated frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.