Impedance measurement system for power system transmission lines
US6397156B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1998 |
| Grant date | May 28, 2002 |
| Priority date | — |
| Expiry date | Nov 17, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H1/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An accurate impedance measurement method for a power system transmission line is disclosed for improving various protection functions, i.e., distance protection and/or fault location estimation. The method is less sensitive to harmonics and other transient problems introduced to power systems by series capacitance and the like, and is easily incorporated into existing protective relays. In the method, a number (n) of current and voltage samples (Ik, Vk) representative of values of current and voltage waveforms are measured, respectively, at successive instants of time on a conductor in a power system. The number n is an integer greater than I and the index k takes on values of 1 to n. Resistance (R) and inductance (L) values are computed in accordance with an equation in which R and L are related to sums of differences in values of successive current and voltage samples. A prescribed power system function is then performed based on the computed R and L values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.