Current compensation method and device for power system protection
US7002784B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 2001 |
| Grant date | Feb 21, 2006 |
| Priority date | — |
| Expiry date | Oct 13, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/283
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a method for current compensation of a protection system for protecting a zone in a power system, which zone comprises a number of transmission lines connected to power sources and a number of transmission lines connected to a number of loads where the power sources and the loads are arranged outside the zone and a number of current transformers (CT) arranged to the transmission lines, wherein the method comprises the steps of continuously measuring all the incoming currents (Iin) to the zone, continuously measuring all the outgoing currents (Iout) from the zone, continuously calculating the differential current (Id) according to Id=Iin−Iout, continuously calculating q=Iout/Iin, continuously comparing q with set values and continuously comparing Iout with a set value Set1. The invention is characterised by setting Iout=Iin=Icomp at the instant when q changes and Iout exceeds the value set1, which is an indication of the occurrence of a fault external to the protection zone due to saturation of the CT of the faulted outgoing transmission line, and using the value Icomp in the protection system in order to prevent tripping of the protection system. Th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.