Method for determining the direction of the origin of a disturbance affecting an element of an electrical energy transfer network
US4560922A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1984 |
| Grant date | Dec 24, 1985 |
| Priority date | — |
| Expiry date | Oct 31, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/265
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A directional relay for providing indication of the direction of a fault on an electric power transfer network has an adder (9), a subtractor (10) and filters (11) which receive signals from voltage and current transformers (6,7) and derive signals related to fault-induced forward and backward transient waves on the network. To ensure reliable operation even when the relay is close to a low impedance element such as a generator (2), the forward wave related signal is delayed in a delay unit (12) by an amount equal to the propagation time of the wave along the section protected by the relay, before the difference between its square and that of the backward wave related signal are integrated (16) to derive the fault direction signal. If the protected section has a low distributed capacitance, the voltage and current signals can instead be combined by a differentiator (22) and adder (23) and filtered (11B) to produce a signal related to the forward transient wave appearing at a point X along the protected section. The integrator (16) receives the product of this signal and the filtered current signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.