Technical Presentations

Secondary arc in hybrid AC DC overhead lines872

Abstract
This presentation covers a specific issue related to hybrid AC / DC overhead transmission lines: the extinction of the secondary arc current of a faulted DC pole. As a result of a pole-to-ground fault... see more, breaker openings interrupt the short-circuit current. Because of the inductive and capacitive coupling between the AC circuit and the faulted pole, a small AC current (a few 10ths Amps) keeps flowing in the fault. This current is known as the secondary arc current and it may disappear after some time.

Tag(s): AC/DC Lines, Secondary Arc, Sensitivity Analysis, Frequency Scan, Shunt Reactors, High-Speed Earthing Switches

HVDC grid protection algorithm based on fault parameter estimation786

Abstract
This presentation focuses on voltage and current sensors modelling and its application on a transient based protection algorithm within a 4-terminal HVDC grid simulated in EMTP.

Fully selec... see moretive protection strategies for meshed HVDC grids need very fast DC fault identification and isolation which constitutes one of the main locks for large deployment of such grids. Transient based fault identification algorithms based on the modelling of the voltage and current traveling waves are seen as a promising solution to achieve fast fault identification. In addition, such algorithms are able to estimate the fault parameters such as the fault distance using local sensor data.As a model based approach, the accuracy of the sensors may impact the fault identification results as well as the precision of the estimated fault parameters.

In depth sensitivity analysis for different parameters of the sensor are carried out to outline the influence of the sensor characteristics on the fault identification results as well as the accuracy on the estimated fault parameters.