Abstract
The disconnection of HV underground cables may, if unsuccessful, originate a restrike in the circuit breaker, leading to high overvoltages, and potentially damaging the cable and near equipment.
Due to the cable high capacitance and low resistance the voltage damping is slow, resulting, half a cycle after the disconnection, in a voltage of approximately 2 pu at the circuit breaker terminals. In case of restrike in that instant, it is
theoretical possible to attain an overvoltage of 3 pu. The overvoltage can be even larger in hybrid cable-Overhead Lines (OHL), due to voltage magnifications in the junction point.
This paper explains the phenomenon for pure cable lines and hybrid cable-OHL lines, and uses Denmark’s high voltage transmission grid, as planned for the year 2030, as test system.
The accuracy of different cable models, and the number of substations from the transient event requiring detailed modeling
is also addressed. It is shown how cross-bonding the cables screens may affect the results and that the grid should be modeled for more than two busbars distance from the restrike event.
Due to the cable high capacitance and low resistance the voltage damping is slow, resulting, half a cycle after the disconnection, in a voltage of approximately 2 pu at the circuit breaker terminals. In case of restrike in that instant, it is
theoretical possible to attain an overvoltage of 3 pu. The overvoltage can be even larger in hybrid cable-Overhead Lines (OHL), due to voltage magnifications in the junction point.
This paper explains the phenomenon for pure cable lines and hybrid cable-OHL lines, and uses Denmark’s high voltage transmission grid, as planned for the year 2030, as test system.
The accuracy of different cable models, and the number of substations from the transient event requiring detailed modeling
is also addressed. It is shown how cross-bonding the cables screens may affect the results and that the grid should be modeled for more than two busbars distance from the restrike event.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of the International Conference on Power System Transients, IPST 2011 |
| Number of pages | 8 |
| Publisher | Delft University Press |
| Publication date | 2011 |
| Publication status | Published - 2011 |
| Event | International Conference on Power System Transients, IPST 2011 - Delft, Netherlands Duration: 14 Jun 2011 → 17 Jun 2011 |
Conference
| Conference | International Conference on Power System Transients, IPST 2011 |
|---|---|
| Country/Territory | Netherlands |
| City | Delft |
| Period | 14/06/2011 → 17/06/2011 |
Keywords
- Power system transients
- Power cables
- Restrikes
- Modeling