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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. The modeling detail is particularly relevant when simulating a restrike and an accurate simulation may require a modeling depth larger than recommended by the standard. A restrike of a hybrid line results in larger overvoltages than the restrike of a pure cable/OHL line. For the same length, the overvoltage associated to a restrike of a hybrid-line can be more than two times the overvoltage associated to the restrike of an equivalent pure cable line. This large difference is consequence of reflections and refractions in the joint cable-OHL node, which originates a voltage magnification when an electric wave flows from a cable to an OHL. The maximum overvoltage is a function of several factors (e.g. reflection factor, waves speeds, initial voltage at the CB terminals), and its calculation requires the use of simulation tools. The cable modeling is very important, and simplifications should not be used. During a restrike part of the current flows in the cable's screen and the reflections in the cross-bonded points will affect the final simulation outcome. As a result, it is necessary to model accurately all cross-bonding points. Three countermeasures that can be used to reduce the restrike overvoltage value were presented.