Protection performance assessments of two types of sheath voltage limiters in 220kV single point bonded cable system

The growth of the power system contributes to the appearance of large short-circuit currents after a single-line to ground in the 220 kV single-point bonding cable system. The sheath voltage limiters installed may undergo a long-duration overvoltage and the absorbed energy by the limiters may exceed the energy absorption capacity. The sheath voltage limiter may breakdown and the failure poses a threat to the power system equipment and personnel as a result. To provide an effective method about assessing the protection performance when selecting the right sheath voltage limiters for the cable system, two types of limiters are adopted and the overvoltage, current and absorbed energy by limiters are simulated using the software ATP-EMTP in this article. The in-fluences of fault initial phase angle, cable length, short-circuit current, and fault position under a single-line to ground fault are investigated and the variation range of the overvoltage and energy absorption are achieved. On the other hand, the power frequency withstand capability (including voltage withstand capability and energy absorption capability) of sheath voltage limiters, are obtained through laboratory experiments. By comparing the simulation calculation results with the power frequency withstand capability, the protection performance of the two types of limiters is evaluated in the article. The results demonstrate that the transient amplitude of voltage and current as well as absorbed energy of sheath voltage limiters reach the peak values at 0 and 180 for the A phase voltage initial angle. With increase of the cable length, short-circuit current and the distance between the fault point and the sending end of cable, the flowing current and energy absorbed by the type B of limiters rise apparently, whereas the voltage over it shows a slight change. Both the overvoltage and energy absorption of type B of sheath voltage limiter go beyond its power frequency withstand capability, namely evaluated as dangerous under all simulation fault conditions, while the type A is safety, considering the scenarios of the short-circuit currents less than 20 kA and the fault positions of 0 m and 200 m from the sending end of cable.