A novel grounding scheme for secondary cable shielding is put forward in this paper， in which one terminal in the switchyard is grounded via a suitable resistance， and the other in the control room is directly grounded. The electromagnetic compatibility（EMC） effect of the novel grounding scheme is compared with that of the traditional grounding scheme under multiple electromagnetic interference（EMI） coupling modes. An EMC effect comparison of two schemes under the complicated EMI inductive coupling mode is emphasized， showing that a good EMC effect can be achieved by both schemes， but the shield burning due to the over-large earth current can only be avoided using the novel grounding scheme.