International audienceThis paper presents a new control strategy for High Voltage Direct Current (HVDC) transmission based on the synchronverter concept: the sending-end rectifier controls emulate a synchronous motor (SM), and the receiving end inverter emulates a synchronous generator (SG). The two converters connected with a DC line provide what is called a Synchronverter HVDC (SHVDC). The structure of the SHVDC is firstly analyzed. It is shown that the droop and voltage regulations included in the SHVDC structure are necessary and sufficient to well define the behavior of SHVDC. The standard parameters of the SG cannot be directly used for this structure. A specific tuning method of these parameters is proposed in order to satisfy the usual HVDC control requirements. The new tuning method is compared with the standard vector control in terms of local performances and fault critical clearing time (CCT) in the neighboring zone of the link. The test network is a 4 machine power system with parallel HVDC/AC transmission. The results indicate the contribution of the proposed controller to enhance the stability margin of the neighbour AC zone of the link

This paper presents a new control strategy for High Voltage Direct Current (HVDC) transmission based on the synchronverter concept: the sending-end rectifier controls emulate a synchronous motor (SM), and the receiving end inverter emulates a synchronous generator (SG). The two converters connected with a DC line provide what is called a Synchronverter HVDC (SHVDC). The structure of the SHVDC is firstly analyzed. It is shown that the droop and voltage regulations included in the SHVDC structure are necessary and sufficient to well define the behavior of SHVDC. The standard parameters of the SG cannot be directly used for this structure. A specific tuning method of these parameters is proposed in order to satisfy the usual HVDC control requirements. The new tuning method is compared with the standard vector control in terms of local performances and fault critical clearing time (CCT) in the neighboring zone of the link. The test network is a 4 machine power system with parallel HVDC/AC transmission. The results indicate the contribution of the proposed controller to enhance the stability margin of the neighbour AC zone of the link.

The interconnection of weak electric power grids opens new issues into power system stability and control. This paper proposes a control strategy of HVDC transmission yielding increased power transfer capacity and enhanced transient stability of weak interconnected systems. The proposed control is a recently developed synchronverter-based control and emulation of the HVDC link (SHVDC). Methodologically, the transient stability of the neighbouring zone is a priori taken into account at the design level of the control. The parameters of the SHVDC regulators are tuned based on a specific residues method. The performances of the control strategy are analyzed by the power transfer limit li mit P when the interconnection is a pure DC link, and by both the li mit P and the Critical Clearing Time (CCT) when the interconnection is a hybrid DC/AC link. The study further investigates the impact of the inertia emulation that the synchronverter provides, and of the tuned control parameters on li mit P . The proposed control is tested in comparison to the standard vector control. The simulation results indicate that the synchronverter based control improves both the dynamic transfer capacity and the transient stability of weak interconnected power systems.

International audienceThis paper investigates the impact of High Voltage Direct Current (HVDC) transmission on the transient stability of a two-machine power system, considering three transmission line configurations: parallel HVAC-HVAC, parallel HVDC-HVDC, and a hybrid HVAC-HVDC operation. The faults are balanced three-phase short-circuits in AC lines, and single phase faults on DC lines, applied in the mid-point of the interconnection. For each configuration, transient stability of the AC systems is assessed in terms of the fault critical clearing time (CCT), and for different DC power levels. The results indicate the contribution of HVDC transmission in increasing the critical clearing time; and therefore enhancing the systems stability margin and operational security