Abstract: The present disclosure relates to a control method for an energy storage converter. The method includes: determining a current fault component; determining a voltage fault component; determining a fault component of a positive-sequence current of the energy storage converter in a dq coordinate system of the new energy converter; determining a fault component of a current in a dq coordinate system of the energy storage converter; determining dq-axis currents of the energy storage converter according to the fault component of the current in the dq coordinate system of the energy storage converter and a pre-fault current of the energy storage converter; and controlling the energy storage converter to output current according to the dq-axis currents of the energy storage converter, so as to reduce an impact of the fault.

Abstract: The application relates to a method and system for a pilot directional protection of LCC-HVDC lines based on virtual grounding resistance. The method comprises: Obtaining a conduction state information of a converter and characteristic parameters of a converter circuit within one commutation period after a fault occurs; according to the conduction state information and characteristic parameters, determining characteristic frequency of the circuit; according to the characteristic frequency and characteristic parameters, determining a virtual grounding resistance; according to the virtual grounding resistance, determining fault areas.

Abstract: The present disclosure provides a method and device for calculating fault measurement impedance of a hybrid-connected grid-following and grid-forming wind power system. The method includes: obtaining characteristics of the grid-following and grid-forming converters and a corresponding low voltage ride-through control strategy; establishing an equivalent circuit under a corresponding fault state; conducting a simplified analysis on the wind power system to obtain an equivalent network diagram; obtaining a sub-circuit diagram of each power source excitation acting alone; obtaining short-circuit currents on both sides of the corresponding system and a grid connection point voltage; superimposing to obtain total short-circuit current on both sides of the wind power system and total grid connection point voltage; and obtaining a measurement impedance at a protection installation location on the new energy source side.

Abstract: The present disclosure discloses a safety and stability analysis method for a new energy power system based on Lyapunov function, including: obtaining a new energy grid connection point voltage, a new energy grid connection point voltage phase angle, an internal potential of a synchronous machine, a line susceptance and a rotor position angle of the synchronous machine of the new energy power system, to obtain an output power of synchronous machine; obtaining a synchronous machine rotor motion equation according to the output power of synchronous machine; constructing a Lyapunov function of synchronous machine based on the new energy power system according to the synchronous machine rotor motion equation; obtaining a stability domain boundary of the synchronous machine with respect to the state variables according to the Lyapunov function; determining a transient stability of the synchronous machine according to real-time values of post-fault state variables.

Abstract: The present disclosure provides a method and device for calculating fault measurement impedance of a hybrid-connected grid-following and grid-forming wind power system. The method includes: obtaining characteristics of the grid-following and grid-forming converters and a corresponding low voltage ride-through control strategy; establishing an equivalent circuit under a corresponding fault state; conducting a simplified analysis on the wind power system to obtain an equivalent network diagram; obtaining a sub-circuit diagram of each power source excitation acting alone; obtaining short-circuit currents on both sides of the corresponding system and a grid connection point voltage; superimposing to obtain total short-circuit current on both sides of the wind power system and total grid connection point voltage; and obtaining a measurement impedance at a protection installation location on the new energy source side.

Abstract: The invention relates to a fault transient features optimization method and system of AC/DC system based on dissipated energy, which belongs to the HVDC transmission technology and is used to solve the problem that the DC pulsed current is too high and the generator power angle swing of the AC system on the rectifier side is too large during the process of the HVDC transmission system restart on fault.

Abstract: The application relates to a method and system for a pilot directional protection of LCC-HVDC lines based on virtual grounding resistance The method comprises: Obtaining a conduction state information of a converter and characteristic parameters of a converter circuit within one commutation period after a fault occurs; according to the conduction state information and characteristic parameters, determining characteristic frequency of the circuit; according to the characteristic frequency and characteristic parameters, determining a virtual grounding resistance; according to the virtual grounding resistance, determining fault areas.

Abstract: The invention relates to a fault transient features optimization method and system of AC/DC system based on dissipated energy, which belongs to the HVDC transmission technology and is used to solve the problem that the DC pulsed current is too high and the generator power angle swing of the AC system on the rectifier side is too large during the process of the HVDC transmission system restart on fault.