Abstract: A system and a method of black start for a combined operation of wind power, photovoltaic power, energy storage, and thermal power includes a renewable energy alternating current microgrid module, a power transmission and distribution module, and a thermal power generation module, the power transmission and distribution module is coupled to the renewable energy alternating current microgrid module and the thermal power generation module respectively. The renewable energy alternating current microgrid module includes a photovoltaic unit, a wind power unit, and an energy storage unit. The power transmission and distribution module is configured to transmit the electrical energy generated by the renewable energy alternating current microgrid module to the thermal power generation module. The thermal power generation module is configured to start an auxiliary equipment using the electrical energy transmitted by the power transmission and distribution module.

Abstract: The system for frequency modulation based on Direct Current (DC) controllable load for a high-voltage plant includes a frequency modulator and a DC-controllable load for the high-voltage plant connected to the frequency modulator. The frequency modulator includes a centralized rectifier configured to adjust power of loads in the DC-controllable load in response to a frequency modulation command. The DC-controllable load is configured to respond to an adjustment of the power of loads performed by the centralized rectifier.