Operation and Control of Wind Farm Interconnected to Grid using LCC Bipolar HVDC Link

Abstract

The use of HVDC is usually required for transmission distance longer than 50 Km of submarine cables to be economical. But the high cost of power converter in HVDC systems is the main drawback that is holding back to use of HVDC in wind farms, Although it has many advantages that is can help in increasing the amount of wind power  when connected to a bipolar link. The use of HVDC brings another advantage that is capable of operating at variable frequency source, the inland substation will be operated to 60Hz synchronized with the 50Hz grid. The offshore wind farm can be operated at variable frequency due to its variable wind speed allowing the HVDC to operate at constant Volt/Hz. In this paper an interconnection between two variable frequency systems wind farm in Zafarana-Egypt and another grid (50Hz-60Hz) using HVDC links (monopolar and bipolar) it was studied and simulated. A simulated wind farm is performed based on real data and real configuration (Zafarana-Egypt) and connected to grid (220kV-60Hz) through a bipolar link HVDC as a case study by adjusting the firing angle of rectifier valves (α) and extinction angle of inverter (γ). Minimum firing angle control, minimum extinction angle control and constant current control are implemented for the HVDC link control.