Use of VSC-HVDC for industrial systems having onsite generation with frequency control

Artikel i vetenskaplig tidskrift, 2008

This paper presents a voltage-source-converter (VSC)-FfVDC-supplied industrial system with onsite generation where the VSC-HVDC and generator are taking part in the voltage and frequency control. The reason for using a frequency controller in the converter is to increase the ridethrough capability of the VSC-HVDC-supplied industrial system by exploiting the inertia energy of rotating masses in case of voltage disturbances. The investigation is performed using the PSCAD/EMTDC program and the dynamic performance of the system is evaluated during grid faults and load changes. Three comparisons are done to analyze the system response when the inverter uses different frequency-control strategies, the impact on the system when the turbine operates in different modes, and the VSC-HVDC's ability to mitigate voltage dips from the grid. Simulation results show that the use of a VSC-HVDC for feeding industrial plants can mitigate voltage dips in the grid. Different frequency-control strategies have different responses on the system. The best frequency response is achieved when the turbine is also equipped with a frequency controller.