A Comparative Study on MMCs and DCCBs with and without Co-ordination for HVDC Grid Protection
Keywords:
Grid Protection, Hybrid DC Circuit Breaker (DCCB), Modular Multilevel Converter (MMC)Abstract
The HVDC grids face multiple challenges but major challenge is to limit the higher magnitude of the dc fault current. This paper consists of a strategy in order to protect the HVDC grids from such dc disturbances. This novel technology consists of Hybrid DC Circuit breakers (DCCBs) and Modular Multilevel Converters (MMCs). A co-ordination is formed between these two devices to control the dc fault current magnitude. This includes bypassing of MMCs for a short interval of time and resuming its operation once the fault has been cleared by the DCCBs. A comparison is made between two conditions viz. when the DCCBs don’t coordinate with MMCs and when the DCCBs coordinate with MMCs using thyristors. A four terminal HVDC system model is designed in the MATLAB/SIMULINK and tests are performed for the above mentioned conditions. The results obtained from the tests are analyzed and explained in this paper.
