| Title |
A Study on Operation Algorithm for Protection Coordination in 20kV MVDC Radial Distribution System |
| Authors |
이후동(Hu-Dong Lee) ; 태동현(Dong-Hyun Tae) ; 노대석(Dae-Seok Rho) ; 김주용(Ju-Yong Kim) |
| DOI |
https://doi.org/10.5370/KIEE.2020.69.6.869 |
| Keywords |
MVDC Distribution System; Protection Coordination; CLR; Slope Characteristics of Fault Current; Main Converter; Section Converter |
| Abstract |
Recently, MVDC(medium voltage direct current) distribution system has been interested worldwide due to introduction of renewable energy sources, an increase of DC load and customer’s demands for high quality and high reliability of the power system. Although these MVDC systems have technologies to improve and modernize the performance of the distribution system with high reliability, high flexibility and high efficiency, they have faced challenges and difficulties in the early stages of research and development. In particular, since power converter devices to supply DC sources have extremely high sensitivity, protection method of the MVDC distribution system is being required in order to protect and operate the MVDC system in a stable manner. Therefore, this paper proposes operation algorithm of protection coordination in MVDC distribution system to rapidly separate fault sections by using slope characteristics of fault currents and presents prevention method for shutdown of the main power source based on the CLR(current limit resistor). And also, this paper performs modeling of 20kV MVDC distribution system which are composed of substation, main and section converter based on the PSCAD/EMTDC S/W. From the simulation results of fault characteristics the at primary and secondary side in MVDC, it is confirmed that the main converter in primary feeder cannot be shutdown due to keeping fault currents within allowable limits of main converter, if the proper capacity of the CLR is installed at secondary side of section converter. In addition, it is found that the proposed method can separate outage sections in primary feeder and minimize them, if slope ranges of fault current are properly determined at each protection section. |