Analysis of the behavior of MVDC system in a distribution grid compared to a UPFC system

Abstract

The increase in electricity demand, the incorporation of renewable energies, or the trend toward deregulation in the power market, implies significant changes in the power networks. Load flows are considerably altered, giving rise to technical problems in the system, such as stability limitations or voltage level control. In this context, the use of devices based on power electronics to interconnect distribution grids is presented as an excellent option to help solve these problems and control load flows and bus voltages. The topology MVDC (Medium Voltage Direct Current) is starting to be considered an option for enhancing transfer capacity and providing increased power quality at distribution grids. However, this technology is still immature and relatively unknown, for this reason, the main motivation of the article is to help spread the benefits of integrating this technology in distribution grid and to determine the capability of the MVDC to control active and reactive power in distribution grid as well as its behavior in the event of a short-circuit. The main novelty is to analyze the behavior of the MVDC through a case study, based on a real situation, but comparing it with one of the most complete and flexible FACTS devices, Unified Power Flow Controller (UPFC), noting that MVDC technology is a better option for operation in medium voltage networks, since allows the control of the active and reactive powers independently and in the case of a short-circuit acts on the currents circulating through the electrical line mitigating the effect caused by the fault.