A System Engineering Approach to Low Voltage DC Distribution

Abstract

This article focuses on the overall system engineering aspects of low voltage DC (LVDC) electricity distribution.. The interdependencies between different parts of an LVDC distribution system are discussed emphasising the issues related with the interconnection of user-end LVDC installations and public LVDC systems. The main objective is to illustrate the importance of the total system engineering over the piecewise design approach. The aspects affecting on the selection of the DC voltage level, system structures and earthing arrangements are considered. A methodology for selecting the technoeconomic optimal voltage level within the boundary conditions set by the DC system application and the operating environment is introduced with example calculations. Presented discussions and results provide support especially for the development of the standardisation of the LVDC technology

An Advanced Protection Scheme for Enabling an LVDC Last Mile Distribution Network

“…The technical benefits of an LVDC application should be balanced in practice with the cost, where the life-cycle cost and the energy efficiency are the main drivers for the LVDC to take place in future [6]. In general, the lifetime of the electronic conversion devices is normally shorter than traditional transformers.…”

“…There is therefore a need for a rethink of the new standard designs to be adopted in last mile networks. LVDC with the help of smart controls and advanced information and communication technology's (ICTs) have the potential to facilitate this transformation, and offer more advantages over the corresponding LV ac systems [6].…”

Effect of network configuration and load profile on efficiency of LVDC distribution network

“…The low voltage direct current (LVDC) distribution has been intensively studied during the past few years, because it can be a cost effective solution to be considered in future smart grids due to the high power transmission capacity when the present low voltage AC network approaches its end of lifetime [1][2][3]. In a typical LVDC distribution, 20 kV medium voltage is first reduced to a maximum of 1 kV by a transformer, then rectified to1500 V DC at maximum, and finally converted back to AC near the end customer location [4].…”

“…In a typical LVDC distribution, 20 kV medium voltage is first reduced to a maximum of 1 kV by a transformer, then rectified to1500 V DC at maximum, and finally converted back to AC near the end customer location [4]. The LVDC network would improve the power quality and reliability experienced by the customer [1][2][3]. The connection of distributed generation units and energy storages would be easier to the LVDC network compared to the present AC network due to lack of synchronization requirements and reactive power compensation.…”

“…The connection of distributed generation units and energy storages would be easier to the LVDC network compared to the present AC network due to lack of synchronization requirements and reactive power compensation. In addition, telecommunication devices and protection solutions can be integrated into the converters [1][2][3].…”