Complementary Power Control of the Bipolar-type Low Voltage DC Distribution System

Abstract

-In this paper, a new power control strategy for the bipolar-type low voltage direct current (LVDC) distribution system is being proposed. The dc distribution system is considered as an innovative system according to the increase of dc loads and dc output type distribution energy resources (DERs) such as photovoltaic (PV) systems and energy storage systems (ESS). Since the dc distribution system has many advantages such as feasible connection of DERs, reduction of conversion losses between dc output sources and loads, no reactive power issues, it is very suitable solution for new type buildings and residences interfaced with DERs and ESSs. In the bipolar-type, if it has each grid-interfaced converter, both sides (upper, lower-side) can be operated individually or collectively. A complementary power control strategy using two ESSs in both sides for effective and reliable operation is proposed in this paper. Detailed power control methods of the host controller and local controllers are described. To verify the performances of the proposed control strategy, simulation analysis using PSCAD/EMTDC is being performed where the results show that the proposed strategy provides efficient operations and can be applied to the bipolar-type dc distribution system.

Development of fault section identification technique for low voltage DC distribution systems by using capacitive discharge current

“…This step is initiated when di/dt exceeds the set threshold value d as shown in (2). The time satisfying condition (2) is designated as t int as:…”

“…However, there is a paucity of studies related to the construction of a reliable LVDC distribution system due to differences when compared to conventional systems and especially in relation to its structural characteristics [1,2]. According to the Computer Business Equipment Manufacturers Association (CBEMA) curve, sensitive components are damaged by voltage that corresponds to 70% of its rated value even if it only lasts for 100 ms [3,4].…”

Novel coordinated control strategy of urban DC distribution system for large‐scale loads reduction

“…Extensive research work has been performed to discuss the coordinated control strategy of DC distribution network [1–4]. To realise the bus voltage stability in the scenes of short‐term load fluctuation and long‐term load reduction, the distributed controllable load group is considered as an energy asset in the coordinated control strategy to actively participate in the demand response of power grid [5].…”