Protection Scheme of a Last Mile Active LVDC Distribution Network with Reclosing Option

Abstract

A low voltage direct current (LVDC) distribution network is a promising technology to meet the standards of future energy demands for smart loads. An LVDC distribution network can not only supply efficient, smooth and clean energy, but also makes the integration of renewable energy resources in the distribution system easy. A major obstacle in the implementation of the LVDC distribution network is the protection of the network during abnormal grid conditions, such as transients and faults. This paper analyzes DC fault characteristics considering an LVDC distribution network, highlights the worst case scenario during a fault and protection related issues and proposes the protection schemes for the LVDC network. In the proposed protection scheme, a fault is detected and located through superimposed components. To minimize the effect of the DC fault on the distribution network, distributed fault current limiters are introduced and the final decision to disconnect or reconnect the affected line is made on the basis of the type of fault. In addition, a reclosing scheme for a temporary fault is proposed to avoid high inrush currents and false tripping, which eventually increases the reliability. A fast communication-based backup protection is also suggested, and to reduce dependency, a secondary backup is used in the case of communication delay or failure. The proposed scheme is verified using the modified IEEE 13 node test system, which is implemented in ATPDraw. The results show that the proposed scheme can successfully detect, locate and limit a DC fault in an LVDC distribution network with different fault resistances or locations. Moreover, the network is restored successfully in the case of temporary faults.

A Fast DC Fault Detection Method for Multi-Terminal AC/DC Hybrid Distribution Network Based on Voltage Change Rate of DC Current-Limiting Inductor

“…Then the currents of the CLIs on DC lines during the capacitor discharge stage can be obtained by solving (1) and (2). The voltage change rates of all CLIs can be expressed as:…”

“…In recent years, DC distribution networks and AC/DC hybrid distribution networks are attracting increasing attention due to the increasing demand for distributed generation and the need for regional grid interconnection [1,2]. The AC/DC hybrid distribution network can satisfy the above requirements and achieve the interconnection and transition between the AC distribution network and the DC distribution network.…”

A Fuse Saving Scheme for DC Microgrids With High Penetration of Renewable Energy Resources

“…Thus, reclosing operation in the DC Microgrids should be considered. The application of the recloser switches in the DC distribution networks has been discussed in [19] to protect the system against temporary faults considering the high inrush current and avoiding the false tripping. In [20], a DC breaker reclosing operation is suggested, and a novel sequential auto reclosing strategy for DC grids is presented.…”

A Novel Protection and Location Scheme for Pole-to-Pole Fault in MMC-MVDC Distribution Grid

“…Due to the huge differences of operation modes and fault characteristics, the protection methods of the AC system cannot be directly implemented to the MMC-MVDC distribution grid [11]. On the other hand, due to the relatively small values of resistance and inductance in DC cables, the rise rate of fault current is very high and DC circuit breakers are yet to be commercially available [12].…”