Optimal Protection Coordination Scheme for Radial Distribution Network Considering ON/OFF-Grid

Abstract

Technology advancement for renewable energy resources and its integration to the distribution network (DN) has garnered substantial interest in the last few decades. Integrating such resources has proven to reduce power losses and improve the reliability of DN. However, the growing number of these resources in DN has imposed additional operational and control issues in voltage regulation, system stability, and protection coordination. Incorporation of various types of distributed generators (DG) into DN causes significant changes in the system. These including new fault current sources, new fault levels, a blinding effect in the protection scheme, reduction in the reach of relays, and decrement in the detection of lowlevel fault currents for existing relays. Such changes will jeopardize the effectiveness of the entire protection scheme in the DN. This research aims to propose a robust protection scheme in which the relay coordination settings are optimized based on the network layout. The potential impacts of DGs on the DN are mitigated by utilizing a user-defined overcurrent-based relay characteristic to obtain the minimum operating time while satisfying protection coordination constraints. A hybrid optimization algorithm based on Metaheuristic and Linear Programming that has the capability to attain the optimal solution and reduces computational time is proposed in this work. The performance of the proposed technique is tested on radial DN integrated with microgrid (MG). The results obtained show the proposed technique has successfully reduced the relay operating time while meeting the protection coordination requirements for dynamic operating modes of a network.

Two‐stage planning of synchronous distributed generations in distribution network considering protection coordination index and optimal operation situation

“…In some studies, it has been used to reduce consumer downtime in the event of N−1 or N−k events. However, since SDGs cannot rapidly reduce their output power in the event of a fault such as a short circuit, they inject significant fault current into the fault location [11][12][13][14][15][16]. Therefore, the existing protection coordination in the network will be deteriorated.…”

A Comprehensive Review on Protection Strategies to Mitigate the Impact of Renewable Energy Sources on Interconnected Distribution Networks

“…However, such a protection scheme might not be able to protect the network integrated with different types and capacities of RES. The complication arises for the existing protection scheme to detect the fault in the presence of various types of RES-DGs when operating in Grid On/OFF modes [25]- [27]. Moreover, the high penetrated Synchronous DGs inject fault currents in the range of 5-6 times its rated current [6], [7], [28], which causes a considerable change in the fault levels.…”

Comparative Study of Relay Coordination in a Microgrid with the Determination of Common Optimal Settings Based on Different Objective Functions

“…A microgrid is a group of interconnected loads along with distributed energy resources (DERs) within the well-defined electrical boundaries, which acts as a single controllable entity to the electrical grid [1][2][3][4][5]. The microgrid can be operated in the grid-connected mode (GCM) and islanded mode (ISM) when connected and disconnected from the utility grid respectively [6][7][8].…”