A Bridge Type Fault Current Limiter for Energy Management of AC/DC Microgrids

Abstract

This paper proposes a novel structure for fault current limiter (FCL), which not only controls the magnitude of fault current, but also is enable to power management in normal and fault condition of utility. The main capabilities of the proposed structure, which is able to connect both AC and DC systems, are controlling the DC reactor current for fault current magnitude control, and management and control of power flow from AC system to DC system. A boost converter is utilized in the proposed structure, that its output is connected to a DC bus, in order to control the DC reactor current. The proposed FCL, which ensures a high protection level of the system, has no impact on utility voltage and load currents. A boost converter is utilized to provide an almost sinusoidal input current.

Existing System

Switching Technique

Proposed System

In this paper, a new structure for FCL is proposed which is capable to manage power in normal and fault condition of utility, control the magnitude of fault current, and ensure a high protection level of the system. The main advantage of the proposed FCL structure is ability of connection of both AC and DC systems, and management and control of power flow from AC system to DC system. Moreover, the energy stored in FCLs during fault condition can be transmitted to the adjacent DC grid. In addition, protection and power management capability of the proposed structure provides an economical FCL circuit.

Architecture

Power circuit topology of the proposed FCL