Efficient fault detection, localization, and isolation in MT-HVDC systems based on distance protection and LoRaWAN communication

Abstract

Multiterminal High-Voltage Direct Current (MT-HVDC) systems offer numerous benefits compared to conventional alternating current (AC) power systems, including higher power density and improved efficiency. However, the need for adequate protection schemes for HVDC systems remains a significant obstacle to their widespread adoption. Much attention has been given to developing HVDC protection methods to address this. Moreover, the protection of MT-HVDC systems presents a challenge due to bidirectional power flow, dynamic system characteristics, and fault current characteristics that cannot be addressed using conventional methods. This paper represents a centralized protection unit based on a distance protection scheme that involves a two-stage relay process. The first stage involves fault detection by measuring voltage and current to obtain the system impedance, which is then compared to the reach point. The second stage involves identifying the fault location by selecting the correct faulty zone. This technique provides both main and backup protection. A central control unit supports the approach presented in this paper to communicate relays and update their settings. The LoRaWAN communication protocol is employed, as it provides more excellent coverage than other standardized communication technologies and can cover long distances. The proposed method is studied under different scenarios, including system contingency, simultaneous faults, fault resistances, locations, and types. The results of this technique provide the effectiveness of the proposed method. The fault can be cleared within 1.32–1.8 ms.