Open AccessFault location principle and 2‐step isolation scheme for a loop‐type DC grid
Author(s) -
Xue Shimin,
Liu Chong
Publication year - 2018
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2017.1754
Subject(s) - fault (geology) , fault current limiter , transient (computer programming) , capacitor , engineering , thyristor , fault indicator , fault detection and isolation , control theory (sociology) , voltage , grid , harmonic , bottleneck , computer science , electrical engineering , electric power system , power (physics) , mathematics , embedded system , seismology , geology , geometry , control (management) , artificial intelligence , physics , quantum mechanics , actuator , operating system
The rapid discharging and slow charging processes of a DC‐link capacitor in a voltage‐source converter (VSC) have become the primary issues in VSC‐based DC systems, resulting in greatly prolonged fault recovery times. Therefore, blocking measure for capacitors is necessary, but limits the principles of fault location being based on the transient component. Moreover, as the main bottleneck in the development of DC system protections, the DC circuit breakers (DCCBs) adopted in low‐voltage systems have yet to be fully developed. Hence, it is necessary to propose a fault location principle based on steady‐state currents and a fault isolation scheme based on ACCBs. This study presents a 2‐step isolation scheme adopting thyristors and ACCBs to facilitate fault location and clearance. This method retains the harmonic component of the fault current and creates a current zero‐crossing point. Next, a single‐terminal fault location method adopting a steady‐state harmonic component is used to realise the exact fault location function with different fault resistances and to restore system operation within 160 ms. The protection method economising many communication modules and DCCBs is suited for low‐voltage distribution DC systems.