Open AccessImproved voltage‐based protection scheme for an LVDC distribution network interfaced by a solid state smart transformer
Author(s) -
Wang Dong,
Emhemed Abdullah A.S.,
Burt Graeme M.
Publication year - 2019
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.2019.0544
Subject(s) - transformer , low voltage , overcurrent , voltage , electrical engineering , ampacity , electrification , circuit breaker , computer science , engineering , electronic engineering , reliability engineering , electricity , electrical conductor
The increasing electrification of transport and heat will place increasing demand on low voltage (LV) networks with the potential to overload medium voltage (MV)/LV transformers and LV cables. Deployment of a solid‐state transformer (SST) at MV/LV substations and using LV direct current (LVDC) distribution systems offer great potential to address such challenges. However, the SST deployment in addition to the introduction of LVDC will fundamentally change LV fault behaviour and protection requirements due to the limited short‐circuit capabilities of such technologies. The SST will deliver limited fault currents, making current‐based protection (widely used in LV networks) less reliable. Therefore, this study presents an advanced communication‐less protection scheme which can effectively detect and locate DC faults even with reduced fault levels. The developed protection scheme overcomes the selectivity limitations in LVDC voltage‐based protection solutions by using a combination of DC voltage magnitude, voltage concavity (sign of d 2 v /d t 2 ) and the sign of the rate of change of current (d i /d t ) regardless of the current magnitudes. The credibility of the developed protection algorithm is tested against different fault scenarios applied on an active LVDC network model built in PSCAD/EMTDC. Noise signals have been included in the simulation to appraise the resilience of the developed scheme.