TITLE:
Management of Charging Load of Electric Vehicles for Optimal Capacity Utilisation of Distribution Transformers
AUTHORS:
Rilwan Olaolu Oliyide, Liana M. Cipcigan
KEYWORDS:
Electric Vehicles, Load Management, EV Charge Controller, EV Load Controller, Distribution Transformer Monitor
JOURNAL NAME:
Journal of Power and Energy Engineering,
Vol.9 No.11,
November
30,
2021
ABSTRACT: A de-centralised load management technique exploiting the flexibility in
the charging of Electric Vehicles (EVs) is presented. Two charging regimes are
assumed. The Controlled Charging Regime (CCR) between 16:30 hours and 06:00
hours of the next day and the Uncontrolled Charging Regime (UCR) between 06:00
hours and 16:30 hours of the same day. During the CCR, the charging of EVs is
coordinated and controlled by means of a wireless two-way communication link
between EV Smart Charge Controllers (EVSCCs) at EV owners’ premises and the EV
Load Controller (EVLC) at the local LV distribution substation. The EVLC sorts
the EVs batteries in ascending order of their states of charge (SoC) and sends
command signals for charging to as many EVs as the transformer could allow at
that interval based on the condition of the transformer as analysed by the
Distribution Transformer Monitor (DTM). A real and typical urban LV area
distribution network in Great Britain (GB) is used as the case study. The
technique is applied on the LV area when its transformer is carrying the future load demand of
the area on a typical winter weekday in the year 2050. To achieve the load
management, load demand of the LV area network is decomposed into Non-EV load and EV load. The load on the transformer is
managed by varying the EV load in an optimisation objective function which
maximises the capacity utilisation of the transformer subject to operational
constraints and non-disruption of daily trips of EV owners. Results show that
with the proposed load management technique, LV distribution networks could
accommodate high uptake of EVs without compromising the useful normal life
expectancy of distribution transformers before the need for capacity
reinforcement.