Cost optimization and reliability assessment of a microgrid with large-scale plug-in electric vehicles participating in demand response programs

ABSTRACT

In this paper, an effective objective function is proposed to minimize the cost of operation of a microgrid with large-scale plug-in electric vehicles and renewable energy resources. The profit of consumers is taken into account by utilizing the incentives in the demand response programs, and vehicle-to-grid feature of the plug-in-electric vehicles integrated into the grid. The optimization is performed using genetic algorithms. Also, reliability indices of the economically optimized microgrid are computed for various operation configurations in both the grid-tied and islanded modes. Numerical studies are conducted on a microgrid testbed to validate the performance of the proposed strategy.

KEYWORDS:

• Cost optimization
• power management
• reliability
• microgrid
• plug-in electric vehicles (PEV)
• demand response programs (DRP)

Nomenclature

$\mathrm{\Delta }T$	=	Duration of the time intervals $(h)$
$C_c$	=	Interconnection cost $(\mathrm{\$}/kWh)$
$C_t$	=	Day-ahead electricity price $(\mathrm{\$}/kWh)$
$C^{pro}$	=	Power production cost $(\mathrm{\$}/kWh)$
$C^w$	=	Battery wear out cost $(\mathrm{\$}/kWh)$
$\tau$	=	Sets of time intervals
$K$	=	Sets of PEVs
$B$	=	Sets of adjustable loads
$R$	=	Sets of shiftable loads
$p_t^p$	=	Power purchased by the microgrid $(kW)$
$p_t^s$	=	Power sold by the microgrid $(kW)$
$P_t^{pro}$	=	Power of the co-generation plant $(kW)$
$p_t^W$	=	Power generated by the wind turbines $(kW)$
$p_t^{SOL}$	=	Power generated by the solar cells $(kW)$
$L_{crt}$	=	Total critical loads $(kW)$
$L_{t,b}^H$	=	Maximum value of the adjustable loads $(kW)$
$l_{t,b}$	=	Amount of delivered adjustable loads $(kW)$
$l_{t,r}$	=	Amount of delivered shiftable loads $(kW)$
$p_{t,k}^c$	=	Charging power rate of $k^{th}$ PEV $(kW)$
$p_{t,k}^d$	=	Discharging power rate of $k^{th}$ PEV $(kW)$
$\beta$	=	Charging efficiency of PEV’s battery
$\eta$	=	Discharging efficiency of PEV’s battery
$F$	=	Penalty factor for undelivered loads $(\mathrm{\$}/kWh)$