|
Abstract
|
Implementation of distributed energy resources (DERs) has led to a decrement in the cost of supplying
demand in distribution networks. Integration of DERs in the forms of micro-grids (MGs) is a solution
to enhance the operation of these resources in the low voltage networks. To meet the demand by
MG operator, both technical and economic characteristics as well as the prices offered by retailers
are considered to schedule DERs optimally. In these networks, the profit of retailers is maximized
by power trading with MGs and optimally purchasing the energy from wholesale markets. Due
to the existence of several retailers and MGs in active distribution networks (ADNs), hierarchical
decision-making frameworks are needed to model their operation problem. For this purpose, a bi-level
optimization technique is proposed in this paper to model the operation problem of retailers and MGs
as decision-making variables in distribution networks in the upper and lower levels, respectively. To
solve the proposed model, multi-objective particle swarm optimization (MOPSO) algorithm is used.
The proposed model and its solution method are applied to a hypothetical distribution network with
several retailers and MGs to validate the theories and discussions. Numerical results show that the
maximum capacity of DG and the amount of demand have an important effect on this decision and
the prices of purchased power from wholesale markets determine the amount of retailers’ offers to
MGs.
|