Optimal operation of the green port system considering the multiport power electronic transformer in day-ahead markets

Increasing operation costs and carbon emissions have brought great challenges to the development of port systems, which are regarded as prosumers that comprise various renewable energy sources and diversiform electric loads. In this paper, an energy transaction framework for the green port with a multiport power electronic transformer (PET) is established to optimize the operation of the port system in day-ahead energy and reserve markets. The market behavior of the port system is formulated as a bi-level stochastic optimization model. The energy source schedule, berth allocation, and quay crane (QC) assignment are optimized to minimize the total operation cost at the upper level, whereas energy and reserve market clearing problems are settled at the lower level. The aforementioned nonlinear bi-level optimization problem is solved as a mathematical program with equilibrium constraints (MPECs). Karush–Kuhn–Tucker conditions and duality theory convert the proposed nonlinear bi-level problem into a linear single-level problem. Numerical simulations show that the proposed strategy can achieve the lowest total operation cost for the green port.