Real-Time Dispatching Performance Improvement of Multiple Multi-Energy Supply Microgrids Using Neural Network Based Approximate Dynamic Programming
Résumé
In the multi-energy supply microgrid, different types of energy can be
scheduled from a “global” view, which can improve the energy utilization
efficiency. In addition, hydrogen storage system performs as the
long-term storage is considered, which can promote more renewable energy
installed in the local consumer side. However, when there are large
numbers of grid-connected multi-energy microgrids, the scheduling of
these multiple microgrids in real-time is a problem. Because different
types of devices, three types of energy, and three types of utility grid
networks are considered, which make the dispatching problem difficult.
In this paper, a two-stage coordinated algorithm is adopted to operate
the microgrids: day-ahead scheduling and real-time dispatching. In order
to reduce the time taken to solve the scheduling problem, and improve
the scheduling performance, approximate dynamic programming (ADP) is
used in real-time operation. Different types of value function
approximations (VFA), i.e., linear function, nonlinear function, and
neural network are compared to study about the influence of the VFA on
the decision results. Offline and online processes are developed to
study the impact of the historical data on the regression of VFA. The
results show that the neural network based ADP one-step decision
algorithm has almost the same performance as the Global optimization
algorithm, and the highest performance among all others Local
optimization algorithms. The total operation cost relative error is less
than 3%, while the running time is only 31% of the Global algorithm. In
the neural network based ADP, the key technology is continuously
updating the training dataset online, and adopting an appropriate neural
network structure, which can at last improve the scheduling
performance.