Optimal Energy Management and MPC Strategies for Electrified RTG Cranes with Energy Storage Systems

Abstract

This article presents a study of optimal control strategies for an energy storage system connected to a network of electrified Rubber Tyre Gantry (RTG) cranes. The study aims to design optimal control strategies for the power flows associated with the energy storage device, considering the highly volatile nature of RTG crane demand and difficulties in prediction. Deterministic optimal energy management controller and a Model Predictive Controller (MPC) are proposed as potentially suitable approaches to minimise the electric energy costs associated with the real-time electricity price and maximise the peak demand reduction, under given energy storage system parameters and network specifications. A specific case study is presented in to test the proposed optimal strategies and compares them to a set-point controller. The proposed models used in the study are validated using data collected from an instrumented RTG crane at the Port of Felixstowe, UK and are compared to a standard set-point controller. The results of the proposed control strategies show a significant reduction in the potential electricity costs and peak power demand from the RTG cranes.

A Comparative Study of Energy Storage Systems and Active Front Ends for Networks of Two Electrified RTG Cranes

“…This section aims to address the RTG's system topology and introduces the power system structure of a network of cranes. An electrified RTG, as shown in Figure 1, has been retrofitted to be powered by [5,7,9]. This RTG crane has three main types of motors to drive the crane and move containers, as follows:…”

“…An electrified RTG, as shown in Figure 1, has been retrofitted to be powered by the low voltage network at the Port of Felixstowe. This crane was manufactured by Shanghai Zhenhua Heavy Industries (ZPMC, Shanghai, China) [5,7,9]. This RTG crane has three main types of motors to drive the crane and move containers, as follows:…”

“…The literature introducing the potential impact of using energy storage systems (ESS) to support the diesel and electric RTG cranes is beginning to appear [6][7][8][9][10][11]. For example, Flynn et al [10] developed a hybrid energy source model for an RTG crane including a flywheel energy store.…”

Day-ahead industrial load forecasting for electric RTG cranes

“…Consequently, the electrical power consumption at port substations has been increasing as a result of a rise in the number of electrified RTG cranes which connected to low and medium voltage networks. The use of electrified RTG cranes can reduce maintenance and repair parts costs by around 30% and green gas emissions by between 25% and 70% compared to diesel RTG cranes [1,3]. However, shifting from diesel to electrified RTG cranes will lead to an increase in peak CrossCheck date: 9 January 2018 demands and power consumption at the port substations.…”

“…However, shifting from diesel to electrified RTG cranes will lead to an increase in peak CrossCheck date: 9 January 2018 demands and power consumption at the port substations. In this situation, ports may need to upgrade the electrical infrastructure to meet this rise in demand [3]. In addition, there is a gap and lack of understanding of the ports and the RTG crane energy demand behaviour.…”