Optimal hoist scheduling of a deep level mine twin rock winder system for demand side management

Abstract This paper presents a near optimal hoist scheduling and control program for rock winders found in South African deep level mines in the context of demand side management and time-of-use (TOU) tariffs. The objective is to achieve a set hoist target at minimum energy cost within various system constraints. The development of a discrete dynamic and constrained mixed integer linear programming model for a twin rock winder system is presented on which a half-hourly model predictive control (MPC) algorithm containing an adapted branch and bound methodology is applied for near optimal scheduling. Simulation results illustrate the effectiveness of the control program by minimising the energy costs through scheduling according to the TOU tariff and controlling output and ore levels within their boundaries even in the case of significant random delays in the system. Scheduling according to the TOU tariff shows a possible 30.8% reduction in energy cost while approximately 6 h of delays in the system resulted in a mere 14% increase in energy cost.

[1]  Edward Henry Mathews,et al.  A new approach to ensure successful implementation of sustainable demand side management (DSM) in South African mines , 2008 .

[2]  Spyros Voutetakis,et al.  Model-based control of temperature and energy requirements in a fluidised furnace reactor , 2006 .

[3]  Werner Badenhorst,et al.  An MPC approach to deep level mine rock winder hoist control , 2010 .

[4]  Dimitri P. Bertsekas,et al.  Dynamic Programming and Optimal Control, Two Volume Set , 1995 .

[5]  J. Zhang,et al.  A model predictive control strategy for load shifting in a water pumping scheme with maximum demand charges , 2009, 2009 IEEE Bucharest PowerTech.

[6]  Andrew Kusiak,et al.  Reheat optimization of the variable-air-volume box , 2010 .

[7]  S. J. Redford.  The rationale for demand-side management , 1994 .

[8]  Thomas F. Edgar,et al.  Process Dynamics and Control , 1989 .

[9]  Rüdiger Franke,et al.  Optimization of boiler start-up using a nonlinear boiler model and hard constraints , 2004 .

[10]  A near optimal hoist scheduling for deep level mine rock winders , 2009 .

[11]  G. Nicolao,et al.  Stability and Robustness of Nonlinear Receding Horizon Control , 2000 .

[12]  Xiaohua Xia,et al.  A Model Predictive Control approach to dynamic economic dispatch problem , 2009, 2009 IEEE Bucharest PowerTech.

[13]  Jiangfeng Zhang,et al.  An optimal control model for load shifting—with application in the energy management of a colliery , 2009 .

[14]  Paulien M. Herder,et al.  Uncertainties in the design and operation of distributed energy resources: The case of micro-CHP systems , 2008 .

[15]  Manfred Morari,et al.  Model predictive control: Theory and practice - A survey , 1989, Autom..

[16]  G. Thompson,et al.  A Branch and Bound Model for Choosing Optimal Substation Locations , 1981, IEEE Transactions on Power Apparatus and Systems.

[17]  S. Ashok,et al.  Peak-load management in steel plants , 2006 .

[18]  Jiangfeng Zhang,et al.  A model predictive control strategy for load shifting in a water pumping scheme with maximum demand charges , 2009, 2009 IEEE Bucharest PowerTech.

[19]  H. Nilsson.  The many faces of demand-side management , 1994 .

[20]  David Q. Mayne,et al.  Constrained model predictive control: Stability and optimality , 2000, Autom..

[21]  S. Ashok,et al.  Optimal cool storage capacity for load management , 2003 .