Decomposition-Coordinating Method for Parallel Solution of a Multi-area Combined Economic Emission Dispatch Problem

Multi-area Combined Economic Emission Dispatch (MACEED) problem is an optimization task in power system operation for allocating the amount of generation to the committed units within the system areas. Its objective is to minimize the fuel cost and the quantity of emissions subject to the power balance, generator limits, transmission line and tie-line constraints. The solutions of the MACEED problem in the conditions of deregulation are difficult, due to the model size, nonlinearities, and the big number of interconnections, and require intensive computations in real-time. High-Performance Computing (HPC) gives possibilities for the reduction of the problem complexity and the time for calculation by the use of parallel processing techniques for running advanced application programs efficiently, reliably and quickly. These applications are considered as very new in the power system control centers because there are not available optimization methods and software based on them that can solve the MACEED problem in parallel, paying attention to the existence of the power system areas and the tie-lines between them. A decomposition-coordinating method based on Lagrange’s function is developed in this paper. Investigations of the performance of the method are done using IEEE benchmark power system models

Investigation of the influence of network‐induced time delays on the activated sludge process behavior in the networked wastewater distributed systems

This paper examines the effects of networked induced time delays on the dissolved oxygen (DO) concentration in the activated sludge process (ASP) of a networked wastewater treatment plant (WWTP). This is a situation in which the controller and the wastewater plant are separated by wide geographical distance. This is a new type of WWTP control that allows two or more WWTPs to be controlled by a single controller placed in a remote location. The objective is to achieve flexibility of control and to reduce its cost. The communication medium between the controller and the WWTPs introduces communication drawbacks into the control system. The influences of network‐induced time delays [controller to actuator delay (τca) and the sensor to controller delay (τsc)] over the behavior of the DO process controlled by both nonlinear linearizing and proportional‐integral controllers are investigated for constant and random delays. Investigation of the DO process under random delays was also performed with varying linear controller parameters [proportional gain (Kp) and integral time (TI)]. Simulation results reveal that large network‐induced time delays in the closed‐loop DO process leads to depletion of the amount of oxygen available for microorganism metabolism, leading to inefficiency of the ASP. The critical delay during which the DO process becomes unstable due to communication drawbacks was also determined for constant and random delays. These values are found to vary depending on the delay type (constant/random), delay magnitude, and the linear controller parameters Kp and TI. The results of this study would provide useful information for process performance and form the basis for the design of a robust networked control for the DO process capable of mitigating communication drawbacks in a networked wastewater distributed systems. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc

Method for real time optimal control of the activated sludge process

he problem for optimal control of the activated sludge process based on ASM1 model is considered. The objective is to determine a method for real time calculation of an optimal dissolved oxygen trajectory and the corresponding optimal state trajectories subject to minimization of both the deviations from the effluent requirements and the control energy consumption. The paper presents the developed reduced biological model of the activated sludge process, Athlone plant mass balance model and method for the optimal control problem solution in a real time. The optimal control problem solution is calculated in Matlab environment and the real time control is implemented in Adroit SCADA environment

Optimal PID control of the dissolved oxygen concentration in the wastewater treatment plant

The biological process for treatment of the municipal wastewater, the Activated Sludge process, is considered. The efficient performance of the water treatment process depends on the optimal control of the concentration of oxygen in the aeration tanks. This paper describes application of two standard PID controllers tuning methods for control of the nonlinear dissolved oxygen concentration process as a part of an adaptive optimal control strategy. Procedures for real time implementation of the tuning methods and the calculated control in the frameworks of Adroit SCADA and Matlab/Simulinks software are described. The calculations are done for COST benchmark and the University of Cape Town process structures and the ASM1 biological model

Application of the particle swarm optimization algorithm to a combined economic emission dispatch problem using a new penalty factor

IEEE Power & Energy Society Conference and Exposition in Africa: Intelligent Grid Integration of Renewable Energy Resource

Robust non-linear networked control of wastewater distributed systems

CPUT Water Research Semina

Power sector in Tanzania: performance, trends and reforms

The United Republic of Tanzania is currently facing energy problems that have seriously affected its socio-economic development and environment. To solve these problems, the country is striving to exploit its renewable energy potential, among other efforts. This paper highlights the prevailing energy situation in Tanzania and provides a short review of potential energy resources. It then discusses current institutional efforts and capabilities in development, and commercialization of renewable energy technologies. The paper also identifies some barriers to promotion of renewable energy technologies as well as actions taken by the government of Tanzania to promote renewable energy technologies

Design and PLC implementation of non-linear PID controllers for control of non-linear processes

CPUT Water Research Semina

Method for a parallel solution of the multi area economic dispatch problem

The power system simulation software tools are traditionally designed for serial codes and optimized using single-processor computers. They are inadequate in terms of computational efficiency and execution time for the ever-increasing complexity of the power grid. Due to the above-mentioned sequential computing demerits, this paper used MATLAB data parallelism message passing interface software to execute the Lagrange's and Particle Swarm Optimization (PSO) algorithms in parallel with multiple processor units with different and large data sets for the solution of the Combined Economic Emission Dispatch (CEED) problem. The two important advantages of using parallel computing approach to solve the power system economic dispatch problem are 1) to increase the efficiency (solution quality) and 2) to reduce the execution time (speed-up) of the parallelization process for the CEED problem solution. The comparison between the Lagrange's and PSO data-parallel solution quality and execution time is presented for the CEED problem for Institute of Electrical and Electronic Engineers (IEEE) 30 bus and IEEE 118 bus systems. The paper contributes to the on-line real-time market analyses of the deregulated power system, which need improved solution quality and a fast computation process to solve the power system energy management (CEED) problems for proper discussion and decision making at the control center level