Jawad Talaq

A summary of environmental/economic dispatch algorithms

Traditionally electric power systems are operated in such a way that the total fuel cost is minimized regardless of emissions produced. With increased requirements for environmental protection, alternative strategies are required. This paper presents a summary of algorithms of environmental-economic dispatch in electric power systems since 1970. The algorithms attempt to reduce the production of atmospheric emissions such as NO/sub x/ and SO/sub x/ caused by the operation of fossil-fueled thermal generation. Such reduction is achieved by including emissions either as a constraint or as a weighted function the objective of the overall dispatching problem. >

Adaptive fuzzy gain scheduling for load frequency control

An adaptive fuzzy gain scheduling scheme for conventional PI and optimal load frequency controllers has been proposed. A Sugeno type fuzzy inference system is used in the proposed controller. The Sugeno type fuzzy inference system is extremely well suited to the task of smoothly interpolating linear gains across the input space when a very nonlinear system moves around in its operating space. The proposed adaptive controller requires much less training patterns than a neural net based adaptive scheme does and hence avoiding excessive training time. Results of simulation show that the proposed adaptive fuzzy controller offers better performance than fixed gain controllers at different operating conditions.

Optimal Coordination of Directional Overcurrent Relays Using Biogeography-Based Optimization Algorithms

Optimal coordination of directional overcurrent relays (DOCRs) is a highly constrained and nonlinear optimization problem. The operating time of each relay depends on two independent variables called plug setting and time multiplier setting. As the network becomes larger and more complex, the number of relays will increase and, thus, finding the optimal solution becomes very hard. In this paper, a new population-based evolutionary algorithm called biogeography-based optimization (BBO) is proposed and the performance of ten types of constraint-handling techniques is evaluated. In addition, a new hybrid BBO with linear programming (BBO-LP) is proposed to enhance the performance of the conventional BBO algorithm. The performance of the proposed BBO-based algorithms is evaluated by using five test systems. The results show the effectiveness and superiority of the proposed algorithms compared with the performance of the other optimization methods presented in the literature.

Modeling and elimination of load buses in power flow solutions

This paper presents a method to solve the power flow problem after eliminating load buses from the system. Loads are first modeled and reflected in the admittance matrix and then their respective buses are eliminated. The obtained model is a reduced model of the original system. The admittance matrix is of the same order as the number of voltage-controlled buses in the system. The variables of the reduced model are the voltage-controlled buses voltage angles only. The Newton Raphson method is used to calculate the voltage angles of the reduced model and then the voltage and angles of the original system are calculated by a direct method. The simulation is carried out on two systems, the IEEE 118 bus test system and a 131 bus actual system. It is shown that solution time is significantly reduced when compared to the conventional Newton Raphson method using the original system. >

MODELING AND ELIMINATION OF LOAD BUSES IN OPTIMAL POWER FLOW SOLUTIONS

ABSTRACT This paper presents a method to solve the optimal power flow problem after eliminating load buses from the system. Loads are first modeled and reflected in the admittance matrix and then their respective buses are eliminated. The obtained model is a reduced model of the original system. The admittance matrix is of the same order as the number of voltage-controlled buses in the system. The variables of the reduced model are the voltage-controlled buses voltages, angles and active power generations. Newton Raphson method is used to calculate the variables of the reduced model while minimizing an objective function. Voltages and angles of the original system are then calculated by a direct method. These voltages are required to update load models and to check for voltage and line current violations at the eliminated portions of the network. The simulation is carried out on two systems, IEEE 118 bus test system and a 131 bus actual system. It is shown that solution time is significantly reduced when ...

Minimum emissions power flow using Newton's method and its variants

Abstract This paper presents a formulation of the optimal power flow problem to include the minimum emission objective. A computational solution using the basic Newtons approach is suggested. Fuel cost and emissions such as NO x objectives are included in the formulation. Emissions also may be added as constraints while minimizing cost. A decoupled Newtons approach, as well as a hybrid technique are also investigated in this presentation. It is shown that faster convergence is achieved using these latter two techniques.

A New Approach to Economic Dispatching Using Load Bus Elimination Techniques

This paper presents a new technique to solving the economic dispatch problem based on a reduced order model of the original system. Loads are first modeled by their appropriate voltage-dependent models as load admittances. Load admittances are then added to the bus admittance matrix and their respective buses are eliminated. The obtained model is a reduced model of the original system. The admittance matrix is of the same order as the number of voltagecontrolled buses in the system. The variables of the reduced model are the voltage-controlled buses’ angles and active power generations. Newton Raphson method is used to calculate the angles and active generations of the reduced model while minimizing the operational cost. Load bus voltages and angles of the original system are then calculated by a direct method and load admittances are modified. The process is repeated until convergence is achieved. The simulation is carried out on IEEE 118 bus test system. A comparison between the new approach and the penalty factors method has been made. It is shown that operational cost is improved and solution time is significantly reduced when compared to the penalty factors method of economic dispatch.

ALLEVIATION OF VOLTAGE VIOLATIONS AND LINE OVERLOADS IN POWER FLOW SOLUTIONS

ABSTRACT This paper describes a method to alleviate bus voltage violations and line overloads by minimizing a weighted quadratic performance index. The performance index consists of a weighed sum of active and reactive power mismatches together with system variable increments. Violations of voltages and line overloads are identified from the base case of the power flow solution. The performance index is minimized to alleviate these violations. Different weighting factors are assigned to the variables in order to control the amount of change in these variables. The variables are bus angles and voltages, transformer tap positions and active power generation. Generator voltages and active power generation together with transformer tap positions are then modified and the power flow problem is solved. The process is repeated until convergence is achieved. Simulation results of IEEE 30 and 118 bus test systems are given. The results demonstrate the ability of the method to alleviate bus voltage violations and l...