Majlesi Journal of Energy Management
Volume:5 Issue: 1, Mar 2016

The objective of dynamic economic emission dispatch (DEED) problem is scheduling of the optimal power outputs of the online generating units over a time horizon by minimizing the fuel cost and emission level simultaneously while satisfying the generators and system constraints such as power balance constraint, ramp-rate, and generation limits. In this paper for a more practical and comprehensive study, in addition to the above constraints, the valve-point effect and spinning reserve constraints have been taken into account too. With considering the above conditions, DEED becomes a complex multi-objective optimization problem with non-convex and non-smooth objective function that traditional methods are not able to solve it. So, in this paper random drift particle swarm optimization (RDPSO) has been used to solve the above problem. In addition, a ten unit test system has been studied to demonstrate the effectiveness of the mentioned algorithm and the results are compared with the other algorithms.

This paper present honey bee mating optimization (HBMO) for optimal power flow (OPF) problems to aim the minimum cost as an objective function and satisfying other constrain such as generation capacity limits, power balance, line flow limits, bus voltage and operating limits of power system and dependent variables. The proposed method has been examined and tested the standard IEEE 30 bus test system. The HBMO method has been demonstrated and compared with the other intelligence heuristic algorithm such as Particle Swarm Optimization (PSO), Shuffle frog leaping algorithm (SLFA) Modified Differential Evolution OPF (MDE-OPF), Simulated Annealing (SA), Improved Evolutionary Programing (IEP), for 30 bus test system. At the end by comparing the results, superiority of presented method has been demonstrated over the mentioned method.

Combined heat and power economic dispatch (CHPED) is one of the important issues in power systems. CHPED is a challenging optimization problem of non-linear and non-convex type. Thus, evolutionary and heuristic algorithms are employed as effective tools in solving this problem. This paper proposes a new approach to solve CHPED problem using particle swarm optimization with unique inertia factor (PSO-UIF) algorithm in which there is no similar inertia coefficient for all population. Contrary to the particle swarm optimization (PSO), in the proposed method, there is an inertia weight, in each iteration, for each member of the population. Hence, in the proposed method, some populations have unique inertia coefficient and consequently a unique velocity in looking for the global optimum points. In order to examine the proposed algorithm's capabilities two test systems are optimized considering valve-point effect, system power loss and system constraints. The numerical results were compared to those of the other existing techniques. The result of comparisons shows the effectiveness and superiority of the proposed method.

System stability study is the important parameter of economic, reliable and secure power system planning and operation. Power system studies are important during the planning and conceptual design stages of the project as well as during the operating life of the plant periodically. This paper presents the power system stability analysis for IEEE-9 bus test system. The fault is created on different busses and transient stability is analyzed for different load and generation conditions. The critical clearing time is calculated by using time domain classical extended equal area criterion method. The system frequency and voltage variation is observed for different fault locations and critical clearing time. The IEEE-9 bus test system is simulated and stability is analyzed on ETAP software.

This contribution is aimed at representing the characteristics of neutral wire and also obtaining an optimalgrounding resistancein different situations in a three-phase four-wire distribution network. To this end, various effects of the system components have been investigated on neutral wire characteristics and grounding system. On the other hand, it is concluded that, in addition to system imbalance, there are other determinative factors in which the neutral wire and grounding system have irregular characteristics. These factors include: transformer type and capacitor bank failure.The investigation also achieved an optimized grounding resistance for grounding system for different types of transformers.

Disturbances and faults cause power swing in the power system. Under these dynamic conditions, the power swing blocking (PSB) function prevents the misoperation of the distance relay. However, if a fault occurs during power swing, the relay must be unblocked and let it trip. In other words, the relay should be capable of detecting faults during power swing. The power swing phenomenon involves all three-phases of power system and thus, the detection of the symmetrical faults in this situation is great complexity. In this paper, single-criterion methods for the symmetrical fault detection during power swing are implemented and their performances in different situations including fault location, fault inception time, fault resistance and the angle difference between two buses at the ends of transmission line, are evaluated and compared with respect to speed and accuracy.