Volume 16, Issue 4 -

This article focuses on the past, present, and future of environments in the Association of Southeast Asian Nations (ASEAN) as the region moves toward the 2015 launch of the ASEAN Economic Community (AEC). Policies and data are compared between the ten nations in the group and with others such as the United States, Australia, and European Union (EU) members. Opportunities to promote and support expansion of renewable energies are explored alongside factors constraining green growth initiatives. Climate science and statistical analyses are used to bolster recommendations in favor of implementation of new environmental legislation such as a regional cap-and-trade mechanism and carbon tax. A holistic approach to environmental protectionism is proposed in consideration of conflicting economic and scientific interests, which have resulted in poor enforcement of existing regulations.

This paper presents an integral Sliding Mode Controller (SMC) of a DC-DC boost converter integrated with a photovoltaic (PV) system for maximum power extraction. In view of improving the steady-state performance of the maximum power point tracking (MPPT), an integral of the error term is included in the sliding surface. The output of PV panels is connected to a DC-DC boost converter to regulate and enhance the voltage up to a desired level. By using SMC with integral term, the steady-state condition is obtained at less than 0.1 sec. With the proposed ISMC MPPT the maximum power extracted is more than 10% than the traditional Perturb & Observe (P&O) MPPT at standard test conditions (STC). The results obtained using the SMC are compared with that of the fixed step size P&O MPPT controller. The performances of the proposed sliding mode controller and the P&O controller are validated through experimentations using a Real-Time Digital Simulator (RTDS)-Opal RT.

Nowadays, deregulation and liberalization in the power market has increased the competition in the retail power sectors. As a result, power companies need to reduce the operational cost and maximize profits by operating generators with high efficiency. On the other hand, the all electric residences are increasing, so controllable loads such as the electric water heater, heat pump and electric vehicle are being introduced to the power systems. The conventional system does not operate using thermal units with controllable loads in a coordinated manner. Therefore, the smart grid has become very popular in all over the world. This paper focuses on the reactive power scheduling of controllable loads, and determines the optimal operation of thermal units by satisfying the voltage constraints. The proposed method can satisfy the voltage constraint and reduce the rate of the power cost for a power system. The optimal control algorithm has been determined by the Tabu search method. Simulation results verify the proposed method and validate the performance and effectiveness of the control algorithm applied to the controllable loads and batteries.

This paper investigates a modified simple soft switching dc-dc converter for low power applications. This simple topology uses an auxiliary switch, an inductor and a capacitor to operate the converter without switching losses. The efficiency of the converter is improved by transferring the energy that would be dissipated during the switching to the load. The main switch turns-on with zero current switching (ZCS) and turns-off with zero voltage switching (ZVS), while the auxiliary switch turns-on and turns-off with zero voltage switching (ZVS). The detailed theoretical analysis and the design equations are described. In addition to that, the analysis of proposed converter is demonstrated by both simulation and experimental results for effectiveness of the study.

This paper presents a new adaptive differential protection scheme which efficiently adapts the change in tap position of a power transformer. The proposed scheme is based on analytical derivation of pick-up and slope of the differential relay characteristic. By acquiring information such as rating & connection of CTs and present tap position as input, the proposed scheme enhances sensitivity of differential relay during internal faults. This is accomplished either by decreasing pick-up and/or adjusting slope of the differential characteristic of the relay in case of change in tap position. Numerous test cases consisting of various types of internal and external faults have been simulated for an existing power transformer of Gujarat Energy Transmission Corporation Limited (GETCO), Gujarat, India using PSCAD/EMTDC software package. The proposed scheme increases percentage of winding to be protected during internal faults for power transformers having different ratings and connections compared to the conventional differential protection scheme. Furthermore, it has been observed that the detection sensitivity during special types of turn-to-turn and inter-winding faults with varying fault resistances is also enhanced compared to the conventional scheme. Moreover, it equally maintains stability during CT saturation condition. At the end, comparative evaluation of the proposed scheme with the existing schemes clearly indicates superiority of the proposed adaptive scheme.

With the rapid development of power grid construction, appropriate maintenance can bring great benefits to the electricity company. On the contrary, it will cause sacrifices, even effect the development of economy. Thus, electrical equipment condition-based maintenance plays a key role to assure healthy operation of electrical equipment and improve power supply reliability. Under the background, in this paper, we combine the Cloud Model with TOPSIS which is improved by Grey Correlation Theory and propose a new decision-making method for electrical equipment condition-based maintenance. In this method, Cloud Model is used to solve the fuzziness and randomness of uncertain linguistic sets in the progress of decision-making. At the same time, we integrate the grey correlation degree into TOPSIS, and calculate the comprehensive relative closeness. Through the numerical example and comparing the sensitivity of some related methods about decision-making, the method in this is proved to be credibility. The basis of electrical equipment condition-based maintenance decision-making can be provided and supply dispatcher decision-making reference when arrange the CBM plan.

Electrical power quality has been an important and growing problem because of the proliferation of nonlinear loads such as power electronic converters in typical power distribution systems in recent years. Particularly, voltage harmonics and power distribution equipment problems result from current harmonics produced by nonlinear loads. The Electronic equipment like, computers, battery chargers, electronic ballasts, variable frequency drives, and switch mode power supplies, generate perilous harmonics and cause enormous economic loss every year. Problems caused by power quality have great adverse economic impact on the utilities and customers. Due to that both power suppliers and power consumers are concerned about the power quality problems and compensation techniques. Power quality has become more and more serious with each passing day. As a result active power filter gains much more attention due to excellent harmonic and reactive power compensation in two-wire (single phase), three-wire (three-phase without neutral), and four-wire (three-phase with neutral) ac power networks with nonlinear loads. However, this is still a technology under development, and many new contributions and new control topologies have been reported in the last few years. It is aimed at providing a broad perspective on the status of APF technology to the researchers and application engineers dealing with power quality issues.

Installation of a wind power distributed generator in a distribution system alters the reactive power drawn by the system. This affects the load bus voltages. Any deviation in load bus voltages from their limits is sensed by an on load tap changer of a transformer and it responds to maintain the bus voltages within their limits. The reactive power requirements of a wind generator vary due to the intermittent behaviour of wind, which will in turn vary the bus voltages. This has an affect on number of tap changings of a transformer. Frequent tap changing of a transformer increases wear and tear of it and ultimately reduces the life of it. A mathematical model is developed to analyze the voltage sensitivity at a load bus to the tap change of a transformer under different scenarios and conditions in the distribution system. A possible solution to reduce the number of tap changings is presented in this paper.