Slack Bus Modeling and Cost Analysis of Distributed Generator Installations

The installation and operation of distributed generators (DGs) has great potential for local utilities to improve distribution system reliability and lower their operating and expansion planning costs. To evaluate this potential, distribution system analyses must reflect its new operating environment with significant DG. Resulting tools can be utilized by both utilities and DG owners to improve their decision making algorithms. As such, this work investigates two different slack bus models for unbalanced distribution power flow and their impacts on subsequent cost analysis. The models include the traditional single slack bus model which assigns the substation as the slack bus and a distributed slack bus model which assigns slack to the substation and DGs according to network-based participation factors. Detailed expressions for cost analysis which directly depend on the distributed slack bus model are presented and discussed. Simulations illustrate that the different slack bus models have significant impacts on cost analysis. The difference in estimated annual profit for local utilities reached up to 265% using the different slack models.     

Optimal Expansion Planning for the Deployment of Wind Energy

With the growing concern regarding climate change, the integration of renewable electric technologies into the grid has taken on increased importance over the past decade. In particular, the integration of wind energy is increasing the attention paid to power transmission investment planning, generation adequacy, and secure system operation. This attention calls for the development of new tools that can simultaneously address the economics, transmission, ancillary services, and reserve requirements associated with wind energy. This paper proposes a method for choosing the optimal plan for expanding transmission and generation considering optimal power flow, discrete plant sizes, and the resource variability of wind energy. The method minimizes total cost, i.e., the sum of the construction cost and the operation cost, to fulfill expected load. Due to the nature of transmission expansion planning and the economies of scale associated with conventional power plants, finding the expansion plan is an integer programming problem solved by a branch and bound method. The proposed method is tested by applying it to a nine-bus system.     

System Electrical Power Monitoring Manifold Based on Software Development and an Embedded System for Intelligent Buildings

Monitoring electric parameters and electrical consumption for multiple circuits to determine exactly where and how much electric power is consumed is one of the primary problems of intelligent buildings. In this paper, the development of a power consumption and quality monitoring system called MonitoUAQ is described, and the results obtained during its testing are discussed. The MonitoUAQ system was created to maximize the effective and efficient use of energy resources. It was developed around a field-programmable gate array (FPGA) to monitor multiple branch circuits on a common distribution panel and enhanced by a client-server interactive network architecture. This intranet-controlled power-monitoring system integrates control, measurement, and communication. Its implementation is economical by eliminating the need for extra network construction and the associated hardware investment. Moreover, the multicast Web application allows multiple users to access the power metering results in a variety of applications in a soft-real-time manner.     

Integrating Large Wind Farms into Transmission Planning of Hydrothermal System

This paper is aimed at presenting a methodology leading to the incorporation of large wind farms to the transmission planning of hydrothermal systems. We resorted to a simulation program for an optimum operation of a generation-transmission system based on stochastic dual dynamic programming and incorporated the wind energy features as well as undertook the simulations. This work was applied to an existing hydrothermal system; chiefly for evaluating the wind farm impact in three specific areas: the network expansion, the energy cost, and the effect on the reservoir water level.     

Wind Energy in India: Shifting Paradigms and Challenges Ahead

The Indian wind industry was placed third in terms of total installed capacity of wind electricity in the world some years back. It suffered a great setback when this rank shifted down to fifth after the United States, Germany, Denmark, and Spain in the later years. The falling profitability of private wind farm operations in the country today has been the cause of deep concern to many. As a result of the initiatives taken by the government to promote wind energy, different states have started supporting the wind power companies and investors with liberal policy initiatives. The steps to be adopted by the government agencies in order to ensure the desired growth of the wind industry in the country have been suggested in the paper. The paper also lists suggestions to meet the technical challenges faced by the Indian wind industry and to improve the performance of wind farms in India. It further suggests that a right choice of wind electric generators with an optimum rated wind speed will improve the wind farm performance. Potential markets and the role of utilities have also been described.     

Optimal Capacity Expansion in Electric Power Subtransmission Networks

A procedure is proposed to determine where and when to increase the capacity of lines and transformers in a power subtransmission network. The expansion plan must minimize cost while supplying the demand for energy over a time horizon, keeping the quality and reliability standards of the network and minimizing the impact over the environment. The procedure is iterative and takes into account AC flows, reliability analysis, different scenarios, demand uncertainty, discrete investment costs, voltage constraints, capacity, and power factor. A significant contribution of this procedure is that, along with the expansion plan, it considers the optimization of the operation, specifically the movement of transformer taps and the location and sizing of reactive banks. This allows significantly reducing or delaying the investment, thus reducing its present value. The approach ensures convergence when computing the power flows and allows making an analysis of the effects of distributed generation and, if necessary, load curtailment. The model is tested on the power subtransmission network of the most important electric power distribution company in Chile, serving a city of 6 million people.     

选煤厂供配电系统的节能探讨

本文从选煤厂供配电系统节能的关键环节和企业管理两方面简要探讨了节能措施。     

Combined Heat and Power as a Feature of Energypark

The use of combined heat and power (CHP) in manufacturing plants that have relatively large thermal and power loads has long been recognized as an efficient alternative that also translates to less fuel consumption, i.e., less polluting of the environment. Making use of the full potentials of this mature concept still faces several technical and regulatory challenges. The concept of an ecopark is one that creates a cluster of industrial plants in close proximity, so that relevant inputs and outputs of the park can be optimized and shared by the park affiliates in order to maximize economic and environmental benefits. The design objectives of such an ecopark are large and include travel time, raw material bulk pricing, energy use, toxic substances, local resources, infrastructure, and regulations and operation guidelines, etc. Solving a problem with so many design objectives may be complex, requiring an extensive organizational network, intricate planning, and flexibility even once the design is completed. The ecopark, with its primary optimizing tool, a CHP system, is introduced in this paper to show how to achieve optimum energy use by a cluster of appropriately selected plants. The manufacturing park optimized for maximum energy efficiency, called an energypark, can then work hierarchically toward adopting more useful performance and waste-related parameters as secondary objectives for further optimization whenever possible.     

Distribution Networks with Linear and Nonlinear Loads: Cost-Based Method for Planning Dispersed Generation and Capacitor Units under Uncertainty

This paper discusses the optimal allocation of capacitors and dispersed generation units in a medium-voltage distribution system with linear and nonlinear loads. An optimization problem is formulated and solved for optimal siting and sizing, with the objective of minimizing costs sustained by the distributor for reactive power service, even containing the impact of the waveform distortions. A three-step procedure, based on genetic algorithm and decision theory, is applied to obtain a solution for the optimization problem that takes into account the unavoidable uncertainties that the dispersed generation production and the loads introduce. The numeric applications performed on an 18-bus test distribution system demonstrate of the effectiveness of the proposed procedure.     

Investment Model for Power Generation and Transmission Network Expansion in Turkey

Provision of adequate electricity is one of the major factors for industrial and commercial development. However, decisions on the expansion of electricity are bogged down by high investment requirements and nonsynchronized expansion between electricity generation and transmission systems. As a rule, the investment requirements for these types of projects are immediate but their benefits can be obtained only in the long-term basis albeit electricity planners base their decisions on immediate requirements of shorter terms. As investment funds are very hard to come by, the funds, if available, should be utilized to maximum by minimizing the investment through a synchronized expansion planning of both electricity generation and transmission systems. This paper attempts to address this opportunity. We have proposed here a mixed integer model to develop concurrent transmission and generation investments plans. The model selects new generation plants or generation capacity expansions for existing plants that are located on the interconnected network by considering explicitly congestion in the transmission network. Hence the model contributes to this area by filling in the gap between models for developing long-term power generation policies and power flow models focusing on transmission network expansion. The application of the model in Turkey’s electricity network highlights the country’s congested areas in the transmission network, which might lead to loss of load and inefficient generation capacity expansion if not tackled properly. The analysis shows that a cost efficient generation expansion is possible to realize in congested regions if proper transmission expansion decisions are made concurrently with generation expansion decisions.     

Localized Aggregation of Diverse Energy Sources for Rural Electrification Using Microgrids

Extension of electrical service to large rural populations in developing nations is a key requirement to realize human development goals set forth by international agencies. This paper presents the case for distributed generation in the form of microgrids, which should be the preferred path towards rural electrification in developing communities and a vital complement to expensive centralized grid expansion. The technical features of frequency and voltage control for distributed generation devices in a microgrid are discussed along with a presentation of their stability attributes. Computer simulation results and experimental results from a laboratory scale microgrid are also presented.     

露采配电室6kV无功补偿应用实践

根据无功功率的平衡原理,依据无功补偿的原则,介绍无功补偿和电压优化控制原理及流程,并说明其在露采配电室的应用效果。     

无功电压调整在武钢电网经济调度中应用

研究了武钢电网经济调度中的无功电压调整问题,从有载变压器档位调整、无功补偿装置调节、利用自发电机组进相运行调整几个方法提出了无功电压的调整思路。     

无功补偿技术在主降压变电所的应用

结合主降压变电所实际运行情况,介绍了无功补偿控制原理、方案制定、优化和控制设备的选择等。应用无功补偿技术后,提高了系统功率因数,降低了电能损耗,稳定了电网电压,提高了经济效益。     

降低武钢供电网络配电损失率的措施

分析了武钢集团供电网络配电损失率偏高的原因，重点从电网运行技术的多个方面，尤其是电网运行方式、变压器的投运、提高功率因数、加强负荷监控、电能计量、平衡工作等方面采取措施，降低了配电损失率。     

我国能源可持续发展的战略决策--大力发展水电

概述了国内外常规能源的资源量、可采储量、消费量和使用年限.研究分析了在我国开发水电是实施能源可持续发展战略的最有效途径.介绍了目前我国水电开发的现状和前景.     

高压无功补偿装置在电解排烟机的应用

针对电解冶炼排烟电动机运行功率因数普遍低的问题,本文提出了包括补偿方式选择和安装位置确定在内的解决方案,进行了补偿设备的选型和补偿容量的确算,评价了项目实施后的经济效益和社会效益。     

我国电炉炼钢工序能耗现状和供电制度的优化

文中介绍了我国电炼钢工序能耗现状及电炉炼钢过程的节能增效，供电制度的优化研究与应用研究。     

山东省冶金工业利用余能发电设备建设和运行情况

介绍了山东冶金工业利用余能发电的设备建设和运行情况及特点。在已建成的59台发电机组中,大多数是利用富余煤气、余热和余压,能源利用形式多样,装机容量不断增加,单机容量也在不断增大,发电量不断提高,发、用电量比例有明显提高。但存在装机品种多、小容量比例多、发展不平衡等问题。同时提出,国家有关部门应对富余能源综合利用给予政策和资金上的支持,企业应统筹规划,进一步做好余能的回收和利用等方面的工作。     

“十四五”中国锂动力电池产业关键资源供需分析

随着我国新能源汽车产业的不断发展壮大,对矿产资源的需求快速增长,同时对未来关键资源的供需形势产生深刻影响。以国家相关产业规划为主要依据,对我国"十四五"新能源汽车产量及锂动力电池装机量进行了预测,在识别产业关键材料的基础上测算了锂、钴、镍等矿产资源的需求量,重点分析了动力电池回收再利用对产业关键资源需求的保障程度。结果显示,"十四五"期间,锂、钴、镍需求量分别为12.9万t、70.8万t和15.1万t;通过废旧锂动力电池回收及资源再生可分别产生3.1万t锂、12.0万t镍和4.8万t钴,占同期国内锂动力电池产业资源需求量的比例分别为24.0%、16.8%和31.2%。