S. A. Khaparde

Placement and Penetration of Distributed Generation under Standard Market Design

Distributed Generation (DG) can help in reducing the cost of electricity to the costumer, relieve network congestion and provide environmentally friendly energy close to load centers. Its capacity is also scalable and it provides voltage support at distribution level. Hence, DG placement and penetration level is an important problem for both the utility and DG owner. The cost of electricity as a commodity depends upon market model. The restructured power markets are slowly maturing with standardizations like Standard Market Design (SMD). The key feature of SMD is the Locational Marginal Pricing (LMP) scheme. This paper examines placement and penetration level of the DGs under the SMD framework. The proposed approach is illustrated by case studies on MATPOWER 30 bus and IEEE 118 bus systems.

Evaluation of configuration plans for DGs in developing countries using advanced planning techniques

Many developing countries have emphasis on distributed generation (DG) technology for their generation expansion planning. The planning considerations and judicious choice of attributes are dictated by prevailing conditions. The attributes considered are capital costs, energy not served per annum, and profits from injecting power into the grid at peak load, all of which are important for a developing country. The uncertain futures considered are three possible loading conditions, which can be low, medium and high. Different scenarios (plans) are generated by various combinations of configurations. DGs can be configured as stand-alone mode, hybrid operation, or micro-grid formation with or without grid connection. With the increased complexities in DG planning options along with the multiple attributes to be accounted, more sophisticated techniques other than conventional economic analysis are needed to arrive at correct decisions by decision makers. The analytical hierarchy process (AHP) is used for obtaining relative weights in an objective way. Further, the statistical method like interval-based multi-attribute decision making with tradeoff analysis is used for shortlisting the feasible plans and identifying the most appropriate plan. It is proposed to use the weights obtained from AHP for finding the performance efficiencies in data envelopment analysis (DEA) for evaluating the plans. A new composite utility function is proposed to resolve cases where performance efficiency is insufficient for evaluation in DEA application. The sample system is derived with reference to a rural electrification scheme in India. The assessment of plans is presented and discussed. The comparative strengths and weaknesses of the methods are reported on the basis of the results obtained.

An adaptive approach in distance protection using an artificial neural network

All relay settings are a compromise. Adaptive relaying accepts that relays that protect a power system may need to change their characteristics to suit the prevailing power system conditions. This philosophy has a wide range of applications covering many protective schemes. Here we consider a two-terminal transmission line, confirm that fault resistance and the location of faults can produce erroneous relay function and finally suggest ways to ensure the generation of the correct signal for relay operation. Retaining the microprocessor based framework, we show how artificial neural networks (ANNs) can be used effectively to achieve adaptive relaying for the above-mentioned problem. Adaptive relaying covers a large number of applications and the characteristics of relays vary widely, so the philosophy of adaptive relaying must vary accordingly. A modified multilayered perceptron model employs an additional node in the input layer. This additional input facilitates changes in the relay characteristic. The desired change in the quadrilateral relay characteristic is achieved by making appropriate changes in the thresholds and weights of the hidden layer neurons. A multiparameter adaptive scheme assumes that the additional input of the phase angle is available. Simulation results using ANNs for the different applications of adaptive relaying mentioned above are presented and discussed.

A Comprehensive Assessment of the Evolution of Financial Transmission Rights

Financial transmission rights (FTRs) are complementary to the locational marginal pricing of energy. The basic aim of the FTR mechanism is to guard forward contracts from uncertain congestion charges. FTRs are also useful to individual generators and loads for selling and buying power, respectively, at the prices of other locations. The concept has evolved, encompassing many features such as a simultaneous feasibility test, various ways to conduct auctions and allocations and secondary trading. FTRs also have a close relation to market power and transmission investment. This paper reviews most of the landmark research papers on the evolution of the FTR concept. It reports a comprehensive assessment of various facets of FTRs and allied issues. Financial transmission rights and flowgate rights (FGRs) are compared. The concept of long-term FTRs is discussed. The paper also touches upon future proposals in this area.

Optimal sizing of distributed generators in microgrid

Hybrid optimization model for electric renewables (HOMER), developed by National Renewable Energy Laboratory (NREL), enables economic analysis for single source and hybrid distributed energy resources (DERs). However, current version of HOMER does not support microgrid analysis. In this paper, economic analyzer for distributed energy resources (EADER) is developed. It finds minimum cost of energy (COE) and optimal mix of DERs with multiple sources and sinks. In addition to single source distributed generator (DG) and hybrid DG, EADER is also capable to analyze microgrid. EADER results are validated for single source DG and hybrid DG with results obtained from HOMER for the same systems. Further, a sample practical system from Western Maharashtra, India, is analyzed using EADER. The results which consider all practical constraints are presented and discussed

CIM-Based Connectivity Model for Bus-Branch Topology Extraction and Exchange

In terms of scope and granularity of data, two kinds of connectivity models are broadly in vogue for representing power network data, namely, node-breaker model and bus-branch model. This paper examines both the connectivity models from the perspective of common information model (CIM). Although CIM is primarily designed for most detailed node-breaker representation, with certain extensions CIM can be leveraged to achieve a standard, interoperable bus-branch model representation and exchange format. To facilitate this, it is proposed to introduce new class called TopologyBranch. By decoupling the connectivity information and the equipment parameter information, a mechanism for efficient exchange of time varying system models with minimum information transfer between the power control centers is described in this paper. The proposed CIM bus-branch connectivity model has wide applications in an interoperable, decentralized, hierarchical structure of control centers. Three illustrative examples including one on a practical 20-substation model of the 400 kV transmission network of Maharasthra state, India, are then presented for demonstrating the benefits.

Deployment of MicroGrids in India

The MicroGrid concept using renewable energy sources is a building block towards the future energy networks for long-term viable solution of energy needs. The focus of the paper is centred around the encountered and foreseen issues, enabling technologies and economics for encouraging the deployment of MicroGrids in India. This paper presents state-of-the-art issues and feasible solutions associated with the deployment of MicroGrid technologies leading to the conceptualization of efficient and smart MicroGrids. The role of enabling technologies, automation and communication for sustainable development of MicroGrids is also explained here.

Towards Indian Smart Grids

India is struggling to meet the electric power demands of a fast expanding economy. Restructuring of the power industry has only increased several challenges for the power system engineers. A major chunk of the power losses is a direct derivative of the poor management of distribution networks. Distribution automation (DA) has been aimed at reducing losses, and improving reliability and financial viability of state utilities. Firstly, this paper presents various benefits achieved by major Indian utilities in transitioning towards automation. Enroute to the proposed vision of introducing viable Smart Grids (SG) at various levels in the Indian power systems, it is recommended that an advanced automation mechanism needs to be adapted. This is then projected to be feasible through invariable dependance on several open standards, whose integration for interoperability, flexibility, scalability, modularity and vendor neutrality is deemed pivotal. Various examples of existing structures of automation in India are employed to underscore some of the views presented in this paper. Finally, a potential SG architecture for Indian power systems is proposed with a discussion on its implications.

Power sector reforms and restructuring in India

The need for restructuring the power sector was felt due to the scarcity of financial resources available with Central and State Governments, and necessity of improving the technical and commercial efficiency. Electricity Act 2003 has come into force from June 2003. As the act allows third party sales, it introduces the concept of trading bulk electricity. The act also provides open access to transmission as well as distribution of electricity. Some of the important issues addressed by this Act and their impact on power system restructuring are discussed in this paper.

Stray loss evaluation in power transformers-a review

Survey of current research papers reveals the continued interest in application of advanced techniques for accurate estimation and control of stray losses in transformers. This paper gives an overview of research, development and application of various computational tools for stray loss analysis, based on over 50 published papers. All landmark papers are systematically classified. Practicality of application of methods by transformer designers is discussed. The report concludes with critical comments on efficacy of all approaches and directions for pursuing further research.