C. Radhakrishna’s research while affiliated with The Institution of Engineers (India) and other places

This paper presents an analysis of Greenhouse Gas (GHG) emission projections for grid-connect thermal power generation in India till 2030. Future power generation projections are obtained by utilizing an integrated power and energy planning tool. The optimal mix of thermal power generation from coal, natural gas and diesel is found by using a multiperiod generalized network flow model. Using a novel hybrid approach, the study, comprising different scenarios of thermal power generation efficiencies, highlights an important national strategy for low carbon growth.

This article presents a simple method for investigating the problem of contemporaneously choosing optimal location and size of shunt capacitors in three-phase unbalanced radial distribution systems. The main objective function formulated consists of two terms: cost of energy loss and cost related to capacitor purchase and capacitor installation. The problem of choosing optimal locations and sizes for shunt capacitors in an unbalanced radial distribution system is addressed with the two algorithms in this article—one is for selecting the best locations of capacitor placement and candidate node identification algorithm; the second is for the sizing of capacitors, a variational technique algorithm according to available standard size of capacitors. The objective function used in this article is to maximize the net savings in the distribution system. This article presents the results of simulations for 25-bus and IEEE 37-bus unbalanced radial distribution systems.

A novel approach for investigating the problem of both choosing the optimal location and size of shunt capacitors in three-phase unbalanced radial distribution network (URDN) for loss minimization has been presented in this paper. There are two parts in the main objective function formulated: One, the cost related to capacitor purchase, capacitor installation and the other, cost of energy loss. This paper addresses the problem of choosing optimal locations and sizes for shunt capacitors in unbalanced radial distribution network with two algorithms:One,the capacitor placement node identification algorithm for selecting the best locations of capacitor placement, and another the variational technique algorithm for the sizing of capacitors, as per the standard size availability of capacitors. The objective function used in this paper aims at maximizing the net savings in the unbalanced radial distribution network by optimal capacitor placement and sizing. The results obtained with the proposed methodology for 25-bus and IEEE 37-bus Unbalanced Radial Distribution networks demonstrate its applicability.

In this paper a new approach using the 0-1 integer programming method for reconfiguration of unbalanced radial distribution systems with the presence of distributed generators for voltage profile improvement and power loss minimization is presented. In practice, unbalanced distribution feeders of power utilities are characterized by low power quality, low voltage profile, more investment and high operating costs. By installing Distributed generators, voltage profile and reliability of unbalanced power distribution systems can be improved with minimization of power losses. In this paper the distributed generators have been modeled as photovoltaic (PV) systems in the unbalanced distribution system. Reconfiguration of unbalanced feeders is a good technique to balance the unbalanced distribution systems to improve the voltage profile and minimize the power losses. The results obtained with the proposed methodology on an example unbalanced power distribution system demonstrate its applicability.

The aim of the study is to develop a simple and direct approach for unbalanced radial distribution system three-phase load flow solution .The special topological characteristics of unbalanced radial distribution networks have been fully utilized to make the direct three phase load flow solution possible. Two developed matrices-the node-injection to line section-current matrix and the line section-current to node-voltage matrix-and a simple matrix multiplication are used to obtain the three phase load flow solution. Due to the distinctive solution techniques of the proposed method, the time-consuming Lower Upper decomposition and forward-backward substitution of the Jacobian matrix or admittance matrix required in the traditional load flow methods became not necessary. Therefore, the proposed method is observed as robust and time-efficient. Results obtained on 8 node and IEEE 13 node test systems demonstrate the validity of the proposed method. The proposed method has got good potential for the usage in distribution automation applications.

The aim of the study is to develop a simple and direct approach for unbalanced radial distribution system three-phase load flow solution .The special topological characteristics of unbalanced radial distribution networks have been fully utilized to make the direct three phase load flow solution possible. Two developed matrices-the node-injection to line section-current matrix and the line section-current to node-voltage matrix - and a simple matrix multiplication are used to obtain the three phase load flow solution. Due to the distinctive solution techniques of the proposed method, the time-consuming Lower Upper decomposition and forwardbackward substitution of the Jacobian matrix or admittance matrix required in the traditional load flow methods became not necessary. Therefore, the proposed method is observed as robust and time-efficient. Results obtained on 8 node and IEEE 13 node test systems demonstrate the validity of the proposed method. The proposed method has got good potential for the usage in distribution automation applications.

This article presents a simple reconfiguration algorithm that is specially suited for balanced and unbalanced radial distribution systems. The proposed algorithm involves less complex mathematical expressions, and a more efficient network configuration can be obtained with reduced power losses. The choice of the switches to be closed is based on the calculation of bus voltages and the minimum total system losses using a power flow program. This method takes a smaller number of switchings and less CPU time. Results obtained on one balanced system and two unbalanced systems are also presented and compared with the existing methods.

This paper describes how integrated energy-emissions planning can be carried out for evolving energy strategies that facilitate greenhouse gas mitigation. The India case study highlights different energy scenarios, keeping in view the need for clean environment. This study has been carried out using an integrated energy planning tool which takes emissions into account. The importance of energy efficiency, fuel switching, and utilization of hydro, nuclear and renewable energy sources, for greenhouse gas mitigation is clearly brought out. These findings would be of interest to those working on national energy planning, sustainable development, and climate change mitigation.

Load flow method suitable for both radial and weakly-meshed network structures common to distribution systems is proposed in this paper. Here the concept duality of network has been exploited to obtain the solution. Unique data feeding technique and creation of single matrix [branch-voltage drop to node-current] based on dual nature of the electrical network are used in the procedural technique. A single informative forward path impedance [FPI] matrix is developed in the proposed method and it is found to be adequate for the analysis. The method first arranges constant input data and then proceeds further by collecting the information about forward path-impedances in matrix form. Then identify the dual of forward path-impedance matrix, which gives backward nodal-current injection information about the network. The solution is derived using forward path impedance and branch currents. This methodology is programmed for an IEEE 15-Node network using MATLAB Ver. 7.0. and it is demostrated that computational efficiency has been improved by the algorithm suggested. This paper also includes equations for two real-world issues like, when lines are modeled as Pi section and for network having tap changing transformer. The proposed method is flexible to extend for 3-phase networks also.

This paper presents a simple three phase power flow method for solution of three-phase unbalanced radial distribution system (RDN) with voltage dependent loads. It solves a simple algebraic recursive expression of voltage magnitude, and all the data are stored in vector form. The algorithm uses basic principles of circuit theory and can be easily understood. Mutual coupling between the phases has been included in the mathematical model. The proposed algorithm has been tested with several unbalanced radial distribution networks and the results are presented in the article. 8- bus and IEEE 13 bus unbalanced radial distribution system results are in agreements with the literature and show that the proposed model is valid and reliable.