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Integration of Distributed Generation (DG) has occupied a great interest in modern power engineering due to its significant merits over the conventional power generation techniques. However, several aspects such as climatic conditions, land and fuel availability, DG location and DG size need to be carefully considered to harness the best results from integrating DG units for power networks. Among them, sizing of DG units has taken a prominent place as it affects the network operation as well as the cost aspect. Optimizing the sizes of prospective DG units that are intended to be integrated for a given network will facilitate in gaining the expected merits such as minimizing active power losses and voltage deviations without causing any stability, protection and power quality issue. The existing methodologies for determining optimal DG sizes are rather sophisticated. This paper presents a robust mathematical solving approach based on Lagrange Multiplier Method (LMM) for determining the optimal DG sizes for minimizing the active power losses and voltage deviations. The problem is formulated and solved as a multi objective function. Validation of the proposed mathematical solution strategy was tested using the IEEE-6 and IEEE-33 standard test bus systems. Results demonstrate the effectiveness of the proposed methodology.

Integration of Distributed Generation (DG) into power networks has taken a great interest in power industry because of its wide range of merits over the conventional methods of generation. Nevertheless, several aspects need to be considered before deploying them to the network for facilitating enhanced system performance. Optimal DG placement in terms of sizing and location are crucial in minimizing the active power loss and maintaining stipulated network voltage levels. This paper presents a novel analytical method for optimal DG placement by defining a new sensitivity index referred to as Loss-Voltage Sensitivity Index (LVSI) combining traditional Voltage Sensitivity Index (VSI) and Loss Sensitivity Index (LSI). The best location for DG allocation evaluated by new index reflects the conditions for minimum power loss and voltage deviations in the network effectively as both VSI and LSI are utilized in the new formulation. The proposed method was verified using the IEEE-6 bus test system considering several operating scenarios. Results show that proposed methodology is accurate in determining the optimal sites for allocating DG units.

Recent government policy initiatives have significantly increased the number of grid connected solar PV systems in distribution networks. Thus, it is of vital importance to understand the technical impacts of high penetration levels of solar PV systems on the operating performance of these networks. This paper presents an analysis of power quality aspects of an urban low voltage (LV) distribution network with high solar PV penetration levels in Sri Lanka. The study includes three-phase load flow analysis carried out by modeling the selected network in DIgSILENT PowerFactory simulation platform using 15 - minute load data. Effects on net power flows and voltages of the LV network, which have been verified using field measurements, are discussed. Factors influencing the hosting capacity of solar PV are investigated by analysing technical impacts at varying solar PV penetration levels.

The concept of the micro grid is still growing with regard to co-ordination strategies and the development of proper controllers to enhance the reliability aspects under different operating modes. In this context,due to the growing interest of renewable energy sources droop based inverter dominated micro grids are one of the fastest emerging technologies. This research paper aims to study reactive power sharing and voltage variation under different scenarios in an inverter dominated islanded micro grid. In this regard, non-linear equations that describe the model have been derived and an averaged model is used in the derivation of the mathematical model resulting in simplified equations which are used to model large signal equivalent circuits in PLECS software. In addition, the impact of load perturbations, filter parameters, line impedances and droop variations are analyzed