Optimal placement of distributed generation with sensitivity factors considering voltage stability and losses indices

Abstract

Loss minimization in distribution networks has considered as great significance recently since the trend to the distribution generation will require the most efficient operating scenario for economic viability variations. Furthermore, voltage instability phenomena can occur in distribution systems and caused a major blackout in the network. The decline of voltage stability level will restrict the increase of load served by distribution companies. To control distribution networks, it can be used from Distributed Generation (DG). DG is increasingly drawing great attention and development of DGs will bring new chances to traditional distribution systems. However, Installation of DG in non-optimal places can result in an increasing in system losses, voltage problems, etc. This paper presents two scenarios for distributed generation placement in a distributions system. In the first scenario only minimizing the total real power losses in the system is considered. Both the optimal size and location are obtained as outputs from the exact loss formula. The next scenario considered the voltage stability index (SI) to find optimum placement. In these scenarios Different DG placements are compared in terms of power loss, loadability and voltage stability index. To improve power transfer capacity, two line stability indices have been introduced. Distribution power flow solution algorithm is based on the equivalent current injection that uses the bus-injection to branchcurrent (BIBC) and branch-current to bus-voltage (BCBV) matrices. These scenarios are executed on typical 33 and 30 bus test system and yields efficiency in improvement of voltage profile and reduction of power losses; it also may permit an increase in power transfer capacity, maximum loading, and voltage stability margin.

Development of a Decision-Making Algorithm for the Optimum Size and Placement of Distributed Generation Units in Distribution Networks

“…Figures 5-7 present the voltage profiles of network buses when each one of the seven DG units has been connected at buses 18, 33, and 6, respectively, while Figure 8 presents the total network apparent power losses when each one of the seven DG units has been connected at buses 18, 33, and 6, respectively. Table 4 presents the produced results as well as the results of other methodologies that have been also applied and tested on the IEEE 33-bus radial distribution system and have been presented in [9][10][11]. The decision-making algorithm results are comparable to these produced by the other methodologies, something which clearly implies that the proposed decision-making algorithm is well working and has an acceptable accuracy.…”

“…Furthermore, the position that is installed the DG unit (of any type) is of paramount importance, since its influence on the total power losses of the network (both real and reactive) is Table 4 presents the produced results as well as the results of other methodologies that have been also applied and tested on the IEEE 33-bus radial distribution system and have been presented in [9][10][11]. The decision-making algorithm results are comparable to these produced by the other methodologies, something which clearly implies that the proposed decision-making algorithm is well working and has an acceptable accuracy.…”

“…The decision-making algorithm results are comparable to these produced by the other methodologies, something which clearly implies that the proposed decision-making algorithm is well working and has an acceptable accuracy. [9] 2.4818 0.8471 1.2872 Injeti, Kumar [10] 2.5 0.9 1.2 Mahat, Ongsakul, Mithulananthan [11] 2.9 1.7 0.8…”

Smart Grid for the Smart City

“…Moreover, the computation of the optimal parameters is done once for all (offline) when DGs are installed. In [41], the authors used the voltage stability margin proposed in [49], which differs from the SNB presented above. This margin, referred to here as SI, turns out to be useful when placing and sizing DGs, as it requires to solve the power flow equations of the grid only once, considering pairs of buses connected by one distribution line.…”

“…The bus with the lowest SI is the most prone to voltage collapse, and hence is the best candidate for the placement of a DG. The sizing of DGs highly depends on the grid load conditions and in [41] is determined heuristically. This method results in a considerably increased stability margin for all the considered scenarios, although, if no attention is paid to the reduction of power losses, these may actually increase as a result of placing the DGs.…”