In this paper, a novel risk-based, two-objective (technical and economical) optimal reactive Power dispatch method in a wind-integrated Power system is proposed which is more consistent with operational criteria.  The technical objective includes the minimization of the new voltage instability risk index. The economical objective includes cost minimization of reactive Power generation and active Power loss. The proposed voltage instability risk employs a hybrid possibilistic (Delphi-Fuzzy)-probabilistic approach that takes into consideration the operator’s experience, the wind speed and demand forecast uncertainties when quantifying the risk index. The decision variables are the reactive Power resources of the system. To solve the problem, the modified multi-objective particle swarm optimization algorithm with sine and cosine acceleration coefficients is utilized. The method is implemented on the modified IEEE 30-bus system. The proposed method is compared with those in the previously published literature, and the results confirm that the proposed risk index is better at estimating the voltage instability risk of the system, especially in cases with severe impact and low probability. In addition, according to the simulation results compared to typical security-based planning, the proposed risk-based planning may increase the security and economy of the system due to better utilization of system resources.

Today, the electricity Power system is the most complicated engineering system has ever been made. The integrated Power generating stations with Power transmission lines has created a Network, called complex Power Network. The reliability estimation of such complex Power Networks is a very challenging problem, as one cannot find any immediate solution methods in current literature. In this paper, we advanced a new method for estimating the reliability of such Networks, which is based on 1) decomposition of the whole Network into subNetworks called islands, 2) estimating each island’ s reliability in exact form using the Network reliability theory, and 3) assembling the islands back together to estimate the whole Network reliability, again in exact form. We applied the new method on Iran’ s Power Network with 105 generation stations and 16460 kilometres of transmission lines.

Load is one of the most important part of the system which has to be modeled accurately in determining the Power system status. Measurement and component based are two different approaches for determination of models and dynamic load modeling. The component based load modeling approach is used in this paper. To study the load modeling using component based approach three sets of data such as: load class mix data, load composition data and load characteristics data are required. These three sets of data are usually not available with the Power system Network utilities. These data are to be prepared by the utilities from other relevant data available. This paper deals with preparation of such data for load modeling purposes. In this paper load class mix data are obtained using the consumer bills, load composition data are obtained using statistic analysis and load characteristics data are obtained using laboratory measurements for different load components in the Boshehr Power System Network (BPSN) simulation studies. It has been observed that the load characteristics data obtained can be used for the entire Networks in the world and also load composition data are useful to study all buses for the BPSN. These data can also be useful as a data base for load modeling simulation in all other parts of the country having similar weather and load pattern as that of BPSN. Finally, static and synamic load modeling for BPSN presented in this paper.