Summary The performance of a new approach for multiobjective voltage stability constrained‐optimal power flow (VSC‐OPF) formulation is compared with a conventional VSC‐OPF approach for improving the steady‐state power systems security in this paper. The compared OPF problems involve the minimization of the fuel cost and minimization of novel line stability index (NLSI) for case 1 and minimization of fuel cost and maximization of line static stability margin (CBI) for the proposed case 2. Clerc's constricted PSO algorithm modified with the nondominated sorting algorithm is used for obtaining the best solution point for each of the decision variables. Network security constraints and bus voltage limits are considered along with the constraint on permissible line stability margin limit adopting the quadratic penalty model for constraints violations. The approach is tested on a load‐modified IEEE 30‐bus and actual Nigerian 28‐bus systems. From the results obtained, the proposed OPF formulation performed better for simultaneous consideration of voltage stability improvement and line loss reduction.

Modern utilities are forced to operate very close to their loadable limits (maximum capacity) due to geographical, economical and some technical reasons. The deregulation of the power industry, the competitive nature of modern electricity markets and the continuous quest for modernization of cities and hamlets all over the world has also led to fast increase in the load demand. The stability of power systems all over the world are threatened with recurrent occurrences of voltage stability issues. Hence, Inter-zonal energy transactions between willing supplier and buyers need to be done with adequate consideration for power system security. In this work, a voltage security-constrained optimal generator active and reactive power rescheduling is carried out using the IEEE 30 and IEEE 57 bus systems. The simultaneous maximization of available transfer capacity (ATC) and voltage stability margin (VSM), using the weighted sum approach, is the objective function. Credible optimal power flow and power system security constraints are considered. Three variants of particle swarm optimization in MATLAB® are used in this work for analyzing the results for objectivity. The technical and economic benefits of the optimal generator rescheduling on the system’s ATC, VSM, line losses, line flow and voltage profile are adequately analyzed.

Transmission lines operating in steady state are prone to several challenges such as; poor steady-state power flow control, active and reactive power loss and voltage limit violations. These challenges can be solved either by the use of Flexible Alternating Current Transmission System (FACTS) controllers such as Interline Power Flow Controller (IPFC) and Generalized Unified Power Flow Controller (GUPFC) or other non-economical means such as building additional generation and transmission facilities. Previous works have incorporated IPFC to solve the challenges in meshed transmission system but has not been applied to solve the challenges of the longitudinal Nigerian transmission system operating in steady state. This work performs power flow analysis with the incorporation of IPFC into the Nigerian 330-kV, 28-bus transmission system to solve its steady state challenges. Steady state power system component model produces a set of algebraic equations while the steady state IPFC model in rectangular form produces another set of algebraic equations for power flow analysis. The sets of equations were solved simultaneously using Newton-Raphson numerical iteration method, due to its fast quadratic convergence and high efficiency. Newton-Raphson power flow algorithm was implemented using MATLAB 8.1.0.604 (version R2013b) and the analysis was performed without and with the incorporation of IPFC data into the Institute of Electrical and Electronic Engineers (IEEE) 14-bus and the Transmission Company of Nigeria (TCN) 330-kV, 28-bus system. The performance evaluation of IPFC was investigated using active and reactive power as performance variables. The incorporation of IPFC rectangular model into the Nigerian 330-kV, 28-Bus TCN and IEEE 14-bus system demonstrated the capability of IPFC to control active and reactive power flow. IPFC typifies effective enhancement and the maximum use of Nigerian 330-kV, 28-Bus TCN and IEEE 14-bus transmission infrastructure for better delivery of electrical power to the end users.

Modern radio communication services transmit signals from an earth station to a high-altitude station, space station or a space radio system via a feeder link while in Global Systems for Mobile Communication (GSM) and computer networks, the radio uplink transmit from cell phones to base station linking the network core to the communication interphase via an upstream facility. Hitherto, the Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been adopted for uplink access in the Long-Term Evolution (LTE) scheme by the 3GPP. In this journal, the LTE uplink radio resource allocation is addressed as an optimization problem, where the desired solution is the mapping of the schedulable UE to schedulable Resource Blocks (RBs) that maximizes the proportional fairness metric. The particle swarm optimization (PSO) has been employed for this research. PSO is an algorithm that is very easy to implement to solve real time optimization problems and has fewer parameters to adjust when compared to other evolutionary algorithms. The proposed scheme was found to outperform the First Maximum Expansion (FME) and Recursive Maximum Expansion (RME) in terms of simulation time and fairness while maintaining the throughput.