There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Distribution System Modeling and Analysis

Integration of distributed generation units (DGs) and capacitor banks (CBs) in distribution systems aim to enhance the system performance. This paper proposes water cycle algorithm (WCA) for optimal placement and sizing of DGs and CBs. The proposed method aims to achieve technical, economic, and environmental benefits. Different objective functions: minimizing power losses, voltage deviation, total electrical energy cost, total emissions produced by generation sources and improving the voltage stability index are considered. WCA emulates the water flow cycle from streams to rivers and from rivers to sea. Five different operational cases are considered to assess the performance of the proposed methodology. Simulations are carried out on three distribution systems, namely IEEE 33-bus, 69-bus test systems, and East Delta network, as a real part of Egyptian system. The simulated results demonstrate the effectiveness of the proposed method compared with other optimization algorithms. Also, the results demonstrate that the proposed WCA gives superior performance for the system and give distinguished improvements in both economic and environmental benefits. Moreover, the results give the flexible operation with controllable power factor DGs that is better than those using DGs at fixed power factor.

Optimal Placement and Sizing of Distributed Generation and Capacitor Banks in Distribution Systems Using Water Cycle Algorithm

COVID-19 cases prediction by using hybrid machine learning and beetle antennae search approach

A hybrid multi-objective grey wolf optimizer for dynamic scheduling in a real-world welding industry

This study presents a two-stage procedure to identify the optimal locations and sizes of capacitors in radial distribution systems. In first stage, the loss sensitivity analysis using two loss sensitivity indices (LSIs) is employed to select the most candidate capacitors locations. In second stage, the ant colony optimisation algorithm is investigated to find the optimal locations and sizes of capacitors considering the minimisation of energy loss and capacitor costs as objective functions while system constraints are fully achieved. The fixed, practical switched and the combination of fixed and switched capacitors are considered to find the optimal solution. The backward/forward sweep algorithm is developed for the load flow calculations. The proposed procedure is applied to different standard test systems as 34-bus and 85-bus radial distribution systems. In addition, the application of the proposed procedure on a real distribution system of the East Delta Network as a part of the Unified Egyptian Network is used as a test system. Numerical results show the capability of the proposed procedure to find the optimal solution for significant saving in the total cost with more accurate and efficient, competitive compared with other methods in the literature especially with increasing the distribution system sizing.

Optimal capacitor placement in distribution systems for power loss reduction and voltage profile improvement

In recent years, with the widespread use of non-linear loads power electronic devices associated with the penetration of various renewable energy sources, the distribution system is highly affected by harmonic distortion caused by these sources. Moreover, the inverter-based distributed generation units (DGs) (e.g., photovoltaic (PV) and wind turbine) that are integrated into the distribution systems, are considered as significant harmonic sources of severe harmful effects on the system power quality. To solve these issues, this paper proposes a harmonic mitigation method for improving the power quality problems in distribution systems. Specifically, the proposed optimal planning of the single tuned harmonic filters (STFs) in the presence of inverter-based DGs is developed by the recent Water Cycle Algorithm (WCA). The objectives of this planning problem aim to minimize the total harmonic distortion (THD), power loss, filter investment cost, and improvement of voltage profile considering different constraints to meet the IEEE 519 standard. Further, the impact of the inverter-based DGs on the system harmonics is studied. Two cases are considered to find the effect of the DGs harmonic spectrum on the system distortion and filter planning. The proposed method is tested on the IEEE 69-bus distribution system. The effectiveness of the proposed planning model is demonstrated where significant reductions in the harmonic distortion are accomplished.

Optimal Harmonic Mitigation in Distribution Systems with Inverter Based Distributed Generation

Summary Taking advantage of the favorable operating efficiencies, photovoltaic (PV) with Battery Energy Storage (BES) technology becomes a viable option for improving the reliability of distribution networks; however, achieving substantial economic benefits involves an optimization of allocation in terms of location and capacity for the incorporation of PV units and BES into distribution networks. This article suggests a methodology based on the Equilibrium Optimization (EO) algorithm for optimal integration of PV with BES in radial distribution networks. Multifarious objectives are comprised to minimize the cost of energy not supplied (CENS), the investment cost of PV and BES installations, their operational costs, the power losses through the distribution lines, the produced CO2 emissions relative to the grid and PV systems. Added to that, the power losses through the voltage source converter (VSC) interface between integrated PV and BES with the grid are assessed. The proposed methodology is applied on two radial distribution systems of 30-bus and 69-bus. The optimal integration of PV systems with BES have been obtained by considering various case studies by imposing several limits on the number of PV-BES and the state of charge (SoC) for BES. Subsequently, comparative performance analysis is performed using genetic algorithm (GA), EO algorithm, particle swarm optimization (PSO), differential evolution (DE), and grey wolf optimization (GWO).

PV and battery energy storage integration in distribution networks using equilibrium algorithm

This study proposes a multi-objective fuzzy-based procedure for solving reactive power management in competitive environment. The proposed procedure incorporates both economical and technical aspects of reactive power support. The economical aspect aims to minimise the total costs of reactive power purchase from service providers as primary objective function, whereas the technical aspect is taken care of through the secondary objective function that minimises the total transmission losses. The proposed procedure achieves security constraints such as the bus voltage limits, reactive power capability limits and transmission line reactive transfer limits. The proposed procedure is applied to the west-delta region system as a part of the Egyptian Unified network. The numerical results show that the proposed procedure achieves a minimum real power loss with maximal reactive reserve for power systems for different operating conditions.

Adel A. Abou El-Ela

Papers

Optimal Placement and Sizing of Distributed Generation and Capacitor Banks in Distribution Systems Using Water Cycle Algorithm

Optimal capacitor placement in distribution systems for power loss reduction and voltage profile improvement

Optimal Harmonic Mitigation in Distribution Systems with Inverter Based Distributed Generation

PV and battery energy storage integration in distribution networks using equilibrium algorithm

Multi-objective fuzzy-based procedure for enhancing reactive power management