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This paper aims to survey the need for full capacity utilisation of transmission lines in power systems network operations. It proposes a review of the N-1 security criterion that does not ensure reliable dispatch of optimum power flow during outage contingency. The survey aims to enlarge the network capacity utilisation to rely on the entire transmission lines network operation.

The paper suggests transmission line switching (TLS) approach as a viable corrective mechanism for power dispatch. The TLS process is incorporated into a constraint programming language extension optimisation solver that selects the switchable line candidates as integer variables in the mixed integer programming problem.

The paper provides a practical awareness of reserve capacity in the lines that provide network security in outage contingency. At optimum power flow dispatch, the TLS is extended to optimal transmission line switching (OTLS) that indicates optimal capacity utilisation (OCU) of the available reserve capacity (ARC) in the network lines.

Computational efficiency influenced the extension of the OTLS to optimal transmission switching of power flow (OTSPF). The application of OTSPF helps reduce the use of flexible AC transmission systems (FACTS) and construction of new transmission lines..

The paper surveys TLS efforts in network capacity utilisation. The suggested ARC fulfils the need for an index with which the dispatchable lines may be identified for the optimal capacity utilisation of transmission lines network.

This paper aims to present an analysis of a hybrid high‐voltage switch based on the parallel connection of IGBT and IGCT. The proposed configuration combines the advantages of both semiconductors, resulting in substantially reduced power losses. Such energy efficient switches could be used in high‐power systems where the requirements of high switching frequency or decreased cooling systems are a major concern.

The operation principle of the switch is described and simulated. The power dissipation is estimated at different operation conditions. Further, the implementation possibilities of the proposed switch configuration in a three‐level NPC inverter are analysed. The operation with the proposed PWM control algorithm is simulated and inverter power loss distribution is estimated.

According to estimations, the proposed hybrid switch configuration allows the reduction of total losses in semiconductors by at least 50 percent. If two of these switches are used in a three‐level NPC inverter as outer switches, the total losses of the inverter are reduced by 27 percent, at the same time the losses in the most stressed semiconductor device are reduced by a factor of 2.25. Therefore, achieving higher power density is possible.

The proposed switch configuration is intended for high‐power (>500 KVA) industrial, marine and railway traction systems, such as FACTS and high power variable frequency AC drives.

The paper presents the novel energy‐efficient high‐voltage switch based on the parallel connection of commercially available IGBTs and IGCTs.

This article discusses some of the forces at work within today's online database environment which could lead to the emergence of a distributed information network. Several important modules in such a network are identified, including an automated subject switching module. Switching options include: exact matching, equivalency matchings and word‐ and phrase‐stem matching. Research investigations, critical issues, and preliminary findings with regard to switching options and strategies are reported. It is anticipated that one of the primary benefits from automated subject switching will be much greater utlization of the online STI resource.

This paper aims to propose a new transformer-less inverter structure to reduce the common-mode leakage current in grid-connected photovoltaic (PV) systems.

The proposed circuit structure is the same as the conventional full-bridge inverter with three additional power switches in a triangular structure. These three power switches are between the bridge and the output filter, and they mitigate the common-mode leakage current flowing toward the PV panels’ capacitors. The common-mode leakage current mitigation is done through the three-direction clamping cell (TDCC) concept. By clamping the common-mode voltage to the middle voltage of the DC-link capacitors, the leakage current and the total harmonic distortion (THD) of the injected current to the grid is effectively reduced. Therefore, the efficiency is improved.

The switching modes and the control method are introduced. A comparison is carried out between the proposed structure and other solutions in the literature. The proposed topology and its respective control method are simulated by PSCAD/EMTDC software. The simulation results validate the advantages of the presented structure such as clamping the common-mode voltage and reducing leakage current and THD of injected current to the grid.

Presenting a single phase-improved inverter structure with low-leakage current for grid-connected PV power systems represents a significant original contribution to this work. The proposed structure can inject a sinusoidal current with low THD to the AC grid, and the power factor is unity on the AC side. In the half positive cycle, one of the switches in the TDCC is turned off under zero current. Besides, one of the other switches in TDCC is turned on with zero voltage and, therefore, its turn-on switching losses are zero. The efficiency of the proposed topology is high because of the reduction of leakage current and power losses. Accordingly, the presented topology can be a good solution to the leakage current elimination.

The purpose of this work is that of showing some efficient techniques to perform PV-PQ node type switching in multiple power flow computations.

Reactive generation limits of generation buses must be taken into account to obtain realistic power flow solutions. This may result computationally demanding when many power flow computations are required as in contingency screening or Monte Carlo simulations. In the present paper, the implementation of efficient PV-PQ node type switching is examined with particular emphasis on the efficiency of computation. Some different methods are proposed and compared on the basis of computation speed and accuracy.

Tests show the efficiency of the proposed methods with reference to actual networks with up to 800 buses.

The classical method of (partial) re-factorisation is not very efficient when many power flow solutions are to be evaluated. In the present work, a different approach is proposed; it is based on grounding each PV node by a fictitious short-circuit branch which is removed when the node type is changed to PQ. This operation is carried out by compensation of the solution and combined with the modifications required for contingency simulation.

The purpose of this paper is to derive the user‐perceived availability of M‐for‐N shared protection systems composed of multiple user groups, each with a protection‐switching priority.

The paper assumes a shared protection system with M protection units and N working units. The memoryless state transition diagram viewed from the system administrator, combined with combinatorial analysis of state probabilities on protection switching, yields a generic formula of the availability viewed from an arbitrary end user.

The numerical examples of availability reveal the effect of prioritized protection switching. It is observed that the total protection capacity is constant regardless of the ways of priority grouping. The shared protection system with multiple protection units enables more flexible availability allocation compared with the case of a single protection unit.

User‐perceived reliability is still an unexplored research area. Many variations of the system treated in this paper can be applied to various applications.

The analysis provides useful information for the design and operation of, for example, telecommunication network devices. The analysis is applicable to general shared protection systems that are subject to service level agreement (SLA) involving user‐perceived reliability measures.

This paper establishes the model of the priority shared protection systems for the first time and shows a practical computation method of prioritized user‐perceived availability.

This paper aims to present the design and implementation of a new general-purpose single-phase buck-type inverter.

The operation of the proposed inverter is based on the general-purpose buck converter. The proposed buck-type inverter topology is designed with reduced numbers of passive and active elements to minimize design cost and complexity. Also, an efficient hybrid control technique based on the proportional‐integral‐derivative (PID) supported by open-loop control signal is offered for the control of the proposed inverter. The proposed hybrid control method improves the performance of the PID controller during the change of inverter operation parameters. A close to single-phase sine wave output voltage with low total harmonic distortion (THD) can be produced by the proposed inverter in a wide range of voltage and frequency lower than the inverter input voltage value.

Simulation and experimental test studies are applied to the proposed inverter. The experimental laboratory setup is built for 0–50 Hz, 0–100 Vp, 0.5 kW. Both the simulation and the experimental test results show that the single-phase inverter can produce close to sine wave output voltage with THD level under 5% in a wide range of frequency for various operating conditions and for different loads.

In this paper, a new topology and a new hybrid control technique that are patented by the corresponding author are implemented for a single-phase buck-type inverter through a scientific project. The operating results of the study reveal the efficient operating capability with a simple topology structure.

THE Funk Gerat 10 equipment is the latest standardized type, and is installed in all the later bombers and reconnaissance machines of the Luftwaffe.

This paper aims to propose Hidden Converter (H-Converter) combined with dual port 3Ø inverter for energy storage application to produce wide range of voltage. Some of the application required wide range of voltages, but problem from E-chopper is either boost or buck mode of operations, both modes are not possible. To overcome this drawback, H-Converter is combined with dual port 3Ø inverter controlled by carrier-based pulse width modulation (CB-PWM) technique is added with zero sequence injection.

Hidden converter is a bidirectional DC-DC chopper used to convert fixed DC to variable DC and vice versa in both buck and boost modes of operations. Dual port inverter is combined with hidden DC-DC converter can produce wide range of voltages.

The bidirectional DC-AC converter requires less power for processing and consumes less power losses by using modest carrier built- pulse width modulation scheme through proposed zero structure addition.

By using this proposed strategy H-Converter can produce wide range of voltage in both the sides and mostly power is processed in the 3Ø inverter with a one stage conversion with less power loss. As a result, with one stage power conversion has more efficiency because of less power loss. This proposed converter has designed by analysis, and the real time result is tested in an experiment.

Should allowance for fatigue be made in Rating? The orthodox answer to this is that it should not.