ATC with ZIP load model – A comprehensive evaluation with third generation FACTS in restructured electricity markets

In this paper, an optimal power flow based approach has been applied for multi-transactions in deregulated environment for ATC determination with third generation FACTS devices. The main contribution of the paper is (i) OPF based approach for evaluation of ATC with multi-transactions, (ii) ATC enhancement with third generation FACTS devices viz. Static Compensator (STATCOM), Static Synchronous Series Compensator (SSSC), and Unified Power Flow Controller (UPFC) for intact and line contingency cases (iii) Impact of ZIP load on ATC determination and comparison of ATC obtained with ZIP load model and constant P,Q load model, (iv) Comparison of ATC obtained with DC/AC-PTDFs based method along with FACTS devices for comparison. The results have been determined for intact and line contingency cases taking simultaneous as well as single transaction cases for IEEE 24 bus RTS.     

Time–optimal current control with constant switching frequency for STATCOM

In this paper a time–optimal current control algorithm with constant switching frequency for a STATCOM is presented. The method enables a fast transient response of the device limited only by its output voltage rating. The main idea behind the time–optimal current control is to find such control voltage that enables us to reach current reference values in a pre-determined minimal length of time. This control approach utilizes the mathematical model of the STATCOM and computes the exact required output to move the system state to the reference waveform. The algorithm is tested by means of simulations using the STATCOM mathematical model and a detailed model. The performance of the control algorithm is validated for reference current tracking and balanced and unbalanced network voltage sags. Simulations were carried out in PSCAD.     

An informationally complete Wigner function for the Tavis–Cummings model

Journal of Computational Electronics - Here we consider an informationally complete Wigner function approach to look at multiple atoms (qubits) coupled to a field mode. We consider the...     

A fast time–frequency transform based differential relaying scheme for UPFC based double-circuit transmission line

This paper presents a new differential relaying scheme for a mutually coupled, double circuit transmission line in presence of Unified Power Flow Controller (UPFC) in the line. The process starts at retrieving the three phase current signals at both ends of the transmission line synchronously and processing it though the time–frequency transform such as Fast Discrete S-Transform to derive the spectral energy content of the current signals. The differential spectral energy of current signals (difference between the spectral energy of the current signal at the sending and receiving ends, respectively) of the respective phases of transmission line is used to register the fault pattern. The proposed approach includes fault detection and classification along with identification of the fault section with respect to UPFC location in one of the double-circuit transmission line. The extensive test results indicate that the proposed differential relaying scheme is highly reliable in registering fault patterns in UPFC based transmission line including wide variations in operating parameters of the power network.     

Optimized PI+ load–frequency controller using BWNN approach for an interconnected reheat power system with RFB and hydrogen electrolyser units

This paper investigates a renewable energy resource’s application to the Load–Frequency Control of interconnected power system. The Proportional-Integral (PI) controllers are replaced with Proportional-Integral Plus (PI+) controllers in a two area interconnected thermal power system without/with the fast acting energy storage devices and are designed based on Control Performance Standards (CPS) using conventional/Beta Wavelet Neural Network (BWNN) approaches. The energy storing devices Hydrogen generative Aqua Electroliser (HAE) with Fuel cell and Redox Flow Battery (RFB) are incorporated to the two area interconnected thermal power system to efficiently damp out the electromechanical oscillations in the power system because of their inherent efficient storage capacity in addition to the kinetic energy of the generator rotor, which can share the sudden changes in power requirements. The system was simulated and the frequency deviations in area 1 and area 2 and tie-line power deviations for 5% step- load disturbance in area 1 are obtained. The comparison of frequency deviations and tie-line power deviations of the two area interconnected thermal power system with HAE and RFB designed with BWNN controller reveals that the PI+ controller designed using BWNN approach is found to be superior than that of output response obtained using PI+ controller. Moreover the BWNN based PI+ controller exhibits a better transient and steady state response for the interconnected power system with Hydrogen generative Aqua Electroliser (AE) unit than that of the system with Redox Flow Battery (RFB) unit.     

Design of a 2-DOF-PID controller using an improved sine–cosine algorithm for load frequency control of a three-area system with nonlinearities

This paper proposes an improved sine–cosine algorithm (ISCA) based 2-DOF-PID controller for load frequency control. A three-area test system is built for study, while some physical constraints (nonlinearities) are considered for the investigation of a realistic power system. The proposed method is used as the parameter optimizer of the LFC controller in different scenarios. The 2-DOF-PID controllers are used because of their capability of fast disturbance rejection without significant increase of overshoot in set-point tracking. The 2-DOF-PID controllers’ efficacy is observed by examining the responses with the outcomes obtained with PID and FOPID controllers. The simulation results with the suggested scheme are correlated with some of the existing algorithms, such as SCA, SSA, ALO, and PSO in three different scenarios, i.e., a disturbance in two areas, in three areas, and in the presence of physical constraints. In addition, the study is extended to a four-area power system. Statistical analysis is performed using the Wilcoxon Sign Rank Test (WSRT) on 20 independent runs. This confirms the supremacy of the proposed method.     

Design of a 2-DOF-PID controller using an improved sine–cosine algorithm for load frequency control of a three-area system with nonlinearities

This paper proposes an improved sine–cosine algorithm (ISCA) based 2-DOF-PID controller for load frequency control. A three-area test system is built for study, while some physical constraints (nonlinearities) are considered for the investigation of a realistic power system. The proposed method is used as the parameter optimizer of the LFC controller in different scenarios. The 2-DOF-PID controllers are used because of their capability of fast disturbance rejection without significant increase of overshoot in set-point tracking. The 2-DOF-PID controllers’ efficacy is observed by examining the responses with the outcomes obtained with PID and FOPID controllers. The simulation results with the suggested scheme are correlated with some of the existing algorithms, such as SCA, SSA, ALO, and PSO in three different scenarios, i.e., a disturbance in two areas, in three areas, and in the presence of physical constraints. In addition, the study is extended to a four-area power system. Statistical analysis is performed using the Wilcoxon Sign Rank Test (WSRT) on 20 independent runs. This confirms the supremacy of the proposed method.     

Novel chaos game optimization tuned-fractional-order PID fractional-order PI controller for load–frequency control of interconnected power systems

In this work, chaos game optimization (CGO), a robust optimization approach, is employed for efficient design of a novel cascade controller for four test systems with interconnected power systems (IPSs) to tackle load–frequency control (LFC) difficulties. The CGO method is based on chaos theory principles, in which the structure of fractals is seen via the chaotic game principle and the fractals’ self-similarity characteristics are considered. CGO is applied in LFC studies as a novel application, which reveals further research gaps to be filled. For practical implementation, it is also highly desirable to keep the controller structure simple. Accordingly, in this paper, a CGO-based controller of fractional-order (FO) proportional–integral–derivative–FO proportional–integral (FOPID–FOPI) controller is proposed, and the integral time multiplied absolute error performance function is used. Initially, the proposed CGO-based FOPID–FOPI controller is tested with and without the nonlinearity of the governor dead band for a two-area two-source model of a non-reheat unit. This is a common test system in the literature. A two-area multi-unit system with reheater–hydro–gas in both areas is implemented. To further generalize the advantages of the proposed scheme, a model of a three-area hydrothermal IPS including generation rate constraint nonlinearity is employed. For each test system, comparisons with relevant existing studies are performed. These demonstrate the superiority of the proposed scheme in reducing settling time, and frequency and tie-line power deviations.     

A current-based model of the static synchronous series compensator (SSSC) for Newton–Raphson power flow

In this paper, a new approach to modeling a static synchronous series compensator (SSSC) for power-flow calculations by applying the Newton–Raphson method is presented. This new approach differs from known methods in terms of the interpretation of the device's branch. It is considered on the basis of its current and is therefore denoted as a current-based model of an SSSC. This approach might in principle be applicable also for other FACTS devices (i.e., UPFC, IPFC, GUPFC). In the paper, the current-based model of an SSSC is presented as the models of this device have difficulties with convergence in power-flow calculations and there are very few references covering these topics. First, the basic features of an SSSC are presented, as it is the basis for the current-based model that is incorporated into the Newton–Raphson load-flow model. The results of the tests at the IEEE 57-bus system are discussed in detail and compared with the existing injection SSSC load-flow model [X.P. Zhang, Advanced modeling of the multicontrol functional static synchronous series compensator (SSSC) in Newton power flow, IEEE Trans. Power Syst. 18 (November (4)) 2003].     

A hybrid time–frequency approach based fuzzy logic system for power island detection in grid connected distributed generation

A new time–frequency approach for power island detection in distributed generation systems is presented in this paper, using a hybrid fast variant of the S-Transform (ST) algorithm and a fuzzy expert system. The fast S-Transform algorithm with different types of frequency scaling, band pass filtering and interpolation techniques, results in significantly reduced computational cost, than the conventional S-Transform approach. The relevant spectral features of negative sequence voltage and current signals obtained from the distributed generation (DG) system terminals are extracted from the time–frequency matrix, obtained through fast ST. These features are used as inputs to a fuzzy expert system (FES), to distinguish between an islanding or non-islanding event, over a variety of operating conditions of the DGs including the change of system configurations, power imbalance, etc. The accuracy and response time of this new approach is compared with several well-known techniques (including time–frequency transform based methods), by applying it on both standard and existing distribution networks.     

An Intelligent Starter–Generator for Power-Supply Systems of Aircraft with Increased Direct-Current Voltage

This paper presents the results of an investigation of an intelligent starter–generator (SG) with a capacity of 16 kV A and rotation frequency of 12000 rpm. In designing the SG, a multidisciplinary approach was used in which all the calculations of an electrical machine were interdependent and had the form of a symbiosis of electromagnetic, thermal, and mechanical calculations concerning the rotor dynamics. Interrelated optimization problems were simultaneously solved during such calculations using genetic algorithms. Such an approach provides maximum accuracy, especially when designing highly loaded electrical machines, where even an insignificant change of any parameter can lead to a considerable change in the structural diagram of the SG and its dimensions. The experimental model of the SG was tested in the full-power regime and at rated speed. The measurement results of the output voltage and heating temperature of the active elements correspond to the design ones. The deviation from the design voltage data was 1.7%. This small error confirms the efficiency of the multidisciplinary design methods used. Based on the test results, a comparison with the characteristics of aircraft generators of similar power is carried out and the developed SG is shown to be efficient.     

Membership functions dependent adaptive sliding mode fault-tolerant control for uncertain T–S fuzzy systems with performance bounds

This article is concerned with the problem of adaptive sliding mode control for uncertain Takagi–Sugeno fuzzy systems in the presence of actuator faults. In order to accommodate fuzzy systems, a membership function weights dependent sliding function is first given. Compared with the existing linear sliding function based results, a reduced-order fuzzy sliding motion through parallel distributed compensation structure is obtained, then less conservative results are achieved. By exploiting a restricted potential function, a continuous sliding mode fault-tolerant control scheme is established. Then the closed-loop system trajectory is maintained in practical sliding mode with a preset sliding band, which improves the robustness performances of system especially for the occurrence of abrupt actuator faults. Moreover, with the usage of the property of fuzzy product inference engines through equivalence class in set theory, a less conservative stability criterion in terms of linear matrix inequalities is derived to guarantee the uniformly boundedness of the reduced-order sliding motion. At last, some illustrative examples are offered to validate the effectiveness of our proposal.     

An Ultra-High-Speed Starter–Generator with a Magnetic Core of Amorphous Iron for Unmanned Aerial Vehicles

Results of research on an ultra-high-speed starter–generator with permanent magnets and tooth windings for unmanned aerial vehicles are presented. Technologies for manufacturing of a stator magnetic core of amorphous iron, as well as methods of selection of the number of pole pairs of an ultra-high-speed starter—generator, are studied, the advantages of amorphous iron are substantiated. A particular stage of the work is devoted to the problems of optimization of the slotted area of a starter–generator on the basis of the criterion of the presence of minimum losses in permanent magnets for eddy currents. To minimize these losses, a multicriterion optimization of the slotted area is performed using the genetic algorithms, as a result of which the losses were a quarter those of the initial variant. A cooling diagram of the synchronous machine in the structure of the turbojet engine is proposed. Thermal calculations are presented. A full-scale mockup with a capacity of 5 kW, rotation frequency of 60000 rpm, power density of 0.2 kg/kW, and coefficient of efficiency 96.4% was created to check the proposed design sequence, as well as to determine the efficiency of using amorphous iron. Initial tests of the experimental mockup backed up the theoretical conclusions and showed that the use of amorphous iron allows reducing the losses in the magnetic core of the stator by five to seven times.     

3-Phase 4-leg unified series–parallel active filter system with ultracapacitor energy storage for unbalanced voltage sag mitigation

This paper presents the analysis and design of a 3-phase 4-leg (3P4L) unified series–parallel active filter (USPAF) with ultracapacitor energy storage (UCES) for improving the power quality in three-phase four-wire (3P4W) distribution system. The series and parallel active filter (AF) of 3P4L USPAF system are realized by four-leg voltage source inverters (VSIs) to a common dc-link capacitor. Due to its high power density, the UCES is well-suited to supply high power for short period of time. The objective of this paper is to enhance the unbalanced voltage sag mitigating capability of the 3P4L USPAF system by adding UCES, directly connected in the dc-link. This is achieved by injecting energy from the UCES to maintain the dc-link voltage constant. Thus, the proposed system is capable of mitigating unbalanced voltage sag with zero-sequence component in the source voltage and compensating harmonic, reactive power and unbalanced current of the load in 3P4W distribution systems. The proposed scheme is validated by an experimental prototype with a 1.93 F UCES bank and using dSPACE DS1103 real-time control platform in the laboratory. The experimental results show that the combined system offer improved performance to maintain the load voltage constant at its rated value during unbalanced voltage sag in the supply voltage.     

A simulation study of short channel effects with a QET model based on Fermi–Dirac statistics and nonparabolicity for high-mobility MOSFETs

In this paper, the quantum confinement and short channel effects of Si, Ge, and \(\hbox {In}_{0.53}\hbox {Ga}_{0.47}\)As n-MOSFETs are evaluated. Both bulk and double-gate structures are simulated using a quantum energy transport model based on Fermi–Dirac statistics. Nonparabolic band effects are further considered. The QET model allows us to simulate carrier transport including quantum confinement and hot carrier effects. The charge control by the gate is reduced in the Ge and \(\hbox {In}_{0.53}\hbox {Ga}_{0.47}\)As bulk n-MOSFETs due to the low effective mass and high permittivity. This charge control reduction induces the degradation of short channel effects. In double-gate structures, different improvements of drain induced barrier lowering (DIBL) and subthreshold slope (SS) are seen. The double-gate structure is effective in the suppression of DIBL for all channel materials. The SS degradation depends on channel materials even in double-gate structure.     

FLC based shunt active filter (p–q and Id–Iq) control strategies for mitigation of harmonics with different fuzzy MFs using MATLAB and real-time digital simulator

Problems caused by power quality have great adverse economical impact on the utilities and customers. Current harmonics are one of the most common power quality problems and are usually resolved by the use of shunt active filters (SHAFs). Control strategies (p–q and I_d–I_q) for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source conditions. Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme.The performance of the control strategies has been evaluated in terms of harmonic mitigation and DC link voltage regulation. The proposed SHAF with different fuzzy MFs (Trapezoidal, Triangular and Gaussian) is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using MATLAB/SIMULINK software are presented to support the feasibility of proposed control strategies. To validate the proposed approach, the system is also implemented on a real-time digital simulator (OPAL-RT) Hardware and adequate results are reported for its verifications.