Showing papers in "International Journal of Emerging Electric Power Systems in 2019"
TL;DR: A comparative study was done among the different well known CM methods in this work and a comprehensive overview of congestion management methods is provided.
Abstract: Abstract Congestion in the power system network is a threat to security, reliability, and economy of the power industry. Congestion management in deregulated power markets has become one of the significant tasks of system operators to address congestion in the transmission network. Many methods have been presented in literature with the aim of congestion management, improvement of the security and efficiency of the deregulated power market in the past few decades. This review paper explains various approaches/methods of congestion management in past few years and provides a comprehensive overview of congestion management methods. A comparative study was done among the different well known CM methods in this work. These methods were tested and analysed on modified 6-bus system, modified IEEE 14-bus system, and modified IEEE 30-bus system.
22 citations
TL;DR: In this paper, a hybrid real-time power system simulator (HRTSim) is proposed to simulate real electric power systems (EPS) with distributed generation (DG) objects in the world.
Abstract: Abstract Currently, the number of distributed generation (DG) objects in the world is growing mainly due to renewable energy sources (RES). However, the integration of a large volume of DG based on RES into existing electric power systems (EPS) is associated with a number of significant problems. For a comprehensive study and solution of these problems, it is necessary to carry out detailed simulation of real EPS, which is not always feasible with the help of existing tools. Therefore, the article proposes the use of an alternative solution – the Hybrid Real-Time Power System Simulator (HRTSim). To confirm the properties and capabilities of the HRTSim, the simulation results of a test scheme obtained using the HRTSim and the widely used digital hardware-software complex RTDS were compared. The results of a comprehensive comparison in both complexes confirmed the adequacy of information about the processes in equipment and EPS as a whole, obtained by the HRTSim. Thus, it is proved that further use the HRTSim as a tool for detailed and adequate simulation of real EPS with DG will provide complete and reliable information about normal and abnormal quasi-steady-state and transient processes, which is necessary for reliable and efficient design, research and subsequent operation of EPS with DG.
11 citations
TL;DR: The main advantages of this simulator are the adequate simulation of a single spectrum of processes in the object for training – any real electric power system (EPS), as well as the real-time control of the equipment circuit-mode states in modes of the EPS operation.
Abstract: Abstract The article presents the Hybrid Real-Time Dispatcher Training Simulator (HRTDTS). The main advantages of this simulator are the adequate simulation of a single spectrum of processes in the object for training – any real electric power system (EPS), as well as the real-time control of the equipment circuit-mode states in modes of the EPS operation. This is achieved by the HRTDTS development within the concept of hybrid simulation, which allows to surpass the modern widely-used simulators based purely on numerical simulation, which do not comprehensively reproduce processes in the EPS and limit the training of certain dispatchers skills. The dispatcher simulator structure and the developed specialized HRTDTS software are demonstrated. The developed dynamic dashboards for monitoring and operating, implementing the circuit-mode states visualization of the equipment or the EPS districts that correspond to specific objects for training, are presented. The special panels that display extended information about the processes in the EPS are also shown in the article. The comparison of simulation results with the data, obtained via RTDS, for the HRTDTS validation was carried out. The practical emergency scenario for the training of dispatching personnel, including the assignment of an emergency situation and the actions of dispatchers to eliminate it, was created for testing and demonstration of the HRTDTS capabilities.
10 citations
TL;DR: The objective is the real time, dynamic and optimal scheduling of battery storage which reduces grid power consumption and achieves the peak load shaving and the optimization technique provides more optimal regulation of battery which provides the lesser electricity cost.
Abstract: Abstract This paper presents optimal power flow management in real time for grid connected photovoltaic (PV)–battery system. The objective is the real time, dynamic and optimal scheduling of battery storage which reduces grid power consumption and achieves the peak load shaving. For this purpose, two strategies are developed; one is rule-based and other is optimization algorithm based. Two strategies are compared, pros and cons of those strategies are established. Though rule-based technique is simple & easy to implement, the optimization technique provides more optimal regulation of battery which provides the lesser electricity cost. Forecasted PV/load powers are used to get optimal value of battery power. In order to handle uncertainties due to forecasted data, fuzzy-based corrective strategy is developed to modify the reference battery power as per the present values of PV/load powers. The proposed analysis is carried out for over one exemplary day. The simulations are presented using typical load/PV data of India and Finland as a part of research collaboration. Experimental results are also carried out using proposed scheme.
9 citations
TL;DR: A robust planning method of regional integrated energy system (IES) considering the uncertainty of cooling, heat and electrical loads on the demand side is submitted and the robust programming model can be transformed into a convex mixed integer planning model and then solved.
Abstract: Abstract In this paper, a robust planning method of regional integrated energy system (IES) considering the uncertainty of cooling, heat and electrical loads on the demand side is submitted. First, the energy hub (EH) model of regional IES with Combined Cooling Heating and Power (CCHP), electric air-conditioning unit (EC) and gas boiler (GB) is established. Second, the uncertainty of load is described by the method of adjustable interval, and the robust planning model of regional IES is formed. Third, the robust programming model can be transformed into a convex mixed integer planning model, and then solved. Finally, the case study is carried out with a comprehensive area of Tianjin in China, the results are analyzed to verify the effectiveness of the proposed planning method.
8 citations
TL;DR: Simulation results show that how amount and cost of reserve could be adjusted to cover power balance, cost of power production and load interruption and required reliability of consumers.
Abstract: Abstract Determining the optimal reserve in power systems is closely related to uncertainties in power generation and risks of outage of supply to consumers. Distributed generation sources such as wind farms are usual reasons for uncertainties in MW production. This uncertainty can be alleviated by providing enough reserve in which demand response (DR) programs can play role of resources for reserve. In an electricity market structure, the mentioned points are usually handled by Independent System Operator (ISO) in energy and reserve markets. This paper deals with the problem of reliability-based reserve management. In the mentioned problem, the DR program in the form of interruptible loads is also considered. A new method is proposed in which ISO settle energy and reserve markets simultaneously while employing the DR in the first stage. In addition, consumers’ requirements of reliability are included by assuming that they have possibility to offer their desired levels of reliability to the ISO. The amount of reserve obtained from market settlement is adjusted based on the different reliability requirements of the consumers and different scenarios of the wind farm operation, in the second stage of the proposed method. Also the cost of the reserve adjustment is fairly allocated to producers and consumers. The proposed method applies stochastic programming formulation and its validity is assessed by the GAMS software. Simulation results show that how amount and cost of reserve could be adjusted to cover power balance, cost of power production and load interruption and required reliability of consumers.
8 citations
TL;DR: In this article, a multi-objective framework is proposed to evaluate the size of the DG to be installed by reducing power loss and deviation in bus voltage, and genetic algorithm is used to optimize the DG size.
Abstract: Abstract This paper investigates the performance of a radial system while installing a Distributed Generator (DG) in existing Distribution Network (DN). The investigation has been performed with various types of DG units for different topologies of the DN. The present work uses a Voltage Stability Index (VSI) for identifying the location for installing a DG in the DN. A multi-objective framework is proposed to evaluate the size of the DG to be installed by reducing power loss and deviation in bus voltage. Genetic Algorithm (GA) is used to optimize the size of DG. The proposed method has been tested with different types of DG units on standard systems (IEEE-33 bus and IEEE-69) with different radial topologies of DN.
7 citations
TL;DR: The proposed battery control and monitoring system (BCMS) shows better operational performance for various operating conditions in terms of monitoring and control of the batteries power in the grid-connected DC micro-grid.
Abstract: Abstract This paper presents a battery control and monitoring strategy for a DC microgrid feed by a public utility (PU) photovoltaic (PV) including with multi-battery bank (BB). The BBs respond to the changes in a power imbalance between generation and demand within a DC micro-grid, to maintain the micro-grid voltage and reliability enhancement. The fuzzy model reference learning control (FMRLC) controller has been designed to power control of the battery bank. The proposed battery control and monitoring system (BCMS) strategy keep the battery charging and discharging power as per standard charging/discharging characteristics of the battery. The BCMS allows continuous monitoring and intelligent control of distribution system operations such as battery bank energy storage (BBES), the PV system and the electric load of the consumer. A power sharing between the sources has been controlled for smooth supply. A graphical user interface (GUI) in the MATLAB environment has been configured to demonstrate the control and monitoring of the DC micro-grid and the operation performance of the BCMS algorithm for various scenarios (i. e modes). The proposed BCMS shows better operational performance for various operating conditions in terms of monitoring and control of the batteries power in the grid-connected DC micro-grid.
7 citations
TL;DR: Results show that the proposed MB-LDR based controller gives better response as compare to other two methods in terms of peak transient deviation, settling time and number of oscillations.
Abstract: Abstract The paper presents a real time modelling of self-reliant isolated grid comprising both governable and ungovernable sources. The frequency of this system must be maintained to its desired value by reducing its deviation occurred when there is a mismatch between the load demand and the actual power generation. In order to achieve it, the actual power output of the micro-grid is required to regulate. Therefore, an attempt is made in this paper to design a modified bias (MB) with LDR (load disturbance rejection) based PID (proportional integral derivative) Controller and it can also be called droop based controller (DBC). Simulation of the micro-grid system with proposed MB-LDR based control scheme is successfully done in Real Time Simulation platform using the digital simulator of OPAL-RT OP4510. Simulation results of the system for different conditions are presented and analysis is given in details. Thereafter, comparative performance of the results obtained using proposed MB-LDR based controller with that of LDR and classical controllers is made. Results show that the proposed MB-LDR based controller gives better response as compare to other two methods in terms of peak transient deviation, settling time and number of oscillations.
7 citations
TL;DR: In this article, two Linear Fresnel Reflector (LFR) plants with a total capacity of 120MW were introduced to overcome the present challenges in Kabul city. But the proposed LFR units are incorporated with an energy storage system of full capacity production for five hours to cover the power shortage at night.
Abstract: Abstract Power sector, as one of the least progressed division, is limiting the socioeconomic development in Afghanistan. Although the country has a vast solar energy potential with a bright prospect for growth, however inadequate endorsement and attention have prevented its proper use. Meanwhile, Kabul the capital city and one of the fastest growing cities in the world, is suffering severe challenges to supply its energy needs. Presently, Kabul electrical system is subjected to insecure and insufficient supply due to the lack of integrated networks and deployment of Renewable Energy (RE) sources. This research investigates an appropriate approach by introducing two Linear Fresnel Reflector (LFR) plants with a total capacity of 120 MW to overcome the present challenges in Kabul city. The proposed LFR units are incorporated with an energy storage system of full capacity production for five hours to cover the power shortage at night. The design aspect of LFR is specified by using of System Adviser Model (SAM). Levelized Cost of Electricity (LCOE) and the total annual output of the proposed LFR units are estimated as 0.2508$/kWh and 294,657.28 kWh respectively. To minimize the total operating costs of the integrated model and mitigate CO2 emissions, an optimal Unit Commitment is (UC) fulfilled as well. UC is accomplished by using MATLAB INTLINPROG optimization toolbox.
6 citations
TL;DR: In this article, the effects of different fault locations, lengths of coupling sections, and different transposition modes of AC lines on the secondary arc current and recovery voltage of AC and DC lines are studied.
Abstract: Abstract With the continuous expansion of the scale of power system, corridor resources of overhead transmission lines tend to be saturated in China, making AC/DC erection on the same tower a trend in future development. The AC/DC coupling effect will cause DC line to generate secondary arc current at the point of failure when transmission line fails, which affects the DC restart. On account of the mechanism of generating secondary arc current by AC/DC lines erected on the same tower, this paper uses PSCAD to establish simulation model for AC/DC erected on the same tower. And the effects of different fault locations, lengths of coupling sections, and different transposition modes of AC lines on the secondary arc current and recovery voltage of AC and DC lines are studied. The results show that secondary arc current on DC line is greatly affected by fault location and length of coupling line, and using different transposition modes of AC lines can reduce secondary arc current on the DC lines effectively. According to Yunguang UHV DC restart time sequence, setting the restart time sequence can increase the first restart deionization time to ensure the stable operation of the system.
TL;DR: A new approach to create an algorithm for controlling the technical means of regulation and voltage stabilization in 0.38 kV electrical networks and the requirements to the functional capabilities of this system are considered.
Abstract: Abstract Development of smart grids for power supply to rural consumers assumes the creation of adaptive voltage regulation systems in 0.38 … 10 kV electrical networks as one of the directions. This paper considers a new approach to create an algorithm for controlling the technical means of regulation and voltage stabilization. The proposed adaptive voltage regulation system allows collecting and processing information on the actual voltage at the consumer inputs and automatically determine the voltage regulation coefficient. The developed mathematical model allows calculating the voltage regulation coefficient depending on the voltage at various points of the 0.38 kV electric network. In the paper there are also new methods of adaptive automatic voltage regulation in the 0.38 kV electrical networks and the requirements to the functional capabilities of this system. The article suggests technical solutions for the implementation of adaptive automatic voltage regulation system. The successful tests of experimental model of this system have been carried out.
TL;DR: In this paper, a multi-agent based communication framework for gridable electric vehicle (GEV) aggregation in power distribution network is proposed and multi objective optimization is presented for the minimization of power losses and maximization of voltage.
Abstract: Abstract In this paper a multiagent based communication framework for gridable electric vehicle (GEV) aggregation in power distribution network is proposed. Also, multi objective optimization is presented for the minimization of power losses and maximization of voltage. Furthermore multiagent system (MAS) based analytical model is proposed for GEV aggregation. Comprehensive case studies are conducted on IEEE 33 and 69 bus test distribution systems using MATLAB and it is observed that the timely and optimal placement of GEV aggregation in distribution network using multiagent communication (MAC) will lead to reduction in power losses and improvement in voltage profile. MATLAB and MOBILE C were used for the simulation studies and results demonstrate significant benefits of GEV aggregation in distribution network.
TL;DR: In this article, the authors investigated the impact of different DR strategies in a home-energy management system having consumer with regular load, electric vehicle (EV) and battery-energy storage system (BESS) in the home.
Abstract: Abstract Demand response (DR) programs have become powerful tools of the smart grids, which provide opportunities for the end-use consumers to participate actively in the energy management programs. This paper investigates impact of different DR strategies in a home-energy management system having consumer with regular load, electric vehicle (EV) and battery-energy storage system (BESS) in the home. The EV is considered as a special type of load, which can also work as an electricity generation source by discharging the power in vehicle-to-home mode during high price time. BESS and a small renewable energy source in form of rooftop photovoltaic panels give a significant contribution in the energy management of the system. As the main contribution to the literature, a mixed integer linear programming based model of home energy management system is formulated to minimize the daily cost of electricity consumption under the effect of different DR programs; such as real time price based DR program, incentive based DR program and peak power limiting DR program. Finally, total electricity prices are analysed in the case studies by including different preferences of the household consumer under mentioned DR programs. A total of 26.93 % electricity cost reduction is noticed with respect to base case, without peak limiting DR and 19.93 % electricity cost reduction is noticed with respect to base case, with peak limiting DR.
TL;DR: In this paper, an assortment study between the virtual inertia control (VIC)-based a new optimal PID controller, load frequency control (LFC), and the digital protection for an islanded microgrid (MG) taking into consideration the emerging level of renewable energy resources (RERs), which is a promising solution.
Abstract: Abstract This paper presents an assortment study between the virtual inertia control (VIC)-based a new optimal PID controller, load frequency control (LFC), and the digital protection for an islanded microgrid (MG) taking into consideration the emerging level of renewable energy resources (RERs), which is a promising solution. However, the reduction in system inertia due to increasing the amount of RERs causes undesirable impact to MG dynamic stability, threatens the system security, and could lead to complete blackouts as well as damages to the system equipment. Therefore, maintaining the dynamic security in MGs is one of the important challenges, which considered in this paper using a specific design of a digital over/under frequency relay (OUFR) with coordination of the VIC to protect the MG against high-frequency variations. To prove the effectiveness of the proposed coordination strategy, it has been tested considering sudden load change, high integration of RERs. Moreover, the sensitivity analysis of the presented technique was examined by varying the inertia level of MG system. The results stated that the proposed coordination can effectively regulate the MG frequency and maintain the dynamic stability and security.
TL;DR: The results show that the developed method can effectively detect islanding with low misclassification and has the advantages of small non-detection zone and robustness against noises.
Abstract: Abstract This paper presents a new composite approach based on wavelet-transform and ANN for islanding detection of distributed generation (DG). The proposed method first uses wavelet-transform to detect the occurrence of events, and then uses artificial neural network (ANN) to classify islanding and non-islanding events. Total harmonic distortion and voltage unbalance are extracted as feature inputs for ANN classifier. The performance of the proposed method is tested by simulations for two typical distribution networks based on MATLAB/Simulink. The results show that the developed method can effectively detect islanding with low misclassification. The method has the advantages of small non-detection zone and robustness against noises.
TL;DR: In this article, a new approach based on Multi-criteria Data Envelopment Analysis and Shannon Entropy analysis (MCDEA-SEA) is presented that strengthens the solution hunt process of DNEP problems.
Abstract: Abstract Power distribution network expansion planning (DNEP), based on innovative load flow analysis and optimization techniques, has drawn great attention of researchers around the world to cater for ever increasing demand of electrical power. In the present work, a new approach based on Multi-criteria Data Envelopment Analysis and Shannon Entropy analysis (MCDEA-SEA) is presented that strengthens the solution hunt process of DNEP problems. In the first stage of proposed methodology, various probable configurations are determined through load flow analysis considering different objective functions and constraints. In the next stage, large amount of complex data sets generated for various configurations from power flow perusal, then analyzed using pooled MCDEA-SEA. This multi-stage approach expedites search for best and impeccable solution, which leaves no space for sub-optimality. The efficacy of the proposed method has been verified by applying it on IEEE 33-bus test distribution system, considering impending load scenarios and the results show that the proposed methodology can effectively solve DNEP problem and provide optimal solution for DNEP problems, consuming lesser computation time compared to conventional approaches.
TL;DR: In this article, a model of energy management system is introduced for the energy scheduling at home, where appliances are scheduled under real time pricing combined with inclined block rate pricing scheme so that the peak to average ratio of power could be maintained in the satisfactory range.
Abstract: Abstract With the latest smart technologies in the electricity sector, the consumers of electricity got the opportunity to reduce their electricity consumption cost by participating in the demand response programs offered by the utility companies. In this paper, a model of energy management system is introduced for the energy scheduling at home. Residential automatic smart appliances of general use are selected for energy scheduling. The energy controlling device in the EMS model receives the real time electricity price signals from the utility company and schedule the appliances according to the user requirements in such a way so that the electricity consumption cost could be minimized. The appliances are scheduled under real time pricing combined with inclined block rate pricing scheme so that the peak to average ratio of power could be maintained in the satisfactory range. This helps the utility companies in maintaining the system reliability. For the solution of the scheduling problem, particle swarm optimization algorithm is used due to its effectiveness and easy implementation. Finally, the results have been compared and verified against the results achieved by genetic algorithm.
TL;DR: In this paper, the authors present the possible impact photovoltaic generation will likely have on the medium voltage grid and the means to lessen these impacts: they investigate various control options for solar inverters and a line voltage regulator as well.
Abstract: Abstract The traditional distribution grid is operated radially and has passive consumers that only draw power from the grid but feed nothing back This operation is already under change so the traditional voltage regulation methods currently used in distribution systems need major modifications if we are to uphold the proper quality of electricity supply. In our paper we present the possible impact photovoltaic generation will likely have on the medium voltage grid and the means to lessen these impacts: we investigate various control options for solar inverters and a line voltage regulator as well. Simulation results indicate that the voltage profile can be maintained within the allowed limits with these regulation methods.
TL;DR: In this article, a feeder of PSPCL is modelled using EPRI open source distribution system simulator (Open DSS) and effect of harmonics due to nonlinear loading measured from distribution system on the power transformer at grid substation supplying the modelled feeder is evaluated for capacity reduction and loss of life as per IEEE standard C57.110−1998.
Abstract: Abstract Harmonics in the power system are increasing due to increased use of power electronic devices in load. Power electronic devises results in nonlinear loading of the distribution system network creating problem of harmonics. Harmonics effects the distribution transformers in distribution system as well as Power Transformer at the grid substation resulting in more losses, production of extra heat, reduction in efficiency and accelerated ageing of insulation. In this paper a feeder of PSPCL is modelled using EPRI open source distribution system simulator (Open DSS) and effect of harmonics due to nonlinear loading measured from distribution system on the power transformer at grid substation supplying the modelled feeder is evaluated for capacity reduction and loss of life as per IEEE standard C57.110–1998.
TL;DR: An improved passive islanding detection scheme is proposed by using the two newly derived indices from the sequence components of the current signal with the conventional voltage and frequency parameters, which confirm the effectiveness of the proposed scheme.
Abstract: Abstract In distributed generation (DG) systems, the rate of change of voltage and the rate of change of frequency are the two most common and widely used simple and low-cost passive islanding detection schemes. Unfortunately, these passive islanding detection schemes find limitation for detecting the islandings that cause very small power imbalance. In this paper, an improved passive islanding detection scheme is proposed by using the two newly derived indices from the sequence components of the current signal with the conventional voltage and frequency parameters. The performance of the proposed scheme is tested for numerous islanding and non-islanding cases generated on IEEE Std 399–1997 and IEC microgrid model distribution system integrated with both inverter-interfaced and synchronous DGs through PSCAD/EMTDC. The obtained results confirm the effectiveness of the proposed scheme.
TL;DR: In this paper, the authors presented an indirect method for measuring the mechanical power produced by three-phase induction motors using only one phase current transducer, which can be used in low cost multipoint measurement system where no other transducers or voltage dividers are necessary.
Abstract: Abstract This paper presents an indirect method for measuring the mechanical power produced by three-phase induction motors. The proposed technique is based on the hypothesis that three-phase induction motors are balanced systems that transform electrical power into mechanical one. The measurement of a single phase current is used to estimate the mechanical power generated at the axis. The relationship between electric current and mechanical power is generally non-linear. By expressing the quantities in p.u., this trend is approximated with a second order polynomial. From the analysis of the mechanical power characteristics related to 13 motors we obtained the parameters of the interpolating parabolic curves of motors from 1.1 kW to 75 kW rated power. The proposed technique can be easily adopted in order to monitor the mechanical power of three phase induction motors using only one phase current transducer. Starting from the motor nameplate no experimental measurement or other data are necessary to estimate the mechanical power. This technique can be widely used in low cost multipoint measurement system able to monitor the mechanical power where no other transducer or voltage divider are necessary.
TL;DR: In this paper, an approach using Pigeon Inspired Optimization (PIO) for selective harmonic elimination in a cascaded H-bridge (CHB) multilevel inverter fed with unequal dc sources is presented.
Abstract: Abstract This paper presents an approach using Pigeon Inspired Optimization (PIO) for selective harmonic elimination in a cascaded H-bridge (CHB) multilevel inverter fed with unequal dc sources. The aim of this work is to find the optimal combination of switching angles, such that the lower order harmonics are eliminated and the output voltage is constant irrespective of voltage change in the input side. This paper the PIO has been used to find the optimal angles for a 7-level inverter and the method can be scaled to any number of levels. To show the effectiveness of PIO the results have been compared with other evolutionary algorithms such as genetic algorithm (GA), particle swarm optimization (PSO). An adaptive switching angle strategy has also been developed using ANN to make the proposed strategy suitable to the real-time applications. In order to verify the results, an experimental prototype of 7 level CHB has been developed in the laboratory using dSPACE ds1104 R&D controller board. The results show that the PIO is the most accurate and fastest evolutionary algorithm for switching angle optimization and the experimental results are in close agreement with the simulation results.
TL;DR: In this method, the non-linear equations related to SPV systems, located at multiple locations, are solved with the main load flow equations in an integrated fashion, considerably reducing the implementation task.
Abstract: Abstract A method is proposed to modify the conventional load flow programme to accommodate large-scale Solar PhotoVoltaics (SPV) power plant with series power specifications. The programme facilitates easy handling of any number of SPV systems with standard control strategies such as pf-control and voltage-control, considering solar inverter’s power constraints. In this method, the non-linear equations related to SPV systems, located at multiple locations, are solved with the main load flow equations in an integrated fashion, considerably reducing the implementation task. This task is achieved by augmenting the inverter buses to the existing power system network in such a way that the changes required in the conventional programme are minimal. To show the effectiveness of the proposed method, it is compared with the alternate-iteration method popularly followed in the literature. The workability of the proposed method has been demonstrated by using a Single Machine Infinite Bus (SMIB) system and the IEEE14-bus power system with SPV systems. Various test cases pertaining to meteorological variables and control strategies are also presented.
TL;DR: In this paper, a detailed comparative analysis between Symmetrical and Asymmetrical Quasi Z-Source Cascaded Multilevel Inverter (QZS-CMI) is presented.
Abstract: Abstract This paper presents a detailed comparative analysis between Symmetrical and Asymmetrical Quasi Z-Source Cascaded Multilevel Inverter (QZS-CMI). The comparative analysis investigates for boost operation in both Symmetrical and Asymmetrical System. Analysis is done based on the achieved input current, capacitor voltage of the upper capacitor and parallel capacitor and the two inductors current of DC link (Quasi Z-Source network) which is combined with H-bridge. In Asymmetrical QZS-CMI, the input voltage for three DC sources are given in the ratio of 1:3:9, i. e. the system is designed for 27 level. Asymmetrical QZS-CMI is new system and proposed in this paper for comparative analysis with Symmetrical QZS-CMI. An advanced optimal Alternative Phase Opposition Disposition (APOD) technique is developed and implemented. Symmetrical system has high boosting capability of output voltage, reducing the switching losses, high voltage gain and lower spikes in switching voltage. The comparative study is done and results are verified with Experimental 250 W prototype model and also verified by using MATLAB/ Simulink.
TL;DR: A modified model of an induction motor including stator fault and a new technique are proposed for detection of stator winding faults and Walsh-Hadamard transform is applied to stator currents.
Abstract: Abstract Fault detection in induction motors has drawn growing attention due to importance of these motors in different industries. Analysis of motor currents is a common method for the fault detection. This method is preferred compared with other approaches because of its economic and technical superiorities. In this paper, a modified model of an induction motor including stator fault and a new technique are proposed for detection of stator winding faults. Firstly, Walsh-Hadamard transform is applied to stator currents. Then, variation of Walsh-Hadamard transform is used as the criterion for the detection. Plenty of simulation cases are utilized to evaluate the method. To enhance accuracy of the model, isolation layer resistance (Rf) is also taken into account. For further evaluation, a large number of experimental data were recorded from different experiments to assess the method in practice.
TL;DR: In this paper, the authors proposed a methodology for developing Price Responsive Demand Shifting (PRDS) based bidding strategy of an industrial buyer, who can reschedule its production plan, considering power system network constraints.
Abstract: Abstract This paper proposes a methodology for developing Price Responsive Demand Shifting (PRDS) based bidding strategy of an industrial buyer, who can reschedule its production plan, considering power system network constraints. Locational Marginal Price (LMP) methodology, which is being used in PJM, California, New York, and New England electricity markets, has been utilized to manage the congestion. In this work, a stochastic linear optimization formulation comprising of two sub-problems has been proposed to obtain the optimal bidding strategy of an industrial buyer considering PRDS bidding. The first sub-problem is formulated as to maximize the social welfare of market participants subject to operational constraints and security constraints to facilitate market clearing process, while the second sub-problem represents the industrial buyer’s purchase cost saving maximization. The PRDS based bidding strategy, which is able to shift the demand, from high price periods to low price periods, has been obtained by solving two subproblems. The effectiveness of the proposed method has been tested on a 5-bus system and modified IEEE 30-bus system considering the hourly day-ahead market. Results obtained with the PRDS based bidding strategy have been compared with those obtained with a Conventional Price-Quantity (CPQ) bid. In simulation studies, it is observed that the PRDS approach can control the LMPs and congestion at the system buses. It is also found that PRDS can mitigate the market power by flattening the demand, which led to more saving and satisfying demand.
TL;DR: In this paper, the authors proposed a methodology to repair crews dispatch during distribution feeders restoration immediately after remotely controlled actions have been taken, based on the expected number of faults for each sector considering a previously calculated fault probability.
Abstract: Abstract This paper proposes a methodology to repair crews dispatch during distribution feeders restoration immediately after remotely controlled actions have been taken. Our method determines the sectors patrol sequence using the expected number of faults for each sector considering a previously calculated fault probability. Next, a road graph mapping of the buses is obtained by associating each bus with its real-world position. The crews’ route inside each sector is determined by the application of the nearest neighbor algorithm on that mapping. The case studies analyzed 24 real faults available in the database of a Brazilian power distribution company, and, a comparison was made between the time spent to locate the failures by simulating both the proposed methodology and the usual greedy strategy. The average time spent in localizing all the failures was from 9.49 % to 41.81 % shorter than in the usual method. Moreover, the speed and distance of repair crews showed weak influence in the crew dispatch methodology efficiency. Such results indicate an enhancement of the power distribution QoS indicators by using the proposed methodology to deal with faults.
TL;DR: In this paper, the fast transient voltages arising due to the switching operation of disconnectors or circuit breakers may impair the service reliability and the dominant frequency content has been identified for different rise times and the percentage attenuation in amplitude is determined at different distances from the source.
Abstract: Abstract The increasing demand in transmitting electrical energy at very high voltages with low transmission losses and improved efficiency has led to the development of compact metal enclosed gas insulated substation. There are various advantages of gas insulated substations over conventional substations yet there are a few problems associated with the switching operation in gas insulated substation. The fast transient voltages arising due to the switching operation of disconnectors or circuit breakers may impair the service reliability. The fast transient currents are associated with these fast transient voltages. The main aim of this paper is to characterize the fast transient currents generated due to the switching operations in a gas insulated substation. The dominant frequency content has been identified for different rise times of the fast transient currents and the percentage attenuation in amplitude is determined at different distances from the source. The variation in the peak value of current with distance from the source is also analysed. The experimental work is carried out on 145 kV gas insulated substation models of different configurations and comparison of the results for different case studies are reported.
TL;DR: In this article, a new system including sensing terminals and hand-held intelligent terminals is presented to locate partial discharge in gas insulated switchgears, where the acoustic vibration caused by the discharge will propagate from the source, resulting in the highest intensity at the sensor closest to the discharge.
Abstract: Abstract Partial discharge location in gas insulated switchgears is important for timely identifying incipient problem and taking remedial actions to prevent later catastrophic breakdowns. This paper presents a new system including sensing terminals and hand-held intelligent terminals to locate partial discharge. Sensing terminals, housing the sensors, are attached to outside enclosure walls of the switchgear to collect acoustic signals, which are transmitted wirelessly to the hand-held terminals. The acoustic vibration caused by the discharge will propagate from the source, resulting in the highest intensity at the sensor closest to the discharge. By examining the signal signatures of the distributed sensors, the location of the partial discharge can be derived. The system is applied in both staged simulation environment and actual factory high voltage tests. The results have demonstrated that the system developed is highly effective in locating partial discharge in gas insulated switchgears and is suitable for practical applications.