A Magnetic linked modular cascaded multilevel converter for medium voltage grid applications
- Authors: Hasan,Md Mubashwar , Islam, Syed , Abu-Siada, Ahmed , Islam, Rabiul Md
- Date: 2019
- Type: Text , Conference proceedings
- Relation: 2019 29th Australasian Universities Power Engineering Conference (AUPEC); Nadi, Fiji; 26-29 November 2019
- Full Text: false
- Reviewed:
- Description: One of the key advantages of cascaded multilevel inverters (CMLI) is their ability to generate medium voltage output by using low voltage rated circuit components. For this reason, CMLI has been given much attention in renewable and industrial applications. However, in spite CMLI advantages, balanced input dc voltage management at the cascaded cells is still considered one of the main drawbacks, which limits its straightforward applications. Moreover, galvanic isolation between the input dc supply and the inverter output voltage is essential for grid-connected application. In such case, a step-up transformer is utilized between the inverter output terminals and the grid. This solution incurs additional cost, increases implementation size, weight and maintenance. In this paper, a CMLI is proposed for medium voltage applications by utilizing high frequency magnetic link to ensure galvanic isolation without the need to a conventional step-up transformer as per the current practice. 3 rd harmonic-injected sine pulse width modulation strategy is adopted as a switching controller for the proposed cascaded inverter that is implemented and tested. Experimental results attest the simulation results and confirm the feasibility of the proposed inverter
Verification of latency and delays related to a digital topology based on IEC 61850
- Authors: Kumar, Shantanu , Das, Narottam , Islam, Syed , Abu-Siada, Ahmed
- Date: 2019
- Type: Text , Conference proceedings , Conference paper
- Relation: 2019 29th Australasian Universities Power Engineering Conference (AUPEC2019); Momi Bay, Fiji; 26th-29th November 2019
- Full Text: false
- Reviewed:
- Description: Digital Communication systems have matured to a point of acceptance in the last decade enormously based on IEC 61850 guidelines from Substation Automation System (SAS) perspective. However, these networks have issues related to latency, data clogging delays, errors etc. in the digital protection system. Measuring propagation delays and assessing the performance of IED's and other peripherals in an Ethernet topology play a critical role in relay coordination setting. This paper discusses issues associated with a digital network and addresses the problems that could mitigate spurious tripping or compromise the protection of the assets in the feeders leading to a reliable operation of the protection system. The discussion in this paper is carried out based on a case study related to a digital star topology using Optimized Network Engineering Tool (OPNET) software of a 132/22-kV zone substation. We report the practical case of measuring delay time during frame exchanges of Generic Object Oriented Substation Event (GOOSE) and Sampled Value (SV) messages amongst the IED' and peripherals.
A novel generalized concept for three phase cascaded multilevel inverter topologies
- Authors: Hasan,Md Mubashwar , Abu-Siada, Ahmed , Islam, Syed , Muyeen, S
- Date: 2017
- Type: Text , Conference proceedings
- Relation: 9th Annual IEEE Green Technologies Conference (GreenTech 2017); Denver, CO; 29th-21st March, 2017 p. 110-117
- Full Text: false
- Reviewed:
- Description: Many new cascaded multilevel inverter (MLI) topologies have recently been proposed and published in the literature. All proposed topologies demand significant amount of semiconductor components and input dc supplies, which is considered the main drawback for the implementation of three phase cascaded MLIs. This paper proposes a new generalized concept that could be employed within any existing cascaded MLI topology in order to reduce its size in terms of device count including semiconductor switches, diodes, and dc power supplies. The new generalized concept involves two stages namely, cascaded stage (CS) and phase generator stage (PGS). The PGS stage is a combination of conventional three phase two level inverter (CTPTLI) and three bidirectional (BD) switches, while the cascaded stage can be modified using any existing cascaded topology. The proposed concept is validated through extensive simulation and experimental analyses. Results show the capability of the proposed technique in reducing device count of the existing topologies while maintaining its performance.
A three-phase half-bridge cascaded inverter with reduced number of input DC supply
- Authors: Hasan, Mubashwar , Abu-Siada, Ahmed , Islam, Syed , Muyeen, S.
- Date: 2017
- Type: Text , Conference proceedings
- Relation: 2017 Australasian Universities Power Engineering Conference, AUPEC 2017; Melbourne, Australia; 19th-22nd November 2017 Vol. 2017, p. 1-7
- Full Text: false
- Reviewed:
- Description: Cascaded multilevel inverters (MLI) have recently received much attention due to its ability to perform well in various high voltage and high power applications with high efficiency. Cascaded inverters are able to generate high voltage output by utilizing a number of low voltage DC supplies and switches of low blocking voltage rating, which make cascaded MLI a cost effective choice for high voltage/power applications. The main drawback of cascaded MLI is the requirement of large number of isolated DC sources particularly, for three phase applications where the number of required input DC sources is three times that of single phase structure. In addition to the extra cost it will incur, the use of large number of DC supplies within the inverter will significantly increase its physical size, and complicate the management of such large number of DC sources. This paper presents a new topology for three phase MLI with a minimum number of input DC supplies. Symmetric and asymmetric input DC supply modes are developed for the proposed topology. Simulation and experimental results are provided to assess the performance of the proposed MLI topology.
Impact of insulating oil degradation on the power transformer frequency response analysis
- Authors: Aljohani, Omar , Abu-Siada, Ahmed , Islam, Syed
- Date: 2015
- Type: Text , Conference proceedings , Conference paper
- Relation: 11th IEEE International Conference on the Properties and Applications of Dielectric Materials, ICPADM 2015; Sydney, Australia; 19th-22nd July 2015 Vol. OCT, p. 396-399
- Full Text: false
- Reviewed:
- Description: Frequency Response Analysis (FRA) has become a reliable tool to detect mechanical deformation within power transformers. Many researchers have investigated the impact of various mechanical winding and core deformations on transformer FRA signature using either simulation analysis or practical testing to establish a standard code for FRA signature interpretation. None of them however, have given attention to the impact of power transformer insulating oil degradation on the transformer FRA signature. This paper investigates the effect of insulating mineral oil degradation on power transformer FRA signature. In this regard, the physical geometrical dimension of a single-phase transformer filled with insulating mineral oil is simulated using three dimensional finite element analysis to emulate the real transformer operation. Transformer FRA signature is measured and analysed with various health conditions of the insulating oil. Results show that, insulating oil degradation has a significant impact on the transformer FRA signature.
Optimal scheduling of LTC and switched shunt capacitors in smart grid concerningovernight charging of Plug-in Electric Vehicles
- Authors: Deilami, Sara , Masoum, Amir , Masoum, Mohammad , Abu-Siada, Ahmed , Islam, Syed
- Date: 2015
- Type: Text , Conference proceedings , Conference paper
- Relation: AASRI International Conference on Applied Engineering Science, ICAES 2014; Los Angeles, United States; 23rd-24th July 2014 p. 71-76
- Full Text: false
- Reviewed:
- Description: It is well-known that load variation and nonlinearity have detrimental impacts on the operation and performance of the conventional power systems and future smart grids (SGs) including their voltage profiles, power quality, losses and efficiency particularly during the peak load hours. This paper will perform optimal scheduling of transformer load tap changer (LTC) and switched shunt capacitors (SSCs) in smart grid with nonlinear loads and plug-in electric vehicle (PEV) charging activities to improve voltage profile, reduce grid losses and control the total harmonic distortion (THD). An established genetic algorithm (GA) for the dispatch of LTC/SSC and a recently implemented algorithm based on maximum sensitivity selections (MSS) optimization for coordination of PEVs are used to perform detailed simulations and analyses.
Overnight coordinated charging of plug-in electric vehicles based on maximum sensitivities selections
- Authors: Masoum, Amir , Deilami, Sara , Masoum, Mohammad , Abu-Siada, Ahmed , Islam, Syed
- Date: 2015
- Type: Text , Conference proceedings , Conference paper
- Relation: AASRI International Conference on Applied Engineering Science, ICAES 2014; Los Angeles, United States; 23rd-24th July 2014 p. 65-70
- Full Text: false
- Reviewed:
- Description: The future smart grid (SG) will be populated with high penetrations of plug-in electric vehicles (PEVs) that may deteriorate the quality of electric power. The consumers will also be seeking economical options to charge their vehicles. This paper proposes an overnight maximum sensitivities selection based coordination algorithm (ON-MSSCA) for inexpensive overnight PEV charging in SG. The approach is based on a recently implemented online algorithm (OL-MSSCA) that charges the vehicles as soon as they are randomly plugged-in while considering SG generation, demand and voltage constraints. In contrast to the online approach, ON-MSSCA relies on inexpensive off-peak load hours charging to reduce the cost of generating energy such that SG constraints are not violated and all vehicles are fully charged overnight. Performances of the online and overnight algorithms are compared for the modified IEEE 23kV distribution system with low voltage residential feeders populated with PEVs.
A new control approach to improve the overall performance of DFIG-based WECS
- Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed , Masoum, Mohammad
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: Doubly Fed Induction Generators (DFIGs) are currently extensively used in variable speed wind power plants due to their superior advantages that include reduced converter rating, low cost, reduced losses, easy implementation of power factor correction schemes, variable speed operation and four quadrants active and reactive power control capabilities. On the other hand, DFIG sensitivity to grid disturbances, especially for voltage sags represents the main disadvantage of the equipment. In this paper, a coil is proposed to be integrated within the DFIG converters to improve the overall performance of a DFIG-based wind energy conversion system (WECS). A proportional integral (PI) controller to control the charging and discharging of the coil is introduced. Simulation results reveal the effectiveness of the proposed topology in improving the overall performance of the WECS under study.
Application of digital image processing to diagnose transformer winding deformation using FRA polar plot
- Authors: Aljohani, Omar , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 2014 International Conference on Condition Monitoring and Diagnosis, CMD 2014; Jeju, Korea; 21st September 2014
- Full Text: false
- Reviewed:
- Description: Digital image processing (DIP) technique has been growing rapidly as an essential tool to interpret various image features for many applications of science and engineering. Condition monitoring and diagnosis are considered the main areas that relay on DIP. Frequency response analysis (FRA) technique has become a popular and reliable diagnostic tool in detecting various winding deformations within power transformers. However, interpretation of FRA signatures still requires high expertise because of its reliance on graphical analysis. This paper presents a new technique for the interpretation of transformers FRA signatures. The proposed technique relies on incorporating both magnitude and angle of the FRA signature in one polar plot, which is manipulated to extract some unique features using DIP techniques. The proposed technique can assess in identifying and quantifying various winding deformation within power transformers. The proposed technique is easy to implement in any frequency response analyser.
Application of SMES unit to improve the overall performance of DFIG-based WECS
- Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed , Masoum, Mohammad
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 2014 IEEE Power and Energy Society General Meeting; National Harbor, United States; 27th-31st July 2014 Vol. 2014, p. 1-5
- Full Text: false
- Reviewed:
- Description: Doubly Fed Induction Generators (DFIGs) are nowadays extensively used in variable speed wind power plants due to their advantages that include reduced converter rating, low cost, reduced losses with an improved efficiency, easy implementation of power factor correction schemes, variable speed operation and four quadrants active and reactive power control capabilities. On the other hand, DFIG sensitivity to grid disturbances, especially for the voltage dip represents the main disadvantage of the equipment. This paper presents the application of superconducting magnetic energy storage (SMES) unit to improve the overall performance of a DFIG-based wind energy conversion systems (WECS). Two control approaches namely; hysteresis current controller (HCC) along with proportional integral (PI) controller and a fuzzy logic (FL) controller for the SMES unit are presented and compared. Various grid codes are used to examine the capability of the two proposed controllers to improve the low voltage ride through (LVRT) capability of the DFIG to maintain the wind turbine connection to the grid through fault durations.
- Description: IEEE Power and Energy Society General Meeting
Detection of power transformer disk space variation and core deformation using frequency response analysis
- Authors: Hashemnia, Naser , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 2014 International Conference on Condition Monitoring and Diagnosis, CMD 2014; Jeju, Korea; 21st September 2014
- Full Text: false
- Reviewed:
- Description: Frequency response analysis (FRA) has become a widely accepted tool to detect power transformer winding deformation due to the development of FRA test equipment. Because FRA relies on graphical analysis, interpretation of its signature is a very specialized area that calls for skilled personnel, as so far, there is no reliable standard code for FRA signature classification and quantification. Many researchers investigated the impact of various mechanical winding deformations on the transformer FRA signature by changing particular electrical parameters of the transformer equivalent electrical circuit. None of them however, investigated the impact of physical fault levels on the transformer FRA signature as it is very difficult to implement faults within real transformer without damaging it. In this paper, the physical geometrical dimension of a power transformer is simulated using 3D finite element analysis to emulate the real transformer operation. Physical core deformation and disk space variation are simulated and the impact of each fault on the transformer FRA signature is investigated.
DFIG-based WECS fault ride through complying with Australian grid codes
- Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: Doubly Fed Induction Generators (DFIGs) are widely used in variable speed wind turbine owing to its superior advantages that include ability to extract more energy from turbine, capability to control active and reactive power independently and the use of reduced converter rating that reduces its overall cost. On the other side fluctuating output power, weak fault ride through capability and high sensitivity to grid disturbances are the main issues that affect DFIG performance. In this paper, superconducting magnetic energy storage (SMES) unit is proposed to improve the fault ride through (FRT) capability of DFIG-based wind energy conversion system (WECS) during voltage sag and voltage swell events in the grid side. A new control approach for SMES unit using hysteresis current controller (HCC) along with proportional integral (PI) controller is introduced. Australian grid codes are used to examine the capability of the proposed controller to improve the FRT of the DFIG and hence maintaining the wind turbine connection to the grid during studied faults. Simulations results show the effectiveness of the SMES controller in maintaining system parameters within safety margins that comply with the Australian grid codes.
Effects of transformer oil properties and contamination on its spectral response
- Authors: Abu Bakar, Norazhar , Abu-Siada, Ahmed , Islam, Syed , El-Naggar, M.
- Date: 2014
- Type: Text , Conference proceedings
- Relation: 2014 International Conference on Condition Monitoring and Diagnosis, CMD 2014; Jeju, Korea; 21st September 2014
- Full Text: false
- Reviewed:
- Description: UV Spectrophotometry is a non-intrusive test that can be employed to determine power transformer’s integrity. Light transmitted through transformer oil sample containing various contaminations is decreased by that fraction being absorbed and is detected as a function of wavelength. This paper investigates the impact of various contaminations and oil properties such as water content, acidity, interfacial tension and average voltage breakdown on the spectral response of the transformer oil. In this regard, various transformer oil samples are collected from in-service transformers and the aforementioned parameters are measured. Same oil samples are scanned with UV-Vis spectroscopic and the spectral responses are obtained and analysed.
Offline to online mechanical deformation diagnosis for power transformers
- Authors: Hashemnia, Naser , Masoum, Mohammad , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: Internal winding deformations of power transformers can be detected using the conventional offline frequency response analysis (FRA) which is a well-known and widely accepted tool for the detection of winding and core deformations. In addition of being offline technique, interpretation of FRA signature is based on graphical analysis that requires skilled personnel as there is no reliable standard code for FRA signature identification and quantification. This paper presents the possibility of using an alternative online technique based on construction a voltage-current (ΔV-I) locus of the operating transformer and considering it as a reference signature. In order to fully explore the performance and reliability of the new proposed approach particularly for real-life distribution transformers, the paper investigates and compares the performance of the proposed and the FRA approaches for disk space variation and axial displacement faults. The transformer distributed parameter model is used to simulate FRA signatures while a detailed three-dimensional finite element model is used to generate the ΔV-I louses for healthy and faulty operating conditions. Simulation results are compared to highlight the advantages and limitations of the two internal fault detection strategies.
Online coordination of plug-in electric vehicle charging in smart grid with distributed wind power generation systems
- Authors: Masoum, Amir , Deilami, Sara , Masoum, Mohammad , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 2014 IEEE Power and Energy Society General Meeting; National Harbor, United States; 27th-31st July 2014 Vol. 2014, p. 1-5
- Full Text: false
- Reviewed:
- Description: Plug-in electric vehicles (PEVs) and wind distributed generations (WDGs) will represent key technologies in the future smart grid configurations. PEV charging at high penetration levels requires substantial grid energy that can be partially supplied by WDGs. This paper examines the impacts of WDGs on performance of recently implemented online maximum sensitivities selection based coordination algorithm (OL-MSSCA) for PEV charging. The algorithm considers random arrivals of vehicles and time-varying market energy price to reduce the total cost of energy generation for PEV charging and the associated grid losses while providing consumer priorities based on defined charging time zones. OL-MSSCA will be improved to also consider DGs while maintaining network operation criteria such as maximum generation limits and voltage profiles within their permissible limits. Detailed simulation is performed on the modified IEEE 23kV distribution system with three WDGs and 22 low voltage residential networks populated with PEVs. The main contributions of this paper are inclusion of WDGs in OL-MSSCA, as well as detailed investigations on the impacts of their peak generation times, penetrations and locations on the performance of smart grid populated with PEVs.
- Description: IEEE Power and Energy Society General Meeting
Performance evaluation of on-line transformer winding short circuit fault detection based on instantaneous voltage and current measurements
- Authors: Masoum, Ali , Hashemnia, Seyednaser , Abu-Siada, Ahmed , Masoum, Mohammad , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 2014 IEEE Power and Energy Society General Meeting; National Harbor, United States; 27th-31st July 2014 Vol. 2014, p. 1-5
- Full Text: false
- Reviewed:
- Description: This paper investigates the performance of a recently proposed on-line transformer winding short circuit fault detection approach through detailed nonlinear three-dimensional finite element modelling of windings, magnetic core and transformer tank. The technique considers correlation of instantaneous input and output voltage difference Δ V=(v1(t)-v2(t)) and instantaneous input current I=i(t) at the power frequency as a fingerprint of the transformer. The on-line measured ΔV-I locus of healthy and faulty transformer are compared to detect the internal fault. A detailed three-dimensional finite element transformer models based on the physical dimensions, parameters and magnetic core characteristics are developed and used to emulate internal winding short circuit faults and calculate the corresponding transformer ΔV-I locus. Detailed simulations and some laboratory measurements are performed and analysed to investigate the impact of winding short circuit faults on the on-line transformer ΔV-I locus.
Image processing-based on-line technique to detect power transformer winding faults
- Authors: Abu-Siada, Ahmed , Islam, Syed
- Date: 2013
- Type: Text , Conference proceedings , Conference paper
- Relation: 39th Annual Conference of the IEEE Industrial Electronics Society, IECON 2013; Vienna, Austria; 10th-14th November 2013 p. 1-6
- Full Text:
- Reviewed:
- Description: Frequency Response Analysis (FRA) has been growing in popularity in recent times as a tool to detect mechanical deformation within power transformers. To conduct the test, the transformer has to be taken out of service which may cause interruption to the electricity grid. Moreover, because FRA relies on graphical analysis, it calls for an expert person to analyse the results as so far, there is no standard code for FRA interpretation worldwide. In this paper an online technique is introduced to detect the internal faults within a power transformer by constructing the voltage-current (V-I) locus diagram to provide a current state of the transformer health condition. The technique does not call for any special equipment as it uses the existing metering devices attached to any power transformer to monitor the input voltage, output voltage and the input current at the power frequency and hence online monitoring can be realised. Various types of faults have been simulated to assess its impact on the proposed locus. A Matlab code based on digital image processing is developed to calculate any deviation of the V-I locus with respect to the reference one and to identify the type of fault.
Impact of axial displacement on power transformer FRA signature
- Authors: Hashemnia, Naser , Abu-Siada, Ahmed , Islam, Syed
- Date: 2013
- Type: Text , Conference proceedings , Conference paper
- Relation: 2013 IEEE Power and Energy Society General Meeting, PES 2013; Vancouver, Canada; 21st-25th July 2013 p. 1-4
- Full Text:
- Reviewed:
- Description: Frequency response analysis (FRA) is gaining global popularity in detecting power transformer winding movement due to the development of FRA test equipment. However, because FRA relies on graphical analysis, interpretation of its signatures is still a very specialized area that calls for skillful personnel to detect the sort and likely place of the fault as so far, there is no reliable standard code for FRA signature classification and quantification. This paper investigates the impact of transformer winding axial displacement on its FRA signature as a step toward the establishment of reliable codes for FRA interpretation. In this context a detailed model for a singlephase transformer is simulated using 3D finite element analysis to emulate a close to real transformer. The impact of axial displacement on the electrical distributed parameters model that are calculated based on the transformer physical dimension is examined to investigate how model’s parameters including inductance and capacitance matrices change when axial displacement takes place within a power transformer.
Impact of conducting materials on furan-spectral correlation of transformer oil
- Authors: Das, Narottam , Abu-Siada, Ahmed , Islam, Syed
- Date: 2013
- Type: Text , Conference proceedings , Conference paper
- Relation: 2013 Australasian Universities Power Engineering Conference, AUPEC 2013; Hobart, Australia; 29th September-3rd October 2013 p. 1-4
- Full Text: false
- Reviewed:
- Description: This paper investigates the impact of conducting materials on the correlation of furan concentration in transformer oil and its spectral response characteristics. The presence of furan derivatives in aged-transformer oil has been one of the key indicators for solid dielectric deterioration. Identification and quantification of furan derivatives are currently performed using high performance liquid chromatography or gas chromatography-mass spectrometry based on ASTM D5837 standard. Although these techniques are well established, they need an expert personal to conduct the test and to analyse its results. Moreover, the test is relatively expensive and the analysis of oil sample may take days as most utilities sending transformer oil samples to external laboratories to be tested. Recently, it has been proven that furan concentration in transformer oil has a strong correlation to the oil spectral response. This paper is to validate this finding and to investigate the impact of conducting materials within transformer oil on this correlation. In this context, extensive experimental tests are conducted to assess the impact of various concentration of conducting materials (e.g., copper dust) dissolved in transformer oil samples of different furan contents on its absorption and transmission spectra. The measured experimental results show that, the impact of such small amount ofdissolved conducting materials on the oil spectral response is minimal.