Jayashri Ravishankar's research while affiliated with UNSW Sydney and other places

Publications (39)

Article
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The ongoing development of renewable energy and microgrid technologies has gradually transformed the conventional energy infrastructure and upgraded it into a modernized system with more distributed generation and localized energy storage options. Compared with power grids utilizing synchronous generation, inverter-based networks cannot physically...
Article
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Second-order generalized integrator (SOGI) requires fast and accurate grid voltage frequency information for quadrature signal generation (QSG) in single-phase systems. Conventionally, synchronous reference frame phase-locked loop (SRFPLL) is used in a cascade manner and provides the frequency feedback to SOGI. PLL is a non-linear closed-loop contr...
Article
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Second-order generalized integrator phase-locked loop (SOGIPLL) relies on the frequency feedback from the PLL estimation. The frequency is used to generate the equivalent in-phase and in-quadrature signals of the single-phase grid voltage. The phase-angle coupled frequency feedback makes the SOGIPLL structure vulnerable to various grid voltage tran...
Chapter
In the age of digital revolution, technology plays a vital role in transforming education practices. Online courses are gaining a lot of attention and demand in recent times as universities try to manage resources and cope with increasing number of student enrolments. In this study, an existing electrical safety course comprising of various activit...
Article
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Inaccurate phase-angle jump estimation of the grid voltage during faults is one of the major causes for poor fault ride-through performance of converters. To overcome this issue and make the converter’s current controller robust, this paper proposes a hybrid grid synchronization transition technique. In this concept, a synchronous reference frame b...
Conference Paper
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The deployment of distributed generation contributes to the facilitation of the microgrid concept and grid modernization on a global scale. An increasing number of workforces are required for further development of microgrid systems. However, the mismatch between the University education and industry expectation places a negative impact on workforc...
Conference Paper
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Loss of synchronization (LOS) in the case of a synchronous reference frame based phase-locked loop (SRFPLL) affects the low voltage ride-through performance of grid-connected power converters. To avoid this issue, this paper proposes a hybrid grid synchronization technique that includes two frequency and two phase-angle estimators. It uses the freq...
Article
Current power networks and consumers are undergoing a fundamental shift in the way traditional energy systems were designed and managed. The bidirectional peer-to-peer (P–P) energy transactions pushed passive consumers to be prosumers. The future smart grid or the internet of energy (IoE) will facilitate the coordination of all types of prosumers t...
Article
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Inhabited isolated areas require independent power systems called isolated microgrids. Conventional protection schemes are not suitable for isolated microgrids due to their dependence on significant fault current. This article introduces an adaptive differential feature-based protection scheme for fault detection and faulty phase identification for...
Conference Paper
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Highly fluctuating renewable sources create enormous stability issues in microgrids. Small signal and transient stability are the major classifications in microgrid stability. For small signal studies, eigenvalue analysis based on state space modeling is the most common method. Detailed dynamic modeling of the system is required for transient analy...
Conference Paper
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Microgrids can connect and disconnect from the grid to enable them to operate in both grid-connected and islanded modes. Stability issues are often a concern in islanded microgrids due to a decrease in system inertia. In addition, the quick response of power electronic inverters in the system creates a high rate of change in frequency, voltage and...
Conference Paper
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Insignificant fault current in inverter-based islanded AC microgrids makes fault detection challenging. This paper introduces a voltage signal-based fault assessment method for islanded AC microgrids. It considers a new set of features such as instantaneous jumps in amplitude, phase angle and frequency of voltage signal for fault detection and clas...
Article
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In this paper, the impacts of uncoordinated energy management systems (EMS), with a rebound effect, on a renewable energy-dependent microgrid are discussed and feasible solutions are presented. Two different approaches, i.e. load-based and price-based EMS are modelled which consider PV units, battery energy storage systems (BESS), and electric vehi...
Article
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Inverters in Microgrids (MGs) face significant challenges during their parallel operations; such as accurate power sharing, deviations in system voltage magnitude and frequency, imbalance between generation and load demand. To solve these techno-economic challenges, hierarchical control structures are implemented in MGs. The structure consists of t...
Article
Full-text available
Inverters in Microgrids (MGs) face significant challenges during their parallel operations; such as accurate power sharing, deviations in system voltage magnitude and frequency, imbalance between generation and load demand. To solve these techno-economic challenges, hierarchical control structures have been implemented in MGs. The structure cons...
Article
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This paper proposes a new technique to manage the domestic peak load demand through peer-to-peer (P-P) energy transaction among multiple homes. In this process, the houses willing to sell energy are identified as the Parent, and the houses that require energy are identified as a Child. The parents having energy resources such as photovoltaics (PV),...
Article
In this paper, the impact of prediction errors on the performance of a domestic power demand management is thoroughly investigated. Initially, a real-time peak power demand management system using battery energy storage systems (BESSs), electric vehicles (EVs) and photovoltaics (PV) systems is designed and modeled. The model uses real-time load dem...
Article
This paper proposes a coordinated multilayer control strategy for energy management (EM) of grid-connected AC microgrids. The strategy predicts the customer's power demand and photovoltaics (PV) power generation for day-ahead energy management. It utilizes the PV power generations and the bidirectional energy transactions from electric vehicles and...
Conference Paper
Full-text available
The limited fault current tolerance of inverters in AC Microgrids demands the necessity of faster and accurate fault detections. At the point of common coupling, the occurrence of various symmetrical and unsymmetrical faults degrades the performance and robustness of the inverter-interfaced local controllers. To achieve faster fault detection in in...
Article
This paper proposes a new real-time load-support (RTLS) system with a coordinated control using electric boats (EBs), community generators and battery storage systems. It analyzes the management of the intermittent sources-dependent small-scale grid in real time, under various weather, and battery state-of-charge conditions. The RTLS system coordin...
Conference Paper
Full-text available
The limited fault current tolerance of inverters in AC Microgrids demands the necessity of faster and accurate fault detections. At the point of common coupling, the¬ occurrence of various symmetrical and unsymmetrical faults degrades the performance and robustness of the inverter-interfaced local controllers. To achieve faster fault detection in i...
Article
Full-text available
The rate of change of frequency (RoCoF) following any disturbance in low voltage islanded microgrids is not only relatively high compared to conventional systems, but also becomes location specific due to the presence of highly resistive lines. This makes the disturbance detection challenging. A novel real‐time disturbance detection technique for l...
Article
Full-text available
The rate of change of frequency (RoCoF) following any disturbance in low voltage islanded microgrids is not only relatively high compared to conventional systems, but also becomes location specific due to the presence of highly resistive lines. This makes the disturbance detection challenging. A novel real-time disturbance detection technique for l...
Conference Paper
Full-text available
The rate of change of frequency following any disturbance in LV islanded microgrids is not only relatively high compared to conventional system, but also becomes location specific, due to their high R/X ratio lines. This makes the disturbance detection challenging. Conventional power imbalance calculation methods are not applicable due to variation...

Citations

... However, the gain of the ESOGI-PLL should be selected carefully so that it does not deteriorate the transient response and harmonic attenuation capability. Two types of PLLs combining an open-loop frequencyestimator and SOGI block are introduced in [27] using different normalization schemes to remove the dependency of the frequency estimator on grid frequency or phase angle information. The DC offset is canceled using an extra integrator added to the SOGI block to provide accurate grid information estimation with four grid cycles convergence speed. ...
... The lower bandwidth design can enhance the harmonic rejection capability at the expense of a slower dynamic response. In contrast to recent trends in synchronization, both dynamic performance enhancement and elimination of steady-state grid disturbances of the singlephase PLL are essential [18]. To achieve a fast dynamic response with high filtering capability, various nonlinear PLL was proposed [19]- [23]. ...
... According to the concept of FRT, PVs should stay connected to the grid even when the bus voltage is very low [85]. The feasibility of such condition for existing grid-connected generators could be obtained using a modified grounding system which ensures the system against the LG faults [76,84,86]. According to the necessities of grid codes, the FRT capability should be applied for DC-grids especially when DC-grids are constituted from interconnected AC/DC converters. ...
... Changing the thyristor-controlled series capacitor can improve the voltage control capability, meaning that the system can maintain a steady operation with a higher wind power penetration rate [5]. Therefore, the impact on the system's voltage stability of having distributed generation to the power grid should be carefully studied [5][6][7][8]. ...
... If a fault exists, then the DG nearest to the fault injects harmonic at a correctly selected frequency and the impedance seen at this point is measured and sent to the SVM classifier to detect the accurate location of the fault section. A similar approach has been discussed in [152] that concludes the FFT and SVM for effective classification and detection to control the system stability in an islanded microgrid. The minimum average error in fault localisation for the longest line in IEEE 34 bus system was found 0.0012 and 0.0021 for clean and noisy data respectively. ...
... However, they also do not offer backup protection. In [36,37], intelligent micro-grid protection schemes based on data mining are presented. These schemes allow coordination considering several fault situations under different operating conditions. ...
... A differential protection technique by Kar et al. [13] is established on a statistical approach that collects much more sensible variables from the fault current and voltage and utilizes the differential parameter as a fault indicator. Moreover, a differential protection technique that uses the Hilbert-Huang transform [14][15][16] and PS components [17][18][19] has been suggested in the literature. Nonetheless, a differential scheme is not yet developed that can offer complete protection for various operational conditions and responds quickly for all types of DGs. ...
... In recent, the increasing concern of energy shortage and environmental change has facilitated a reconsideration for the current energy system. To curb carbon emission and improve energy efficiency, the concept of integrated energy system (IES) where different types of energy carriers are integrated was proposed [1,2]. In contrast to electric power systems, the IES is more complicated and flexible. ...
... They are advantageous to centralized and distributed systems due to the absence of communication infrastructure and its costs. Furthermore, they allow plug-and-play capabilities and fast reconfiguration of the MG [13], [14], [16]. However, as they are established around utilizing the estimation and prediction of state variables, they require an accurate system model. ...