Power System Scenario Research Articles

Frequency Stability of the European Interconnected Power System Under Grid Splitting in Market Zones

This paper proposes a graph theory-based approach to define the possible separation of the market zones in large power systems. The market zone partitioning is used to assess the frequency stability based on a set of parameters, including the inertia, the running capacity of the separated areas, and the power exchanged on the interconnection lines. A system split indicator is finally used to rank the worst split lines. The methodology has been tested on real scenarios of the interconnected Continental Europe power system.

An Uplink Secure CB-NOMA with SIC Receiver for Wireless Applications

The nonorthogonal multiple access (NOMA) techniques are considered one of the main methods to realize the goals of 5G mobile and wireless systems such as link communication reliability and high user connectivity. Yet, when the amount of simultaneously connected users increases, many concerns will arise regarding the users’ data security. Various chaotic systems in the communication field have been presented to mitigate the data security concerns offering a cost-efficient technique to provide physical layer security. This work presents an uplink secure chaos-based NOMA (SCB-NOMA) system by exploiting the power domain. For signal modulation at the transmitters’ node, chaos shift keying is used, with controlled transmit power to satisfy the receiver conditions. For multiuser detection, the receiver side employs successive interference cancellation with chaotic demodulation. The efficiency of designed SCB-NOMA is demonstrated by considering different power control factors, system scenarios, and chaotic sequence length compared with different reference systems. It is shown that the efficient selection of the power allocation parameter has a direct effect on the bit error rate (BER) performance. Meanwhile, when the amount of power difference for the successive interference cancellation process is not adequate, the chaotic codes maintain the desired data security and enable robust BER performance for connected users. Besides, the correlation between the utilized chaotic codes has more impact on BER regardless of the considered sequence length.

Voltage Profile Enhancement and Loss Minimization Using Optimal Placement and Sizing of Distributed Generation in Reconfigured Network

Power loss and voltage instability are major problems in distribution systems. However, these problems are typically mitigated by efficient network reconfiguration, including the integration of distributed generation (DG) units in the distribution network. In this regard, the optimal placement and sizing of DGs are crucial. Otherwise, the network performance will be degraded. This study is conducted to optimally locate and sizing of DGs into a radial distribution network before and after reconfiguration. A multi-objective particle swarm optimization algorithm is utilized to determine the optimal placement and sizing of the DGs before and after reconfiguration of the radial network. An optimal network configuration with DG coordination in an active distribution network overcomes power losses, uplifts voltage profiles, and improves the system stability, reliability, and efficiency. For considering the actual power system scenarios, a penalty factor is also considered, this penalty factor plays a crucial role in the minimization of total power loss and voltage profile enhancement. The simulation results showed a significant improvement in the percentage power loss reduction (32% and 68.05% before and after reconfiguration, respectively) with the inclusion of DG units in the test system. Similarly, the minimum bus voltage of the system is improved by 4.9% and 6.53% before and after reconfiguration, respectively. The comparative study is performed, and the results showed the effectiveness of the proposed method in reducing the voltage deviation and power loss of the distribution system. The proposed algorithm is evaluated on the IEEE-33 bus radial distribution system, using MATLAB software.

Bat Algorithm for Congestion Alleviation in Power System Network

Congestion in power transmission lines is designated as one of the critical issues in the deregulated power system scenario. The System Operator (SO) bears the responsibility to manage the congestion in order to ensure a secure and reliable operation of the power system framework. This article proposes a Congestion Management (CM) strategy based on the generator rescheduling approach using Bat Algorithm (BA). BA is one of the recent nature inspired optimization approaches based on the echolocation strategy adopted by the bats in search of prey. In the proposed CM scheme the BA is used to minimize the congestion cost with the optimal rescheduling of the active power output of the generators. The participation of the generators in the CM is accomplished considering the generator sensitivity values. The potency of the proposed method is tested on 39-bus New England framework, IEEE 30 bus system, IEEE 118 bus system and a comparative analysis is established with other recent optimization approaches. The outcomes obtained with the proposed BA for CM outperforms the outcomes achieved with other algorithms. The proposed approach ensures a better convergence profile avoiding the traps into local minima and also aids the SO to manage congestion efficiently.

A Data-Driven Method for Power System Transient Instability Mode Identification Based on Knowledge Discovery and XGBoost Algorithm

Aiming at the difficulty of unstable pattern recognition after power system fault, a novel identification framework for transient instability mode identification based on knowledge discovery by accuracy maximization (KODAMA) and extreme gradient boosting (XGBoost) algorithm is proposed. In this method, the transient stability of all typical fault scenarios of power system is obtained firstly by XGBoost. Then, to make full use of the structure of the raw data and mine the contained data information, a novel data mining algorithm KODAMA is introduced to cluster the mode of rotor angle in case of instability, thus to convert pattern-unlabeled case data into pattern-labeled data. Finally, based on this labeled data, to fully reflect the dynamic characteristics, a multiple XGBoost assessment strategy is designed to recognize different instable modes. The proposed technique is tested on the Nordic test system, and the results indicate that the proposed approach can provide fast and accurate recognition of instable mode and has a certain prospect of online application.

Smart Sampling for Reduced and Representative Power System Scenario Selection

With increasing penetration of renewable energy and active market participation, power system operation scenarios and patterns have increased exponentially. This has led to challenges in identifying a good subset of scenarios for routine planning, operation, and emerging machine learning applications. To address these challenges, we develop an approach integrating comprehensive exploratory data analyses and smart sampling techniques to identify and select a small subset of representative power system scenarios that maintain the coverage of system scenarios and operation envelope, therefore, leading to very efficient, yet representative studies and analysis. We propose a hierarchical Latin Hypercube Sampling (LHS) technique for smart sampling, which allows free-form distributions of system load and considers generator commitment status along with generation levels. A set of performance metrics are also defined for systematic evaluation of the adequacy and efficiency of the sampled cases. The developed approach and metrics are demonstrated using the Texas 2000 bus system in this paper and will be extended to the more complex real world systems such as Western Interconnect System.

Quantifying the sensitivity of european power systems to energy scenarios and climate change projections

Climate simulations consistently show an increase in European near-surface air temperature by the late 21st century, although projections for near-surface wind speeds and irradiance differ between models, and are accompanied by large natural variability. These factors make it difficult to estimate the effects of physical climate change on power system planning. Here, the impact of climate change on future European power systems is estimated.We show for the first time how a set of divergent future power system scenarios lead to marked differences in Europe’s total energy balance (demand-net-renewable supply) by 2050, which dominate over the uncertainty associated with climate change (∼50% and ∼5% respectively). However, within any given power system scenario, national power systems may be subject to considerable impacts from climate change, particularly for seasonal differences between renewable resources (e.g., wind power may be impacted by ∼20% or more). There is little agreement between climate models in terms of the spatio-temporal pattern of these impacts, and even in the direction of change for wind and solar. More thorough consideration of climate uncertainty is therefore needed, as it is likely to be of great importance for robust future power system planning and design.

Study on home energy management system with battery storage for peak load shaving

Demand for electricity is increasing day-by-day for the development of new technological innovations. Because of an increase in demand, there are specific issues like demand and supply mismatch. To reduce the peak load demand, increasing of a generation with the help of fossil fuels may lead to the release of pollutant gases like NOx and SO 2 into the atmosphere. To reduce demand, renewable sources are playing a crucial part in the present power system scenario. These renewable energy sources with a battery storage system, used with particular control and energy management, are useful for peak load shaving. In this paper, we have modelled a Solar Photovoltaic system with battery storage for the residential load of 5KW as a complimentary supply and grid power as a primary supply, composed with power conditioning controller to reduce the load demand.

Design and Implementation of a Data-Driven Approach to Visualizing Power Quality

Numerous underlying causes of power-quality (PQ) disturbances have enhanced the application of situational awareness to power systems. This application provides an optimal overall response for contingencies. With measurement data acquired by a multi-source PQ monitoring system, we propose an interactive visualization tool for PQ disturbance data based on a geographic information system (GIS). This tool demonstrates the spatio–temporal distribution of the PQ disturbance events and the cross-correlation between PQ records and environmental factors, leveraging Getis statistics and random matrix theory. A methodology based on entity matching is also introduced to analyze the underlying causes of PQ disturbance events. Based on real-world data obtained from an actual power system, offline and online PQ data visualization scenarios are provided to verify the effectiveness and robustness of the proposed framework.

SVM Based Reduction of Input Current Harmonics in Three Phase Rectifier

Current Scenario of power system engineering field is facing problem of harmonics in voltage and current. In power converter harmonics are mainly disturb the stability of voltage and current in uncertainty of load and transient. This paper proposes space vector modulation based analysis of input current in 3 phase converter. Harmonics in input current in converter is a big challenge of power Electronics research. In power converters non-linear load are one of the reason for increasing the harmonics in electronic circuits. Modified space vector modulation is proposed for reducing the harmonics in 3 phase converter and also control the total harmonic distortion. Matlab simulink software is used to simulate and analyse the 3 phase converter and SVM is modelled for above converter. In this propose method THD of input current harmonics has reduced below 5 percentages and compared with IEEE standard.

A Framework for Modeling and Structural Vulnerability Analysis of Spatial Cyber-Physical Power Systems From an Attack–Defense Perspective

This article provides a framework for modeling and analysis of spatial cyber-physical power systems (CPPSs). Previous studies on structural vulnerability analysis of CPPS mainly focused on network topology without any spatial information. In this article, we first propose a hierarchical information system evolution model for spatial power grids. Then, a spatial CPPS model is established by combining power and information systems that accounts for overlapped power and information lines. Finally, the structural vulnerability under global and localized failures is investigated based on direct current (dc) power flow. Under global failures, different types of components have distinguishing effects, and the power-node failure is the most serious case. For localized failures, key zones can be identified by the cascading failure scale, and similarly, different failure modes affect different areas. Furthermore, considering power system scenarios with only defenders and those with both attackers and defenders, we investigate two resource allocation situations. For defenders, increased resources and appropriately dispersed allocation can work effectively. However, in the attack-defense scenario, the perfect subgame equilibrium suggests that both attackers and defenders must concentrate all their resources on the most vulnerable zone. These findings may establish a foundation for future efforts to model and protect spatial CPPSs.

Harmonic Elimination and dc–link Voltage Balancing in Bipolar Hybrid Microgrid by ILCs: A Review

In this advanced power system scenario, the bipolar hybrid microgrid application plays a vital role, which owns both DC and AC bus instantaneously. In this grid-connected technology, renewable energy performs a major role in the generation of power demand. Due to the alternating nature of renewable sources, the grid should have stability with different energy sources like battery storage systems, vehicle to grid, etc. Hence, to retain the quality of power supply it is more significant to consider an interlinking bidirectional converter between a source and the grid. The most important indispensable component in the bidirectional link is an AC/DC bidirectional converter. This paper elaborates about the advantages and disadvantages of the prevailing AC/DC bidirectional converter topologies for the advancement in the microgrid applications. These types of three-phase ac/dc bidirectional converters are preferred to reduce the THD content in the grid side, power factor correction, and regulated dc output voltage with unidirectional and bidirectional power flow. The dc-link voltage has balanced at the dc bus with these bidirectional topologies. By use of this bidirectional converter, it has designed to perform various essential applications in the microgrid with the help of space vector modulation.

APPLICATION OF ANFIS CONTROLLER TO 3-LEVEL NPC BASED APF TO IMPROVE POWER QUALITY

Nowadays, the improvement of power quality is the major concern in power system scenario. As per literature analysis so far a huge number of technique implemented to improve power quality of the system. Out of these, the FACTS controllers plays a key role. This paper is presents a concept of series and shunt active filters implemented with 3-level inverters to reduce the harmonic distortions. The series active filter control structure is implemented with system and load voltages, the reference currents required for shunt active filter is implemented using PQ-control theory. To get better improvement of power quality and harmonic distortion, the series and shunt controllers are implemented with ANFIS controller. This proposed system is tested and verified in MATLAB/SIMULINK.

Research on the Coordinated Operation Mode of Nuclear Power in the Evolution of High-Penetration New Energy Power System

With the large-scale intermittent new energy integration into the power system, the safe and stable operation of the power grid faces huge challenges. Nuclear power output is stable and the inertia is large, which can provide the necessary power, electricity and inertia support for the power system with a high penetration of new energy integration. This paper comprehensively considers various factors such as China’s energy resource conditions, environmental constraints, demand pattern, development schedule, construction cycle, and faces the development scenario of power systems with different penetration of new energy integration for medium and long-term construction. The regional power grid proposes a coordinated development strategy for nuclear power and other new energy that meets the requirements of power system safety and stability, energy conservation, and emission reduction, and provides a useful reference for the healthy development of China’s future nuclear power and new energy industries.

Comparing negative emissions and high renewable scenarios for the European power system

Emerging literature highlights the essential role played by decarbonised electricity generation in future energy systems consistent with the Paris Climate Agreement. This analysis compares the impacts of high levels of renewable electricity and negative emissions technologies on exploratory visions of the future EU power system (2050) in terms of emissions reduction, technical operation and total system costs. The analysis shows that high renewable power system scenarios coupled with low levels of negative emissions technologies, such as biomass carbon capture and storage (< 2% of installed capacity), can deliver a net-negative European power system at lower comparable cost without breaching published sustainable biomass potentials in Europe (or requiring imports) or geological storage potentials while also contributing to power system inertia. Direct air capture has the capability to further decrease overall carbon emissions. While carbon capture and storage and power-to-gas must overcome market, regulatory and social acceptance challenges, given their potential benefits to emissions reduction, costs and system operation their role in a future power system should be further explored.

Multi-Objective optimisation of a micro-grid hybrid power system for household application

This research study aimed to design and optimise hybrid renewable energy systems at two optimisation objectives. The economic and environmental optimisation objectives of four hybrid power system scenarios were tested based on a non-dominated sorting genetic algorithm. The selected optimisation objectives were used simultaneously and parallel to sensitivity analysis in order to determine optimum system configuration under specific criteria. The environmental objective targeted the reduction of CO2 emissions, which resulted in a system with high renewable energy fractions. The economic objective targeted the reduction of system cost (net percentage cost), which resulted in a system size that could meet desired electrical loads. The novelty of this work lay in determining the relationship between two different optimisation objectives i.e., environmental and economic. Result showed that the optimisation process under the economic objective recorded the lowest energy cost for all scenarios with and without storage units. By contrast, the optimisation process under the environmental objective demonstrated a higher system cost value compared with that in the case of the economic optimisation objective for all scenarios. The analysis also shows the CO2 emission with and without considering systems components manufacturing primary emissions.

Resilience-oriented protection scheme for TCSC-compensated line

This paper presents a resilience-oriented protection scheme for TCSC-compensated Line. A cross-differential protection scheme is proposed to enhance the resilience of a parallel transmission line (PTL) in the presence of a thyristor controlled series capacitor (TCSC). The faulty phase(s) is (are) identified by estimating the spectral energy of the three-phase currents and computed by applying an efficient powerful signal processing tool known as fast discrete orthonormal S-transform (FDOST). The proposed scheme is widely evaluated against various faults and dynamic power system conditions. The obtained results indicate the proposed resilience-oriented protection scheme is adaptable to different power system scenarios. The scheme precisely classifies the fault with effective discrimination between internal and external faults on a transmission line and a response time of a maximum one cycle from the fault inception.

Designing of wide-area damping controller for stability improvement in a large-scale power system in presence of wind farms and SMES compensator

The main aim of this paper is the stability improvement of a large-scale power system including wind farms and SMES (Superconducting Magnetic Energy Storage) compensator. For this purpose, at first, the mathematical model of the whole system is extracted in order to accurately investigate the role of wind farms and SMES in the stability studies. The stability analysis is based on the design of damping controllers which is provided through the global signals dependent on the time delay and local signals without the time delay. In modeling of the time delay, damping factor of inter-area oscillation mode is used to obtain larger delay margin, and then, the Lyapunov-Krasovskii function and inequality integral are employed to evaluate the stability condition related to the time delay. The controllability/observability index is used to choose the best candidate signals in the input of WADC (Wide-Area Damping Controller) in order to enhance the residual value of the weakest critical mode identified by modal analysis. The simulation results are investigated through different scenarios of wind turbine and power system in non-linear time domain as well as frequency domain using eigenvalues analysis. The results verify the effectiveness of the proposed controller under various time delays.

Review and Comparison of Grid-Tied Inverter Controllers in Microgrids

Grid-tied inverters are widely used for interfacing renewable energy sources or storage devices to low-voltage electrical power distribution systems. Lately, a number of different control techniques have been proposed to address the emerging requirements of the smart power system scenario, in terms of both functionalities and performance. This article reviews the techniques proposed for the implementation of current-controlled or voltage-controlled inverters in microgrids. By referring to a voltage source inverter with an LCL output filter, different control architectures are classified as single, double, and triple loop. Then, the functionalities that are needed or recommended in the grid-connected, islanded, and autonomous operating modes of the grid-tied inverter are identified and their implementation in the different control structures is discussed. To validate the analysis and to better illustrate the merits and limitations of the most effective solutions, six control strategies are finally implemented and experimentally compared on a single-phase, grid-connected inverter setup.

Esa Based Upqc Controller to Improve Power Quality in Microgrid System

Generally, Power Quality is the main concern parameter in present power system scenario, the main causes for effecting the power quality is due to either harmonic distortion, voltage imbalances, reactive power variations. There are many techniques applied to maintain this power quality in literature. In Facts family, the UPQC controller plays a key role, because it uniquely controls all the transmission parameters. The UPQC controller is combination of series-shunt converters with common dc link. The signals required for these converters are generated by reference and actual signals of bus and dc link capacitor. Phase locked loop helps to provide the phase angle sequence required to improve power factor. In addition with, this paper is implemented with extended search algorithm to better control the dc link voltage for improving power quality. Mat lab/Simulink is used to test the system conditions and performance.