Thank you for reading voltage stability of electric power systems. Maybe you have knowledge that, people have search hundreds times for their chosen books like this voltage stability of electric power systems, but end up in infectious downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some harmful bugs inside their desktop computer. voltage stability of electric power systems is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library hosts in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the voltage stability of electric power systems is universally compatible with any devices to read.

Voltage Stability Of Electric Power Systems

https://iopscience.iop.org/article/10.1088/1757-899X/331/1/012023/pdf

Optimal placement of FACTS devices using optimization techniques: A review

In this work, a reactive power-voltage (QV)-based framework to evaluate the voltage instability sensitivities of power system buses to increase in renewable energy (RE) penetration has been developed using two sensitivity indices, namely, Critical Voltage Sensitivity Index (CVSI) and Critical Reactive Power Sensitivity Index (CQSI). The rise or fall in the critical voltage level is measured by CVSI and the reactive power loss intolerance of each bus is evaluated by the CQSI as the RE penetration level increases. The bus sensitivity analysis obtained from the CVSI and CQSI provides information on the voltage instability sensitivity of each power system bus to increase in RE penetration level. The proposed methodology has been evaluated using IEEE 14-bus system and New England 39-bus system. DIgSILENT PowerFactory was used to perform the simulations and Matrix Laboratory (MATLAB) used to analyse the results. The sensitivity analysis of the buses can provide insights on the most suitable placement for large reactive loads or devices such as Flexible Alternating Current Transmission Systems (FACTS) as the RE penetration level (PL) increases.

/pdf/reactive-power-voltage-based-voltage-instability-sensitivity-c7reze8axt.pdf

Reactive Power-Voltage-Based Voltage Instability Sensitivity Indices for Power Grid With Increasing Renewable Energy Penetration

A micorgrid is a small size distribution grid that integrated various on-site distributed energy sources to satisfy the local energy demand. A microgrid can either be connected to the main utility grid or operate in islanded mode. The technical, economic and environmental benefits associated with microgrids have led to extensive research in this area. However, development of advanced planning and operation algorithms is necessary to justify the investment cost and pave the way for microgrid deployments. This paper presents a new planning approach based on particle swarm optimization (PSO) to determine the optimal size and placement of distributed generation (DG) units in a microgrid. The economics of DG units, power exchange with the main grid, and penalty for not supplying the loads are taken into consideration.

Distributed generators optimal sizing and placement in a microgrid using PSO

A key focus recently has been in assessing the risk of a coordinated cyber-physical attack and minimizing the impact of a successful attack. Most of the cyber-attackers will have limited system information and conventional power grid N − 1 security analysis cannot be extended to assess the risk. Centrality measures are widely used in the network science and an attacker with incomplete information can use it to identify power system vulnerabilities by defining the system as a complex network but without real-time system measurements. This paper presents a graph theory based centrality indices for vulnerability assessment of the power system due to various bus and branch contingencies using limited system information and provides a preliminary defense mechanism to prevent such an attack. Proposed work answers the fundamental question of possible attack scenarios by balancing risk (limited information with low risk to get caught or high risk attack to access more system information) and impact (identifying contingencies with maximal impact on system operation). Statistical comparisons are made between the graph theory measures compared to the corresponding DC power flow based N − X linear sensitivity measures. A unified N − X centrality based performance index is proposed and validated against the AC power flow based performance index by doing the real-time simulations of an N − 3 attack scenario. Defensive mechanisms using topology-based performance indices are also presented.

/pdf/graph-theoretic-algorithms-for-cyber-physical-vulnerability-1l9dbrnkft.pdf

Graph-theoretic algorithms for cyber-physical vulnerability analysis of power grid with incomplete information

Electrical power grids are often susceptible to voltage instability and have been a growing concern. In this study, the authors propose techniques based on network response structural characteristics for voltage stability assessment and for the identification of important nodes in electrical power grids. First, the network response structural characteristic indices (NRSCIs) which are inherent in the conventional power grids in terms of the Kirchhoff matrix is formulated. The eigenvalue decomposition (ED) technique is then applied to a submatrix of the Kirchhoff matrix to determine the topological strength of the electrical network graph. The vertex (node) that has a minimum eigenvalue is taken as the critical mode, from which its contributions to the entire graph is identified using the proposed network response structural characteristics theory participation factor (NRSCTPF). To demonstrate the magnitude of the concept formulated, the known degree centrality is modified in terms of the established NRSCI, which are then used to determine the important nodes of the network graph. The results obtained show that the proposed NRSCTPF and the degree centrality based on the NRSCI can be used for voltage stability assessment and identification of important nodes. The proposed approach is also less computationally intensive compared with the traditional approach.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-gtd.2016.0745

Voltage stability assessment and identification of important nodes in power transmission network through network response structural characteristics

The frequent occurrence of voltage instability in a modern power system is alarming and thus, has been of great concern to power system utilities. In this paper, a new performance index based on the power flow solutions for voltage stability assessment of a power system is presented. First, the voltage deviation with respect to reactive power load variation at each load bus is found. Thereafter, the performance voltage bus index for each load bus is computed. An improved modal analysis technique (IMAT) is used to identify weak nodes that are liable to voltage instability in a power system. This technique uses a submatrix of the full Jacobian matrix for voltage stability analysis. Comparison of the proposed method is done with existing voltage stability indices and the conventional modal analysis technique (CMAT). The effectiveness of all the approaches presented are tested on both Western system coordinating Council (WSCC) 9-bus, IEEE 30 bus and IEEE 57 bus test systems. Results obtained show that the proposed techniques can serve as an alternative tool to other conventional techniques for voltage stability assessment in a power system and can be of tremendous benefits in the planning and operation of a power system by system operators.

New Performance Indices for Voltage Stability Analysis in a Power System

Abstract This paper proposes two techniques for the identification of critical buses in a power system. The technique of Network Structural Theory Participation Factor (NSTPF) depends on the network structural interconnection of buses as captured by the admittance matrix of the system and is formulated based on the fundamental circuit theory law using eigenvalue decomposition method. Another power flow based technique which depends on the system maximum loadability, the system step size among other factors is also proposed. Traditional power flow based techniques are used as benchmarks to determine the significance of the proposed methods. To ensure voltage stability enhancement, STATCOM FACTS device is installed at the selected weak load buses of the practical Nigerian 24 bus and IEEE 30 bus test systems. The results of the simulation obtained show that, the suggested approach of NSTPF is more suitable in the identification of weak buses that are liable to voltage instability in power systems as it requires less computational burden and also saves time compared to techniques based on power flow solutions.

Techniques for the Identification of Critical Nodes Leading to Voltage Collapse in a Power System

In this paper, the use of techniques based on the Artificial Intelligent (AI) and the network topological structure of the power system network, for optimal location of the reactive power compensator is investigated. To determine the suitable location for the power electronics based UPFC and TCSC FACTS devices, with the proposed Network Structural Characteristics Participation factor (NSCPF), the critical mode and the associated eigenvectors of the system are found. Comparative analysis with an optimization technique of genetic algorithm (GA) to determine the optimal location, size and rating of each UPFC and TCSC FACTS devices is also carried out. All the techniques presented are tested on the IEEE 14 bus power system. The results of simulation obtained show that, the proposed NSCPF is more superior in the identification of suitable nodes for the placement of FACTS devices compared to the traditional approach of GA, as it saves time and require no iteration processes before the best location is identified.

Optimal location identification of FACTS devices through genetic algorithm and the network structural characteristics techniques

Achieving the goals of distribution systems operation often involves taking vital decisions with adequate consideration for several but often contradictory technical and economic criteria. Hence, this paper presents a modified analytical approach for optimal location and sizing of solar PV-based DG units into radial distribution network (RDN) considering strategic combination of important power system planning criteria. The considered criteria are total planning cost, active power loss and voltage stability, under credible distribution network operation constraints. The optimal DG placement approach is derived from the modification of the analytical approach for DG placement using line-loss sensitivity factor and the multiobjective constriction factor-based particle swarm optimization is adopted for optimal sizing. The effectiveness of the proposed procedure is tested on the IEEE 33-bus system modeled using Matlab considering three scenarios. The results are compared with existing reports presented in the literature and the results obtained from the proposed approach shows credible improvement in the RDN steady-state operation performance for line-loss reduction, voltage profile improvement and voltage stability improvement.

Isaiah G. Adebayo

Papers

Voltage stability assessment and identification of important nodes in power transmission network through network response structural characteristics

New Performance Indices for Voltage Stability Analysis in a Power System

Techniques for the Identification of Critical Nodes Leading to Voltage Collapse in a Power System

Optimal location identification of FACTS devices through genetic algorithm and the network structural characteristics techniques

Modified Analytical Approach for PV-DGs Integration into a Radial Distribution Network Considering Loss Sensitivity and Voltage Stability