Performance evaluation of voltage stability indices for dynamic voltage collapse prediction (original) (raw)
Voltage Collapse Detection in Iraqi Electrical Network Using Different Types of Indices
2015
Voltage stability is anxious with the ability of a power system to protect worthy voltages at all buses in the framework under ordinary condition and in the wake of being liable to an unsettling influence. In this paper study and analyze the high voltage 400 kV in Iraqi electrical network. In order to identify the voltage collapse in Iraqi electrical network by using different types of indices, these indices provide reliable data about nearness of voltage instability in a PS. Two types of Indices used to analysis and detect the weakness bus voltage and weakness lines in the Iraqi electrical network, indices for detect weak buses such as: Power Transfer Stability Index (PTSI) and Voltage Collapse Predication Index (VCPI) and indices for detect weak lines such as: Fast Voltage Stability Index (FVSI), Line Stability Index (L_mn) and On Line Stability Index (LVSI). The effectiveness of these indexes is confirmed through 24 bus Iraqi networks under increased the load on each bus until re...
) 1 A Recap of Voltage Stability Indices in the Past 2 Three Decades 3
2019
Increasing demand for electricity and modernization of power systems within competitive 18 markets induce power systems to operate close to their stability limits. Therefore, a power system 19 continuous monitoring and control by using voltage stability indices are known exigence. This is 20 the first-ever effort, examined more than 40 voltage stability indices thorough an exhaustive study 21 based in on their formulation, application, performance, and assessment measures. Which is 22 conducted based on a logical and chronological order considering the most recent worldwide 23 applied voltage stability indices. However, the generalizability of such an immense diversity of 24 these indices in term of multivariable objectives subjects to a certain limitation to summate into a 25 deciphered outcome. Despite all these obstacles, this study systematically reviews available indices 26 in the literature within the past three decades to set out an integrated knowledge with an insight 27 up-...
A Contemporary Novel Classification of Voltage Stability Indices
Applied Sciences
Within the framework of this study, the inductive analysis of voltage stability indices’ theoretical formulation, functionality, and overall performances are introduced. The prominence is given to investigate and compare the original indices from three main dimensions (formulation, assessment, and application) standpoints, which have been frequently used and recently attracted. The generalizability of an exhaustive investigation on comparison of voltage stability indices seems problematic due to the multiplicity of the indices, and more importantly, their variety in theoretical foundation and performances. This study purports the first-ever framework for voltage stability indices classification for power system analysis. The test results found that indices in the same category are coherent to their theoretical foundation. The paper highlights the fact that each category of the indices is functional for a particular application irrespective of the drawback ranking, and negated the ap...
Iraqi Journal for Electrical And Electronic Engineering
The continuously ever-growing demand for the electrical power causing the continuous expansion and complexity of power systems, environmental and economic factors forcing the system to work near the critical limits of stability, so research's stability have become research areas worthy of attention in the resent day. The present work includes two phases: The first one is to determine the Voltage Stability Index for the more insensitive load bus to the voltage collapse in an interconnected power system using fast analyzed method based on separate voltage and current for PQ buses from these of PV buses, while the second phase is to suggested a simulated optimization technique for optimal voltage stability profile all around the power system. The optimization technique is used to adjust the control variables elements: Generator voltage magnitude, active power of PV buses, VAR of shunt capacitor banks and the position of transformers tap with satisfied the limit of the state variables (load voltages, generator reactive power and the active power of the slack bus). These control variables are main effect on the voltage stability profile to reach the peak prospect voltage stable loading with acceptable voltage profile. An optimized voltage collapse based on Particle Swarm Optimization has been tested on both of the IEEE 6 bus system and the Iraqi Extra High Voltage 400 kV Grid 28 bus. To ensure the effectiveness of the optimization technique a comparison between the stability indexes for load buses before and after technical application are presented. Simulation results have been executed using Matlab software).
A critical review of the state-of-art schemes for under voltage load shedding
International Transactions on Electrical Energy Systems
A blackout is usually the result of increasing load beyond the transmission capacity of the power system. One of the main reasons for power blackouts is voltage collapse. To avoid this problem, the proper corrective measures called load shedding is required. In critical and extreme emergencies, under voltage load shedding (UVLS) is performed as a final remedy to avoid a larger scale voltage collapse. Therefore, UVLS is considered state of the art to achieve voltage stability. This review summarizes and updates the important aspects of UVLS; it also provides principle understanding of UVLS, which are critical in planning such defense schemes. Moreover, this article provides a discussion on recent state-of-art UVLS schemes applied in various power industries. Additionally, the pros and cons of the conventional and computational intelligence techniques are discussed. It is envisioned that this work will serve as one-stop information for power system engineers, designers, and researches.
Voltage Stability Assessment and Loss Minimisation by Power System Reconfiguration
https://www.ijrrjournal.com/IJRR\_Vol.6\_Issue.8\_Aug2019/Abstract\_IJRR0062.html, 2019
This paper represents a circuit theory approach for voltage stability assessment in an interconnected power system network. The basic methodology implied in this technique is the investigation of each line of the system by calculating line stability indices. Here, an interconnected IEEE 14-bus network has been reconfigured into 12-, 10-and 8-bus networks using graph theory. The line stability index and fast voltage stability indicators have been used for voltage stability assessment under normal and faulted conditions for the original IEEE 14-bus network and the reconfigured i.e. 12-bus, 10-bus and 8-bus networks. Genetic algorithm has been used to determine the optimal operating condition i.e. optimum value of line stability index and fast voltage stability index with best voltage stability for the original and the reconfigured networks. The voltage stability assessment under normal and faulted conditions can be efficiently determined for the reconfigured networks compared with the original network, this has been shown by the results. It analyses the performance of line stability indices. These indices were tested in IEEE 14 bus bar test systems, with satisfactory results. The effect of reconfiguration of 14 bus power system network on power losses in branches and computation time required for finding stability indices has been observed. Also the effect of reactive load variation on stability indices of respective buses and maximum allowable load or maximum loadability of bus is found.
Synchrophasor-Based Real-Time Voltage Stability Index
2006
This paper presents a new online voltage stability index (VSI) that predicts the power system steady-state voltage stability limit. Starting with deriving a method to predict three types of maximum transferable power (real power, reactive power, and apparent power) of a single-source power system, a new VSI based on the calculated load margins is devised. In order to apply the VSI to large power systems, a method is developed to simplify the large network behind a load bus into a single source and a single transmission line using time-synchronized phasor measurements and network parameters. The simplified system model, to which the devised VSI can be applied, preserves power flow and voltage information of the particular load bus under study. The proposed VSI combined with the network simplification method provides the voltage stability margin of each individual load bus in an informative format and identifies the load bus that is the most vulnerable to voltage collapse. Test results from applying the VSI on two test systems validate its applicability for online applications.
A new analysis method for early detection and prevention of cascading events
Electric Power Systems Research, 2007
This paper introduces a new analysis method for early detection and prevention of power system cascading events. It uses the vulnerability index (VI) and margin index (MI) to evaluate the vulnerability and security of the individual system parts, as well as the whole system during an operating state. It identifies the vulnerable parts of the power system using the topology processing and operation index methods. For a given disturbance, it calculates the power flow, evaluates the vulnerability and security, identifies the vulnerable part, finds the transmission line overload and bus voltage problems, and predicts the possible successive events. The approach defines the control means using the following methods for early detection and prevention of cascading events: network contribution factor (NCF), generator distribution factor (GDF), load distribution factor (LDF), and selected minimum load shedding (SMLS). This approach has been tested using the IEEE RTS-96 24-bus system and promising results have been obtained. The proposed approach allows the power system operator to detect initial stages of cascading events and assert actions that will prevent such events from unfolding.
Contribution of Distribution Network Control to Voltage Stability: A Case Study
IEEE Transactions on Smart Grid, 2015
A case study dealing with long-term voltage instability in systems hosting active distribution networks is reported in this paper. It anticipates future situations with high penetration of dispersed generation, where the latter are used to keep distribution voltages within desired limits, in complement to load tap changers. The interactions between transmission and active distribution networks are investigated on a 3108-bus test system. It involves transmission grid, large generators, and forty distribution networks, each with dispersed generation steered by a controller inspired of model predictive control. The reported simulations show the impact of distribution network voltage restoration as well as the benefit of load voltage reduction actuated by the dispersed generators.
IET Generation, Transmission & Distribution, 2014
Voltage stability improvement is a challenging issue in planning and security assessment of power systems. As modern systems are being operated under heavily stressed conditions with reduced stability margins, incorporation of voltage stability criteria in the operation of power systems began receiving great attention. This study presents a novel voltage stability constrained optimal power flow (VSC-OPF) approach based on static line voltage stability indices to simultaneously improve voltage stability and minimise power system losses under stressed and contingency conditions. The proposed methodology uses a voltage collapse proximity indicator (VCPI) to provide important information about the proximity of the system to voltage instability. The VCPI index is incorporated into the optimal power flow (OPF) formulation in two ways; first it can be added as a new voltage stability constraint in the OPF constraints, or used as a voltage stability objective function. The proposed approach has been evaluated on the standard IEEE 30-bus and 57-bus test systems under different cases and compared with two well proved VSC-OPF approaches based on the bus voltage indicator L-index and the minimum singular value. The simulation results are promising and demonstrate the effectiveness of the proposed VSC-OPF based on the line voltage stability index.