Loadability Of Lines Research Articles

Artificial Neural Network based FACTS in a Contingency Situation

The two biggest issues facing today's energy management systems are the ongoing monitoring of online voltage stability and the improved loadability of the transmission lines for the current electrical power system. As a result, it is highly difficult and time-consuming to assess online voltage stability under diverse loading conditions. This study describes a practical voltage stability monitoring system that automates online voltage monitoring and alerts the operator before voltage drops by computing line voltage stability indices using an ANN. This study compares evaluations of system voltage stability and loadability at the load with FACTS devices. The results suggest increase in system loadability while ensuring the security of power system operation.

Enhancing Loadability of Transmission Lines Using Static Synchronous Series Compensator Devices: A Case Study of the Syrian Network

Enhancing Loadability of Transmission Lines Using Static Synchronous Series Compensator Devices: A Case Study of the Syrian Network

L-M Based ANN for Predicting the Location of DG under Contingency Condition

The continuing monitoring of online voltage stability and the increased loadability of the transmission lines for the existing electrical power system are the two major challenges that today's energy management systems must deal with. As a result, evaluating online voltage stability under various loading situations is extremely challenging and time-consuming. The line voltage stability indices using an Artificial Neural Network (ANN), the system describes online voltage monitoring and warns the operator before voltage dips. The simulation's findings show that the proposed system may boost system loadability while also lowering the cost of installing an electrical power system and guaranteeing the security of power system operation.

Reduction of operational restrictions of the transmission system in electrical systems through facts implementation

Operational constraints cause an increase in complexity, operating cost, and environmental and socioeconomic impact on electrical systems; operational constraints can be due to power flow, voltage, or frequency deviations. These restrictions force the grid operator to perform unplanned actions. This article identifies the various Alternating Current Flexible Transmission Systems (FACTS) devices with their characteristics, attributes, and implementation methods to lessen operating constraints on isolated and relatively small transmission systems with frequent power flow limit violations and voltage deviations. The case study is carried out in the National Interconnected Electric System (SENI) of the Dominican Republic, where the Fast Stability Voltage Index is used as an indicator to see the impact of the implementation of FACT to mitigate the operational restrictions of the electric system. Simulations are performed in the PowerFactory DIgSILENT software to obtain the results when modeling the interconnected FACTS devices on the transmission lines. The use of FACTS reduces the loadability of transmission lines, which is an essential factor in the emergence of power flow control and voltage constraints in isolated power systems.

The estimation of transmission line loadability Based on Artificial Intelligence Algorithm & Voltage Stability Index

The continuous changes in electricity demand and supply are contributing to the disparity in quantities of power transferred between transmission networks, i.e. some lines are lightly loaded and others are overloaded. This presents a significant challenge to the secure and reliable operation of the power system. The current research is concerned with enhancing the loadability of electric transmission lines, that secure the increase in load demand through Flexible AC Transmission System (FACTS) injection. This paper is focused on the -Thyristor Controlled Series Compensator (TCSC), the optimum location of the TCSC was determined by applying two different techniques. The first technique was based on an artificial intelligence algorithm while the second technique was based on the level of voltage stability indices for all system lines. The optimal location is based on the fulfillment of multi-objective functions represented by an increase in the load capacity, reduce levels of the voltage stability index, the cost of installing the TCSC, and the voltage deviation. The IEEE-9 bus standard test system as a study case and MATLAB-programmes has been used for the analysis of the optimal power flow, and estimating the loadability of transmission lines without and with TCSC.

Effect of Dynamic Line Ratings on Optimal Dispatch Considering Uncertainty Costs due to Intermittent Renewable Energy

Abstract Dynamic line ratings (DLRs) provide a more flexible use of power transmission networks by reducing the conservativeness of transmission line loadability constraints. The reduced system congestion due to increased loadability of lines monitored for DLR would allow for more economical generation scheduling. This paper analyses the impact that DLR would have on power dispatch with a specific assessment of the allowable uncertainty levels due to IRE generation in a power network. This is done using a solution of an optimal dispatch problem that includes costs due to uncertainty of IRE sources and DLR of monitored lines. Simulation results carried out on a benchmark test system show that the savings occasioned by reduction in conventional generation costs due to DLR can allow for increasing the uncertainty levels in power networks which would translate to increased use of IRE sources.

The Loadability of Overhead Transmission Lines—Part II: Analysis of Double-Circuits and Overall Comparison

This is the second part of an investigation aimed at providing a thorough technical comparison between traditional and alternative overhead power transmission lines based on the loadability characteristics. The previous Part I outlined and applied the fundamentals of the loadability analysis to three comparable single-circuit lines. In Part II, the analysis is broadened to three comparable double-circuit lines: traditional three-phase ac double-circuit lines (assumed as the reference system for the comparison) and bipolar HVDC lines and nonconventional combined ac-dc lines. As in Part I, the loadability analysis takes into account thermal limits, voltage drop, power losses, and - when feasible - steady state and transient stability. Part II also performs an overall comparison among the different systems in single-circuit and double-circuit configuration to draw final conclusions.

Comparative study of GA & DE algorithm for the economic operation of a power system using FACTS devices

Abstract The problem of improving the voltage profile and reducing power loss in electrical networks must be solved in an optimal manner. This paper deals with comparative study of Genetic Algorithm (GA) and Differential Evolution (DE) based algorithm for the optimal allocation of multiple FACTS (Flexible AC Transmission System) devices in an interconnected power system for the economic operation as well as to enhance loadability of lines. Proper placement of FACTS devices like Static VAr Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC) and controlling reactive generations of the generators and transformer tap settings simultaneously improves the system performance greatly using the proposed approach. These GA & DE based methods are applied on standard IEEE 30 bus system. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is observed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. GA and DE based algorithm is then applied to find the amount of magnitudes of the FACTS devices. Finally the comparison between these two techniques for the placement of FACTS devices are presented.

VSI‐based series compensation scheme for transmission lines

AbstractThis paper addresses the loadability of long transmission lines. An advanced series compensation scheme is presented consisting of a series‐connected voltage‐sourced inverter and fixed series‐capacitors. This scheme provides substantial increase of the line loadability beyond that achievable with fixed capacitive compensation alone. In addition, it provides smooth power‐flow control. Results from simulation studies demonstrate its effectiveness in improving the loadability of long transmission lines and providing damping of interarea oscillations.

Improvement of transient stability limit in power system transmission lines using fuzzy control of FACTS devices

The objective of this paper is to investigate the application of FACTS devices to increase the maximum loadability of the transmission lines which may be constrained by a transient stability limit. Hence, the on-line fuzzy control of the superconducting magnetic energy storage (SMES) and the static synchronous series compensator (SSSC) are suggested. The fuzzy rule-bases are defined and explained. The validity of the suggested control strategies are confirmed by simulation tests. The simulation results show that by the use of the proposed method, the line power transfer can be increased via the improvement of the transient stability limit. Finally, the effect of the control loop time delay on the performance of the controller is presented.

Advanced static compensator for flexible AC transmission

An advanced static VAr compensator capable of operating in all four quadrants of the P-Q plane is presented. It is realized by combining a GTO-controlled inverter with a battery energy storage system and a GTO-switched damping resistor. A hierarchically structured control system that fully utilizes the capabilities of the compensator to provide reactive power support in steady-state operation and both real and reactive power modulation in the event of power oscillations is developed. Results from simulation studies are presented to demonstrate the effectiveness of this compensator in improving the loadability of long transmission lines and in providing damping in interarea oscillations.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effect of a modulated HVDC link on power system transients

This paper presents the details of a digital computer study of the effects of transient interactions, during large system disturbances, between an AC system and an associated high voltage DC transmission line with the rapid change in power transfer capability (modulated HVDC). The combined system consists of a large turboalternator synchronized to an infinite bus through two long-distance high voltage AC lines in parallel with an equally long controlled HVDC link. In the analysis, a rigorous nonlinear mathematical model, based on Park's equations, is formed by transforming the machine variables and the AC and DC transmission line parameters to a rotating reference frame attached to the alternator rotor, thereby providing the detailed transient behavior of the interconnected AC/DC system. Results of the studies demonstrate that a modulated HVDC link can provide significant increases in the loadability of AC lines by reducing or eliminating the constraints imposed by transient stability limitations. It appears, however, that, for certain systems, adverse stability behavior may result if the modulation setting exceeds 50%. Possible effects of HVDC modulation on the incidence of turboalternator torsional interactions are also considered. These interactions, however, are dependent upon parameters such as AC transmission, configuration, and the control mode characteristics of the HVDC terminals.

Analytical Development of Loadability Characteristics for EHV and UHV Transmission Lines

This paper contains the development of an analytical basis for the St. Clair line loadability curve and presents the extension of its use into the EHV and UHV transmission area. A brief historical background describes the origin and pertinent aspects of the St. Clair curve including the fact that the old curve, originally intended for transmission voltages up to 330-kV, is derived empirically based upon practical considerations and experience. In order to extend the usefulness of such line loadability characteristics into the EHV and UHV range, a simplified representation of the system, which incorporates flexibility to include both line and system parameters, is utilized to compute maximum line loadability subject to assumed system performance criteria. It is shown that, for a reasonable and consistent set of assumptions, with regard to system parameters and performance criteria, EHV and UHV transmission line loadability characteristics are nearly identical to the original St. Clair curve. The paper further illustrates the relative influence of these assumptions on the derived characteristics, In particular, the electrical strength of the sending- and receiving-end systems is found to have an increasingly important influence on the loadability of transmission lines as the voltage class increases. The analytical approach to determination of transmission line loadability curves enables the user to examine specific situations and assumptions and to avoid possible misinterpretation of generalized conceptual guides-particularly in the EHV/UHV range where system parameters can have a significant impact on loadability.