Stability Of Transmission Lines Research Articles

Mitigating Low-Frequency Oscillations and Enhancing the Dynamic Stability of Power System Using Optimal Coordination of Power System Stabilizer and Unified Power Flow Controller

The integration of a flexible alternating current transmission system (FACTS) and a power system stabilizer (PSS) can increase dynamic stability. This paper presents the enhancement of power system dynamic stability through the optimal design of a power system stabilizer and UPFC using an ant lion optimization (ALO) technique to enhance transmission line capacity. The gained damping ratio, eigenvalue and time domain results of the suggested ALO technique were compared with a base case system, ALO-based PSS and ALO-based PSS-UPFC to test the effectiveness of the proposed system in different loading cases. Eigenvalues gained from an ant lion approach-based UPFC with a PSS and a base case system are compared to examine the robustness of the ALO method for various loading conditions. Thus, this paper addresses the mechanism regarding the power system dynamic stability of transmission lines by integrating the optimal size of a PSS and UPFC into the power system. Therefore, the main contribution of this manuscript is the optimal coordination of a power system stabilizer, power oscillation damper and unified power flow using ant lion optimization for the mitigation of low-frequency oscillation.

The feasibility of continuous basalt fibre‐reinforced polymer application to composite cross‐arms

AbstractComposite cross‐arms have the advantages of high lightning resistance but impose onerous requirements on mechanical and insulation reliability. Traditional glass fibre composites fail to meet the needs of practical applications. Basalt fibre exhibits better mechanical properties and stability than glass fibre and has potential application value. This study aims to evaluate the feasibility of its application to composite cross‐arms. The mechanical, electrical, and physical properties of basalt fibre‐reinforced polymer (BFRP) were investigated and compared with glass fibre‐reinforced polymer (GFRP). The results indicate that BFRP has better thermal stability and mechanical properties than GFRP. Among them, the temperature at the maximum weight loss rate of BFRP is 14°C higher than that of GFRP, and the tensile and flexural modulus of BFRP is 43% and 29% higher than those of GFRP. Furthermore, the dielectric losses of BFRP and GFRP at 50 Hz are 2%, and the breakdown field strength is 22 kV/mm, both of which have the same insulation properties. BFRP meets the requirements of composite cross‐arm for quality and reliability to ensure the safety and stability of transmission lines. However, the interlaminar shear test and SEM show weak interfacial bonding strength between basalt fibre and resin. Furthermore, micro‐computed tomography scanning of BFRP and GFRP and 3D construction of their internal microstructures indicate that the pore defect content of BFRP reaches 0.034%, which far exceeds that of GFRP. These findings show that the wettability and adhesion between basalt fibre and resin must be improved. Developing special sizing agents for basalt fibre is necessary further to improve the mechanical and electrical properties of BFRP.

Research on the Application of Computer Vision Technology in Power System UAV Line Inspection

The stability of transmission lines is one of the important factors to ensure stable power supply. In this paper, a set of UAV intelligent power line inspection flight control system is designed according to the special flight requirements of UAV in power line inspection operation based on the principle of photogrammetry. The key technologies of the system include UAV flight attitude control, high-precision time synchronization between multiple sensors, defect detection and intelligent diagnosis, airborne sensor calibration, wireless communication, and ground data processing. In this paper, a camera and an on-board computer are innovatively used for real-time image processing and pattern recognition for wire feature acquisition. At the same time, this paper proposes an improved Canny edge detection algorithm combined with image segmentation technology to achieve wire feature extraction and identification. The field test results show that the system can complete the remote control of the UAV and realize the intelligent navigation and inspection of the transmission line UAV.

Classification of Transmission Line Ground Short Circuit Fault Based on Convolutional Neural Network

Ground short circuit faults in current transmission lines are common in the power systems. In order to prevent the power system from aggravating the accident caused by short-circuit faults of transmission lines, a novel convolutional neural network (CNN) model is constructed to identify the short-circuit fault of the transmission line in the power system. The CNN model is mainly consisted of five convolutional layers, three max-pooling layers, one concatenate layer, one dropout layer, one fully connected layer, and a Softmax classifier. This method uses a fixed time window to intercept system short-circuit fault data, extracts the deep features of these data from the training samples, and then corresponds the extracted features to labels one-to-one. Finally, in PSCAD/EMTDC, the new England 10 machine 39 nodes are taken as an example to realize the simulation. The experimental results show that the CNN model can quickly and accurately identify the short-circuit fault types, and the optimal model accuracy rate reaches 99.95%. The results of this manuscript -have positive effect on enhancing the disaster prevention capability and the operation stability of transmission lines.

Discussion and analysis on corrosion causes of metallic components used in transmission tower

With the rapid development of power grid and the continuous aggravation of heavy industry pollution, more and more attention would be paid to the corrosion of metallic components of transmission line. The chemical and electrochemical corrosion of transmission tower and its fittings would shorten the service life. Therefore, it requires regular anti-corrosion coating treatment or even overall replacement, which not only wastes a lot of financial and material resources, but also causes safety accidents. In this paper, different testing methods such as macro inspection, metallographic analysis and energy spectrum analysis were adopt to investigat and analyse corrosion behaviour of cotter pin, fitting, guyed rod and angle steel used in transmission tower. Additionally, corresponding anti-corrosion measures were put forward in order to improve the anti-corrosion performance of the metallic components and guarantee the safety and stability of transmission line.

Risk Analysis of Transmission Line Patrol Based on DEMATEL Method

As the scale of power network construction increases, transmission lines that undertake transmission tasks are facing greater challenges in patrol and maintenance work. Therefore, analyzing the factors that affect transmission line patrol and maintenance has become an urgent problem in the power industry. This paper analyzes the influencing factors from the four dimensions of natural risk, transmission operation risk, transmission line risk, and other man-made risks, and uses the DEMATEL analysis method to identify the relationship between different factors, and obtains the key influencing factors, and then proposes Corresponding strategies to deal with the risk of transmission line patrol, hope to have a certain reference effect on the patrol work, so as to ensure the stability of transmission lines.

An Insulator in Transmission Lines Recognition and Fault Detection Model Based on Improved Faster RCNN

Insulators are critical electric components in transmission lines. Recognizing insulators and detecting the faults timely and accurately is essential for maintaining the safety and stability of transmission lines. Traditional methods have low accuracy and poor applicability in insulator recognition and fault detection. An insulator recognition and fault detection model was proposed in the article aiming at improving the insulator recognition and fault detection accuracy. First, based on the faster region convolutional neural network (RCNN), the feature pyramid networks (FPNs) were used to improve the Faster RCNN model and locate the insulators with complex background image. Then, the target area was clipped to remove the redundant background noise, and the hue, saturation, and value (HSV) color space adaptive threshold algorithm was applied for image segmentation due to the influence of light, background noise, and shooting angle. Finally, line detection, image rotation, and vertical projection were used to finish the insulator fault detection. The experimental results show that the proposed insulator recognition and fault detection model can recognize the insulators and detect fault types with better accuracy and achieve a mean average precision (mAP) of 90.8% for glass insulators and 91.7% for composite insulators on the testing dataset. Additionally, the proposed method meets the intelligent inspection of insulator faults in transmission lines and has good engineering application value.

Stability Evaluation of the Transmission Line by using Galloping Simulation

Galloping phenomenon is one of the vibrations caused by icing. If galloping phenomenon continues, short-circuit or ground fault may occur, so analysis of galloping phenomenon through research on transmission line stability is necessary. The DenHartog method, which is frequently used for the galloping stability determination of the transmission line, considers only the vertical movement of the transmission line. In this study, we analyze the motion of multi-degree-of-freedom objects, using a computer aided engineering program. We modeled transmission lines as a multi mass-spring-damper systems using RecurDyn, which is a multibody commercial dynamics analysis program to analyze the galloping phenomenon dynamically. Damping inside transmission line derived from the Rayleigh damping theory through the free vibration experiment of transmission line. ANSYS Fluent, a flow analysis program, was used to derive the aerodynamic coefficients for transmission line with asymmetric cross-section. Using the derived aerodynamic coefficient, we confirmed the galloping occurrence condition of DenHartog method and modeled the wind load acting on the transmission line to conduct galloping simulation. Through the analysis of the motion of a multi-degree-of-freedom transmission line, the occurrence of galloping was classified into ovoid and vertical trajectories, and the case of no galloping was defined as regular trajectory, and the range of angle of attack that causes the instability of transmission lines was defined.

Analysis of Transmission Line Stability for Sulselbar Interconnection System with the Penetration of Renewable Energy to Prevent Voltage Collapse

There are three main requirements to meet the criteria both in the electric power system, namely reliability, quality, and stability. Stability is the ability of the system to return to work normally after experiencing interference. System stability analysis is a guide for operators to detect or prevent voltage drops and power outages. This research discusses the stability of the 150 KV electrical system in South Sulawesi before and after interconnection with the Sidrap and Jeneponto Wind Power Plant. The method used is the Line Stability Index (Lmn Index) to view the voltage profile. Index Lmn coding is run and simulated using Matlab. Validation is done by IEEE 14 bus simulation data, and comparing the results of the analysis before and after penetration with PLTB. The study was conducted on the Sulselbar 150 KV system before penetration with PLTB, namely 44 buses, 14 generators, and 52 lines / networks. The highest Lmn index result is the network from bus 38 to bus 39 that is equal to 0.0292. Second is bus 15 to bus 16 which is 0.0291, and third is bus 40 to 42 that is 0.0273. After penetration with PLTB Sidrap and Jeneponto, the number of generators will be 16 generators. The highest Lmn index results are from bus 38 to 39 that is 0.0292, then bus 15 to bus 16 that is 0.0290 ranks second, and bus 40 to 42 equals 0.0272 or keeps the third order. After the sidrap load bus is converted to a bus generator, the Lmn index before in reactive power supplied to the load by a generator is a certain thing, this condition must be maintained so that the plant continues to work in stable conditions.

Monitoring and Risk Assessment of Wildfires in the Corridors of High-Voltage Transmission Lines

The scale of China's power grid is becoming larger and larger, more and more high-voltage long-distance overhead transmission lines are exposed to the wild environment. Wildfire disasters seriously threaten the safety and stability of transmission lines. In order to monitor and warn the fire points that may affect the operation of the transmission line in advance, this research is carried out. Suomi National Polar-orbiting Partnership (Suomi NPP) polar orbiting satellite and Himawari-8 geostationary satellite are used to monitor wildfires in a complementary manner, combined with improved relative threshold and adaptive dynamic threshold to identify fire points based on background radiation information. Then, a fire risk assessment system based on the entropy weight method and variable weight theory for transmission line corridors was constructed from four aspects: meteorology, underlying surface, topography and power grid. Engineering practice shows that the method proposed in this study effectively monitors and scientifically warns wildfires in the transmission line corridor, which greatly reduces the losses and working pressure caused by wildfires.

Transient Stability Analysis of 33 KV Transmission Network of Egi Community, Nigeria

Transient analysis of 33 KV power transmission line stability of Egi communi-ty is considered in this research work with the aim of reducing the frequency of fault occurrence and voltage collapse in the network. The supply is taken from Egi generating station located at Total Nigeria Limited Gas Plant Obite at voltage level of 33 KV to Egi communities. This work focuses on the transient nature of network stability since transient fault is the most dangerous in elec-trical systems. The swinging of the generator rotor in the event of transient three-phase short circuit fault can be monitored by the circuit breakers and the protective relays which causes mal-functioning of the circuit breakers and pro-tective relays leading to abnormal behavior of the network. Therefore, data obtained from the power station were used as a case study of Independent Power Producer (IPP) in Nigeria. For investigation of the power angle, angular velocity, rotor angle differential changes, and angular velocity differential changes, an electrical transient analyzer tool was employed (ETap version 16.00) for circuit breaker and protective relay time setting of (0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60). The work used the Trapezoidal numerical technique for data analysis. The graphs were plotted using Matlab R2015a and the results obtained showed that when a symmetrical three-phase short circuit fault occur at one or any of the feeders, the fault must be cleared as quick as possible through the coordination of the circuit breakers and protective relays. For this research work, 17 cycles corresponding to relay time setting of t = 0.34 s were recommended and at each cycle, changes in time with respect to changes in rotor angle, angular velocity, rotor differential and angular velocity differential were calculated on the power network simultaneously. The results demonstrated that the Trapezoidal method is numerically stable, accurate and has faster respond time when compared to Modified Euler and swing equation techniques in event of fault occurrence in network.

Transmission Line Monitoring System Based on Beidou High Precision Positioning Technology

The tower deformation, ground deformation and environmental changes of transmission lines in unmanned or undermanned areas have serious impact on the safety and stability of transmission lines. At the same time, the condition of transmission lines is difficult to transmit to monitoring centers in unmanned areas with weak signals. Aiming at this phenomenon, a transmission line monitoring system based on Beidou high precision positioning technology is proposed. The system can sense the tower deformation, ground deformation and environmental change of transmission line through image sensor, temperature and humidity sensor, rainfall sensor and wind speed sensor, and then realize the data transmission and location function through Beidou high-precision positioning technology. The designed system has the characteristics of high accuracy, fast transmission speed and low power consumption.

An optimal voltage stability enhancement in the power systems by locating optimal place with more contingency risk

The electrical components of a power system network take advantage to supply, transmission and service electrical power. Abnormal flow of voltage through the transmission lines might lead to big causes. Thyristor controlled series compensator (TCSC) devices are most frequently used device in the power to maintain the voltage stability. However, this device is costlier and cannot be fixed on every transmission line which would lead to more processing cost. Thus, the maintaining voltage stability of transmission lines with reduced production cost attracts a various researcher to find the novel approaches. In the existing system, to improve the stability of power system and minimize the losses by include the reactive power through TCSC device at applicable location by the algorithm of particle swarm optimization is available with the help of line stability index value. The PSO is constrained to poor exploitation problem which might generate inaccurate results. In the proposed research work, Biogeography Based Krill Herd (BBKH) method is used for optimal identification of TCSC's, STATCOM and UPFC size and location. Voltage collapse proximity indicator (VCPI) value is used in this work for the finding of the voltage instability measurement by finding the critical lines among the entire transmission lines. The proposed research effort is implemented in IEEE 39 test bus system using MATLAB software and verified, it furnishes improved outcome than other investigation methodologies.

An Optimal Voltage Stability Enhancement in the Power Systems by Locating Optimal Place with More Contingency Risk

The electrical components of a power system network take advantage to supply, transmission and service electrical power. Abnormal flow of voltage through the transmission lines might lead to big causes. Thyristor controlled series compensator (TCSC) devices are most frequently used device in the power to maintain the voltage stability. However, this device is costlier and cannot be fixed on every transmission line which would lead to more processing cost. Thus, the maintaining voltage stability of transmission lines with reduced production cost attracts a various researcher to find the novel approaches. In the existing system, to improve the stability of power system and minimize the losses by include the reactive power through TCSC device at applicable location by the algorithm of particle swarm optimization is available with the help of line stability index value. The PSO is constrained to poor exploitation problem which might generate inaccurate results. In the proposed research work, Biogeography Based Krill Herd (BBKH) method is used for optimal identification of TCSC's, STATCOM and UPFC size and location. Voltage collapse proximity indicator (VCPI) value is used in this work for the finding of the voltage instability measurement by finding the critical lines among the entire transmission lines. The proposed research effort is implemented in IEEE 39 test bus system using MATLAB software and verified, it furnishes improved outcome than other investigation methodologies.

Modern Analysis of Power Flow and Network Stability of Transmission Lines for Nuclear Power Dispatch

This article presents an general approach to improve the power system planning, load flow pattern and stability of transmission lines using modern analysis concept. The objective is to categorize and characterize the existing system reliability concerns inherited from the adopted deterministic criteria, so that power utilities can accordingly adjust their reliability criteria to manage with real-life system uncertainties and hence to improve the overall system reliability. In the past many wide spread blackouts had occurred in interconnected power systems. Therefore it is necessary to ensure that grid should be operated economically and reliably. Contingency analysis is a well-known function in modern power system management. The aim of this analysis is to give the operator information about the static security, power flow pattern and stability. In general an outage largest capacity of one transmission line or transformer may lead to disturb the vital parameters in other lines. Modern analysis is used to calculate the violation on the network and improvement. Nuclear power plant is a base unit and best way to dispatch the power to the grid with minimum disturbance. This paper also shows the network stability, power flow management for 500MW Nuclear power plant transmission lines and connected to southern region network of India.

EFFECT of DG Optimizing on overload Transmission line Stability

Typical steady state studies always treat the peak power demands as the worst case conditions. Periods of light load are also critical in the assessment of the possible state of a power system. While heavy load conditions are generally associated with overload, low voltage and generation deficiency, light load conditions may give rise to over-voltage and undesirable reactive power requirements at generation side. This paper focus on study the effect of DG Optimizing on overload Transmission line Stability. The system dispatch constraints should be taken into account to compensate or varying DG generation output and to enhance the operational performance of power systems. This dispatching operation depends on the change of DG generation and the dispatching strategy. The impact of DG generation uncertainty is limited with the generation dispatching operation and should not be neglected in system analysis.

Leakage Current Based Thermal Modeling of Glass Disc Insulator Surface

The stability of transmission lines relies on the health of the insulators, such as glass string insulators, which may occasionally flashover during an overvoltage. The likelihood of flashover increases notably when the glass insulator is wrapped by a wet contaminant layer. In this paper a study of the surface thermal profile of glass disc insulators insulation had been carried out for both clean and polluted surfaces. A finite-element simulation with time dependent model was carried out using COMSOL Multiphysics software. The variation of the insulator surface temperature with applied voltage as well as with pollution layer thickness is explained. The results illustrate the significant effect of pollution conductivity on heat propagate along the surface of the glass insulators with the increase higher voltages' magnitudes. Study of the aging level impact on a steady state thermal for glass insulation surface is also carried out.

EFFECT of DG Optimizing on Overload Transmission Line Stability

Background: Typical steady state studies always treat the peak power demands as the worst case conditions. Periods of light load area also critical in the assessment of the possible state of a power system. While heavy load conditions are generally associated with overload, low voltage and generation deficiency, light load conditions may give rise to over-voltage and undesirable reactive power requirements at generation side. Method: This paper focus on study the effect of DG Optimizing on overload Transmission line Stability. The system dispatch constraints should be taken into account to compensate for varying DG generation output and to enhance the operational performance of power systems. Findings: This dispatching operation depends on the change of DG generation and the dispatching strategy. The impact of DG generation uncertainty is limited with the generation dispatching operation and should not be neglected in system analysis. Application: distributed generators based wind turbine to investigate the effect of DG on Transmission line stability.

A Line Utilization Factor and Krill Herd Algorithm based Optimal Utilization of Interline Power Flow Controller for Congestion Management

In order to increase transmission line stability, control power flow and improve the security of transmission systems FACTS technology has been extensively employed. And these devices must be optimally placed in the transmission systems for their best usage. In this paper to control the congestion in the transmission lines we use DLUF (Disparity Line Utilization Factor) for the appropriate placement of IPFC. The difference between the percentages MVA utilization of each line connected to the same bus is determined by the DLUF. The IPFC is placed in the lines with maximum DLUF. Krill Herd Algorithm has been used for optimal tuning of IPFC for a multi objective function. The multi objective function comprises of minimization of active power loss, security margin, voltage deviation and capacity of installed IPFC. The effectiveness of proposed method is tested for IEEE–30 bus test system.

Analyzing the Effect of Wind Farm to Improve Transmission Line Stability in Contingencies

Todays, contingency analysis is being used to predict the effect of line outages in power system operation. This analysis is mostly offline to predict the line outage effects on the blackout of power system. To investigate the grid’s sensitivity to each line outage, power flow equations are analyzed. The ranking process of line outage and their effects on the other lines overloading is done by calculating an index (PI MVA) which represents the sum of deviations of each line power from the maximum rating of the line. Furthermore the effect of wind farm connection to the grid is investigated to improve the sensitivity of the grid in line outage contingencies. The effectiveness of the method is tested on IEEE-14 Bus standard benchmark. The simulations are done, using ETAP software. Keywords: Contingency, PV Bus, PQ Bus, Slack Bus, Wind Farm