scholarly journals Research on wind load characteristics of conductors in transmission lines of Gansu power grids

2018 ◽  
Vol 199 ◽  
pp. 052047
Author(s):  
Shang Yadong ◽  
Li Peng ◽  
Su Junhu ◽  
Bao Chengjia ◽  
Wang Feixing ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Wind Load ◽  
Power Grids ◽  
Load Characteristics

scholarly journals Experimental Study on Glaze Icing Detection of 110 kV Composite Insulators Using Fiber Bragg Gratings

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1834
Author(s):  
Jie Wei ◽  
Yanpeng Hao ◽  
Yuan Fu ◽  
Lin Yang ◽  
Jiulin Gan ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Temperature Compensation ◽  
Fiber Bragg Gratings ◽  
Polar Angle ◽  
Bragg Gratings ◽  
Strain Sensors ◽  
Power Grids ◽  
Wavelength Shift ◽  
Detection Technology ◽  
Load Characteristics

Icing detection of composite insulators is essential for the security and stability of power grids. As conventional methods have met difficulties in harsh weather, a 110 kV composite insulator with embedded Fiber Bragg Gratings (FBGs) was proposed for detecting glaze icing in this paper. FBG temperature compensation sensors in ceramic tubes were adopted for simultaneous measurement of icicle loads and temperature. Then, temperature calibration experiments and simulated icicle load experiments were carried out to obtain temperature and icicle load characteristics of FBGs. The results showed that temperature sensitivities of FBG strain sensors and FBG temperature compensation sensors were 18.16 pm/°C, and 13.18 pm/°C, respectively. Besides, wavelength shifts were linearly related to icicle loads within the polar angle range of −60° to 60°, and the load coefficient of FBG facing the icicle was -34.6 pm/N. In addition, the wavelength shift generated by several icicles was equal to the sum of wavelength shifts generated by each icicle within the polar angle range of −15° to 15°. Finally, icicles can cause wavelength shifts of FBGs within a big shed spacing. The paper provides a novel icing detection technology for composite insulators in transmission lines.

scholarly journals Probabilistic Vulnerability Assessment of Transmission Lines Considering Cascading Failures

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1994
Author(s):  
Yanchen Liu ◽  
Minfang Peng ◽  
Xingle Gao ◽  
Haiyan Zhang
Keyword(s):  
Transmission Lines ◽  
Large Scale ◽  
Failure Process ◽  
Power Grids ◽  
Weak Links ◽  
Cascading Failure ◽  
Cascading Failures ◽  
Stable Operation ◽  
Chain Model ◽  
Systems Research

The prevention of cascading failures and large-scale power outages of power grids by identifying weak links has become one of the key topics in power systems research. In this paper, a vulnerability radius index is proposed to identify the initial fault, and a fault chain model of cascading failure is developed with probabilistic attributes to identify the set of fault chains that have a significant impact on the safe and stable operation of power grids. On this basis, a method for evaluating the vulnerability of transmission lines based on a multi-criteria decision analysis is proposed, which can quickly identify critical transmission lines in the process of cascading failure. Finally, the proposed model and method for identifying vulnerable lines during the cascading failure process is demonstrated on the IEEE-118 bus system.

scholarly journals An Optimized Coordination Strategy between Line Main Protection and Hybrid DC Breakers for VSC-Based DC Grids Using Overhead Transmission Lines

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1462 ◽  
Author(s):  
Zheng ◽  
Jia ◽  
Gong ◽  
Zhang ◽  
Pei
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Short Circuit ◽  
Power Grids ◽  
Fault Line ◽  
Long Distance ◽  
Coordination Strategy ◽  
Overhead Transmission Lines ◽  
Depth Analysis ◽  
Dc Breaker

Compared with alternating current (AC) power grids, the voltage-sourced converter (VSC)-based direct current (DC) grid is a system characterized by “low damping”, as a result, once there is a short-circuit fault on the DC transmission line, the fault current will rise more sharply and the influence range will be much wider within the same time scale. Moreover the phenomenon that a local fault causes a whole power grid outage is more likely to occur. Overhead transmission lines (OHLs) have been regarded as the mainstream form of power transmission in future high-voltage, large-capacity and long-distance VSC-based DC grids. However, the application of overhead transmission lines will inevitably lead to a great increase in the probability of DC line failure. Therefore, research on how to isolate the DC fault line quickly is of great significance. Based on the technology route for fault line isolation using DC breakers, on the basis of in-depth analysis of traditional coordination strategy, an optimized coordination strategy between line main protection and a hybrid DC breaker for VSC-based DC grids using overhead transmission lines is proposed in this paper, which takes the start-up output signal of line main protection as the pre-operation instruction of the corresponding hybrid DC breaker. As a result, the risks of blockage of the modular multilevel converter (MMC) closer to the fault position and of damage to power electronic devices in main equipment can be reduced effectively. Finally, the proposed coordination strategy was verified and analyzed through simulation.

scholarly journals A Classification Method for Transmission Line Icing Process Curve Based on Hierarchical K-Means Clustering

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4786
Author(s):  
Yanpeng Hao ◽  
Zhaohong Yao ◽  
Junke Wang ◽  
Hao Li ◽  
Ruihai Li ◽  
...  
Keyword(s):  
Prediction Model ◽  
Transmission Lines ◽  
Prediction Models ◽  
Power Grids ◽  
Curve Shape ◽  
Clustering Method ◽  
Characteristic Parameters ◽  
Prediction Ability ◽  
Icing Prediction

Icing forecasting for transmission lines is of great significance for anti-icing strategies in power grids, but existing prediction models have some disadvantages such as application limitations, weak generalization, and lack of global prediction ability. To overcome these shortcomings, this paper suggests a new conception about a segmental icing prediction model for transmission lines in which the classification of icing process plays a crucial role. In order to obtain the classification, a hierarchical K-means clustering method is utilized and 11 characteristic parameters are proposed. Based on this method, 97 icing processes derived from the Icing Monitoring System in China Southern Power Grid are clustered into six categories according to their curve shape and the abstracted icing evolution curves are drawn based on the clustering centroid. Results show that the processes of ice events are probably different and the icing process can be considered as a combination of several segments and nodes, which reinforce the suggested conception of the segmental icing prediction model. Based on monitoring data and clustering, the obtained types of icing evolution are more comprehensive and specific, and the work lays the foundation for the model construction and contributes to other fields.

Seismic Design Scope of Tower Structures for UHV Transmission Lines on the Zone of Earthquake Fortification Intensity 8

2012 ◽  
Vol 446-449 ◽  
pp. 3730-3735
Author(s):  
Ni Na Zheng ◽  
Ying Min Li ◽  
Jing Zhao ◽  
Zheng Lun Chen
Keyword(s):  
Seismic Design ◽  
Transmission Lines ◽  
Structural Design ◽  
Wind Load ◽  
Seismic Action ◽  
Action Effects ◽  
Overhead Transmission Line ◽  
Control Load ◽  
Intensity Region ◽  
Uhv Transmission Lines

The seismic action effects of tower structures for ultra-high-voltage(UHV, upon 750KV) overhead transmission lines are much greater than those of 500KV and below, it is necessary to inspect the control load in structural design and specify the seismic design scope of tower structures for these UHV transmission lines. In this paper, the current regulations of seismic design and non-seismic design of tower structures for overhead transmission line were contrasted firstly; then, a series of typical towers including large-crossing towers and cup-towers at soft sites, on the zone of earthquake fortification intensity region of 8, were analyzed. The ratios of seismic action effects and wind load effects for characteristic value were calculated and the control load in structural design of tower structure was investigated. The results show that, although the height and the weigth of tower structures for UHV transmission lines are increasing, the control load in structural design is still the wind load on the zone of earthquake fortification intensity region of 8 and below.

Development of a Software Tool for Calculating Transmission Line Parameters and Updating Related Databases

2014 ◽  
Vol 15 (6) ◽  
pp. 513-526
Author(s):  
Wanjing Xiu ◽  
Yuan Liao
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Software Tool ◽  
Power Grids ◽  
System Model ◽  
Software Packages ◽  
Essential Components ◽  
Simulation Based ◽  
Electric Power Grids

Abstract Transmission lines are essential components of electric power grids. Diverse power system applications and simulation based studies require transmission line parameters including series resistance, reactance, and shunt susceptance, and accurate parameters are pivotal in ensuring the accuracy of analyses and reliable system operation. Commercial software packages for performing power system studies usually have their own databases that store the power system model including line parameters. When there is a physical system model change, the corresponding component in the database of the software packages will need to be modified. Manually updating line parameters are tedious and error-prone. This paper proposes a solution for streamlining the calculation of line parameters and updating of their values in respective software databases. The algorithms used for calculating the values of line parameters are described. The software developed for implementing the solution is described, and typical results are presented. The proposed solution is developed for a utility and has a potential to be put into use by other utilities.

scholarly journals Research on the decision of state maintenance for transmission line based on set pair analysis

2021 ◽  
Vol 71 (1&2) ◽  
pp. 17
Author(s):  
Shiyang Zhu ◽  
Le Wang
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Grids ◽  
Financial Control ◽  
Set Pair Analysis ◽  
Overhead Transmission Lines ◽  
Maintenance Work ◽  
Maintenance Decision ◽  
Pair Analysis

Overhead transmission lines are important parts of a power system; their operation state directly affects the reliability level of the entire power system. With the in-depth development of state maintenance work for power grids, correctly evaluating the reliability of overhead transmission lines is the key to successful maintenance. A maintenance decision model for transmission lines is established in this study based on set pair analysis to achieve human financial control and low maintenance efficiency. Full consideration is provided to the influence of environmental factors, and a theoretical basis for transmission line maintenance decision is established.

scholarly journals Prediction of geomagnetically induced currents (GICs) flowing in Japanese power grid for Carrington-class magnetic storms

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Yusuke Ebihara ◽  
Shinichi Watari ◽  
Sandeep Kumar
Keyword(s):  
Transmission Lines ◽  
Power Grid ◽  
Magnetic Storms ◽  
Power Grids ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Disturbances ◽  
Low Latitude ◽  
Solar Eruptions ◽  
Induced Currents ◽  
Extra High Voltage

AbstractLarge-amplitude geomagnetically induced currents (GICs) are the natural consequences of the solar–terrestrial connection triggered by solar eruptions. The threat of severe damage of power grids due to the GICs is a major concern, in particular, at high latitudes, but is not well understood as for low-latitude power grids. The purpose of this study is to evaluate the lower limit of the GICs that could flow in the Japanese power grid against a Carrington-class severe magnetic storm. On the basis of the geomagnetic disturbances (GMDs) observed at Colaba, India, during the Carrington event in 1859, we calculated the geoelectric disturbances (GEDs) by a convolution theory, and calculated GICs flowing through transformers at 3 substations in the Japanese extra-high-voltage (500-kV) power grid by a linear combination of the GEDs. The estimated GEDs could reach ~ 2.5 V/km at Kakioka, and the GICs could reach, at least, 89 ± 30 A near the storm maximum. These values are several times larger than those estimated for the 13–14 March 1989 storm (in which power blackout occurred in Canada), and the 29–31 October 2003 storm (in which power blackout occurred in Sweden). The GICs estimated here are the lower limits, and there is a probability of stronger GICs at other substations. The method introduced here will be immediately applicable for benchmark evaluation of low-latitude GICs against the Carrington-class magnetic storms if one assumes electrical parameters, such as resistance of transmission lines, with sufficient accuracy.

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