scholarly journals Fault Statistics and Analysis of 220-kV and Above Transmission Lines in a Southern Coastal Provincial Power Grid of China

2020 ◽  
Vol 7 ◽  
pp. 122-129
Author(s):  
Binghuang Chen
Keyword(s):  
Transmission Lines ◽  
Power Grid ◽  
Fault Statistics

New aspects of power grid facilities personnel workplaces electromagnetic environment

2020 ◽  
Vol 60 (9) ◽  
pp. 569-574
Author(s):  
Nina B. Rubtsova ◽  
Sergey Yu. Perov ◽  
Olga V. Belaya ◽  
Tatiana A. Konshina
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Power Grid ◽  
Spectral Characteristics ◽  
Ground Level ◽  
Frequency Characteristics ◽  
Frequency Range ◽  
Electromagnetic Environment ◽  
Limit Values ◽  
Special Assessment

Introduction. Electromagnetic safety of power grid facilities staff requires the exclusion of electromagnetic fields (EMF) harmful effects. EMF is evaluated by 50 Hz electric and magnetic fields (EF and MF) values in the framework of working conditions special assessment, and very rarely the analysis of the electromagnetic environment (EME) is carried out in depth. The aim of the study - EME hygienic assessment of power grid EHV facilities personnel workplace with adequate 50 Hz EF and MF levels evaluation as well as the analysis of EF and MF in the frequency range from 5 Hz to 500 Hz amplitude-frequency characteristics. Materials and methods. 50 Hz EF and MF values assessment was carried out on open switchgears (S) of substations and within sanitary breaks of 500 and 750 kV overhead power transmission lines (OTL). Measurements along to OTL trasses was performed using matrix-based method. Measurements and analysis of EF and MF values in 5-500 Hz frequency range amplitude-frequency characteristics were performed in the territory of 500 and 750 kV S. Results. Power frequency 50 Hz measurements results at 500 and 750 kV S ground-level personnel workplaces showed the presence of an excess of permissible limit values by EF intensity and the absence of an excess by MF. The measured EF values within 500 and 750 kV OTL sanitary gaps require limiting the working time of linemen due to the excess of the hygienic norms for full work shift, while the MP levels were almost completely within the standard values for persons not occupationally connected with electrical installations maintenance. MF and EE frequency range from 50 Hz to 500 Hz spectral characteristics analysis showed that 3rd harmonic percentage does not exceed 2.5% for EF and 6% for MF of the main level, the level of the 5th harmonic does not exceed 1% for EF and 3.5% for MF, the level of the 7th harmonic does not exceed 0.2% for EF and 0.8% for MF. These data show despite its low levels the contribution of MF different harmonics in a possible adverse impact on humane than EF corresponding harmonics. Conclusions. There was the confirmation of the previously justified use of the "matrix" scheme for of EF and MF values measurement along OTL routes. The relevance of to EF and MF all frequency components expos ure assessing possible health risk in extremely high voltage S territories and under OTL, based on international recommendations due to the lack of sanitary regulations in the Russian Federation for >50 Hz-30 kHz EF and MF, is shown.

scholarly journals Study on icing and its trip laws of transmission lines in Shanxi Power Grid

2021 ◽  
Vol 252 ◽  
pp. 01055
Author(s):  
Bin Zhao ◽  
Li-chun Zhang ◽  
Jia-lun Yang ◽  
Kun-peng Ji
Keyword(s):  
Transmission Lines ◽  
Power Grid ◽  
Electric Energy ◽  
Energy Transmission ◽  
Safe Operation ◽  
Overhead Transmission Lines ◽  
Power Load ◽  
Capacity Improvement

Overhead transmission lines are important carriers of electric energy transmission. Their icing, galloping and shedding in winter and spring seriously threatened the safe operation of Shanxi power grid. Especially in the recent years, compact lines and double circuit lines on the same tower, typical types of overhead transmission lines in Shanxi Power Grid, were affected by frequent trips induced by icing, galloping, and shedding appeared in their conductors repeatedly, which seriously reduced the capacity of power energy transmission in Shanxi and caused trillions of power load losses. Through detailed investigation and analysis of the characteristics and historical fault cases of compact lines and double circuit lines on the same tower in Shanxi Power Grid, the key causes and main laws of two types of lines in Shanxi Power Grid are clarified, which could provide support for the follow-up line anti-ice technical transformation and capacity improvement.

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.

Geomagnetically induced currents in central Europe

2020 ◽  
Author(s):  
Tatiana Výbošťoková ◽  
Michal Švanda ◽  
Zdeněk Němeček
Keyword(s):  
Geomagnetic Activity ◽  
High Voltage ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Grid ◽  
Occurrence Rate ◽  
Data Sets ◽  
Geomagnetically Induced Currents ◽  
Transmission Networks ◽  
Electric Power Grid

<p>Eruptive events on the Sun interacts with the magnetosphere and can affect even the Earth-bound structures such as power transmission networks via geomagnetically induced electric currents (GICs). We quantify the geomagnetic activity by the K-index computed from local measurements of the geomagnetic field and investigate its effects on the Czech electric power grid represented as disturbances recorded in the maintenance logs of the power network operators in course of last 12 years. In data sets recording the disturbances on high and very high voltage power lines, we found a statistically significant increase of anomaly rates within tens of days around maxima of a geomagnetic activity compared to the adjacent activity minima. Moreover, we modeled GICs for two (east-west and north-south oriented) high-voltage transmission lines in the Czech Republic and found surprisingly high values of currents, in the order of tens of amperes. Based on in-situ observations, we study propagation and properties of the largest CMEs and their relation to the disturbances in the transmission networks of the Central European countries. Our results provide an evidence that GICs may affect the occurrence rate of anomalies registered on power-grid equipment even in the mid-latitude countries.</p>

scholarly journals Study on Emergency Load Shedding of Hybrid AC/DC Receiving-End Power Grid with Stochastic, Static Characteristics-Dependent Load Model

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3912 ◽  
Author(s):  
Yingying Jiang ◽  
Xiaolin Chen ◽  
Sui Peng ◽  
Xiao Du ◽  
Dan Xu ◽  
...  
Keyword(s):  
Direct Current ◽  
Transmission Lines ◽  
Power Flow ◽  
Large Scale ◽  
Power Grid ◽  
Fault Analysis ◽  
Load Shedding ◽  
Total Power ◽  
Power Imbalance ◽  
Factors Affecting

When large-capacity HVDC (high voltage direct current) transmission line blocking occurs in a hybrid AC/DC (alternating current/direct current) power grid, the receiving-end system will encounter a huge power imbalance, which will lead to a frequency drop and redistribution of the power flow, and which may further lead to the overload of other transmission lines, cascading failures and a large-scale blackout. To resolve these problems, an emergency load-shedding strategy for the DC receiving-end system is proposed from the perspective of a quasi-steady state. The proposed method can accurately calculate the actual total power imbalance by modeling more detailed stochastic loads with static frequency/voltage characteristics and involving the inertia effect of the generator during the response delay period, which can effectively reduce the amount of load curtailment. In addition, several factors affecting the power imbalance estimation in stochastic scenarios and their mechanisms are analyzed in detail, and the key aspects relevant to the DC blocking fault analysis are identified as well. Finally, the influence of different load-shedding strategies on the receiving-end system security after a DC blocking fault is compared with the security indices, including those that are relevant to the frequency/load change proposed herein, and a uniform load-shedding coefficient is obtained via the proposed method, even for different power imbalances under a stochastic context, which makes the load-shedding strategy more practical.

Research Progress on Manual Ice Measurement Devices for Overhead Transmission Lines

2013 ◽  
Vol 765-767 ◽  
pp. 2272-2275
Author(s):  
Jia Lun Yang ◽  
Kuan Jun Zhu ◽  
Bin Liu ◽  
Jia Jun Si ◽  
Quan Yin ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Wind Direction ◽  
Power Grid ◽  
Classification Criteria ◽  
Research Progress ◽  
Existing Problems ◽  
Overhead Transmission Lines ◽  
Different Types ◽  
Measurement Devices ◽  
Further Development

Sufficient icing data are very important for the design and operation of power grid in the places with potential accreted ice, meaning that it is necessary to pay due attention to the ice measurement devices. In this paper, the current ice measurement devices are classified into different types according to corresponding classification criteria with the aim of understanding the characteristics of each type of devices. Moreover, the research progress of the manual ice measurement devices are introduced in detail, including the diameter of conductors, the angle between conductor and wind direction. Finally, the existing problems are proposed for the further development of manual ice measurement devices for overhead transmission lines.

The Research and Application of Power Grid Transmission Interface Dynamic Capacity-Increase Technology

2013 ◽  
Vol 462-463 ◽  
pp. 141-149
Author(s):  
Xiang Fu Guo ◽  
Xin Bo Huang ◽  
Di Ming Wan ◽  
Zhi Min Guo ◽  
Lei Liu
Keyword(s):  
Transmission Lines ◽  
Power Grid ◽  
Current Line ◽  
Mathematical Relationship ◽  
Dynamic Capacity ◽  
Capacity Increase ◽  
Interface Dynamic ◽  
New Type ◽  
Allowable Temperature ◽  
Important Significance

The real-time capacity-increase technology of transmission lines is adopted to increase transmission current capacity of transmission lines, by which the conductor temperature, the ambient temperature and the wind speed can be timely measured and the transmission current capacity can be adjusted dynamically without breach of available rules. A new type of Morgan's transmission line dynamic capacity-increase model is established, which can fast and effective computing the current line transmission capacity, and the transient running formula of transmission lines is established, the mathematical relationship between the conductor allowable temperature and the variety of sag of the span is presented, and the application of the monitoring device is introduced, it has important significance to research the power grid transmission interface dynamic capacity-increase technology.

Analysis on Capacity of Transmission Line Based on Thermal Rating

2014 ◽  
Vol 986-987 ◽  
pp. 239-242
Author(s):  
Bo Yang ◽  
Kui Hua Wu ◽  
Yi Qun Wang ◽  
Shen Quan Yang
Keyword(s):  
Transmission Line ◽  
Real Time ◽  
Transmission Lines ◽  
Rapid Growth ◽  
Power Grid ◽  
Transmission Capacity ◽  
Grid Load ◽  
Realistic Significance

The rapid growth of power grid load put forward higher requirements on the transmission capacity of line, with the growing tension of line corridors, building new transmission lines is becoming more and more difficult. Therefore, it is of realistic significance to analyze the transmission capacity of existing transmission line and fully tap the existing power grid transmission capacity. On the basis of previous studies, and consulting a large number of references, this paper summarizes and expounds the methods of improving transmission capacity by using the thermal rating analysis, introducing static thermal rating and real-time static thermal rating. Also, this paper verifies applications of the above methods in actual running environment.

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