The impact of the recession on the liquidity and activity ratios of top power transmission company: case of power grid corporation of India Ltd.

2021 ◽  
Author(s):  
Surbhi Gupta ◽  
Anjali Naithani ◽  
Varsha Gautam
Keyword(s):  
Power Transmission ◽  
Power Grid ◽  
Activity Ratios ◽  
The Impact

scholarly journals Automatic Identification and Importance Evaluation Technology of Power Transmission Section

2020 ◽  
Vol 213 ◽  
pp. 03036
Author(s):  
Yixuan Weng ◽  
Weizhe Ma ◽  
EnYan Xie ◽  
Hui Qi ◽  
Zhenxing Liu ◽  
...  
Keyword(s):  
Cross Section ◽  
Transmission Lines ◽  
Power Flow ◽  
Power Transmission ◽  
Power Grid ◽  
Stability Limit ◽  
Stability Margin ◽  
Automatic Identification ◽  
Flow State ◽  
The Impact

In theory, the cross section is the minimum cut set in the network. For the actual power grid, the transmission cross section is a collection of transmission lines between different regions, which is mainly used for power transmission to achieve the purpose of generating load balance. In this paper, a power grid zoning algorithm is proposed based on the topological structure characteristics and current operation state of the power grid, and the key transmission sections can be directly obtained without depending on the calculation of safety and stability margin. A practical system state partition model and key section sorting method are introduced, and a set of automatic identification method flow of key transmission sections of the system is established by searching for electrical betweenness. The importance of the transmission section is quantitatively evaluated from three angles: the margin from the stability limit, the hub position in the current power flow state, and the impact on the power grid after the power cut-off. The evaluation results can be used as a Reference for decision-making in the planning and reconstruction of the transmission section, safety monitoring, protection configuration, etc.

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 A Model for the Thermal Behaviour of an Offshore Cable Installed in a J-Tube

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 31
Author(s):  
Jeremy Arancio ◽  
Ahmed Ould El Moctar ◽  
Minh Nguyen Tuan ◽  
Faradj Tayat ◽  
Jean-Philippe Roques
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Model ◽  
Thermal Behaviour ◽  
Energy Production ◽  
Power Transmission ◽  
Temperature Fields ◽  
Sobol Indices ◽  
Lumped Element ◽  
Thermal Phenomena ◽  
The Impact

In the race for energy production, supplier companies are concerned by the thermal rating of offshore cables installed in a J-tube, not covered by IEC 60287 standards, and are now looking for solutions to optimize this type of system. This paper presents a numerical model capable of calculating temperature fields of a power transmission cable installed in a J-tube, based on the lumped element method. This model is validated against the existing literature. A sensitivity analysis performed using Sobol indices is then presented in order to understand the impact of the different parameters involved in the heating of the cable. This analysis provides an understanding of the thermal phenomena in the J-tube and paves the way for potential technical and economic solutions to increase the ampacity of offshore cables installed in a J-tube.

scholarly journals Simulation of 2-Coil and 4-Coil Magnetic Resonance Wearable WPT Systems

Proceedings ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 13
Author(s):  
Yixuan Sun ◽  
Stephen Beeby
Keyword(s):  
Power Efficiency ◽  
Power Transmission ◽  
Rotation Angle ◽  
Wireless Power ◽  
Peak Efficiency ◽  
Frequency Splitting ◽  
At Resonance ◽  
Higher Power ◽  
The Impact ◽  
Proper Frequency

This paper presents the COMSOL simulations of magnetically coupled resonant wireless power transfer (WPT), using simplified coil models for embroidered planar two-coil and four-coil systems. The power transmission of both systems is studied and compared by varying the separation, rotation angle and misalignment distance at resonance (5 MHz). The frequency splitting occurs at short separations from both the two-coil and four-coil systems, resulting in lower power transmission. Therefore, the systems are driven from 4 MHz to 6 MHz to analyze the impact of frequency splitting at close separations. The results show that both systems had a peak efficiency over 90% after tuning to the proper frequency to overcome the frequency splitting phenomenon at close separations below 10 cm. The four-coil design achieved higher power efficiency at separations over 10 cm. The power efficiency of both systems decreased linearly when the axial misalignment was over 4 cm or the misalignment angle between receiver and transmitter was over 45 degrees.

scholarly journals Impact of the Generation System Parameters on the Frequency Response of the Power System: A UK Grid Case Study

Electricity ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 143-157
Author(s):  
Jovi Atkinson ◽  
Ibrahim M. Albayati
Keyword(s):  
Power System ◽  
Frequency Response ◽  
Power Grid ◽  
Sudden Increase ◽  
Generation System ◽  
System Parameters ◽  
Primary Frequency ◽  
Primary Frequency Response ◽  
The Impact ◽  
System Inertia

The operation and the development of power system networks introduce new types of stability problems. The effect of the power generation and consumption on the frequency of the power system can be described as a demand/generation imbalance resulting from a sudden increase/decrease in the demand and/or generation. This paper investigates the impact of a loss of generation on the transient behaviour of the power grid frequency. A simplified power system model is proposed to examine the impact of change of the main generation system parameters (system inertia, governor droop setting, load damping constant, and the high-pressure steam turbine power fraction), on the primary frequency response in responding to the disturbance of a 1.32 GW generation loss on the UK power grid. Various rates of primary frequency responses are simulated via adjusting system parameters of the synchronous generators to enable the controlled generators providing a fast-reliable primary frequency response within 10 s after a loss of generation. It is concluded that a generation system inertia and a governor droop setting are the most dominant parameters that effect the system frequency response after a loss of generation. Therefore, for different levels of generation loss, the recovery rate will be dependent on the changes of the governor droop setting values. The proposed model offers a fundamental basis for a further investigation to be carried on how a power system will react during a secondary frequency response.

A Tale of Two Entities

2021 ◽  
Vol 2 (2) ◽  
pp. 1-21
Author(s):  
Hossam ElHussini ◽  
Chadi Assi ◽  
Bassam Moussa ◽  
Ribal Atallah ◽  
Ali Ghrayeb
Keyword(s):  
Power Flow ◽  
Power Grid ◽  
Communication Protocols ◽  
Charging Infrastructure ◽  
Electric Vehicle Charging ◽  
Public Data ◽  
Simulation Based ◽  
Charging Stations ◽  
The Impact ◽  
Ev Charging

With the growing market of Electric Vehicles (EV), the procurement of their charging infrastructure plays a crucial role in their adoption. Within the revolution of Internet of Things, the EV charging infrastructure is getting on board with the introduction of smart Electric Vehicle Charging Stations (EVCS), a myriad set of communication protocols, and different entities. We provide in this article an overview of this infrastructure detailing the participating entities and the communication protocols. Further, we contextualize the current deployment of EVCSs through the use of available public data. In the light of such a survey, we identify two key concerns, the lack of standardization and multiple points of failures, which renders the current deployment of EV charging infrastructure vulnerable to an array of different attacks. Moreover, we propose a novel attack scenario that exploits the unique characteristics of the EVCSs and their protocol (such as high power wattage and support for reverse power flow) to cause disturbances to the power grid. We investigate three different attack variations; sudden surge in power demand, sudden surge in power supply, and a switching attack. To support our claims, we showcase using a real-world example how an adversary can compromise an EVCS and create a traffic bottleneck by tampering with the charging schedules of EVs. Further, we perform a simulation-based study of the impact of our proposed attack variations on the WSCC 9 bus system. Our simulations show that an adversary can cause devastating effects on the power grid, which might result in blackout and cascading failure by comprising a small number of EVCSs.

scholarly journals Optimal Pricing Strategy of Electric Vehicle Charging Station for Promoting Green Behavior Based on Time and Space Dimensions

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xiaomin Xu ◽  
Dongxiao Niu ◽  
Yan Li ◽  
Lijie Sun
Keyword(s):  
Electric Vehicles ◽  
Optimization Problems ◽  
Power Grid ◽  
Economic Benefits ◽  
Pricing Strategy ◽  
Optimal Pricing ◽  
Electricity Pricing ◽  
Optimal Pricing Strategy ◽  
Charging Stations ◽  
The Impact

Considering that the charging behaviors of users of electric vehicles (EVs) (including charging time and charging location) are random and uncertain and that the disorderly charging of EVs brings new challenges to the power grid, this paper proposes an optimal electricity pricing strategy for EVs based on region division and time division. Firstly, by comparing the number of EVs and charging stations in different districts of a city, the demand ratio of charging stations per unit is calculated. Secondly, according to the demand price function and the principle of profit maximization, the charging price between different districts of a city is optimized to guide users to charge in districts with more abundant charging stations. Then, based on the results of the zonal pricing strategy, the time-of-use (TOU) pricing strategy in different districts is discussed. In the TOU pricing model, consumer satisfaction, the profit of power grid enterprises, and the load variance of the power grid are considered comprehensively. Taking the optimization of the comprehensive index as the objective function, the TOU pricing optimization model of EVs is constructed. Finally, the nondominated sorting genetic algorithm (NSGA-II) is introduced to solve the above optimization problems. The specific data of EVs in a municipality directly under the Central Government are taken as examples for this analysis. The empirical results demonstrate that the peak-to-valley ratio of a certain day in the city is reduced from 56.8% to 43% by using the optimal pricing strategy, which further smooth the load curve and alleviates the impact of load fluctuation. To a certain extent, the problem caused by the uneven distribution of electric vehicles and charging stations has been optimized. An orderly and reasonable electricity pricing strategy can guide users to adjust charging habits, to ensure grid security, and to ensure the economic benefits of all parties.

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