Critical Infrastructure in Sectoral Planning: The Example of the Development and Expansion of the Extra High Voltage Network in Germany

2017 ◽  
Vol 04 (04) ◽  
pp. 1850001
Author(s):  
Christoph Riegel

The power network is among the most of critical infrastructures. In Germany, multiple circumstances, triggered by social and political processes of decarbonization and nuclear phaseout, require extensive grid expansion activities. The paper analyzes coincidences of security and reliability aspects with transmission infrastructure planning. It explores essential properties that determine the criticality of power grids, examines to what extent security is subject of grid expansion procedures and finally focuses on selected security-related spatial planning issues such as the concentration of infrastructures or the pros and cons of overhead lines vs. underground cables.

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1405
Author(s):  
Barakou ◽  
Steennis ◽  
Wouters

Contactless capacitive (open-air) sensors are applied to monitor overvoltages near overhead line terminations at a substation or at the transition from underground cables to overhead lines. It is shown that these sensors, applied in a differentiating/integrating measuring concept, can result in excellent characteristics in terms of electromagnetic compatibility. The inherent cross-coupling from open-air sensors to other phases is dealt with. The paper describes a method to calibrate the sensor to line coupling matrix based on assumed 50 Hz symmetric phase voltages and in particular focuses on uncertainty analysis of assumptions made. Network simulation shows that predicted maximum overvoltages agree within typically 7% compared to reconstructed values from measurement, also with significant cross-coupling. Transient voltages from energization of an (extra-)high voltage connection can cause large and steep rising ground currents near the line terminations. Comparison with results obtained by a capacitive divider confirms the intrinsic capability in interference rejection by the differentiating/integrating measurement methodology.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3843
Author(s):  
Sultan Sh. Alanzi ◽  
Rashad M. Kamel

This paper investigates the maximum photovoltaic (PV) penetration limits on both overhead lines and underground cables medium voltage radial distribution system. The maximum PV penetration limit is estimated considering both bus voltage limit (1.05 p.u.) and feeder current ampacity (1 p.u.). All factors affect the max PV penetration limit are investigated in detail. Substation voltage, load percentage, load power factor, and power system frequency (50 Hz or 60 Hz) are analyzed. The maximum PV penetration limit associated with overhead lines is usually higher than the value associated with the underground cables for high substation voltage (substation voltage = 1.05 and 1.04 p.u.). The maximum PV penetration limit decreases dramatically with low load percentage for both feeder types but still the overhead lines accept PV plant higher than the underground cables. Conversely, the maximum PV penetration increases with load power factor decreasing and the overhead lines capability for hosting PV plant remains higher than the capability of the underground cables. This paper proved that the capability of the 60-Hz power system for hosting the PV plant is higher than the capability of 50 Hz power system. MATLAB software has been employed to obtain all results in this paper. The Newton-Raphson iterative method was the used method to solve the power flow of the investigated systems.


2011 ◽  
Vol 11 (8) ◽  
pp. 2227-2234 ◽  
Author(s):  
E. G. Petrova

Abstract. The data base of technological accidents and disasters that have occurred in Russia has been created. More than 13 000 information units have been collected and analyzed. The proportion of accidents triggered by natural events (natural-technological accidents or NTA) in the total number of technological accidents as well as a part of every NTA type in the total number of NTA was estimated. About 10 percent of all accidents registered in the data base were caused by natural events; among some types of accidents this proportion is even higher. Transmission facilities with more than 90 percent of overhead lines are the most vulnerable to the impact of natural hazards. The contribution of different natural hazards was evaluated. Regions with the greatest NTA risk were revealed. The influence of natural events on the technosphere is stronger in the South of the European Russia and in the Russian Far East, which are more exposed to hurricanes, snowstorms, rainfalls, icing and other natural hazards producing NTA. The critical infrastructure needs special protection and modernization in these regions. The problem of the relationship between natural hazards and the technosphere is very complicated and needs further investigation, especially taking the expected climate changes into consideration.


Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 649 ◽  
Author(s):  
Hongshan Zhao ◽  
Weitao Zhang ◽  
Yan Wang

Modelling and estimating power-line communication (PLC) channels are complicated issues due to the complex network topologies, various junctions, and changeable loads. This paper focuses on the frequency response characteristics (FRCs) of medium-voltage (MV) PLC networks with special consideration of two scenarios that are often neglected but generally exist. In the first scenario, the MV distribution network is of the ring topology. In the second scenario, the MV overhead lines and underground cables join at junctions, and the shields of underground cables are grounded with nonzero grounding impedances at the junctions. These conditions lead to the failure of currently popular methods to different degrees. For this reason, we developed an effective method to calculate the FRCs of distribution networks for PLC applications. With this method, the frequency responses of nodes are simply expressed as the binary function of the overall tube propagation matrix and overall node scattering matrix, which is convenient for calculations and analyses. The proposed method was validated by the agreement between the calculated and measured FRCs. The results of two test examples showed that the proposed method performed better in comparison with the traditional approximate method when nonideal grounding conditions were taken into account. The proposed method is also independent of the network topology, so it can adapt to the dynamic changes of the network structure.


2012 ◽  
Vol 503-504 ◽  
pp. 1605-1608
Author(s):  
Hua Ting Tao ◽  
Li Li Ji

CPS test standard has put forward new demands to the management of power grids. This paper analyzes the main influence factors of CPS, and introduces the way of building data warehouse and constructing supplementary analysis system on this basis, which can effectively help power grid workers to research the pros and cons in dispatch and operation. The application of the supplementary analysis system is helpful for Shanghai power grid to enhance AGC control and frequency control ability under the control performance standard.


2021 ◽  
Vol 267 ◽  
pp. 01052
Author(s):  
Chao Xu ◽  
Di Huang ◽  
Zhe Chen ◽  
Dong Peng ◽  
Lang Zhao ◽  
...  

The structure and form of modern power grids are becoming more and more complex, and there are many indicators and factors that need to be considered to evaluate the development status of the power grid. In order to diagnose the development level of power grid, the index system is reconstructed, which includes seven dimensions: the coordination of power grid development speed, the coordination of power grid development scale, the coordination of power grid structure, the security and reliability of power grid, the level of equipment, the utilization efficiency of power grid and the development benefit of power grid, the construction principle and index selection basis are given. When dealing with contradictory problems in reality, methods combining quantitative and qualitative can be applied to study. The matter element analysis method is applied to power grid development diagnosis, and a model of power grid development diagnosis based on matter element analysis is established, the model can not only diagnose the development level of power grid, but also determine the key factors that affect the diagnosis results, and give suggestions for improvement. The practical example verifies the feasibility and rationality of the method, which has good evaluation accuracy and prediction effect.


Energetika ◽  
2015 ◽  
Vol 61 (1) ◽  
Author(s):  
Aleksandrs Ļvovs ◽  
Ilze Priedite

The increasing number of severe weather occurrences that influence the number of large scale outages, especially in rural distribution networks, makes the question on the need of increasing reliability level of power supply of the distribution network even more actual. Distribution system operators and national regulators shall not only find a reliable but also a cost-effective solution for further distribution network development: the optimal reliability level of power supply. One of the reliability improvement solutions that allows effectively dealing with the reduction of the number of outages in rural distribution networks is the cablification of network. Construction costs of the aforementioned solution are quite high in comparison to other network line types, and due to that, the implementation of the solution always raises discussions on cost-effectiveness. The paper presents approaches for the cost/worth assessment of power line lifetime costs in the distribution network and for the assessment of customer costs of reliability that takes into account time-varying loads and outage costs (previously developed by authors of this paper [6, 7]) as well as for the assessment of traders’ losses due to electrical energy not supplied. The case study included in the paper is performed for Latvian conditions and takes into account information on the real customer costs of reliability of Latvian customers (information from the study of the Institute of Physical Energetics), fault statistics of Latvian underground cables and overhead lines, information with a high level of details on the capital costs, operational and fault elimination costs of distribution lines in Latvia.


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