Earth Ground Resistance Testing for Low-Voltage Power Systems

1995 ◽  
Vol 31 (1) ◽  
pp. 206-213 ◽  
Author(s):  
Kenneth M. Michaels
Keyword(s):  
Power Systems ◽  
Low Voltage ◽  
Resistance Testing ◽  
Ground Resistance

scholarly journals Uncontrolled Electric Vehicle Charging Impacts on Distribution Electric Power Systems with Primarily Residential, Commercial or Industrial Loads

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1688 ◽  
Author(s):  
C. Birk Jones ◽  
Matthew Lave ◽  
William Vining ◽  
Brooke Marshall Garcia
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Low Voltage ◽  
Peak Load ◽  
Electric Power Systems ◽  
Primary System ◽  
Maximum Increase ◽  
Actual Distribution ◽  
The Impact ◽  
Ev Charging

An increase in Electric Vehicles (EV) will result in higher demands on the distribution electric power systems (EPS) which may result in thermal line overloading and low voltage violations. To understand the impact, this work simulates two EV charging scenarios (home- and work-dominant) under potential 2030 EV adoption levels on 10 actual distribution feeders that support residential, commercial, and industrial loads. The simulations include actual driving patterns of existing (non-EV) vehicles taken from global positioning system (GPS) data. The GPS driving behaviors, which explain the spatial and temporal EV charging demands, provide information on each vehicles travel distance, dwell locations, and dwell durations. Then, the EPS simulations incorporate the EV charging demands to calculate the power flow across the feeder. Simulation results show that voltage impacts are modest (less than 0.01 p.u.), likely due to robust feeder designs and the models only represent the high-voltage (“primary”) system components. Line loading impacts are more noticeable, with a maximum increase of about 15%. Additionally, the feeder peak load times experience a slight shift for residential and mixed feeders (≈1 h), not at all for the industrial, and 8 h for the commercial feeder.

scholarly journals Power anomaly effects and costs in low-voltage mobile power systems

2006 ◽  
Vol 42 (2) ◽  
pp. 612-624 ◽  
Author(s):  
Shengyi Liu ◽  
C.H. Singer ◽  
R.A. Dougal
Keyword(s):  
Power Systems ◽  
Low Voltage

Characteristic Analysis on Suppressing VFTO in GIS by Ferrite

2013 ◽  
Vol 834-836 ◽  
pp. 385-389
Author(s):  
Xiang Gen Gan ◽  
Shui Ping Zhong ◽  
Sheng Wei ◽  
Dong Bao Yang
Keyword(s):  
Wave Propagation ◽  
Power Systems ◽  
Traveling Wave ◽  
Low Voltage ◽  
Characteristic Analysis ◽  
Fast Transient ◽  
Transient Overvoltage ◽  
Great Harm

When disconnecting switches were operated,Very Fast Transient Overvoltage (VFTO) did great harm to power systems and their equipments in Gas Insulated Substations (GIS). Although VFTO can be suppressed by a few of known methods, there were some problems. Low voltage simulation tests show that putting ferrite rings around a disconnecting generatrix can damp traveling wave propagation and suppress VFTO in GIS. This method is economic and practical. We had analyzed ferrite characteristics of suppressing VFTO and got hold of ways of calculating ferrite size in GIS. Investigation shows that ferrite characteristics and sizes have a great effect on suppressing VFTO.

Soil Resistivity Evaluation and Grounding System Resistance

2018 ◽  
pp. 1-37
Keyword(s):  
Resistivity Measurement ◽  
Potential Method ◽  
Measurement Procedure ◽  
Resistance Testing ◽  
Soil Resistivity ◽  
Factors Affecting ◽  
Grounding Resistance ◽  
Ground Resistance ◽  
Transmission Towers ◽  
Electrode Method

This chapter contains the factors affecting the soil resistivity and grounding resistance such as the soil moisture content, soil mineral content and soil temperature. It discusses the methods of measuring of soil resistivity and grounding resistance using Wenner method. Method to obtain the required samples for obtaining accurate site resistivity is presented. Soil resistivity measurement procedure is given in this chapter. The chapter contains three electrode method or fall-of-Potential method, dead earth method, and ground resistance testing existing systems using ‘Selective' Clamp-on-Measuring of high voltage transmission towers feet resistance. Methods of calculating the apparent soil resistivity of Multi-Layers, apparent soil resistivity of two layers and apparent soil resistivity of three layers are presented in this chapter.

scholarly journals Testing Sensitivity of A-Type Residual Current Devices to Earth Fault Currents with Harmonics

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2044
Author(s):  
Stanislaw Czapp
Keyword(s):  
Power Systems ◽  
Electric Shock ◽  
Low Voltage ◽  
Wide Spectrum ◽  
Residual Current ◽  
Motor Speed ◽  
Earth Fault ◽  
Fault Currents ◽  
Wide Range ◽  
Sinusoidal Waveform

In many applications, modern current-using equipment utilizes power electronic converters to control the consumed power and to adjust the motor speed. Such equipment is used both in industrial and domestic installations. A characteristic feature of the converters is producing distorted earth fault currents, which contain a wide spectrum of harmonics, including high-order harmonics. Nowadays, protection against electric shock in low-voltage power systems is commonly performed with the use of residual current devices (RCDs). In the presence of harmonics, the RCDs may have a tripping current significantly different from that provided for the nominal sinusoidal waveform. Thus, in some cases, protection against electric shock may not be effective. The aim of this paper is to present the result of a wide-range laboratory test of the sensitivity of A-type RCDs in the presence of harmonics. This test has shown that the behavior of RCDs in the presence of harmonics can be varied, including the cases in which the RCD does not react to the distorted earth fault current, as well as cases in which the sensitivity of the RCD is increased. The properties of the main elements of RCDs, including the current sensor, for high-frequency current components are discussed as well.

scholarly journals A Methodology for Dependability Evaluation of Smart Grids

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1817 ◽  
Author(s):  
Gisliany Alves ◽  
Danielle Marques ◽  
Ivanovitch Silva ◽  
Luiz Affonso Guedes ◽  
Maria da Guia da Silva
Keyword(s):  
Smart Grid ◽  
Power Systems ◽  
Information And Communication Technologies ◽  
Power Distribution ◽  
Smart Grids ◽  
Low Voltage ◽  
Hierarchical Topology ◽  
Automation Systems ◽  
Dependability Evaluation ◽  
Information And Communication

Smart grids are a new trend in electric power distribution, which has been guiding the digitization of electric ecosystems. These smart networks are continually being introduced in order to improve the dependability (reliability, availability) and efficiency of power grid systems. However, smart grids are often complex, composed of heterogeneous components (intelligent automation systems, Information and Communication Technologies (ICT) control systems, power systems, smart metering systems, and others). Additionally, they are organized under a hierarchical topology infrastructure demanded by priority-based services, resulting in a costly modeling and evaluation of their dependability requirements. This work explores smart grid modeling as a graph in order to propose a methodology for dependability evaluation. The methodology is based on Fault Tree formalism, where the top event is generated automatically and encompasses the hierarchical infrastructure, redundant features, load priorities, and failure and repair distribution rates of all components of a smart grid. The methodology is suitable to be applied in early design stages, making possible to evaluate instantaneous and average measurements of reliability and availability, as well as to identify eventual critical regions and components of smart grid. The study of a specific use-case of low-voltage distribution network is used for validation purposes.

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