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In the 1990's we were predicting that telecommunications and computing technologies will inevitably converge. Today we don't even see them as separate industries. Let us look at how this convergence has affected the design of grounding systems inside telecommunications and computer room. Mesh bonding network, MBN are common historically and today in AC Data Centers and computer room. MBN is defined...
Asymmetric building structures force to build the earthing arrangements, the armouring of the building and the equipotential bonding system to be asymmetric as well. Another reason of asymmetries in earthing and equipotential bonding arrangements in symmetric building structures is the unawareness of planners and construction workers. As a consequence the building's electromagnetic compatibility (EMC)...
Within the framework of the industrial evolution the digital revolution implicates on the one side that the usage of complex devices for data processing (ICT), data analysis and data collecting increases (smart devices) and consequentially on the other side the energy demand especially in concentrated cities (smart cities) increases too. In combination with new, mostly asymmetric architectural shapes...
This paper is an overview of the different types of grounding, bonding and alarming systems available throughout the world. There has been much confusion and discussion regarding the preferred method of grounding and bonding of power system on board vessels such as pleasure crafts, cargo and naval vessels. This paper will discuss the pros, cons, advantages and disadvantages of each method. It will...
The technical standard IEEE P3003.2 “Recommended Practice for Equipment Grounding and Bonding in Industrial and Commercial Power Systems” published the month of October 2014, is an evolution of Chapter 2 of IEEE Std 142-2007 (also referred to as Green Book). P3003.2 has been developed by industry experts, based on their knowledge and experience in this field, and drafted after wide consultation and...
The terms grounding and bonding are often used interchangeably also if they are a combined protective measure, having a distinct function. The terms need to be understood separately in order to correctly apply equipment in the most beneficial manner. The paper presents the IEC approach that highlights as the two functions are generally in combination and for this reason the IEC standard adopts the...
This paper is focused on the design concept of earthing system composed of two earthing grids in close vicinity of each other. The “vicinity” means that the distance between the investigated earthing grids of the power plant and the switching stations is comparable with the sizes of the earthing grids. As a consequence the earthing grids are in the zone of each-other earth potential rise (EPR).To...
Equipotentiality is one means of preventing electric shock. Grounding is a specific kind of equipotentiality. For most power distribution systems, the resistance of the grounding circuit in an electrical product is critical to establishing equipotentiality. This paper explains equipotentiality and how it provides protection against electric shock. This paper also describes the grounding circuit for...
Increasing load density at electric utilities has driven the trend toward larger distribution conductors and higher settings on overcurrent protective equipment. Not only are pickup values of feeder breakers and reclosers increasing, the protective curves are often slower to achieve coordination with downstream devices. Where there are larger conductors and slower protective settings you will often...
The paper deals with the clarification of basic terms related to the calculation of the earth potential rise (EPR), transferred potential and earth resistance of the earthing grid. In case of earth fault occurring in a substation, significant fraction of the fault current is flowing in the passive conductors (cable sheath, earth wire) of the lines feeding to the fault. These passive conductors are...
The paper presents a methodology and example results of experimental measurements of surge currents and potentials in a radio base station. The goal of the experiment was to provide complex information on the performance of a radio base station affected by surge currents. Such information may be used in further analysis of lightning threat. The presented method is based on the idea of simulation of...
In an electrical installation at the work location de-energizing is only one part of creating an electrically safe work condition for the duration of the work. Unexpected sources can occur, specially when working on overhead lines. Some activities are sensitive to the unexpected sources and in these cases, depending on the electrical energy available, these sources could cause injury or death. The...
Misunderstandings concerning stray current and equipotential planes are prevalent in North America. Clarification of and differences between equipotentials found in high voltage cable and in concrete encased reinforcing bar installations in concrete pads and swimming pools are explained. Misunderstanding and false interpretation of the IEEE Standard 80, ldquoGuide for Safety in AC Substation Groundingrdquo...
Digital microprocessor based protective relays, installed in low voltage compartments of medium voltage switchgear and/or in control panels, become more and more exposed to EMC disturbances due to interferences that may affect the power quality of electrical networks. End-users sometimes report unexpected circuit breaker tripping and significant financial consequences due to process discontinuity...
During the 2005 National Electrical Codereg (NECreg) review cycle, a relatively simple revision was made that will have a significant impact on the cathodic protection systems of petroleum and chemical facilities (plants) in the future. The 2005 NEC now makes it clear that there must be an interconnection of all concrete-encased steel reinforcing bar (rebar) to the facility grounding electrode system...
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