This current will flow through the local electrode TheseĬurrent flows are subtracted from gross value to leave the amount that Will normally include amounts that may return via metallic routes suchĪs the other (un-faulted) phase conductors, the metal screens/sheaths ofīuried cables and the earth wires (if fitted) of an overhead line. The overall (gross) fault current calculated Of the current that returns to its remote sources via the soil and theĮarthing system impedance. Point assumed to be at true (zero) earth potential. That the earthing system of an installation may attain relative to a remote This 'earth potential rise' (EPR) is the maximum voltage When fault current flows through them to earth, a voltage Supports, fencing, etc.) and overhead line steel supports all have an impedance Substation 'earthed' (grounded) metal work (consisting of switchgear enclosures, System earthing (grounding) is reviewed in Section 10, Section 10.2. Small power and lighting installation earthing is covered in Section Additionally, a brief overview of protective Limits and the general procedure followed to design an electrode system, This section is an over-view of the subject, dealing mainly with the design Such as control or communication cables or pipelines. _ Minimize electromagnetic interference between power and other systems _ Provide an earth connection for transformer neutrals, sometimes viaĪn impedance to restrict the fault current magnitude. In any thermal or mechanical damage to connected plant and allows protective _ Provide a route for the passage of fault current which does not result _ Enable connection (bonding) of necessary exposed extraneous conductive _ Provide equipotential grading by electrodes or similar, to control touch
To achieve this, it needs to perform the following functions:
The purpose of a substation earthing system is to ensure safe conditionsįor personnel and plant in and around the site during normal and earthįault conditions. Electrical Transmission and Distribution-Earthing (Grounding) and Bonding Electrical Transmission and Distribution-Earthing (Grounding) and Bonding Home | Articles | Forum
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