ISO 18086:2019 金属および合金の腐食— AC腐食の測定—保護基準 | ページ 6

3.1

AC electric traction system

AC railway electrical distribution network used to provide energy for rolling stock

3.2

AC power supply system

AC electrical system devoted to electrical energy transmission, which includes overhead lines, cables, substations and all apparatus associated with them

3.3

AC power system

AC electric traction system (3.1) or AC power supply system (3.2)

Note 1 to entry: Where it is necessary to differentiate, each interfering system (3.6) is clearly indicated with its proper term.

3.4

copper/copper sulfate reference electrode

CSE

reference electrode consisting of copper in a saturated solution of copper sulfate

3.5

AC voltage

voltage measured to earth (3.9) between a metallic structure and a reference electrode

3.6

interfering system

general expression encompassing an interfering high voltage AC electric traction system (3.1) and/or high voltage AC power supply system (3.2)

3.7

interfered system

system on which the interference (3.15) effects appear

Note 1 to entry: In this document, it is the pipeline system (3.8) .

3.8

pipeline system

system of pipe network with all associated equipment and stations

Note 1 to entry: In this document, pipeline system refers only to metallic pipeline system.

Note 2 to entry: The associated equipment is the equipment electrically connected to the pipeline.

3.9

earth

conductive mass of the earth, of which the electric potential at any point is conventionally taken as equal to zero

[SOURCE:IEC 60050-826]

3.10

operating condition

fault-free operation of any system

Note 1 to entry: Transients are not to be considered as an operating condition.

3.11

fault condition

non-intended condition caused by a short-circuit to earth (3.9) , the fault duration being the normal clearing time of the protection devices and switches

Note 1 to entry: A short circuit is an unintentional connection of an energized conductor to earth or to any metallic part in contact with earth.

3.12

conductive coupling

coupling that occurs when a proportion of the current belonging to the interfering system (3.6) returns to the system earth (3.9) via the interfered system (3.7) or when the voltage to the reference earth of the ground in the vicinity of the influenced object rises because of a fault in the interfering system and the results of which are conductive voltages and currents

3.13

inductive coupling

phenomenon whereby the magnetic field produced by a current carrying circuit influences another circuit

Note 1 to entry: Coupling is quantified by the mutual impedance of the two circuits. The results of which are induced voltages and, hence, currents that depend on, for example, the distances, length, inducing current, circuit arrangement and frequency.

3.14

capacitive coupling

phenomenon whereby the electric field produced by an energized conductor influences another conductor

Note 1 to entry: Coupling is quantified by the capacitance between the conductors and the capacitances between each conductor and the earth (3.9) . The results of which are interference (3.15) voltages into conductive parts or conductors insulated from earth. These voltages depend, for example, on the voltage of the influencing system, distances and circuit arrangement.

3.15

interference

phenomenon resulting from conductive, inductive or capacitive coupling (3.12, 3.13, 3.14) between systems, which can cause malfunction, dangerous voltages, damage (3.17) , etc.

3.16

disturbance

malfunction of a piece of equipment that loses its capability to work properly for the duration of the interference (3.15)

Note 1 to entry: When the interference disappears, the interfered system (3.7) starts working properly again without any external intervention.

3.17

damage

permanent reduction in the quality of service that can be suffered by the interfered system (3.7)

Note 1 to entry: A reduction in the quality of service could also be the complete cancellation of service.

3.18

danger

state of the influenced system that is able to produce a threat to human life

3.19

interference situation

maximum distance between the pipeline system (3.8) and AC power system for which an interference (3.15) is to be considered

3.20

interference voltage

voltage caused on the interfered system (3.7) by the conductive, inductive or capacitive coupling (3.12, 3.13, 3.14) with the nearby interfering system (3.6) between a given point and the earth (3.9) or across an insulating joint

3.21

IR drop

voltage due to any current, developed in an electrolyte such as the soil, between the reference electrode and the metal of the structure, in accordance with Ohm’s Law (U = I × R)

3.22

IR-free potential

E_IR-free

pipe to electrolyte potential measured without the voltage error caused by the IR drop (3.21) due to the protection current or any other current

3.23

off-potential

E_off

pipe to electrolyte potential measured after interruption of all sources of applied cathodic protection current with the aim of approaching an IR-free potential (3.22)

Note 1 to entry: The delay before measurement varies according to circumstances.

3.24

on-potential

E_on

pipe to electrolyte potential measured while the cathodic protection system is continuously operating

3.25

spread resistance

ohmic resistance through a coating defect to earth (3.9) or from the exposed metallic surface of a coupon (3.26) towards earth

Note 1 to entry: This is the resistance which controls the AC or DC current through a coating defect or an exposed metallic surface of a coupon for a given AC or DC voltage.

3.26

coupon

metal sample of defined dimensions made of a metal equivalent to the metal of the pipeline

3.27

probe

device incorporating a coupon (3.26) that provides measurements of parameters to assess the effectiveness of cathodic protection and/or corrosion risk