IEEE Std 2746 pdf free download

IEEE Std 2746 pdf free download.Evaluating AC Interference on Linear Facilities Co-Located Near Transmission Lines.
4.1 Types of ac interference coupling for co-located linear facilities
AC interference effects are driven by three primary coupling mechanisms: inductive, capacitive, and conductive. This clause introduces these topics as they apply to linear facilities co-located to energized electrical systems. For additional discussions, see the reference material provided in Annex A.
4.1.1 Inductive
Inductive coupling in ac systems occurs when time—varying current passes through a conductive path. such as a transmission line or cable, producing a time-varying magnetic field around the path. When this infrastructure is co-located in parallel with other continuous conductive pathways, mutual inductive coupling between the systems can occur. For inductively coupled systems, time-varying current in one conductive pathway induces voltages and currents in the co-located pathway. Common co-located linear facilities and equipment susceptible to the effects of inductive coupling include railroad rails, pipelines, shield wires and optical ground wire (OPGW) cables, grounding systems. communications cables, and other electrical lines or cables.
When systems are inductively coupled. a mutual inductance (L12) exists between the co-located facilities. Figure 1 shows an energized conductor inductively coupled to a co-located linear facility, providing both a current (I,) and a voltage (V2) onto that facility.
4.1.2 Capacitive
Capacitive coupling in ac systems occurs when time-varying electric fields are present within energized transmission lines or cables. When this infrastructure is co-located in parallelwith other continuous conductive pathways, capacitive coupling between the systems can occur. For capacitively coupled systems, time-varying electric fields from the energized conductors interact through free space. causing a voltage on the co-located linear facilities. If the capacitively coupled voltage is of sufficient magnitude. the co-located facility can represent a shoek hazard or cause interference in sensitive electrical equipment. Common co-located linear facilities and equipment susceptible to the efrects of capacitive coupling include railroad rails, above-grade pipelines, shield wires and OPGW cables, metallic fencing, handrails, and other overhead electrical lines. Capacitive coupling between overhead energized lines and below-grade metallic objects is greatly reduced by the surrounding earth material, which causes electric charge to distribute more evenly over a large volume. Higher voltage lines result in greater capacitive coupling as these elTects are proportional to voltage.
When systems are capacitively coupled. an equivalent mutual capacitance (C12) exists between the co-located facilities. Figure 2 shows an energized conductor capacitively coupled to a co-located linear facility, producing a voltage (V2) on that facility. For co-located facilities connected to ground through their self-capacitance (C20) oiilv, excessive voltage buildup due to capacitive coupling presents a shock hazard to personnel and damage to equipment.
4.1.3 Conductive
Conductive coupling in ac electrical systems is the method of energy transfer of which most engineers are familiar. \Vhen time-varying electric Ilelds are present in energized transmission lines, a voltage gradient and electrical current are established within the conductors. If inadvertent physical contact is made between one of the energized conductors and another conductive object. (commonly referred to as an electrical fault). the conductive coupling can result in significant energy transfer and cause severe damage. If the voltage gradient is high enough to exceed the breakdown voltage of the surrounding material, an ionized current conducting channel can be formed, which is referred to as an arc fault.IEEE Std 2746 pdf download.