IEEE Std 2746-2020 pdf free download

IEEE Std 2746-2020 pdf free download.IEEE Guide for Evaluating AC Interference on Linear Facilities Co-Located Near Transmission Lines.
Direct grounding is corn monlv applied as either a buried counterpoise adjacent to the railroad or as a gradient mat around equipment and buildings. Additional grounding to railroad signal huts can be directly bonded to existing grounding systems. but connections to the track themselves may not be permitted due to railroad signaling, though new devices are in the process of being certified for use on signaled rails. Tracks with limited or no signaling may allow for direct grounding to the track.
Buried parallel, but unconnected, counterpoise and aerial shield conductor allow for a current to be induced to counter the eiThets of the transmission line on the railroad. This results in a lower voltage being induced on the railroad. Compared to direct grounding. more conductor is often required but does not interfere with existing track signaling systems.
Several transmission line design changes may help reduce ac interference from a transmission line to a railroad. Transmission lines that consist of two or more circuits may configure the phasing of the conductor to reduce magnetic fields for steady-state operation. Also, the addition of an underbuilt shield wire or underbuilt neutral acts as a shield for ac interference, as well as improves lightning performance of the transmission structures. For conduction concerns, adjusting the location of transmission line poles and changes to the grounding systems can significantly reduce voltages transferred to the railroad. Considering the personnel protection voltage is alTected by the time that a person is exposed to voltages, a protective relay operation ma’ be adjusted to clear a fault faster on the transmission line.
Design changes to the railroad may improve track rail voltages, either rail-to-ground or rail-to-rail. Reducing the continuous track exposure length can be done by adding an insulated joint to the shared corridor, however. these insulated joints may fail and need to be evaluated for signaling operation. Upgrading or adding track signaling can either improve the 60 Hz voltage susceptibility of equipment or remove ac interference concerns. Track signaling aflicted by voltage imbalance from one rail to another max’ be mitigated by the addition of 60 Hz shunts. As mentioned above, some surge protection devices may be added to the track system to operate at voltages below equipment and personnel limits.IEEE Std 2746-2020 pdf free download.