Data Request for AC Interference Study: Power Company
Right-of-Way Data: Conductor Positions & Phasing
- Strip Maps. Please provide strip maps indicating, throughout the common right-of-way, transmission line routing, conductor heights above ground, and structure positions, for all circuits which run parallel to the victim line (including victim line feeds or taps) for even a short distance. Please note that at locations where the power line and victim line veer apart, it is important to know the relative positions of the power line and victim line up to a point where they are about 2 km apart.
- Phase Transpositions. Specify the locations of all phase transpositions as well as the configuration of all conductors whose positions change due to the transpositions: please provide enough information to allow three-dimensional modeling of all conductors throughout each transposition.
- Power Line Cross Sections. Please provide typical cross sections of the power line right-of-way with:
- Phases and circuits labeled;
- Conductor spacings and heights above ground (at structure and midspan) clearly indicated. Include overhead ground wires.
- Remote Substation Locations. For all circuits which are present within the common right-of-way, even for a short parallel distance, please specify the distance between the point where they leave the common right-of-way and the substation beyond the common right-of-way to which they are connected. Please also indicate how many structures are present within this distance.
- Structure Grounding. For all circuits, indicate the footing type of the supporting structures: please provide a detailed description which includes the dimensions of the footing and of any associated grounding conductors, including rebars in concrete foundations. Please also indicate the distance between the structure footings if more than one are associated with a given structure (e.g., for lattice towers).
- Guy Wire Anchors. Please indicate at what locations there are guy wire anchors that are electrically continuous with static wires or neutral conductors: i.e., guy wires do not have insulating breakers in them and are bonded to static wires or neutral conductors at pole top.
- Counterpoises. Please indicate positioning, length and conductor diameter of all existing buried counterpoises or other conductor networks which are within or close to the common right-of-way.
- Nearby Substation and Power Plant Grounding Systems. Please provide drawings of the grounding systems of any substations within 5 grounding system dimensions of the victim line (i.e., for a 30 m x 25 m substation, please provide a sketch if the substation is within 5 x 30 m = 150 m of the victim line) or of power plants (including substations) which are fed by the victim line.
- Single Line Diagrams. Please provide single line diagrams showing networks associated with all circuits present in the common right-of-way.
Specify precisely the conductor type of all phase wires and static wires of all circuits in the common right-of-way. For long counterpoises, please also indicate the conductor type.
- Structure Ground Resistances. Please provide, if available, a listing of the ground resistances of all power line structures in the common right-of-way and of all structures within a distance of 2 km beyond the point where each circuit leaves the common right-of-way. If a listing of measured ground resistance values is unavailable, please provide typical value(s).
- Substation Ground Resistances.Please provide a listing of measured ground resistance values of all substations to which the circuits existing within the common corridor are connected.
- Static Wire Connections.For all circuits, indicate whether the static or neutral wires are electrically continuous with the structures which support them and with the substations at which they terminate. Provide the BIL rating for static wire insulators (if any). Indicate which structures are bonded to the static wires and the locations of static wire discontinuities.
Fault Current Data
- Fault Current Contributions.Please provide the single-phase-to-ground fault current contributions (magnitude and angle) from both sides of the faulted circuit and in all other transmission lines or circuits in the common right-of-way, even those whose parallel exposure to the victim line is short or is far from the fault location, and in all circuits connected to substations/plants fed by the victim line, for the following fault locations:
At roughly 10% intervals of the common right-of-way length on each of the circuits present in the common right-of-way. For circuits with only a short parallel exposure to the victim line, a minimum of one fault is required. Please be sure to include data for a fault occurring at any substations which exist within the common right-of-way.
Note that a printout from a typical short circuit computer software package would be satisfactory and very helpful if a sufficient number of nodes have been defined to include all circuits of interest for every fault location. If possible, please provide currents in all phases (including non-faulted phases), in amps..
- Soil Resistivity.Please indicate what soil resistivity was assumed for the computation of the line parameters used to calculate fault current values.
- Future Expansion.Please indicate for what period of time the fault current values are valid and what percentage increases can be expected in the future.
- Fault Duration:primary and secondary fault clearing times for all circuits for which fault current data has been provided. Please also provide details on automatic reclosure, if any.
- X/R Ratio. Please provide subtransient X/R ratio for each fault.
- Fault Type. Were fault current contributions determined assuming a bolted fault? If not, please explain.
Load Current Data
For all circuits within the common right-of-way, even those with only a short parallel exposure to the pipeline, please indicate the following:
- Phase-to-phase energization voltage,
- Magnitude and angle of present and well-defined future peak load and emergency load flow. Indicate if maximum load currents in one circuit necessarily coincide with small (or large) load currents occurring in another circuit or circuits: i.e., is there any correlation between the magnitudes and angles of the load currents in different circuits?
- What percentage increase can be expected to occur in the future for the values provided in item 2?
- Maximum load unbalance for each circuit.
- Maximum load harmonic currents for each circuit, if applicable.
Please specify the operating frequency of the power system (i.e., 50 Hz or 60 Hz or other).
Power Plants Fed by Victim Line
For each power plant fed by each pipeline under study, please provide the following information, similar to that requested in the previous sections for the power lines paralleling the pipeline:
- Geographical map, to scale, showing all circuits connected to plant and the substations to which they are connected at the far end.
- Cross sections of all power line circuits connected to these plants/substations.
- Single line diagrams for all circuits associated with the power plants/substations.
- Conductor and overhead ground wire characteristics for all circuits.
- Structure ground resistances and span lengths along all circuits.
- Substation and plant ground impedances (at both ends of each transmission line circuit).
- Grounding details of plant and substation (plan and specifications) to which the pipeline is connected.
- Plan drawing of plant, showing and labelling all power line circuits entering the plant.
- Current flows in all circuits connected to the plant/substation and in all circuits running parallel to the pipeline, during single-phase-to-ground faults occurring at the plant/substation and at 10% intervals along each circuit connected to the plant/substation.
Please provide the name, telephone number and FAX number of a resource person who can respond to inquiries related to the data requested above.