All data required pertains to the entire system of transmission lines and pipelines which contribute, either directly
or indirectly, to pipeline potentials within the FPC right-of-way under review.

1. Drawings of Proposed Mitigation
Complete set of drawings and accompanying notes showing the proposed mitigation in
sufficient detail to understand how and where it will be constructed and connected. This includes
zinc ribbon anodes, gradient control mats and any other equipment used to ground the pipeline
or lower touch, step, or coating stress voltages. Indicate whether deadfront construction will be
used and any requirements for earth surface treatment (such as crushed rock). Each drawing
should also include the following:

a. Identification number, revision number, and revision date,
b. Identification of the engineer and organization producing the drawing,
c. Name of project for which the drawing has been produced.

2. Complete Report

a. Identification

i. Revision number and date
ii. Names of authors and signatures
iii. Name of the organization producing the report
iv. Name of the project and title of report

b. Map

Please submit a map providing an overview of the pipeline/transmission line system
under study, such that the reviewer can rapidly identify the following:

i. Transmission lines crossing the pipeline within the FPC right-of-way under study or
within 1000 feet of either end of the FPC right-of-way.
ii. Transmission lines following the pipeline route, less than ½ mile from the pipeline, for a
total distance of more than 500 feet, within 20 miles of either end of the right-of-way
under study or along the right-of-way.
iii. Locations of all substations and power plants within 500 ft of the pipeline under study or
connected to it, both along the right-of-way and within 5 miles of either end of the right-of- way under study.
iv. Locations of all substations and power plants connected to the transmission lines listed
in the items above, paying particular attention to include each substation (and power
plant) transformer supplying a significant fault current contribution to these transmission
lines.
v. Transmission line phase transposition locations.
vi. Locations at which soil resistivity measurements have been carried out. Label these with site numbers.
vii. Sections of the pipeline along which mitigation has been installed: distinguish between
single-wire and double-wire areas.
viii. Mile post numbers
ix. Locations of large pipeline appurtenances, such as valve sites, metering stations, pig
launchers and receivers, etc. Test station locations are not required on this map.

c. Scope

i. Station numbers of starting and ending points of sections of pipeline within FPC rights-of-way.

d. Computer Model Details

i. Scale plot or drawing of pipeline and transmission lines modeled to compute induced or
transferred voltages to the pipeline section within the FPC right-of-way. Label pipeline,
transmission lines and indicate mile post numbers. Indicate the section (span) numbers
from the computer model at mile post locations, deviation locations, and crossing
locations. Indicate locations where faults have been modeled.
ii. Clear hand sketch of circuit models used to model fault and load conditions. Label each
phase with the phase identification number used in the computer model and with the
actual transmission line circuit number and phase (or pipeline name). Indicate ground
resistances used for substations, towers/poles, mitigation wires (in ohms per unit length)
for each range of sections, non-mitigated pipeline sections (in ohms per unit length) and
any other pipeline or transmission line ground wires. Indicate source voltages and
impedances.
iii. Sketches of all transmission line cross sections modeled, including conductor (phase and
static) types, average heights and spacings (both vertical and horizontal). Label phases.
Reference each cross section to a transmission line or portion of a transmission line
shown in the map (Item 2b).
iv. Pipeline (and coating) electrical characteristics and burial depth.
v. List of locations of test stations and other exposed pipeline appurtenances.
vi. Plan view sketches of exposed pipeline appurtenances indicating extent of area
potentially requiring touch voltage protection.
vii. Sketches of towers/poles (and associated grounding) and pipeline (and gradient control
wire or ground mat) sections modeled to compute conductive interference levels for
coating stress voltages, touch voltages, step voltages and pipeline GPR. Specify how
pipeline and towers/poles were energized (i.e., current or voltage type of energization,
which software was used, how energization currents or voltages were derived, whether
inductive and conductive components were computed separately or in a single step).
viii. Indicate which soil model was chosen to compute mitigation wire ground resistances
and conductive interference levels as a function of pipeline station number.

e. Computation Results

i. Soil resistivity data and computed apparent soil resistivities in graphical format, with
computed soil structure in tabular form. Identify these with the site number. For each
site, indicate the dryness of the soil at the time of the measurement (i.e., indicate recent
weather conditions and apparent state of the soil). The report should state that the soil
resistivity data in the plots is an exact and complete representation of the measurements
made in the field. Indicate what method (e.g., Wenner) and instrumentation were used
for the measurements and what organization carried out the measurements.
ii. Ground resistance per unit length and coating stress voltage in %GPR for each soil
structure in which mitigation wires have been modeled.
iii. Tower/pole ground resistances in each soil structure measured along the FPC right-ofway
or within 1 mile beyond the ends of the FPC right-of-way.
iv. Graph(s) of induced pipeline potential versus station number, throughout entire pipeline
length modeled to determine potentials in the FPC right-of-way, with mitigation, during
fault and load conditions. Results for representative faults throughout the FPC right-ofway
or an envelope of the maximum pipeline potentials should be included.
v. Graph(s) of induced pipeline coating stress voltage versus station number, throughout
the length modeled
vi. Graphs of conductive component (i.e., through earth, from nearby faulted towers/poles)
of pipeline coating stress voltage at representative locations modeled
vii. Total pipeline coating stress voltage at representative locations
viii. Graph, for each transmission line, of maximum overhead ground wire leakage current to
earth as a function of pipeline station number, during fault conditions.
ix. Graph(s) showing touch voltages within reach of exposed pipeline appurtenances, with
mitigation: provide both inductive and conductive components, if these were computed
separately, or total, if touch voltages were computed in a single step. Superpose gradient
control grids on these plots.
x. Graph(s) showing step voltages within and up to 2 m outside gradient control grids:
provide both inductive and conductive components, if these were computed separately,
or total, if touch voltages were computed in a single step.
xi. Safety calculation (i.e., maximum allowable touch and step voltages)
xii. Results justifying rating of DC decoupling devices during load and fault conditions.

3. Copies of Key Original Data supplied to the mitigation designer for use in the study. Note that this
information should be provided for all mitigation studies performed (or to be performed) on any portion of
the pipeline within the FPC right-of-way or within 20 miles on either end of the FPC right-of-way:

a. Data Supplied by the Electrical Utility

i. One-line diagrams showing distances and total spans between substations
ii. Fault current contributions from source transformers and currents flowing along
transmission lines, including future growth factor, for single-phase-to-ground faults
occurring within FPC right-of-way. These should be supplied in amperes, magnitude
and phase angle, for all three phases and all circuits. This data should be provided both
in tabular form and on a single-line diagram.
iii. Backup fault clearing times, re-closure details, X/R ratios
iv. Load currents in amperes per circuit (magnitude and angle), load unbalance in percent.
Include the future growth factor.
v. Tower/pole ground resistances and utility tower/pole grounding design specification.
Locations of counterpoise conductors.
vi. Substation and power plant ground resistances
vii. Transmission line conductor (including static wire) data: cross-sectional positions and
conductor types. Label phases.

b. Pipeline Alignment Sheets

4. Data Files in Electronic Format

a. Computer software input and output files used to obtain all the computation results presented to SES
b. Index naming each input and output file and indicating explicitly to what portion of the study it
belongs so that SES may rapidly spot-check results presented in the report.

Study Review Guidelines

SOIL RESISTIVITY ANALYSIS

Check the following:

1. Measurements have been made at the required locations: i.e., exposed pipeline appurtenances,
transmission line crossings, locations where the pipeline becomes especially close to the transmission line
(i.e., 50 ft or less clearance from the transmission line structures), deviations of the pipeline from the
transmission line (or of the transmission line from the pipeline), transmission line phase transpositions, at
transmission line taps or loops to substations, at minimum intervals of 1-2 miles (2 miles if resistivities
remain similar from one site to another, 1 mile if resistivities vary significantly from one site to the next).

2. Pin spacings are adequate: they should range from 0.5 ft to at least 300 ft and increase in sufficiently small
logarithmic increments as to permit a smooth curve to be drawn from the measured data.

3. Measurements are of adequate quality: smooth curve, preferably a plateau at large pin spacings

4. Measurements fit the computed soil model

5. The computed soil model is reasonable: i.e., double-check if layer resistivities lie outside the range of 10 –
10,000 ohm-m or if the zinc ribbon anodes or gradient control mats are located in or near a particularly
high or low soil resistivity layer.

INDUCTIVE INTERFERENCE CALCULATION

General

1. Plot the system modeled:

a. Does it look like the drawings provided?

b. Do the pipeline and transmission lines extend far enough to correctly compute induced voltages
transferred to the FPC right-of-way?

c. If any power plants or substations are located close to the pipeline or are connected to the
pipeline, have they been included in the model?

2. Has the soil resistivity for the inductive coupling calculations been correctly chosen? A conservative
approach is to select the highest bottom layer resistivity measured or to use the bottom layer resistivity
measured in each region.

3. Plot overhead ground wire and pipeline ground wire shunt impedances as a function of position, with a
logarithmic Y-axis scale. Do the transmission line system grounds and pipeline grounds match those
indicated in the designer’s circuit diagram? For those which have been calculated, are these calculations
sound (for example, is the mitigation wire ground resistance per unit length based on the modeling of at
least 1000 feet of pipe length, for a continuous mitigation wire system)?

4. Are pipeline, overhead ground wire, and phase conductor characteristics and positions correct?

5. What modifications have been made to the line parameters automatically computed by the right-of-way software?

6. Is the pipeline correctly terminated at its end points? Check that it is not connected to any of the
transmission line sources, unless there is a deliberate connection to a power plant.

Fault Conditions

7. Have faults been simulated at representative worst case locations on the transmission lines having the
greatest impact on the pipeline within the FPC right-of-way?

8. Have fault current sources been correctly modeled or have appropriate conservative assumptions been
made? Check interconnections between circuits at substations.

9. Plot currents flowing in all conductors throughout the length of the system, for faults occurring at both
ends of the FPC corridor. Are the fault currents correct?

10. Are the source impedances used for the fault study correct?

11. What tower/pole ground resistances have been used: design values, measured values, or values based on
soil resistivity data? What tower/pole ground resistances are obtained when modeling the tower/pole
grounding in the measured soil structures?

12. Is the transmission line overhead ground wire GPR at the fault location on the correct order of magnitude?
(The plot of the envelope of maximum overhead ground wire leakage currents can be multiplied by the
tower/pole ground resistances to obtain GPR). Typical values are on the order of 10-20 kV.

13. Is the pipeline GPR on the correct order of magnitude? Do peaks occur at the expected locations? Is the
maximum current induced in the pipeline on the correct order of magnitude (i.e., no more than: fault
current flowing parallel to pipeline * 0.5).

14. When the coating stress voltage factor is applied to the GPR plot, do we obtain the inductive component
of the coating stress voltage provided by the mitigation designer?

Load Conditions

15. Have results from multiple circuits during load conditions been correctly superposed? Unless the electric
utility has specified unambiguously the phase relationships between all circuits at all times, the
conservative approach is to compute induced voltages due to each circuit independently, then add the
magnitudes of the induced voltages from each circuit together.

16. Plot currents flowing in all conductors throughout the length of the system. Are the load currents in the
model correct?

17. Is the pipeline GPR on the correct order of magnitude? Do peaks occur at the expected locations? Is the
maximum current induced in the pipeline on the correct order of magnitude (estimate upper bound based
on perfect parallelism and good grounding).

18. When the coating stress voltage factor is applied to the GPR plot, do we obtain the inductive component
of the coating stress voltage provided by the mitigation designer?

CONDUCTIVE INTERFERENCE CALCULATION

General

1. Plot the systems modeled:

a. Do they look like the drawings provided?
b. Do the pipeline and transmission lines extend far enough to correctly compute transferred
voltages and account for remote grounding of the pipeline?
c. If any power plants or substations are located close to the pipeline or are connected to the
pipeline, have they been included in the model and correctly modeled? Is the soil resistivity data
appropriate?

2. Check for adequate conductor segmentation, especially for long conductors running past towers/poles

3. Check for short conductors with very large Cartesian coordinates

4. Check for gaps in grounding systems or for grounding systems not connected to the pipeline or to one
another.

5. Have results been generated for all pertinent soil structures?

Gradient Control Wire Modeling

6. Have inductive and conductive components been correctly added together:

a. general approach
b. correct phase angles

7. Have MALZ tower/pole ground resistance and SPLITS tower/pole ground resistance been properly
reconciled?

8. Has sufficient length of pipeline been modeled to represent remote grounding?

Gradient Control Grid Modeling

9. Have inductive and conductive components been correctly added together:

a. general approach
b. correct phase angles

10. Have MALZ tower/pole ground resistance and SPLITS tower/pole ground resistance been properly
reconciled?

11. Have any gradient control wires located under the grid been included in the model up to a distance of at
least 10 grid dimensions from the grid, in both directions?

12. Are point spacings small enough (i.e., at most 0.5 m)? Do they extend at least 2 m outside gradient control
mats for step voltage calculations?

DESIGN CRITERIA

1. Do the computed coating stress voltages meet the design limit?

2. Do the computed touch and step voltages at exposed pipeline appurtenances meet the safety limits during
load and fault conditions?

SAFETY CALCULATION

1. Has this been carried out based on ANSI/IEEE Standard 80-2000, with the decrement factor (for the
asymmetrical component) accounted for?

2. In the choice of the native soil resistivity near the surface, has allowance been made for wet conditions?
Check soil models at depths up to 2-3 feet for the lowest layer resistivities found.

3. Has the back-up fault clearing time been used and have automatic re-closures been accounted for?

CHECKLIST

1. Data required for review has been supplied.

2. Computer model described in report reflects data supplied.

3. Assumptions and approximations made are conservative.

4. Analysis and design approaches are sound.

5. Numerical results of study are reasonable and match results of spot-checks.

6. Study is complete.

7. Proposed mitigation is satisfactory.