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TAR NC Implementation Document – Second Edition September 2017
Example of non-zero distance calculation:
distance D
A,B
between point A and point B is the shortest pipeline distance between
these points which respects the flow scenario principle. It is not possible to connect
A to B by flowing gas between N and D, because this section is a unidirectional pipe-
line between production plant D and the bidirectional network at consumption point
N (there is no distance from N to D identified as such in the distance table, while
distance from D to N is positive). The next-shortest pipeline is the one via points H
and P. Thus, distance between A and B is the sum of distances for sections A to N,
N to H, H to P, and P to B. The table gives 20.5km for distance AB. The same cal-
culations are performed for all the table.
Considering the
case of entry point A
, the table indicates the following results:
\\
Positive distances
for points B, H, I, K, M, N, O, and P which may be
connected with A because of the existence of a flow scenario.
\\
Zero distance
to some exit points due to the lack of a flow scenario for the
following reasons: problem of unidirectional pipelines (points C and R), or no
flow from and to the same point (point A).
The following step (as per Article 8(2)(a)) is to calculate weighted average
distances (WADs)
for entry points (AD
En
) and exit points (AD
Ex
). The result of
calculations also appears in Table 31
1)
. No (further) clusters of points A to R are con-
sidered here, for simplicity.
WADs FOR ENTRY POINTS
The formula for entry points in Article 8 is as follows.
Distances D
En
,E
x
have been calculated according to the shortest pipeline route
approach.
It is important to note that, since some distances have been marked as ‘
0
’ because
of the impossibility of a flow scenario between entry point P1 and exit point P2 , it is
also necessary to mark as ‘
0
’ the forecasted contracted capacities at P2, otherwise
WAD for P1 will be underestimated.
The lack of a flow scenario between two points
implies to amend both distances and capacities used for calculations.
Therefore, for entry points, the following matrix of corrected exit forecasted contract-
ed capacities is used for ADEn derivation, and it displays ‘
0
’ in red where applicable.
1) As indicated in the previous footnote, it is important to notice that the value of D
En,Ex
may be different for WAD calcula-
tions at entry points and at exit points, due to the flow scenario constraint.