IN THE MATTER OF THE
APPLICATION
FOR
APPROVAL
OF
THE
UPGRADING
OF
ORMOCjTONGONAN -ISABEL
138
KV
TRANSMISSION
LINE, WITH PRAYER FOR
THE
ISSUANCE
OF
A
PROVISIONAL AUTHORITY
ERC CASE NO.
NATIONAL
GRID
CORPORATION
OF
THE
PHILIPPINES (NGCP),
Applicant ..
)(-
---------------------
-)(
2014-180
RC
DOCKETED
Date: . ~~.~~
...j]),i ..~~
By: "..,....
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"
DECISION
Before the Commission for resolution is the application filed on 12
December 2014 by the National Grid Corporation of the Philippines
(NGCP) for approval of the upgrading of the OrmocjTongonan-Isabel
138 kV Transmission Line' Project, with prayer for the issuance of a
provisional authority.
I
,"
Having found said application sufficient.in form and in substance
with the required fees having been paid, an Order and a Notice of Public
Hearing, both dated 03 February 2015, were issued setting the case for
initialhearing on 07 APri12~
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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In the same Order, NGCP was directed to cause the publication of
the attached Notice of Public Hearing, at its own expense, twice (2X) for
two (2) successive weeks in two (2) newspapers of general circulation in
the Philippines, with the date of the last publication to be made not
later than ten (10) days before the date of the scheduled initial hearing.
It is also directed to inform the consumers within its franchise area, by
any other means available and appropriate, of the filing of the instant
application, its reasons therefor, and of the scheduled hearing thereon.
The Office of the Solicitor General (OSG), the Commission on Audit
(COA) and the Committees on Energy of both Houses of Congress were
furnished with copies of the Order and Notice of Public Hearing and were
requested to have their respective duly authorized representatives
present at the initial hearing.
Likewise, the Office of the Mayor of Quezon City was furnished
with copies of the Order and Notice of Public Hearing for the appropriate
posting thereof on its bulletin board.
On
07
April
2015,
NGCP filed its "Pre-Trial Brief'.
During the 07 April 2015 initial hearing, only NGCP appeared. No
intervenor / oppositor
appeared
nor
was
there
any
intervention/ opposition registered.
At the said hearing, NGCP presented its proofs of compliance with
the Commission's posting and publication of notice requirements which
were duly marked as Exhibits "D" to "Q". Thereafter, it conducted an
expository presentation of its application.
At the termination of the expository presentation, NGCP presented
its witness Mr. Christian B. Ereno, Head of the Visayas System Planning
Division of NGCP, who testified in support of the application.
In the course of his direct testimony, additional documents were
identified and duly marked as exhibits. Thereafter, the Commission
propounded clarificatory questi~ns o~e
said witness and directed the
submissionofvariousdocumen~1
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
_~.~g~3 ~f!..
4.._
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_ _
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_
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On 10 April 2015 and 13 April 2015, NGCP filed its "Formal Offer
Of Evidence" and "Compliance", respectively.
On 04 December 2015, the Commission issued an Order admitting
the exhibits contained in the said formal offer of evidence and declaring
the case submitted for resolution.
DISCUSSION
1.
PROJECT DESCRIPTION
This project involves the construction of 74 new steel tower
structures along Ormoc/Tongonan-Isabel
138 kV line adopting a new
wind design criteria of 300 kph (from 270 kph). The typical tower design
parameters for the proposed transmission line structures are as follows:
Pronosed UnlU"adinJ!:of Ormoc/Ton
Suspension/
Tower Type
Tension/
Dead End
DTlsus-Zm-138
onan- Isabel 138kV Transmission Lines
Wind Span
Line Angle
(m)
(Degree)
Susoension
0-5
400
Tension
0-5
400
Tension
0-15
400
Tension
0-45
400
DTlde4s-Zm-138
Dead End
0-45
400
STltellls-Zm-138
Tension
0-15
400
STldels-Zm-138
Dead End
0-15
400
DTltens-Zm-138
DTltellls-Zm-138
DTlten 4s-Zm-138
These towers shall require construction of new foundations suitable
for the new wind design criteria. Existing limits for the rights-of-way for
the Ormoc/Tongonan- Isabel 138 kV line shall be utilized. However,
additional
rights-of-way may be required, as other ;~w~shall
be
located at new sites to be able to construct new fOUndatiO~
ERC CASENO. 2014-180 RC
Decision/10 December 2015
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2.
._._
.._.__._. ._
Project Rationale
The project is intended to improve the reliability of the
Ormoc/Tongonan-Isabel 138 kV Transmission Line which suffered
catastrophic damage due to Typhoon Yolanda in 2013.
3.
Diagram
Below is the diagram of the 138 kV transmission system in the
northern part of the Leyte Grid:
Tongonan
Babatng on
"0.
__ •••••
"
,
Paranas
._---:
..
I
..
.. I
,
.,
Ormoc
-.
... ...... ..
,
Maasin
:
:,
:
Legend:
."
l
l,
Isabel
4.
---~-
.......
,
--
--
Portions with toppled towe r structu res
De-energized portion of th e line
Temporary by-pass lines
Project Cost
The estimated capital investment for these proposed projects and
activities to be implemented amounted to Six Hundred Seventy Three
Million Six Hundred Seventy Four Thousand Seven Hundred
Seven and 05/100 Pesos (Php673,674,727.0S) (excluding permit ~
f"':~~
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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______ _
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The contract for the supply of materials for the proposed projects
will be assigned to qualified suppliers and contractors following a
competitive bidding and selection process. The funding will be sourced
from NGCP's Internal Cash Generated (ICG) fund.
The proposed projects will be subject to optimization following the
principles found in the Rules in Setting the Transmission Wheeling Rates
(RTWR).
5.
Need for the Project
Temporary Restoration
Restoration
works were conducted
to establish
by-pass
transmission lines that will link the remaining undamaged portions of
the 138 kV line and provide transmission link towards Isabel Substation.
As an interim scheme, Emergency Restoration System (ERS), lightweight modular towers and steel pole structures, which are being used
for 69 kV lines, were used for the by-pass lines. The ERS utilize 1x795
MCM ACSR conductor. Similarly, the light-weight modular towers and
steel pole structures were arranged to accommodate 1 x 795 MCM ACSR
conductor.
Limitation of the Temporary Scheme
The temporary scheme provides single circuit connection from
Tongonan Power Plant to Ormoc Substation and Ormoc Substation to
Isabel Substation, hence, there is no N-1 provision. Therefore, outage of
the 138 kV line from Ormoc Substation to Isabel Substation will result to
the interruption of power delivery towards the major loads being served
by Isabel Substation.
The by-pass lines are supported by mostly steel pole structures
designed for lower voltage level and some portions are located in difficult
terrain and limited area, hence, the design capability of the by-pass lines
to maintain the required line clearances is limited. As a result, there is
higher possibility of outage due to line to ground fault which will result to
interruption of power towards Isabel Substation. In addition, more
frequent ROW clearing activities will be required along the by-pass 'nes
in order to maintain minimum clearances from nearby vegetation.
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
Page 6 of 14
In order to address the system limitation and improve the
reliability of the Ormoc/Tongonan-Isabel
138 kV Line, transmission
upgrading is being proposed.
USE OF HIGHER WIND VELOCITY IN THE DESIGN OF
TRANSMISSION LINE STRUCTURES AFFECTED BY SUPER
TYPHOON YOLANDA
Being an archipelagic country with 7,100 islands located at the so
called "typhoon alley of the world", the Philippines is exposed to very
strong winds especially during the passage of tropical cyclones.
Over the years, the PAGASA has compiled a database of typhoons
that crossed or made landfall in the Philippines during that past decades.
The frequency of these typhoons from 1948 to 2013 is presented in the
following tables.
Annual Number of Tropical Cyclones in the PAR
Period: 1948-2013
40
35
III
••c
o
>-
U
30
_
Number of Tropical Cyclones
-
Five-year
-
Linear (Five-year
running
y = -0.026.
mean
running mean)
o
-~
c;; 25
,g
-";'\
a.
e
-
20
I..
I-
I
o
t
•••E
i
+ 20.22
- ...
h
\
15
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J
10
5
o
1948
1953
1958
1963
1968
1973
1978
1983
1988
1993
1998
2003
2008
2013
Year
During the 6s-year period, an annual average of 19 to 20 typhoons
occurred in the Philippine Area of Responsibility (PAR). The most
number of typhoons occurred in 1993 which recorded 32 while the least
number of typhoons occurred in 1998 which recorded ~
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
Page 70f14
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20
"
18
16
14
u 12
I-
~ 10
o
z
8
6
4
2
o
48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96 99 02 05
Year
An annual average of 8 or 9 typhoons made landfall/crossed the
country. During the 59 year period, 19 typhoons were recorded to have
made landfall in 1993, which is the highest incidence; while 4 each were
recorded in the years 1955, 1958, 1992 and 1997 which is the least.
Current NGCP Design Basis
The wind loads currently being used by NGCP in the design of
transmission towers are based on the provisions stated in the 2008
Philippine Electrical Code Part 2, particularly the Basic Wind Zoning
Map coveringthe PhiliPPiD;Y
r
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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__.-.-.--.-_ -.--.--_
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..-.-..-.-.-.-Basic Wind Speed is the maximum sustained wind
measured at an interval of 3 seconds at 10 m above ground.
III
kph
;\";.1.1
Evolution of Wind Design Specifications
The tabulation below illustrates the development of wind design
specifications used in the design of power transmission structure~
1
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
Page 9 of 14
Prior to
1970S
NPC/TRANSCO
NGCP Practice
165 kph
NPC
Specs
165 kph
Basis/
Reference
1970S
1990S to 2008
2008 to
present
18Skph
(3-sec gust wind)
Zone 1: 270 kph
Zone 2: 240 kph
(3-sec gust wind)
Zone 1: 270
Zone 2: 240
Zone 3: 160
NPC
Specs
185 kph
2000 PEC-2
128 kph*
(lo-min sustained
wind)
*Equiv to 212 kph
(3-sec gust wind)
2008 PEC-2
(3-sec gust wind)
Zone 1: 270 ,
Zone 2: 240 I
Zone: 160
up to
1990S
OFFICIAL SEVERE WEATHER
BULLETINS ISSUED BY NDRRMC
DATE
TIME
MAXIMUM HIGHEST
LOCATION OF la-MINUTE
-~~
CENTER
~AINE~
GUST
(kph), (kph)
1
6-Nov-13
BPM
PACIFIC OCEAN
195
2
7-Nov-13
2AM
PACIFIC OCEAN
215
3
BAM
PACIFIC OCEAN
215
4
2PM
PACIFIC OCEAN
215
6PM
453 KMSEOF
GUIUAN, SAMAR
225
260
BPM
290 KM ESE OF
GUIUAN, SAMAR
225
260
235
275
215
250
215
250
5
6
S-NOV-13
2AM
I
62KMSEOF
GUIUAN,
SAMAR
OVERDAANG
BANTAYAN,
CEBU
115KMWEST
OFROXAS
CITY
230
7
SAM
S
2PM
9
BPM
OVER PALAWAN
195
230
2AM
WEST OF
MINDORO
175
210
11
BAM
WEST PHIL SEA
175
210
12
2PM
OUTSIDE PAR
185
220
10
9-Nov-13
EQUIVALENT 3SEC GUST WIND
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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As shown in the table below, it is clear that the wind velocities
carried by Super Typhoon Yolanda were greater than the design wind
velocity used on these transmission lines, thus constituting the main
cause of tower toppling.
TRANSMISSION
LINE
NUMBER OF
TOPPLED
TOWERS
WIND
VELOCITY
USED IN
DESIGN
(3-sec GUST)
WIND VELOCITY
DURING YOLANDA
(to-min / 3-sec)
134
240 kph
215 kph / 360 kph
74
270 kph
235 kph / 390 kph
Panitan-Nabas 138 kVT/L
I
I
I
Orrnoc-Isabel138 kVT/L
I
Steel tower type used in this exercise:
6.
TOWER DESIGN CRITERIA
6.1. FOOTING RESISTANCE
10 ohm or less
6.2. DESIGN WIND VELOCITY
ZONE II -240 kph, forVisayas
(except Leyte, Samar & Masbale), Palawan & Mindanao
6.3 WIND PRESSURE ON TOWER DUE TO :
a. TRANSVERSE WIND DIRECTION, (PI)
b. 45 DEGREE WIND DIRECTION, (Pl45)
445 kglm'
315 kglm'
I
I
6.4 WIND PRESSURE ON WIRES DUE TO :
a. TRANSVERSE WIND DIRECTION, (Pw)
b. 45 DEGREE WIND DIRECTION, (Pw45)
167 kglm'
84 kglm'
Refer.to loading diagrams of each towortype
6.5. ULTIMATE DESIGN LOADINGS
7.
TOWER TYPES, UNE ANGLES AND EFFECTIVELOADING SPAN
CLASSIFICATION
TYPE
DA
-OS'"
Suspension
Ei'
..
Slrain _...
~';d.End-
WEIGHT SPAN
(meters)
(meters)
CONDo
OHGW/OPGW
Q'.2'
400
600
800
•.,
._,
O;:w-
400
-0" 45.....
JOO'
.~200 "-__' 18oo~.._
1200
--wo-
1800
UPUFT SPAN
(meters)
",..-, •..-.
.~ ,--
4oo......goo-- .. 1300-'~
Suspension / Strain'
o;-T- .
S~I~ "---0"15;'
--' 400
"'-::i-I--
00
WINO
SPAN
DEF
ANGLE
CONDo
I
'«'1-
OHGW/OPGW
.._' _ .. _ ..: ...
._ .. 400__ ..•. 5()O_
.~..
600
-1'soo,-I---iOO- -
¥
._~~ .... 1
900
900
•
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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_._ _ _
_
- -..- - -----.--.-.
Based on the foregoing, the following are the reasons for the use of
higher wind velocity in the design of transmission line structures:
1.
There is certainly a need to increase the design
to meet the stronger winds carried by typhoons;
wind speeds
2.
It may not be practicable to increase the design wind speed
parameters up to or even greater than the maximum recorded
wind speed experienced; and
3. Striking a balance between structural adequacy and cost
implications, NGCP proposed the use of the design wind
velocity indicated in the table below and to these proposed
project:
TRANSMISSION LINE
WIND VELOCITY
USED IN DESIGN
(3-SEC GUST)
PROPOSED DESIGN
WIND VELOCITY
(3-SEC GUST)
Panitan-Nabas
138 kVT/L
240 kph
270 kph
Ormoc-Isabel
138 kVT/L
270 kph
300 kph
Proposed Upgrading of the Ormoc/Tongonan-IsabeI138
kV Line
The project will involve the construction of new steel tower
structures which are in conformity with required design standards for
138 kV lines and will provide more reliable clearances between overhead
lines and nearby vegetation. It will also improve the reliability of the 138
kV line through upgrading from single circuit to double circuit, hence,
will provide N-1 condition.
Relocation of Tower Structures
New transmission line structures will be constructed in lieu of the
toppled tower structures. The new tower structures shall be located at
new sites to be able to construct new foundations that shall adopt the
newwind designcriteria.~
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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_
There is a need to immediately complete the upgrading of the
Ormoc/Tongonan - Isabel 138 kV Transmission Line in order to achieve
the following:
1.
To minimize exposure to fault along the temporary bypass lines for the Ormoc/Tongonan - Isabel 138 kV Line
which will result to interruption of power towards the
connected loads in Isabel Substation;
2.
To restore the transmission loop between the 138 kV
facilities in Ormoc, Isabel and Tongonan, hence, provide
N -1 contingency; and
3. To retrieve the temporary structures used for the by-pass
lines to ensure sufficient availability of temporary
structures for future emergency use.
A perusal of the evidence presented herein showed that NGCP's
application for the approval of the upgrading of the Ormoc/TongonanIsabel 138kV transmission line project is in accordance with the
provisions of Republic Act No. 9136 or the Electric Power Industry
Reform Act (EPIRA) of 2001 and will redound to the benefit of its
consumers in terms of continuous, reliable and efficient power supply as
mandated by the EPIRA (Section 2. Declaration of Policy - (b) to ensure
the quality, reliability, security and affordability of the supply of electric
power and Section 9. Functions and Responsibilities - (d) That
TRANSCO shall submit any plan for expansion or improvement of its
facilitiesfor approval by the ERC).
WHERFORE, the foregoing premises considered, the application
filed by NGCP for the approval of the upgrading
of the
Ormoc/Tongonan-Isabel
138kV Transmission Line Project, with prayer
for provisional authority, is hereby APPROVED subject to optimization
based on its actual use and/or implementation during the reset process
for the next regulatory period following the procedures stated in the
RTWRand other relevant issnancesofthe commiSSi~
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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.._. _.. ._ __ _
_ - - --
-..- - --.---.-. .
Relative thereto, NGCP is hereby directed to conduct competitive
bidding for the purchase of major materials in the implementation of the
proposed projects.
Further, NGCP is directed to pay, within fifteen (15) days from
receipt hereof, a total permit fee in the amount of Five Million Fifty
Two Thousand
Five Hundred
Sixty and 45/100
Pesos
(Php5,052,560.45), computed as follows:
Permit Fee
Total Estimated Project Cost X 0.75
=
100
PhP 673,674,727.05
=
100
=
Permit Fee
PhP 5,052,560.45
SO ORDERED.
Pasig City, 10 December 2015.
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>
JOSE VICENTE B. S~
Chairman & CEO ?'
AL~~
CommiSSIOner
o.
---
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GLJiUAVicTORIA
Commission
On Official Travel
JOSEFINA PATRICIAA. MAGPALE-ASIRIT
Commissioner
-ERe I
Office of the Chairman
1111!!IIr:~IIIIIIIII!II'lliillll
gt
D-2016-007-0C-02417
. YAP-TARUe
0--
GE ONIMO D. STA. ANA
Commissioner
•
•
ERC CASE NO. 2014-180 RC
Decision/10 December 2015
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Copy Furnished:
1.
Atty. Luis Manuel U. Bugayong, Ronal Dylan P. Concepcion, Mark
Anthony S. Actub, Raycell D. Baldovino and Ari Vergil P. Fabros
Counsel for applicant NGCP
National Grid Corporation of the Philippines (NGCP)
NGCP Building, Quezon Avenue cor. BIR Road
Diliman, Quezon City, Metro Manila
2.
The Office of the Solicitor General
134 Amorsolo Street, Legaspi Village, Makati City
Metro Manila
3. The Commission
on Audit
Don Mariano Marcos Avenue
Diliman, Quezon City, Metro Manila
4. The Senate Committee on Energy
Senate of the Philippines
GSIS Building, Roxas Blvd., Pasay City, Metro Manila
5. The House Committee on Energy
House of Representatives
Batasan Hills, Quezon City, Metro Manila
6. Office of the City Ma/1
Quezon City
/'
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