122
Boletín IIE
julio-septiembre-2012
Artículo de investigación
Assessment and planning of the electrical systems
in Mexican refineries by 2014
Luis Iván Ruiz Flores1, José Hugo Rodríguez Martínez1,
Guillermo Darío Taboada2 y Javier Pano Jiménez2
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
Abstract
Nowadays the refining sector in Mexico needs to increase the quantity and quality of produced fuels by installing new process
plants for gasoline and ultra low sulphur diesel. These plants require the provision of electricity and steam, among other services
to function properly, which can be supplied by the power plants currently installed in each refinery through an expansion of their
generation capacity. These power plants need to increase its production of electricity and steam at levels above their installed
capacity, which involves the addition of new power generating equipment (gas or steam turbo-generators) as well as the raise of
the electrical loads. Currently, the Mexican Petroleum Company (PEMEX) is planning to restructure their electrical and steam
systems in order to optimally supply the required services for the production of high quality fuels. In this paper the present status
of the original electrical power systems of the refineries is assessed and the electrical integration of new process plants in the typical
schemes is analyzed. Also this paper shows the conceptual schemes proposed to restructure the electrical power system for two
refineries and the strategic planning focused on implement the modifications required for the integration of new process plants that
will demand about 20 MW for each refinery by 2014. The results of the analysis allowed to identify the current conditions of the
electrical power systems in the oil refining industry or National Refining Industry (NRI), and thereby to offer technical solutions
that could be useful to engineers facing similar projects.
Keywords: clean fuel, combined efficiency, conceptual design, economic assessment, electrical net, electrical system, electrical transformer, interrupt capacity, load flow, refinery power plant, refining, short circuit, synchronization bus, three wind.
1
2
Instituto de Investigaciones Eléctricas (IIE)
Petróleos Mexicanos (PEMEX)
Artículo de investigación
Assessment and planning of the electrical
systems in Mexican refineries by 2014
Hoy en día, el sector de refinación en
México necesita aumentar la cantidad y
calidad de los combustibles producidos,
mediante la instalación de nuevas plantas
de proceso para la gasolina y el diésel ultra
bajo en azufre. Estas plantas requieren el
suministro de electricidad y vapor de agua,
entre otros servicios, para que funcione
correctamente, los cuales pueden ser suministrados por las fuentes de generación
instaladas en cada una de las refinerías y a
través de una expansión de su capacidad
de generación. Estas centrales eléctricas
necesitan aumentar su producción de
electricidad y vapor de agua a niveles por
encima de su capacidad instalada, lo que
significa integrar nuevos equipos de generación de energía (gas o vapor turbogeneradores), así como el aumento de las cargas
eléctricas. En la actualidad, Petróleos Mexicanos (PEMEX) tiene la intención de reestructurar sus sistemas eléctricos y de vapor,
a fin de suministrar de forma óptima los
servicios requeridos para la producción de
combustibles de alta calidad. En este artículo se presenta la situación actual de los
sistemas de energía eléctricas originales de
las refinerías y se evalúa la integración eléctrica de las plantas de proceso en los nuevos
esquemas típicos. También se presentan los
esquemas conceptuales propuestos para
reestructurar el sistema de energía eléctrica para dos refinerías, cuya planificación
estratégica se centró en la aplicación de
las modificaciones necesarias para la integración de nuevas plantas de proceso que
demandarán alrededor de 20 MW para cada
refinería en el año 2014. Los resultados del
análisis permitieron identificar las condiciones actuales de los sistemas de energía
eléctrica en la industria de refinación de
petróleo o de la Industria Nacional de Refi-
nación (INR), y por lo tanto ofrecer soluciones técnicas que podrían ser útiles para
los ingenieros que desarrollan proyectos
similares.
Introduction
Currently, the oil refining industry is in
upgrading process of its electric system
in order to supply the oil demand. Every
oil refinery are linked up to The National
Electrical System (NES) to ensure the
electrical energy continuity in eventuality situations; however, the acquisition
energy cost and the fees payment is up to
USD $ 800 000 per month.
In the other hand, because of the new
requirements NRI has presented new
action schemes, like migrate from 13.8 kV
to 35.5 kV, and to 115 kV in some cases
(García et al, 2008). Moreover, there are
operative limitations which generate non
programmed shutdowns, for example:
between 2005 and 2006 there were three
non programmed stops because of “the
generation sources floating neutral” (García et
al, 2008; (García et al, 2005).
equipment integration analysis, and new
electric generators which permit it to be
self-sufficient to reach an electrical power
of 120 MW with a 34.5 kV level and
320 MW with a 115 kV level as means of
distribution. The results presented here
can be useful to solve problems in similar
projects.
Background
Current Schemes
Instituto de Investigaciones Eléctricas
(IIE), Mexican public decentralized organism created for technological researches,
has been working with NRI since 2002
about a) development of conceptual engineering for electrical systems, b) technical-financial feasibility study, c) electrical
equipment specifications, d) user bases,
e) tender bases, f) the analysis of power
electrical systems to implement specific
solutions for the electrical, mechanical and
control equipments.
For that reason, and to support the actual
and future electric demands, it is necessary
to use supply steam, compressed air, water
and electric energy in the next decades.
NRI consists of six refineries in
Mexico: Cadereyta, Nuevo León (HRLS);
Cd. Madero, Tamaulipas (FIM); Tula,
Hidalgo (MHI); Salamanca, Guanajuato
(AMA); Minatitlán, Veracruz (LC) y Salina
Cruz, Oaxaca (ADJ). In the table 1, it is
shown the results of the work between
IIE and NRI which generate the necessity
of the construction of 4 electric generators with heat recovery, 1 steam boiler, 2
electrical upgrading with the migration of
the 13.8 kV to 34.5 kV BS in two refineries from the north of Mexico, and 1 electrical upgrading of 13.8 kV to 115 kV in
one refinery from the center of Mexico.
The purpose of that document is to
give the experience, obtained through an
The modernization of every SEP was
regarded because of the convenience of
Additionally NRI tends to process
different crude oil from the ones that
produced more than 30 years ago, that
means that electrical systems must evolve.
NRI has taken in account an investment
for electrical reconstructing for more than
USD $ 120 million only for one refinery.
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
Resumen
123
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Boletín IIE
julio-septiembre-2012
Artículo de investigación
the implementation of 2 alternatives for
the new generation unities: a) with a gas
generator and b) with a steam generator.
The table 2 shows the comparison of
the alternatives to take the decision to
integrate a gas generator into the new
schemes.
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
Taken decisions for upgradings
systems
Many specialists take part into the electrical upgrading asset, somebody have
been developed the conceptual engineering and others decide whether every
project has economical feasibility for
its development. For example, NRI has
different sections which take part into
the project decisions like: a) Investment
Analysis Department (GAIGO: Gerencia
de Análisis de Inversión), b) Projects
Development Engineering Department
(DCIPD: Dirección Corporativa de
Ingeniería y Desarrollo de Proyectos), c)
Operations Department (DCO: Dirección Corporativa de Operaciones), d)
Proscess Engineering Department (GIP:
Gerencia de Ingeniería de Procesos) and
e) The local users of every refinery.
The intervention of NRI entities let the
management and development of projects
which needs a future: a) supply of the same
actual demand of energy, b) the integration
of the new generation modules; c) high
resistance grounding neutral method; d) the
ideal energy flow; e) the charges redistribution and f) the energy supply of the Clean
Fuel Projects Quality (CFPQ) mentioned
in (García et al, 2009; Alcaraz et al, 2008).
In the figure 1 it is shown the IIE participation and the awaited electric upgrading
projection for the 2012.
Table 1. Results of IIE and NRI together working by now.
Concept
Conceptual engineering
Generator tender
PCC Loads tender
Gruunding c/ High impedance
Technical-economic feasibility
Electric upgrading
Technical consultant tender
Steam boiler tender
HRLS
þ
þ
þ
þ
þ
þ
FIM
þ
þ
þ
þ
þ
þ
þ
Refineries
MHI AMA
þ
þ
þ
þ
þ
þ
þ
þ
þ
LC
þ
þ
þ
ADJ
þ
þ
þ
þ
þ
Table 2. Comparison between gas generator steam generator.
TURBOGENERATOR STEAM
This alternative needs:
(180 t/h) additional steam generator to ensure
existent production and rehabilitation
TG1 and TG2 existing electric generators
rehabilitation
To wide the cooling system in case of partial
condensation work. That means an increase
water consumption in the refinery
The actual electric system improvement
Acquiring the turbogenerator and their
peripherial
Advantages:
Use oil or/and gas as fuel in boilers
This schemes are well known in the refineries
Disadvantages:
There is no improvement in global efficiency of
the refinery
Stop the refinery process to make the new turbo
generator connection
TURBOGENERATOR TO GAS
Heat retriever to seize gases combustión and steam
generator of 19 bar
TG1 and TG2 existing steam and electric generator
rehabilitation
To analyze the gas availability and to ponder prices
volatility
The actual electric system improvement
Acquiring the turbogenerator and their peripherial
There is a decrease in the consumption of oil in the
refinery (It is saved medium pressure in boilers)
Use diesel and/or gas as fuel in gas turbines
There is a permanence of actual water
There is an improvement in global efficiency of the
refinery
It is necessary to consider that there is a major maintenance if diesel is burned, moreover the heat retriever
will need soot blower
The users refinery do not know well those schemes
Conceptual engineering of actual and typical future
electrical system
NRI actual typical electric systems
The electrical actual net of the six refineries in Mexico, have limitations in 13.8 kV distribution interruptive capacity switchgear. The actual average capacity of those switchgear is
31.5 kA short circuit in case of three-phase failure (Icc 3F). 31.5 kA means 100% of the
capacity which support the equipments according to manufactures production line; however
it is considered to maintain a 20% security margin for future expansion in that level.
Figure 1. Work together between IIE and NRI for the execution of upgradings projects.
Figure 2. Representative scheme of a refinery which has two generation sources
synchronized with NES.
The generators neutral was connected to
a common point named “neutral bus or
neutral switchgear” through an interrupter
and grounded through a low resistence bank.
Only the link transformer neutral with
the public net and a generator neutral are
grounding, the rest of the generators work
“ungrounded”.
They have a redundant system to supply
energy with at least two generation sources
trough the 13.8 kV distribution buses or
the existent 14.6 kV link interrupters called
“selective secondary”. In case of contingence,
if a switchgear gets out of maintenance,
the charges can be transferred to their adjacent switchgear or through the synchronization bus to obtain the an energy flow
that supplies electric energy in two inclusive
subsystems.
Electrical system with three generation
sources
Figures 2, 3 and 4 shows the actual scheme
of a refinery which has two power plants,
125
that supply the electric energy (92 MW)
and the steam that needs their process
plants with two generators. The power
plant No. 1 has a 18 MW (TE-1) “turbo
expander” installed in the catalytic plant and
two 32 MW steam turbo generator (TG1
and TG-2) and four boilers that generate
60 kg/cm2 man steam and a boiler that
generates 20 kg/cm2 man steam. The generators TG-1 and TG-2 work with extraction, giving 20 kg/cm2 man steam. The
power plant No. 2 has two boilers which
gives 20 kg/cm2 man steam (B-001A and
B-001B) and two boilers that gives 3.520
kg/cm2 man (B-002A and B-002B). Additionally, the refinery has three energy flows,
two of 230 kV and one of 115 kV that
come fron NES. Every flow of 230 kV has
a 84 MVA maximum capacity and the one
of 115 kV has a capacity of of 20 MVA.
The 115 flow is connected to the TDP-3
TDP-3 and currently is out of service
because is used as backup in one of the 230
kV energy flow, that way there is a deficit
energy supply in the refinery through link
substations. Finally, all the 13.8 kV distribution switchgears has an interruptive capacity and the 31.5 kA design for the symmetrical three phase short circuit flow.
In actual conditions, the power plant does
not supply the total electric energy necessity in the 92 MW refinery, therefore is
necessary the exchange of 40 MW from
other sources of NRI or NES.
Electrical system with more than 4
generation sources
Figure 5 shows the actual scheme of a
refinery with more than for electric generators divided into two thermoelectric
plants which supplies a charge average of
97 MW. The plant 1 has 6 boilers called
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
Artículo de investigación
Assessment and planning of the electrical
systems in Mexican refineries by 2014
126
Boletín IIE
julio-septiembre-2012
Artículo de investigación
In actual conditions, the energy plant does
not cover the total electrical energy necessity of the 97 MW refineries it is necessary
14 MW energy exchange from other NRI
or NES work center.
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
Figure 3. Typical actual (representative) scheme of a steam generation refinery with
two electrical generators synchronized with NES.
These descriptions indicate a conceptual
design must have a rational procedure to
determinate the best plan generated by at
least three conceptual scheme models. In
other articles published by these authors,
they present recommendations which have
been usual to modify schemes showed in
figures 2 and 4 (Ruiz et al, 2009).
To describe the alternatives chosen for NRI
electrical upgrading there will be presented
the factors that suffer changes because of
project made by IIE and the benefits that
will receive in 2012.
Future electrical system for NRI
Figure 4. Typical actual (representative) scheme of a steam generation refinery with
two electrical generators synchronized with NES.
MP-B1, MP-B2, MP-B3, MP-B4, CB2 y TG-4, and 4 turbo generators called TG-1, TG-2,
TG-3 and TG-4.
The turbo generators TG-1, TG-2 and TG-3 are designed to work at full condensation,
while TG-4 turbo generator is designed to work with steam extraction and condensation. The switchgear from Plant 1 has 31.5 kA interruptive capacity. The plant 2 has 3
boilers named CB-5, CB-6 and 2 turbo generator named TG-5 and TG-6. The turbo
generators TG-5 and TG-6 work with steam extraction. The 2 plant switchgear has
41 kA interruptive capacity.
The generation capacity of the majority
of the six refineries, is practically the same
as charge demand (100 MW). There is no
warranty in the continuous energy supply,
not even for the actual process plant in
case of emergency, not even for the new
plants. For that reason, it was regarded to
reconstructing the tension to 34.5 kV level
in two refineries. In this clause there will
be included the electrical schemes which
will be established for the figures showed
in figures 2 and 4.
Every scheme showed, for the 3-generator
refinery and for 4-generator refinery, was
analyzed through stable state evaluation
of the electrical system performance with
three phase short circuits, charges flow,
tension falls, power factor and tension
regulation (Ruiz et al, 2009).
Artículo de investigación
Assessment and planning of the electrical
systems in Mexican refineries by 2014
127
Figure 5. Typical actual (representative) scheme of a steam generation refinery with
more than four electrical generators synchronized with NES.
The schemes to be established of the
refineries to migrate at a 34.5 kV distribution level will have supply and installation
phases. The supply, installation, integration, field proves, training and putting into
service are divided as the following:
• Integration of an electrical generator
among 31 - 38 MW capacity for refineries of three generators and 20 - 25 MW
for refineries of more than four generators to supply the actual energy supply.
• Upgrading of 13.8 to 34.5 kV bus
synchronization for both refineries.
• Integration of an electrical generator
among 31 - 38 MW capacity for refineries of three generators and 20 -25 MW
for refineries of more than four generators to supply the future CFPQ demand.
• Electrical distribution in switchgear for
CFPQ.
• High resistance grounding of the three
generation sources.
• Integration of new systems into the
Advanced Operational Control System
(SCOA: Sistema de Control Operacional Avanzado).
Table 3 shows a tentative programming
but no limiting of the electric upgrading projects execution in refineries. The
programming will depend on availability
budget NRI and on fiscal year.
The main specification of the electrical
equipment for the refineries electrical
upgrading implementation embrace take a
decision in economical investment: 1) Elec-
In figures 6 and 7, the descriptive schemes
but non limiting wich will be implemented
for the refineries of three or four electric generators are shown. The figures
represent an integral electrical scheme for
execution of the same economical exercise. The difference in economical investment for the figure 6 scheme is more
than USD $ 50 million, different from
figure 7 scheme which means more than
USD $120 million.
The benefits they get once those schemes
are established are 1) The new scheme will
permit an optimal electrical power flow
to the charges, in all the operation sceneries, without bottlenecks, 2) In contingence conditions, charges fall are less than
+- 5% in all charge buses, 3) The backup
accomplishment has the capacity to substitute a generator of some of the plants,
in case of it is out of service, because of
fall or because of maintenance, 4) Plants
can receive a 18 MW additional integration, 5) All the plants electrical net has
only a neutral grounded for the grounding
fall-protection schemes simplification.
The 115 kV winding has its neutral firmly
grounded. The 34.5 kV synchronization
bus has a zigzag transformer. The generators neutral is high resistance grounded,
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
trical integration generators, 2) Insulated
switchgear technology in SF6, 3) The power
factor technology with double cooling
(OA/FA) using commercial connections
as “multi contact elbow bushing” and also
load tab changer, 4) The decision of installing grounding with zig-zag transformers,
5) The use of charge circuit for 13.8 kV and
34.5 kV with intertwine polyethylene insulation (XLPE) at 133% in insulation level and
6) the integration of new control systems to
the SCOA systems.
128
Boletín IIE
julio-septiembre-2012
Artículo de investigación
Table 3. Tentative programming of the future electrical system implementation phases
in NRI.
Fases
2009
3 4
Programming per three months
2010
2011
1
2
3
4
1
2
3 4
1
1° TG
130
2
BS Upgrading
115
3
Power circuits
90
4
2º TG
112
= =
5
PCC Distribution plants
110
= = =
6
Grounding with high Z
108
6
Systems integration
100
Notes:
T
Working days
TG
Electric generator
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
T
=
=
=
=
=
= =
=
=
=
=
=
Z
2012
1 2
=
=
= =
Impedance
Three months
Parallel solutions to the continuity
projects
The actual refineries has an energy deficit
and an additional 20 MW demand, that
requirement could be supply with a new
electrical generator integration.
The authors propose a transition stage
because of the mentioned changes and
because of the cases that is necessary to
migrate from 13.8 kV to 34.5 kV. That
stage can be implemented in case the refineries do not have budget availability for an
integral project in one execution and at the
same time of 1 and 2 phases (table 3).
The next section will present the transition
alternative to connect an electrical generator to the actual typical electrical system
in a refinery (figure 8).
The analysis shows the integration of
the first generator using two alternatives
for its integration: a) through a limiting reactor of 0.346 ohms short circuit,
1500 A in a serial configuration with
the generator and b) through a three
winding transformer of 35/35/35 MVA,
13.8/14.4/34.5 kV, where the terminals of
TG-“n1” generator are connected to the
13.8 kV winding, its distribution charge
switchgear to the 14.4 kV winding and the
34.5 kV winding will be integrated to the
future project: “34.5 kV synchronization
bus implementation”.
Figure 6. Descriptive scheme but non limiting of SB in 34.5 kV selected for the electrical reconstructing of figure 2 scheme.
6) If a generator is out of service, there will be capacitors banks which can supply the
necessary reactive power to keep 0.9 power factor in bound accomplishment. There are
many other benefits mentioned in references (García et al, 2008; Ruiz et al, 2005).
To determin the technical and economical
most feasible option to connect a new
electrical generator to the electrical actual
system in a typical refinery, there were
regarded the two mentioned alternatives
by means of a short circuit values analysis
and power flow in main charge buses with
Artículo de investigación
Assessment and planning of the electrical
systems in Mexican refineries by 2014
129
established operation conditions exclusively for the first generator.
Integration of a generation module in
the actual electrical system: comparison
with the use of reactor vs the use of
three winding transformers
Figure 7. Descriptive scheme but non limiting of SB in 34.5 kV selected for the electrical upgrading of figure 4 scheme.
The analysis ponder the evaluation in stable
state of the electrical system performance
with three-phase short circuit charges, flow
charges, tension falls, power factor and
tension regulation. There were analyzed
two scenarios including: A) All the electrical energy sources in 115 MW operations
and b) An electrical energy source aou of
service with a 115.5 MW charge.
According to results, it is showed that
both alternatives are operatively reliable,
however, the alternative of integrating the
first TG-8 generator through a limiting
reactor has major tension falls because of
the impedance that affects the electricity
flow. Also, that implies overworking of the
generator TG-8 in case one of the generators from the refinery is out of service.
Figure 8. Descriptive scheme but non limiting of a parallel alternative to connect a
generator with the refineries actual scheme.
On the other hand, in the alternative of
integrating the generator through a three
winding transformer, the tension falls are
compensated by the relation between the
13.8/14.4 kV windings, it means that the
tension difference of 3.04% regulates the
tension in acceptable levels in the distribution switchgear for the power transference
in the generator in 13.8 kV or the 34.5 kV
future synchronization bus.
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
The use of three winding transformers in
NRI is not yet well known, even though
in other oil refined centers like “Deer
Park” in Texas, USA, is used that kind of
technology.
130
Boletín IIE
julio-septiembre-2012
Artículo de investigación
The electrical system flexibility and reliability in both alternatives are almost the same,
for example, the Icc 3f has 80% of interruptive capacity.
Both analyzed alternatives ensure that TG-8
integration generator will be protected by
over tensions because it always will have
an intentional reference of their grounding
neutral and there will be used a high resistance grounding neutral, what will avoid
great energy flows through their winding.
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
The alternative of using a three-phase transformer in contingence conditions, avoids the
overworking of the transformer. Moreover,
with the integration of a 34.5 kV synchronization bus, considered to the future implantation, the transformer keeps operating.
Figure 9. Descriptive scheme but non limiting of a “transition stage” to connect a
generator with the actual scheme in refineries through a electric limiting reactor (I).
Table 4 shows the results summary of
Icc 3 f and the fall tension (Ct %) with
a 115.5MW charge of the alternatives
analyzed through: a) a short-circuit flow
limiting reactor and b) a three winding
transformer.
The alternatives technical evaluation of
transition stage has advantages and disadvantages. Table 5 shows technical advantages and disadvantages for the alternatives
to integrate the first electrical generator
into a typical refinery scheme.
The two alternatives of the integration
of the new electrical generation module:
a) require an additional investment as “transition stage” between phase 1 and phase 2
and b) shows quantities of 3F and Ct %
according to the regulation (ANSI/IEEE,
1993; ANSI/IEEE, 1986).
three winding transformer, moreover it permits the use of power equipments to be installed, instead of limiting energy reactors which will get out of service.
The flexibility and reliability of the electrical system is improved with the use of
Tables 6 and 7 show the economical evaluation of both mentioned alternatives and their
associated equipments for the integration of the first generator. It is important to mention
Figure 10. Descriptive scheme but non limiting of a “transition stage” to connect a
generator to the actual refineries scheme through a three-phase transformer. (2)
Artículo de investigación
Assessment and planning of the electrical
systems in Mexican refineries by 2014
131
Table 4. Comparative results table for the new generator
integration.
Table 5. Technical evaluation of the first generator installation using:
1) an icc energy limiting reactor or 2) a three winding transformer.
Parameter
Maximum Icc 3 f
(All TG’s)
Ct % Maximum
level
(All TG’s)
Maximun Icc 3 f
(TG-6: F.S.)
Ct % máximum
level
(TG-6: F.S.)
Notes:
Advantages
Icc 3f ≤ 25.2 kA and optimal power flow in contingence
conditions
If the NES commitment fails, the turbo can feed 100% of the
charge.
If a generator fails, its charge bus is fed by TBS
If BS fails, every generator remains with its charge bus
If a switchgear is been repaired their charges can be transferred
to an adjacent switchgear
All the generators can operate with grounding neutral.
Can receive a future growing of 60%
Can receive a future growing of 30%
Require the same investment because it maintain 13..8 kV level as
distribution tension
Better feasibility for its implementation.
The equipment investment will be used in future projects.
Disadvantages
When a switchgear is out of service, a generator is out of service
When the bus A or the bus B is out of service, a flow charge
NES is lost
If the synchronization bus fails, the NES is lost.
It needs the greatest investment
It is necessary to recharge the synchronization bus circuits which
go to the TBS
It is not posible to recharge the distribution buses circuits which
go to the TBS
If the synchronization bus fails, the refinery has to import
50 MW
If the synchronization bus fails, the charge of a generator is lost
Icc 3f surpass the switchgear capacity limit even though using
“pyrotechnics fuses “ or “Is-limiters”
If the two generators fail, NES can not feed 100% of the charge
There are no ground power references in synchronization bus
The NES flows does not have charge bus
The new generators does not have charge bus
Scenary
A
115.5 MW
B
1: Reactor
31.6 kA
(TBSII)
1.87 %
(TD-10)
2: Transformer
29.6 kA (TBSII)
1.86 %(TD-10)
27.7 kA
(TD-7)
25.5 kA (TBSII)
3.04 %
(TD-8) *
2.92 %(TD-10)
* New overworking generator
(TG-8)
F.S. Out of service
Table 6. Cost of the main equipment when TG-8 is integrated
through a limiting reactor with an air core (the cost of TG-8 is
not included).
Item
Concept
1
Reactor
2
Load circuit
3
Distribution
switchgear
4
TG-8 Reception cells
TOTAL
Characteristics
Icc limiting charge reactor with a 2300 A,
0.346 Ω air core
4 conductors per phase of XLP wire, 15
kV, class, 133%, 750 kCM caliber and an
approximate length of 500 m.
3000 A of nominal charge switchgear with
an Icc of 40 kA, 6 cells including the one
of TG-8
Two metal Clad cells 15 kV class, including
2000 A vacuum interruptor, measuring and
protection kit.
Cost
[MUSD]
$ .058
$ 0.390
$ 0.210
$ 0.075
$ 0.733
Table 7. Cost of the main equipment when the tg-8 is integrated
through a three winding transformer (it is not include TG-8 cost).
Item Concept
1
Three windind
transformer
2
Charge circuit
3
TG-8 Reception
cells
4
Distribution
switchgear
TOTAL
Characteristics
Three winding transformer of 35/35/35
MWA with transformation relation of
13.8/13.8/34.5 kV
XLP wirw, 15 kV class, 133 %, 750 Kcm
caliber for 500 m and 4 conductors per
phase
Two Clad metal cells, 15 kV class
including 2000 A vacuum interruptor,
measuring and protection kit.
3000 A charge nominal switchgear including a 40 kA Icc, 6 cells including the
three winding transformer
Cost
[MUSD]
$ 1.1
$ 0.390
$ 0.075
$ 0.210
$ 1,775
that assenting both alternatives in economical context, the best
solution is to use the limiting reactor which safes 37.8% compared
to three winding transformer; however this is a short term cost.
It is considered a future 34.5 kV synchronization bus reconstructing, therefore the three winding transformer will be still used in
1
2
þ
þ
þ
þ
þ
þ
þ
þ
þ
þ
1
x
þ
þ
2
x
x
x
x
x
x
x
x
x
x
x
the reconstructing and the long term cost would be less, avoiding
the investment of a transformer to synchronize in 34.5 kV the new
generator in the future.
Conclusions
It is necessary to optimize and to modernize the NRI electrical
systems, because it is well known that in Mexico has not been constructing a new refinery since 1979 and is necessary to acquire new
technology according to NOM-086 regulation for the projects of
2012 and that technology must be implanted in the mentioned
refineries.
The 34.5 kV BS showed in that article for two refineries can receive
new charges an new generation modules, the power flow between
NES and the local system is ideal and does not needs special equipment for its execution, moreover it can be associated to two energy
source for a charges bus.
Paper originally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
Load
132
Boletín IIE
julio-septiembre-2012
Artículo de investigación
It is possible to implement “transition stages”
through technologies like three winding
transformers, every time the budget of
the NRI local users do not have the total
available amount for the execution of the
stages in a parallel way.
Paperoriginally presented at the ASME Power Conference in Denver, Colorado, July 12-14, 2011.
There are three refineries in Mexico
in upgrading process only the investment of electrical equipment: a) the
first in the northeast with $ 38 million
dollars, b) the second in the north with
$ 36 million dollars and c) the third in the
center with $ 32 million dollars. Every
investment should be implemented with
different features, and must be included
in the investment of acquisition of new
generators in every refinery (cost per
generator is $ 25 million dollars).
References
García J., Robles E., Campuzano R. Series Resonant
Overvoltages due to the Neutral Grounding Scheme Used in
Petrochemical Power Systems, IEEE PES T&D LATINAMERICA, Transmission and Distribution Conference and Exposition, Bogota, Colombia, 2008.
Ruiz L. I., García F. A., Rosales I., García J. Electrical
Engineering: Base of the analysis of electrical reconstructing in Mexican typical refineries. Part I. The problem definition and IR spiral, IEEE Mexico, RVP-AI Acapulco,
Guerrero, Mexico, 2005.
García A., Rosales I., García J., Ruiz L. I., Robles E.
Net effect in electric equipment operations, Bulletin IIE,
year 29, vol. 29, num. 2, April-June 2005, page 69-74,
ISSN 0185-0059, Mexico.
Ruiz L. I., García F. A., Rosales I., García J. Ingeniería
Eléctrica: Base of the analysis of electric reconstruction in
Mexican typical refineries. Part II. The solution alternatives
and conclusions”, Mexico, RVP-AI Acapulco, Guerrero,
Mexico, 2005.
García J., Ruiz L. I., Fernández M. F., Alcaraz A. M.
Main services to produce high quality fuel in PEMEX,
Boulletin IIE, year 33, vol. 33, num. 2, April-June
2009, page. 69-74, ISSN 0185-0059, Mexico.
Alcaraz A. M., Fernández M. F., Rodriguez J. H., Ruiz
L. I. Vapor balance and energy in mexican refineries simulator, IEEE PCIC 2008, Río de Janeiro, Brasil, 2008.
Ruiz L. I., García J., García A., Taboada G. Mexican
refineries upgrading of electrical power system, IEEE
Nomenclature
TD
TG
BS
R
E
NRI
CFPQ
Distribution switchgear
Turbogenerator
Syncronization Bus
Reliability
Efficiency
National Refining Industry
Clean Fuel Projects Quality
Std. ANSI/IEEE 141, Red Book. IEEE Recommended
practice for electric power distribution for industrial plants, 1993.
Std. ANSI/IEEE 242, Buff Book. IEEE Recommended
practice for protection of industrial and commercial power
systems, 1986.
NOM-086-SEMARNAT-SENER-SCFI-2005. Official
Mexican regulation, fossil oil specifications for environment
protection, 2005.
También ha sido expositor en conferencias en foros
nacionales e internacionales con diferentes instituciones, empresas, congresos y simposios, denotándose
en las áreas eléctrica, industrial, informática y sistemas
computacionales. Actualmente es investigador y jefe de
laboratorio de la GEE, y contribuye con el diseño de
sistemas informáticos para optimizar los procesos de
licitación y modernización en la industria petrolera.
The ideal energy conditions in the country
are priority of Mexico Federal Government managed by Felipe Calderón Hinojosa, who, in many meetings, has suggested
the modernization of PEMEX.
The execution of the NRI projects has to
supply at least 2.5 million barrels per day.
The reality of the oil products in Mexico
depends on the production increment and
on electrical upgrading of NRI that would
make PEMEX to recover the international
leadership by 2014.
I&CPS 2009, ISBN: 978-1-4244-3399-5, Calgary,
Alberta, 2009.
De izquierda a derecha José Hugo Rodríguez Martínez
y Luis Iván Ruiz Flores.
LUIS IVÁN RUIZ FLORES
[liruiz@iie.org.mx]
Maestro en Ingeniería Industrial por la Universidad
Autónoma del Estado de Morelos (UAEM) en 2004.
Ingeniero Eléctrico por el Instituto Tecnológico de
Orizaba en 1999. Fue becario AIT del Instituto de
Investigaciones Eléctricas (IIE), en la Gerencia de
Simulación de 1999 a 2000. Desde 2001 colabora como
investigador en la Gerencia de Equipos Eléctricos
(GEE) del Instituto, en proyectos relacionados con el
análisis y diseño de sistemas eléctricos de potencia en
plantas industriales. Fue el asesor del 2º lugar nacional
del Certamen de Tesis en Nivel de Licenciatura en
México en 2008, organizado por la ANIEI. Tiene 10
de derechos de autor en las categorías de software y
obra literaria. Es miembro del IEEE y ha sido autor
y coautor de artículos nacionales e internacionales.
JOSÉ HUGO RODRÍGUEZ MARTÍNEZ
[jhrm@iie.org.mx]
Ingeniero Químico por el Instituto Tecnológico de
Ciudad Madero. Actualmente cursa la Maestría en
Ingeniería en el Centro de Investigación en Energía
de la Universidad Nacional Autónoma de México
(UNAM). Ha colaborado con la industria petroquímica
en proyectos de optimización de procesos y mejora de
productos. En 2001 ingresó a la Gerencia de Procesos
Térmicos del IIE, donde ha participado y administrado
proyectos relacionados con la eficiencia energética en
procesos, ahorro de energía y asesoría técnica para la
Comisión Federal de Electricidad (CFE) y Petróleos
Mexicanos (PEMEX). En 2012 ingresó a la Gerencia
de Turbomaquinaria. Sus áreas de especialidad son la
simulación de procesos, análisis de sistemas de generación eléctrica y cogeneración, así como la evaluación
y diagnóstico de sistemas energéticos. Actualmente
trabaja en el diagnóstico energético de la refinería de
Cadereyta, Nuevo León, México. Es autor de varios
artículos nacionales e internacionales. Miembro del
Sistema Estatal de Investigadores (Consejo de Ciencia
y Tecnología del Estado de Morelos) desde 2009.