reserves provided by distributed generation

8/7/2019 Reserves provided by distributed generation

http://slidepdf.com/reader/full/reserves-provided-by-distributed-generation 1/9

Operating Reserves Provided by Distributed Generation

FRANCISCO D MOYA CH(a)

, DUVIER BEDOYA BEDOYA(b)

, Dr GILBERTO DE MARTINO

JANNUZZI(c)

, Dr LUIZ CARLOS PEREIRA DA SILVA(d)

,

FEM, FEEC, UNICAMP

Cidade Universitária "Zeferino Vaz", Campinas, São Paulo

BRAZIL(a)

[email protected] http://lattes.cnpq.br/6867376592649835(b) [email protected] http://lattes.cnpq.br/0918270598381687

(c) [email protected] http://www.fem.unicamp.br/~jannuzzi/index.html

(d)[email protected] http://www.dsee.fee.unicamp.br/~lui

Abstract: - Among the ancillary services, the operating reserves are important researching aspects, which deal with supplying way and selling-buying prices. Currently, distributed generation (DG) rises as a new participant

in providing ancillary services, therefore, it is of main importance in operating reserves subject. This work shows some advantages and technical drawbacks by using DG when operating reserves are supplied. Different

sceneries were computed where the electric generation was performed in a centralized and non-centralized way

respectively. A methodology for identifying the maximum DG, which can be allocated, is proposed; this

maximum level can be assessed without carrying out a negative impact in the network. Diverse DG technologies,which present better performance in supplying such reserves, are also presented.

Key-Words: - Distributed Generation, Operating reserves, Ancillary services.

1 IntroductionThe reliability concept deals with different elements

in electric power systems: security and sufficiency.Security is described as the capacity of the system to

face different disturbs, this is used combined with protection devices, power dispatch and other

auxiliary services. Sufficiency represents the

capability of the system for attending the demandrequirements in any time.

In economical terms, security concept can be defined

as a public good. Transit systems, national defense

infrastructure, laws, etc, are considered as publicgoods also. Some authors consider the system

security as a public good [1], being operating reserves

of an electric system a key security element.

As other public goods, power system security has noclear indications of its cost per user. Some users can

disagree paying the operating reserves when they

don’t utilize such reserves and also if they are payingfor extra security which is provided for other users.

The difficulty is defining the optimal acquisition levelfor every user and develops a methodology for carrying out this acquisition as well as its costs.

The electricity markets in different countries arediscriminated mainly in the methodologies or

procedures in the operative reserve management. For

instance, in Britain the reserves are obtained by long-

term contracts. In the Nord Pool market, the energyutilities, are required to supply specific auxiliary

services, when they take part into the electricity

market. In California there is a reserve marketindependent and parallel to the electricity market. In

New England, there is a capacity market, similar to

an operative reserve market. In Brazil, the regulatoryagency establishes an operating reserve total for the

whole system, equal to the capacity of the major

generator unit. Thus the Itaipu power plant with 6,3GW sets up the maximum level of the operating

reserves. The current capacity of the Brazilian Power

System is 91,17 GW, being the operative reserve

6,7% of the total installed capacity.Currently, electric systems are changing and with the

distributed generation (DG) growing up, the

distribution systems are turning into from passive to

active entities [2]. The new and future DG schemesare allowing a wide possibility of new energy

suppliers and complementary services such as

auxiliary services in which the operating reservestakes part into. DG is a new participant in the current

and future electric systems related to programmingand the operating reserves dispatch [3], [4].Dispatch of centralized units requires a higher

generation level, which should supply energy to all

the network points, including all the load power andthe network losses in the whole system, the

transmission system and the final points related to the

distribution system [5].

On the other hand, delivering active power by thegenerators in the distribution system, close to the



load, reduces the losses and consequently, improves

the voltage levels and increases the system security.This work shows some technical advantages when

DG is used in the dispatch of active and reactive power reserves. In the following section, the

formulation of the problem is described. Afterwards,

it is showed and explanation of the methodology

used. It is also proposed a methodology for establishing the maximum DG level that can be

installed and at the same time, caring of the negativeimpacts in the network and consequently the

maximum DG level that can be provided for the

supply of operating reserves.An application is also showed; it is presented an

analysis when DG is used for supplying operating

reserves. Furthermore, the DG technologies that

attend more efficiently the reserves management is

described. Finally the conclusions of this work are

presented.

2 Problem FormulationThe connection of energy supplies to the distributionsystems modifies the traditional hierarchical

generation way before known. The energy injection

in the distribution networks modifies the power flow

and can develop several impacts such as: losses,investments, voltage profile, maintenance people

security, power quality, short circuit power, and

system operation. This work analyzes the impact on

the active and reactive power losses, and the voltage profile impact on the network.

2.1 Loses modification when DG is usedThe problematic associated to the DG impact has

several implications (economic, technical andenvironmental). For this reason, in the last years

researchers have began to take it into account.Currently due to the multiple studies, it is known that

DG presents limited advantages related to the losses

reduction. In [6] and [7] it is known the importance of

the active and reactive energy supplied by the DG. Inthese works it is also demonstrated that with higher

levels of DG the losses may increase. Thus it isnecessary known the DG capacity that can be

installed without increasing the losses and not

affecting the voltage profile. It is required to know

the energy generation limits through DG, it makes

essential to know the maximum DG capacity for supplying the operating reserves.

In the first part of this work, a methodology for

determining the DG installation limits is presented. It

is also studied the influence on the losses in the

transmission, sub transmission and distribution

systems.

2.1 The DG and its role with the Operating

reservesAfter presenting the DG advantages and drawbacks,

it is possible to note that the operating reserves withDG present different implications; therefore, it is also

necessary assessing the advantages anddisadvantages. With this aim, in the second part of

this work is presented an analysis related to the active

and reactive energy supplied by DG when centralized

generators outages occur.

3 MethodologyThe development of a methodology that lets know the

DG energy production limits, allows assessing

directly the DG maximum capacity for providingoperating reserves. In some works such as [8] and [9],

it is described the importance of the DG allocation

and establishing the necessary capacity for DG

installation in order to reduce the distribution systemlosses. However, its neglects the analysis of possible

impacts like overvoltages produced by DG

installation.

For knowing the effects on determined electricsystem when DG is studied, it is convenient to know

the electric parameters of such system whencentralized generators are used. For instance, when a

load flow is computed it is possible to know some of

the most important electric parameters (such as:voltage profile and the losses level) without using DGon the system. After that, it is possible obtaining the

base case for comparing with the alterations in the presence of generators connected to the distribution

system. The base case allows also verifying the

buses, which presents greater voltage drops and theareas and branches where the losses are more critical.

This buses and areas are the best locations for the DG

installation. After the DG installation in such

sceneries, the possible presence of overvoltages is

lower and the losses reduction is more effective.

This section is based on the procedure presented in

[8]. After assessing the DG units to be installed in thedistribution system, it is necessary to compute loadflows by increasing the generators capacity and

assessing the new electric parameters in order to

evaluate the overvoltage levels produced.This methodology is presented in Fig. 1.



Fig. 1 Methodology for establishing the

maximum DG installation level.

This methodology allows computing the maximum

DG installation level without damaging the network.

It is also possible to establish the maximum DG levelfor the operating reserves. Some works such as [10]

and [11] have presented a methodology for

computing the amount of operating reserves which

can be established for an electric system, but

currently there are no studies related to the evaluationof such reserves in DG. The methodology proposed

in this work arises in response to the necessity of determining the maximum DG admissible level for

supplying operating reserves.

3.1 Study CaseIn this work it is implemented a simulation for different sceneries with the aim of comparing

technical centralized generation aspects and non-

centralized generation when DG is involved.

These sceneries were computed by using a load flow(static model) for an electric system which takes into

account voltage levels for transmission, sub

transmission and distribution in order to assess the

DG impact in every voltage level. The IEEE30 bussystem was used [12] for carrying out the study. Two

buses on the medium voltage level were separated for

generating the distribution network (low voltagelevel). At the buses 30 and 24 it was connected a

distribution system of 70 buses TS2 [13] that is

presented in Fig. (2).

For computing the optimal flow the Newton-Raphsonand Fast-Decoupled Newton methods were used. In

order to develop the simulations, the program for

power system analysis MATPOWER [14] was

utilized.

Fig. 2 Distribution circuit used.

Below the process for the sceneries studied is presented as follows:

Phase I: Load flow without DG (base case): for this

case the active energy generation (P) and the reactive(Q) were delivered in a centralized way without DG.

In this case it is considered that the centralized

generators supply all the active and reactive demand,supposing that the generators are delivering the

operating reserves scheduled previously. In this work

the reserves classified in accordance with theresponse were not considered.

Phase II: Losses and voltage profile analysis: After

computing the base case, it is possible to obtain the

areas where the higher losses level is presented. Theresults for the case analyzed in this work, in only one

of the distribution circuits and determined areas that

are represented with the gross line Fig. (2).In addition, Fig. (3) shows losses level in the

distribution circuit circuit which has more losses. It is

important to emphasize that only one distributioncircuit presents the higher losses level

Fig. (4) shows the voltage profile (V) for each

voltage level: transmission, sub transmission and

distribution (gross line) at base case. The load flowresults show that the voltage levels decrease from the

transmission level until the more distant buses in the

distribution system. These areas are represented withcircles and they are named V1 to V7 Fig. (2).

Phase III: Selection of the more appropriate buses for

the DG installation: After obtaining the areas with

major losses, it is possible to establish the areaswhere the generators can be allocated in the

distribution system.Phase IV: For determining the possible DG impacts

affecting the voltage level, the smaller generators

should be connected only to one of the distribution



circuits and assess the impact when compared with

the distribution circuit without DG presence. For thecase studied, four generators in the first distribution

system were installed. The first distribution systemcorresponds to the areas V5, V4 and V7 (allocated in

the bus 30) Fig. (2).

Table 1 shows all the generators of the system with

their basic features.

Fig. 3 Losses level in the distributionsystem

Fig. 4 Voltage profile at base case

Generator TypeP max

(MW)

Power

Factor

G1 Centralized 200 Free


G3 Centralized 50 FreeG4 Centralized 40 Free



G7 Distributed 2,53 0,9




Table 1 Generators features

Phase V: After installing the generators, several load

flows were computed increasing the DG installedcapacity, with the aim of obtaining the impact on the

different voltage levels of the system that is beingstudied.

The generators selected were allocated for a operation

with a power factor of 0,9 in capacitive or inductive

way.Phase VI: Verification of the electric parameters

after DG installation: in this part of the procedure it iscompared the voltage level and the losses presented

when DG is used related to the base case.

a) Losses analysis: in Fig. (5), it is possible to analyzethe losses behavior in the transmission, sub

transmission and distribution branches by increasing

the DG from zero up to 3,73 % of the total system

load. This is known as DG Penetration Level

(DGPL).

Fig. 5 Losses increasing the DG

penetration

In this case, the active losses level of the transmission

system decreases by 14% and for the sub

transmission system the losses where reduced by 29%when the DGPL is 10%.

In relation to the distribution system, the losses

decrease up to determined level, after this DGLP

level the losses rises highly. At the base case, whenthe DGLP is 0,78%, a limit for the reduction of the

active losses is obtained. For the reactive limit, it is

presented a DGLP different of the active one due tothe reduction of active energy. Table 2 shows the

numerical results that the load flow provided for threeDGPL levels. Thus, DG presents more advantages inthe active and reactive losses reduction in

transmission and sub transmission levels and with a

limit in through the distribution levels. However, it is possible to reduce the losses in a greater rate in the

distribution circuit than in the other circuits.

For instance, at base case, it was possible to reducethe losses in the distribution system by 33% with only

a 0,78 DGPL level.



Net Power 0 0,38 1,23

P (MW) 2,65 2,57 2,28

Q(MVAr) 9,41 9,14 8,12

P (MW) 1,33 1,19 0,95

Q(MVAr) 10,44 9,85 8,68

P (MW) 0,12 0,08 0,60

Q(MVAr) 0,23 0,15 0,47Distribution

Sub transmission

DGPL(%)

Transmission

Table 2 Losses in different system

levels

For analyzing the possible impact that DG can

develop in other distributed systems where initially

DG was not installed, it is necessary assessing thelosses behavior, they are showed in Fig. (6).

The losses in the distribution system where DG has

no been installed, present a similar behavior in the

transmission and distribution systems. The reductionlosses curve presents a linear behavior in the

distribution system, whereas, the reduction losses for the transmission system is concave. This feature for

distribution systems is also shown in [7].

In a persuasive way, the DG decreases the active and

reactive losses in distribution systems where DG isnot intall. As was explained earlier (see Phase IV),

four generators in the first distribution system only

were installed. In addition, when the DGPL is 0.78%,

in the second distribution circuit a losses reduction of 0,36% is obtained, see Fig. (6). The DG presents also

advantages in the active and reactive losses reduction

in others distribution circuits of electrical system.The total losses reduction in the system can be to

measure and compensate economy to DG for thiscontributions.

Fig. 6 losses in the distribution system

b) Voltage analysis:The DG energy production in the distribution system

carries out an increase in the voltage profile of the

system [15], [16]. This impact is due to the localenergy supplied and to the injection or consumption

of energy in the system. In the first place, the active

demand reduction that the generator delivers is lower

than when DG is not used, producing a minor voltage

drop. In addition, the active and reactive power injection increase the voltage profile. In Fig. (4) is

showed a voltage profile for the base case and whenthe DGPL is 1,23%. In Brazil, the technical

regulation establishes that the minimum and

maximum values for systems with voltages level up

to 231 kV should not be minor and major than 95%and 105% respectively.

Fig. (6) shows that the voltage levels in the base casedon’t infringe the limits, however, the upper limits

are infringed when the DGPL is greater than 1,23%.

After increasing the active and reactive power outputin the distribution network, overvoltages can occur,

mainly in the distribution system, and with less

importance in the sub transmission and transmission

systems. An alternative for avoiding such violations

is increase the number of smaller generators in the

distribution networks, this is known as an augment inthe DG dispersion level of lower power, it is shown

in [7] and [16].The methodology proposed in this work recommends

increasing the DGPL and verifying at which values

the generation be on the voltage network limit. Fig.(4) shows that the maximum voltage values are

presented exactly in the distribution system where the

DG has been installed. In this case, when the DGPLis 1,23 % the maximum value is obtained when the

voltage limits are not violated (in Brazil for systemsup to 231 kV).

The penetration value is showed in Fig. (6) for GD3,

this means that respecting the maximum voltage

limit, the maximum losses reduction value is notreached, however, the advantage is obtained with a

major losses reduction in other branches of thesystem (transmission, sub transmission and other

distribution networks). All the results are shown in

Table 2.Phase VII) With the identification of the maximum

penetration level, the electric parameters establishedare respected so, it is possible to obtain the maximum

DG value without carrying out a negative impact on

the system, as was explained earlier, in this case

when the DGPL is 1,23 %. Therefore, with thismethodology it is also possible to obtain the

maximum level that DG can deliver in relation to theoperating reserves.

4 DG as an Operating Reserve SupplierWith the aim of verifying the DG performance and its

impacts in operating reserves deliver, it is necessary

analyzing situations for possible outages of

centralized generators. For this analysis it is studiedthe base case where all the centralized generators are



supplying active and reactive power for all the

system.In the second part of this work, other cases were

simulated turning off a centralized generator in eachcase and the DG deliver operating reserves. The

DGPL is also increased with the aim of assessing the

electric parameters in the system with the output of a

centralized generator and the entry of DG.

4.1 Voltage AnalysisFor the analyzed system, the results showed that the

voltage profiles in every one of the subsystems were

not modified in an important way with the outage of the centralized generators at base case. This means,

without the DG presence, the centralized generators

supplied in an effective way the active and reactive

power demand with the outage of any centralizedgenerator.

The load flow results showed also that the voltage profiles are not modified seriously when DGPL isincrease, being almost the same voltage profiles as

showed in Fig. (4) Section (3.1 b.)

4.2 Losses AnalysisFig. (7) shows the losses level in the transmission andsub transmission branches when compared with the

base case in the worst case, which is when G3 is out

operation. In this case, for the transmission system

the losses increase up to 261% for active power and254% for reactive power.

The impact in the sub transmission and distributionnetworks is minor when G3 is out, the total losses

increases by 2,7% and by 0,7% for active and

reactive power respectively.

Fig. 7 Transmission and subtransmission losses increasing the DG

penetration and with G3 out of operation

Fig. (7) also shows the losses behavior when DGPLis increased form zero up to 3,73%. This is done with

the objective of analyzing the DG impact in the worst

scenery, this happens when the generator G3 is out,

as mentioned before.It is possible to prove that by using DG a minor

losses level is presented when a centralized generator is out. For the studied case, the losses reduction

related to the base case where G3 is out and there is

no DG, the losses level decreased by 7,45% for active

power and by 7,33% for reactive power. In the subtransmission area, the reduction was by 14,7% and by

7,48% for active and reactive power respectively. Inthe distribution system, there are major advantages;

the losses reduction is 23% for active power and

42.3% for reactive power. These results are illustratedin Table 2.

Net Power 0* 0** 1,23

P(MW) 2,646 6,90 6,70

Q(MVAr) 9,407 23,92 23,23

P(MW) 1,334 1,37 1,17

Q(MVAr) 10,44 10,49 9,71

P(MW) 0,123 0,12 0,09

Q(MVAr) 0,229 0,23 0,13

Transmission

Sub transmission

Distribution

DGPL(%)

Table 3 Losses in different DG levels

* base case, all centralized generators on

** base case and G3 is out

Fig. (8) illustrates the curves for the active losses for

the distribution circuits in each case when the

generators are out of operation.

Curves PLC21, PLC22, PLC23 and PLC24, representwhen the generators G1, G2, G3, y G4 are out

respectively. It is observed that for the distribuitedcircuit (1) where DG is installed, there are no changes

in the losses level when the centralized generators are

out.

Fig. 8 Distribution losses increasing the

DG penetration when G3 is out of operation

As explained before (Section 3.1. a.), the losses in the

distribution circuit where DG is not installed present

a linear behavior. Whereas, the curve for the other distribution circuit presents a concave behavior, a



feature of the distribution systems where DG is

installed. In Fig. (8) the area under the curve PLC23

between 0 and GD3 represents the maximum losses

reduction that the DG installation can obtain whenG3 is out. In Section 3.1. b. it was explained that

GD3 represents the maximum DGPL where there are

no violations on the voltage limits, that means, this

point represents the maximum penetration value andtherefore the maximum operating reserves value. This

is the maximum operating reserves value that DG cancontribute without originating negative impacts on

the system. This work shows a individual case, is

necessary to apply this methodoly for peak hours, lowhours and for summer and winter period.

4.3 DG Technologies for providing operating

reserves

There are different technologies that can be used for

DG applications (wind generation, photovoltaic, co-generation, etc). Every technology presents a

different production profile, therefore, the load flows

and losses impact depends on each technology.

Generally, the DG profile varies constantly. Thisvariation can be produced by the primary resource

(wind, sun, water, etc) or due to the process features

(e.g. co-generation process).As the DG production profile is adapted to the

demand profile of the buses where the DG is

installed, the electric parameters will be better or

worse. For instance, if the DG production in each busis exactly equal to the demand in each bus, the losses

will be annulated since all the demand is suppliedlocally and there are no flows in the network.

Therefore, the GD more appropriate technologies for

supplying operating reserves are with constant

production profiles.In this category can be classified the generators

which supply almost constant power all the time

(higher utilization factor, generally classified from 0

up to 1, where 1 is the maximum value). In somecases the DG production can be practically constant,

which is the case of combustible-cells, biomass plants

and the gas micro-turbines. These technologies arewell conditioned to the demand profile. In [7] was

shown that the wind and photovoltaic generation areill conditioned for the demand profile. Table 4 showsthe technologies behavior related to the demand and

the operating reserves delivery.

As was explained earlier, the electricity markets in

different countries are discriminated mainly in the

methodologies or procedures in the operative reservemanagement. In general, the maximum level of

operating reserves and the time for the entry

operating reserve difference each electricity markets.

Normally, Spinning Reserve (also is known as primary reserves) is the use of generating equipment

that is online and synchronized to the grid such thatthe generating equipment can begin to increase output

delivery immediately in response to changes to

interconnection frequency, and be fully utilized

within seconds to <10 minutes to correct for generation/load imbalances caused by generation or

transmission outages. Most on-line DG could performspinning reserve and respond in less than 10 seconds.

Supplemental reserve (non-spinning also is known as

secundary and third reserves) differs from spinningreserve because supplemental does not need to

respond to an outage immediately. Traditional non-

spinning reserve needs to be available within 10

minutes.

Supply

Technologies

Natural Gas Turbine øøø øøø

Micro-turbine øøø øøø

Steam Turbine øøø øøø

Combined Cycle øøø øøø

Electrochemical Devices øøø øøø

Small hydro ▲▲▲ ▲

Wind turbines ▲▲▲ ▲▲▲

Mini-Wind ▲▲▲ ▲▲▲

PhotoVoltaic ▲▲▲ ▲▲▲

PhotoThermal øø ▲

Fuel Cell øø ▲▲

Demand

following

Operating

Reserves

Table 4 DG technologies behaviors for

operating reserves supplying [17] øøø: very good

øø: good

▲: normal

▲▲: bad▲▲▲: very bad

5 ConclusionProviding operating reserves by DG makes that the

large centralized generators reduces the scheduleenergy for delivering reserves. Therefore, these large

generators can have more available power for the basic energy supplied to the system.

By using DG, overvoltage levels can appear, mainly

in the distribution network and with less impact in the

sub transmission and transmission systems. Analternative for avoiding these overvoltages is

increasing the DG penetration level with low power

generators, it means with a greater DG dispersion.The DG contribution to the operating reserves

presents more advantages related with losses in sub



transmission and sub transmission systems, in the

distribution systems the losses reduction is moreconservative since it depends on the technical system

variables and can be manage with a major DGdispersion.

The DG impact on the system depends generally on

the production profile and how it is adaptable to the

demand profile. The DG technologies that canaccomplish a better role in the operating reserves

delivery are those with a constant production profileand also those that can begin to increase output

delivery immediately in response to changes to

interconnection frequency to correct for generation/load imbalances caused by generation or

transmission outages.

References:

[1] L. Wang, C.W. Yu, F.S. Wen, Economic Theory

And The Aplication Of Incentive Contracts To

Procure Operation Reserves”, Copyright

Material Electric Power Systems Research, 2007,

N°77, pp. 518-526.[2] Bayegan, M., A Vision of the Future Grid , IEEE

Power Engineering Review, Vol. 21, pp. 10-12,

December 2001.[3] Fang Z, Editorial Special Issue on Distributed

Power Generation, IEEE Transactions on Power Electronics, V 19, N° 5, September 2004.

[4] Y. Xiaoyan, T. Leon, Ancillary Services Provided

from DER with Power Electronics Interface,

IEEE Power Engineering Review, Vol. 21,December 2006, pp. 10-12.

[5] Pepermans G., Driesen J., Haeseldonckx D.,Belmans R., D’haeseleer W., Distributed generation: definition, benefits and issues,

Energy Policy, N° 33, 2005.[6] S. Persaud, B. Fox and D. Flynn, Impact of

Remotely Connected Wind Turbines on SteadyState Operation of Radial Distribution Networks,

IEE Proceedings. Generation, Transmission and

Distribution, Vol. 147, No. 3; pp. 157-163; 2000.

[7] V.H. Méndez, J. River, J.I. de la Fuente, T.Gómez, Assessment of Energy Distribution

Losses for Increasing Penetration of Distributed Generation, IEEE Transactions on Power

Electronics, V 21, N° 2, May 2006, pp. 533-540.

[8] T. Griffin, K. Tomsovic, D. Secrest and A. Law,

Placement of Dispersed Generations Systems for Reduced Losses, 33rd Hawaii International

Conference on System Sciences; 2000.

[9] A. Naesh, M. Pukar, N. Mithulananthan, Ananalytical approach for DG allocation in primary

distribution network , N° 28, 2006, pp. 669-678

[10] C.W. Yu, X.S. Zhao, F.S. Wen, C.Y. Chung,

T.S. Chung, M.X. Huang, Princing and procurement of operating reserves in competitive

pool-based electricity markets, Electrical Power Systems Research, N° 73, 2005, pp. 37-43.

[11] Kun-Yuan Huang, Yann-Chang Huang, Integrating Direct Load Control With

Interruptible Load Management to Provide Instantaneous Reserves for Ancillary services,

IEEE Transactions on Power Systems, Vol. 19, No. 3, pp. 1626-1634, August 2004

[12] Power Systems, Test Case Archive,

http://www.ee.washington.edu/research/pstca/pf30/pg_tca30bus.htm

[13] Mesut E. Baran, Felix F. Wu, Optimal

Capacitor Placement On Radial Distribution

Systems, Copyright Material IEEE Transactions

on Power Delivery, Vol4, N°1, pp. 725-734.

[14] PSERC, Matpowe, A Matlab Power SystemSimulation Packege, V 3,

www.pserc.edu/matpower/[15] S. Conti, S. Raiti and G. Tina, Small-scale

embedded generation effect on voltage profile: ananalytical method , IEE Proceedings Generation,Transmission and Distribution, Vol. 150, No. 1,

2003, pp. 78-86.

[16] C.L. Masters, Voltage rise, the big issue

when connecting embedded generation to long 11

kV overhead lines, Power Engineering Journal,February 2002, pp. 5-12

[17] V.H. Méndez, J. River, J.I. de la Fuente, T.

Gómez, J. Arceluz, J. Marín, Amadurga, Impac

of distributed generation on distributioninvestment deferral ", Electrical Power and

Energy Systems, N° 28, 2006, pp. 244-252

BiographiesFrancisco D. Moya Ch received the P.E. in Electrical

Engineering from the National University of

Colombia and the M.S. in electrical Engineeringfrom University Los Andes, Colombia, in 2000 and

2005, respectively. He presently is a Ph.D. student inelectrical engineering at UNICAMP (University of

Campinas), Brazil. His main research interests are in

power quality, distributed energy systems, energyefficiency and conservation, renewables, energy andenvironmental policy.

Duvier B. Bedoya areceived the P.E. in ElectricalEngineering with first class honours from the

National University of Colombia, Manizales,

Colombia, in 2004, the M.S. in Electrical Engineering

from UNICAMP (University of Campinas), in 2007,where he is currently researcher. His main research



interests are in voltage stability, high voltaje and

embedded generation studies.

Gilberto de Martino Jannuzzi received Ph.D. degreefrom Cambridge University, U.K. (Energy Research

Group, Cavendish Laboratory). He is an Associate

Professor of Energy Systems at the Department of

Energy, Mechanical Engineering Faculty, UNICAMP(University of Campinas), He is Executive Director

of the International Energy Initiative , a Southern-conceived, Southern-led and Southern-located South-

South-North partnership. My interests are related to

energy planning, with special emphasis on energyefficiency and conservation, renewables, energy and

environmental policy, and technology transfer issues.

Luiz Carlos P. Silva received the B.S. degree in

Electrical Engineering from Goias Federal University

(UFG), Goiania, Brazil, in 1995, and the M.S. andPh.D. degrees from UNICAMP, in 1997 and 2001,

respectively. Currently, he is an Assistant Professor atUNICAMP (University of Campinas), where he has

been with since 2002. His research interests include

dynamic and static voltage stability analysis andgeneration distribution systems.

reserves provided by distributed generation

Documents