Integration of distributed generation in the power distributionnetwork: The need for smart grid control systems, communicationand equipment for a smart city Use cases

Salvador Ruiz-Romero 1, Antonio Colmenar-Santos n,Francisco Mur-Prez 1, frica Lpez-Rey 1

Department of Control System, Electronics, and Electrical Engineering, UNED, Juan del Rosal, 12 Ciudad Universitaria, 28040 Madrid, Spain

a r t i c l e i n f o

Article history:Received 1 April 2013Received in revised form20 April 2014Accepted 23 May 2014

Keywords:Smart gridSmart cityDistributed generationRenewable energyDistribution gridsMicrogrids

a b s t r a c t

The exploitation of renewable energy resources poses great challenges regarding the manner in whichthey can be integrated into the modern electrical distribution infrastructure.

To understand the difficulties of integration of Distributed Generation (DG) in electricity distributionnetwork, the analyses and result of the effects on aspects of power quality are provided, as can be theproblem of failure defects in networks and how DG grid connection affects voltage control at bothmedium-voltage (MV) and low-voltage (LV) levels. Results demonstrated that there was a communicationsystem between all generators protective systems, a selective protective system, a tracking of perturba-tions system to isolate failure defects, and a phase control system between the generators and thenetwork. Also synchronizing voltage regulation is crucial for guaranteeing the quality of the power supply.

Currently, recent and modern technologies allow different services to share a single communicationsinfrastructure while guaranteeing the required levels of security, reliability, and efficiency. This paper aimsto provide a Smart City (SC) project, implemented in the city of Malaga, Spain, where the integration of theapplications of Smart Grid (SG) and the Use Cases (UCs) for the different functionalities of SG has beendeveloped. The SC architecture proposed envisions a hierarchical, distributed, and autonomous structureto address the challenge of smart distribution grids.

As a result of this project, new levels of standardization of languages and protocols and newinterconnection functions will be required. These functions will allow smart devices to recognize eachother so that they can reconnect in case of failure regardless of the state of the network topology.

In conclusion, renewable energy sources (RES) can be optimally integrated into the distribution grid.Generation can approach consumption through the installation of photovoltaic (PV) panels and mini-windgenerators, with the reuse of electrical infrastructure.

& 2014 Elsevier Ltd. All rights reserved.

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2242. DG and power quality: the problem of failure defects in networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

2.1. Power re-supply of outages during reconnections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2252.2. Extending the power outage duration to reduce the area affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2252.3. Possibility of anti-phase reconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

3. The effect on voltage control in distribution grids with DG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2253.1. Influence of DG on voltage control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2263.2. Influence of DG on MV grids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2263.3. Influence of DG on LV grids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

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n Corresponding author. Tel.: 34 913 986 788.E-mail address: acolmenar@ieec.uned.es (A. Colmenar-Santos).1 Tel.: 34 913 986 476; fax 34 913 986 028.

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4. A viable architecture for a multi-service telecommunications network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2284.1. Conceptual architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2284.2. Electrical infrastructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2284.3. Communication and systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2294.4. Technology and equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

4.4.1. Primary equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2294.4.2. Secondary equipment: electronic control devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2304.4.3. Information system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

4.5. Electric vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2305. Use cases, SG functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

5.1. Use cases for MV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2315.1.1. ADA MV use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2315.1.2. MV DER use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

5.2. Use cases for LV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2315.2.1. LV ADA use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2325.2.2. LV DER use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2325.2.3. AMI use cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

5.3. Generic use cases (MV/LV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2325.3.1. COM use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

6. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

1. Introduction

The widespread introduction of renewable energy resources inDG will have a significant impact on both the electrical system andthe electricity market. The technological revision and manage-ment methods of the electrical infrastructure [1,2] will requireredesign of the roles of current electrical companies and also entryof new players into the power generation industry [3,4].

This paper provides an SG concept, with an adequate infra-structure of communications and hierarchy, optimally integratedinto the distribution grid, with the reuse of infrastructure. Also theintegration of the applications of SG, and the UCs for the differentfunctionalities have been developed, which serve as a guide tousing the smart power distribution grid.

The objectives of this paper, as explained in the followingsections, are as follows:

To analyze the difficulties of integration of DG in the electricitydistribution network, Sections 2 and 3.

To submit the technologies proposed under the SG concept,Section 4.

To compare the different functionalities of SG, Section 5. To optimize the infrastructure of the electrical industry, Sections

4 and 5. To present the conclusions and future trends, Section 6.

Also under study, the communication functions include two-way communication with new smart meters and charging pointsfor electric vehicles; cameras and sensors in security systems atfacilities; emergency telephony; real-time applications, such asremote control and teleprotection; advanced distribution automa-tion; and coordination of DG resources towards an optimized andsustainable energy system [5].

For these reasons, we show that new levels of standardizationof languages and protocols and new interconnection functionswill be required [6]. These functions will allow smart devices torecognize each other so that they can reconnect in case of failureregardless of the state of the network topology and can create anintercommunicating electrical infrastructure through communica-tion with appropriate levels of reliability and bandwidth. This newlevel of interaction through each grid element will allow greater

efficiency in supply and demand management [7], reduction ofgrid congestion, and the restoration of energy to the grid [8].

It will be ideal for this process to reuse electrical infrastructure,especially the distribution cables and the associated facilities, asmuch as possible [9].

One of the most important requirements to be satisfied by thegrid is to keep power quality. Section 2 explains briefly how theintegration of GD affects the power quality, creating voltage dips inthe network when failure defects occur; with this explanation wecan understand how GD, as we know it today, cannot be integratedin an effective way in electrical infrastructure.

The connection of electrical generators on the network createsa variation of the voltage levels; this is a problem for maintainingquality standards. Section 3 explains how the integration of DGin the MV/LV network seriously affects the voltage level of thepower grid, and that an intelligent network structure to solve thisproblem is necessary.

In Section 4, the design used in a real project conducted inMalaga intelligent network formed by a system of communicationbetween all units and equipment is explained. This project hasbecome a test for what may be the cities of the near future.In addition, in Section 5, an exposition and analysis are providedof different use cases which perform an SC that it covers all thefunctionalities that should be supported, in both the MV and LVnetworks.

Finally, in Section 6 the conclusions of this study are summar-ized and future trends are provided.

2. DG and power quality: the problem of failure defectsin networks

DG installation affects power quality in various ways. One ofthe major impacts of DG on power quality is its effect on thefunctioning of over-current protection schemes, among which themost important related events are voltage dips [10].

Voltage dips, which are transient voltage reductions between10% and 90% of the nominal effective rms value that last between ahalf cycle and one minute, are commonly called micro-cuts andare associated with the input and output of large loads in thesystem. Currently, voltage dips represent the primary cause of user

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234224

complaints to utilities because of transient departures from powerquality and account for 7585% of the total complaints [11].

Various situations are analyzed to understand the problem offailure defects in networks connected to a DG element [12].

2.1. Power re-supply of outages during reconnections

The devices that perform reconnections, either switches or re-connectors, base their success on eliminating failure during thereconnection time or dead time period without causing currentflow that allows the non-permanent power failure to deionize.

The maximum time that is needed to deionize an arc in voltagedistribution (up to 36 kV) does not exceed 300 ms. Using DG in aradial system, the reconnection operation upstream of thepower failure reduces the current flow without eliminating itcompletely because the additional generator powers the failureand thus eliminates the possibility of deionization.

As a result, a communication system between all generators'protective systems is required; also it has to be a selective system.

2.2. Extending the power outage duration to reduce the area affected

With the introduction of power quality requirements [13], theprotection departments of utility companies changed their safe-guard schemes with the aim of reducing the number of penaliz-able outages and lessening the extent of the affected areas, thusreducing the number of customers affected by outages [14].

The manner in which this goal was achieved consisted of anincrease in the delay of safeguards as much as possible in cases inwhich reconnection devices are located downstream, therebyalso increasing the number of reconnections and thus increasingthe possibility that failures self-extinguish or deionize.

The immediate consequence of this policy is that the operatingtimes or delays will increase as one moves upstream because ofthe demands of coordination. This solution obviously conflictswith the requirements of power quality, such as short-termperturbations, thus bolstering the application of high-speedprotective devices and tracking of perturbations [15].

As in the previous case, the protective communication systemis necessary. In addition, a tracking of perturbations system isneeded as well to isolate failure defects.

2.3. Possibility of anti-phase reconnection

This is one of the most common objections to the use of anisland-operated distributed generator. It is feared that whenreturning power to the system, the independent generator willbe found with a phase or angular position of the three voltagesthat is very substantially different from that of the systemwhen itselectrical power is returned, thereby causing very high electricaland mechanical stresses that could damage both the generator andthe other island-connected elements [16].

Thus, a phase control system between the generators and thenetwork is required.

In conclusion, as a result of this analysis, to attend the problemof failure defects in networks by DG installation, the followingrequirements should be addressed:

A communication system between all generators' protectivesystems.

A selective protective system. A tracking of perturbations system to isolate failure defects. A phase control system between the generators and the

network.

In the next section, another problem of integration of DG isanalyzed, which is the effect of the connection and disconnectionof the DG generators power on grid voltage.

3. The effect on voltage control in distribution grids with DG

The effect on voltage resulting from the integration of DGdepends on different variables, such as the voltage level, the typeof grid (rural-urban, aerial-underground, or radial-ring), the levelof demand, the location of the DG in such grid, and the level ofpenetration of such a DG.

Nomenclature

ADA Advanced distribution automationAMI Advanced metering infrastructureCIGR International Council on Large Electric Systems (Con-

seil International des Grands Rseaux Electriques)CIT Communication and information technologiesCOM CommunicationDENISE Safe and Efficient Intelligent Energy DistributionDER Distributed energy resourcesDG Distributed generationEN European NormEV Electric vehicleERDF European Regional Development FundHEMS Home energy management systemIEC International Electrotechnical CommissionIEEE Institute of Electrical and Electronics EngineersINTEGRISIntelligent electrical grid sensork R/X ratio parameterMCS Motorization and control systemMV Medium voltageNTP Network time protocol

LV Low voltagePEV Plug-in electric vehiclePHEV Plug-in hybrid electric vehiclePLC Power line communicationPTP Precision time protocolPV PhotovoltaicR Resistance of the conductorRES Renewable energy sourcesrms Root mean squareScet Static power capacitySC Smart citySG Smart gridTC Transmission centerTS Transformer substationSMV Sampled measured valuesSQRA Security, quality, reliability, and availabilityUCs Use casesV2G Vehicle to gridV2H Vehicle to homeVr Voltage of the generatorWP Work packageX Reactance of the conductor

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234 225

The IEC 60038 international standard (1999) [17] defines voltagelevels of 230/400 V for supplying low-voltage electrical power at50 Hz.

The European standard EN 50160 (Voltage Characteristics ofPublic Distribution Systems, 1999) [18] provides a series of qualityrequirements for distribution systems. With respect to voltagevariations in the standard, EN 50160 establishes the permissiblerange of voltage variation at the point of common coupling fordistribution systems at medium voltage (MV) and low voltage (LV)at 10%. This margin must be maintained for at least 95% of theweek, where the average of the rms values measured in periods of10 min on the basis of samples taken every 200 ms is considered.The EN 50160 standard is mandatory for all member countries ofthe European Union.

In the Grids 2025 project [19,20], the influence of DG on gridvoltages is analyzed.

3.1. Influence of DG on voltage control

Reactive voltage control is one of the most important comple-mentary services performed by the system operator, who operatesthe distribution and generation grid [21,22].

Two types of analyses are presented:

(1) A noticeable increase in the k(R/X) parameter, which relatesthe resistance and reactance of the conductor with the voltagevariation at the point of grid connection as the function of theactive power injected; this can be observed in Fig. 1.For low values of the k parameter, the active power does nothave a practical influence on the voltage profiles (blue curve);as the k parameter grows, the effect of active power on thevoltages becomes significant (red curve).In Table 1, we can see that the k value at MV and LV is greaterthan 1.This value causes the injection of active power in part of theDG to create significant increases in the voltage at other connectedparts.This effect can be very damaging at these voltage levels becausethe MV and LV networks have been designed according to thescheme of unidirectional flows from boundary points of thetransmission system towards the final consumer.

(2) The reactive power necessary to maintain the voltage at thegrid connection point at the nominal value can be observed inFig. 2, where ScetVr2/X, the static capacity, is the ratio betweenthe square of the voltage in the generator and the reactance ofthe conductor.

The k parameter increases proportionally with the increase inthe amount of reactive power that must be absorbed tomaintain the voltage at the grid connection point.As we have observed previously in table I, in MV grids, thevalue of k is greater than unity; consequently, the reactivepower necessary to compensate for the active-power effect is2 to 1, which indicates that the contribution of DG to voltagecontrol in MV and LV grids via the injection and absorption ofreactive power is not effective because it would yield costoverruns in reactive compensation technologies.

3.2. Influence of DG on MV grids

The effect of active-power flows on the voltage is greater thanthe reactive power because the k parameter of the MV lines isusually greater than unity; the voltage increase is linearly propor-tional to the active-power injection at the node. Fig. 3 shows theimpact of DG location on a concentrated, rural, segmented, MV grid.

Upon injecting active power at a point in the grid, the powerflow in the upstream sections is reduced. This reduction resultsin a smaller voltage drop in those previous sections. As a result,the voltage in the grid increases and maintains similar profiles.The closer the DG to the head of the line, the less impact it exertson downstream voltages because there are fewer sections wherethe power flows are reduced.

The greatest variation in voltages occurs if the injection isperformed at the end of the line because the reduction in powerflow affects many more MV line sections and thus the voltagesincrease markedly [23].

3.3. Influence of DG on LV grids

Compared with the injection of reactive power, the injection ofactive power has a greater impact on the line voltages because the

Table 1Values of the k parameter as a function of the voltage level [21].

Voltage level kR/X R(/km) R(/km)

400 V 4.44 0.400 0.09020 kV Underground 2.29 0.270 0.11820 kV Aerial 1.065 0.426 0.40066 kV 0.31 0.119 0.386132 kV 0.175 0.072 0.410220 kV 0.146 0.046 0.315400 kV 0.097 0.027 0.277

Fig. 1. Powervoltage variation curves for different values of k [21].

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234226

k parameter of LV lines is much greater than unity. In thissituation, when modifying power flows through the lines, thepower flow through the transformer of the transformer substation(TS) from MV to LV also changes, thus combining both effects.We can assert the following:

If active power is injected into the grid, the voltage drop in theTS transformer will change slightly; however, the voltagesthroughout the grid will change substantially.

If reactive power is injected into the grid, the voltage dropalong the line will suffer little variation; however, the voltagedrop in the head transformer will change, thereby affecting allthe nodes in the LV grid that are connected to it.

If power is injected into a node at the end of the line, it is easyto identify two effects in the voltage drop one corresponds tothe lines, for which the active-power effect predominates, andother one corresponds to the transformer, for which the reactive-power effect is relevant.

Power injection at an end node causes over-voltages in thezone next to the injection node, although in no case havevoltages beyond the limit been observed.

If injection is performed simultaneously in different sensitive nodesof the grid, unacceptable over-voltages can occur. The more theactive-power injection is distributed in the grid, the less the impacton grid voltages, and therefore the possibility of over-voltages. Thisis the situation that can be expected in the future, when differentPV units are installed in a distributed fashion [23,24].

In conclusion, as a primary result of this analysis:

For high values of the k parameter the effect of active power onthe voltages becomes significant.

High values of the k parameter cause increases in the amount ofreactive power, which must be absorbed to maintain thevoltage at the grid connection point.

The greatest variation in voltages occurs if the injection isperformed at the end of the line.

Thus, with growing levels of DG penetration, the actual valuesof grid voltage quality cannot be ensured. Synchronizing voltageregulation is crucial for facilitating DG development and guaran-teeing the quality of the power supply.

Currently, recent and modern technologies allow sharingof different services of a single communications infrastructurewhile guaranteeing the required levels of security, reliability, andefficiency.

The SC architecture proposed in the next section envisions ahierarchical, distributed, and autonomous structure to address thechallenge of smart distribution grids. The proposed objectives areas follows:

To optimize the utilization of electrical infrastructure. Minimize energy dependence. Maximize sustainability. Minimize costs.

Fig. 3. Nominal voltage variation as a function of DG location in an MV grid [20].

Fig. 2. Curves of the k parameter required to reach the nominal voltage as a function of the necessary reactive power [21].

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234 227

To optimize supply quality. Maximize wave quality. Maximize reliability and availability.

To create value-added services. Demand management. Electricity gains value. Price in real time.

4. A viable architecture for a multi-servicetelecommunications network

The following concepts have been tested by the electric companyENDESA, the National Electric Company of Spain, in a real SC project[25] in the area of Playa de la Misericordia in the city of Malaga in thesouth of Spain. In this project, 300 industrial customers, 900 servicecustomers, and 11,000 residential customers participated over fouryears (20092013) with a total contracted power of 63 MW (70 GWh/year of consumption), which resulted in emissions of 28,000 t of CO2annually. The project is financed with funds from the EuropeanRegional Development Fund (ERDF) [26], and its goal is to integratemost of the advanced SG applications in a real environment.

The design principles have followed the security, quality, reliability,and availability (SQRA) methodology. SQRA is based on balancing thefollowing properties:

Security: this property is related to information security anddata protection.

Quality: this property is the set of typical performance attri-butes of any communication system, which includes highbandwidth, high quality of service, and low latency.

Reliability: the system and related devices must be robust. Availability: this property is related to redundancy.

Among the many services considered, we can differentiatebetween those that are real time (remote control, teleprotection,distributed-energy resource control, and management of prices inreal time) and those that are not real time (remote equipmentmanagement, reading of new smart meters, and electricvehiclecharging systems).

The project fundamentally relies on a highly reliable communica-tions framework. Thus, it requires a communications network withsufficient bandwidth, low latency, and high reliability for all of therequired services [27]. Once we have this framework, it is possible toimplement different sets of advanced smart grid applications, mainlyadvanced metering infrastructure (AMI), distributed energy resources(DER), and advanced distribution automation (ADA).

4.1. Conceptual architecture

The network is primarily based on a ring topology in which thelinks are connected by optical-fibre gigabit Ethernet links. Twosynchronization protocols are utilized the network time protocol(NTP) and the precision time protocol (PTP, IEEE 1588) [28].

From the electrical point of view, the concept of SG is based onthe three fundamental concepts of AMI, DER, and ADA; these areschematized in Fig. 4, which shows the conceptual architecture ofthe project [29].

The applications in the outer circle are applied to all functions,independent of their position. For that reason, the proposedarchitecture should consider the following:

a. Implemented communication structure.b. The interconnected functional blocks are crucial for implementing

the functionalities of the following: Advanced Metering Infrastructure (AMI). This refers to consumer

management. The efficient utilization of electrical resources req-uires modification of consumer habits. Consequently, flattening

of the daily consumption curve, which is equivalent to allowingthe grid to store energy, can be achieved. Such flattening is evenbetter than storing energy because storage occurs at the point ofconsumption.

Distributed Energy Resources (DER). This refers to generatormanagement.J By bringing the generators closer to consumers, technical

losses due to transmission and distribution can be reduced.J By diversifying and increasing the number of generators,

the criticality of each of the individual generators can bereduced; thus, we maximize the redundancy of genera-tion sources by combining in a balanced and statisticalmanner many heterogeneous generation sources.

J Energy storage: Due to the increase in renewable energysources, the ability to store energy that can be generatedat the moment it is needed has become indispensable.The foreseeable increase in the electric-vehicle fleetconstitutes an extraordinary potential storage capacity.

Advanced Distribution Automation (ADA): This refers to theautomation of the grid. The growing complexity and criti-cality of the electric grid require advanced, infrastructure-control methods with the goal of optimizing efficiency. Itwill be necessary to automate the remote-control topology,maintenance, and prediction capability. It will be necessaryto broaden protection schemes and implement adaptiveself-adjustment mechanisms of grid devices in real time.

c. Necessary control systems for operating and maintaining theentire system.

The creation of an SC entails a great technological advancementand sustainable development, thereby facilitating and contributingglobal solutions to the society of the future and other solutionstailor-made to individual customers.

4.2. Electrical infrastructures

As can be deduced from the above discussion, our fundamentalobjectives are the following:

AMI: Demand management.DER: Distributed generation.ADA: Advanced automation of the distribution grid.

These three systems cannot be considered separately becausethey share infrastructure and are intimately related. We canconsider them as three parallel systems that must coexist.

Fig. 4. Conceptual architecture of the project.Source: CIGRE D2 PS2.

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234228

Expanding the concepts of grid automation will be crucial notonly for the control of the secondary distribution grid but also forthe protection schemes and micro-generator automation (forhomes, vehicles, and other applications) that will constitute thesystem. Real-time information about instantaneous consumptionand quality of service for the final users will also be of great utilityfor running the distribution grids [30].

Basically, the most radical changes that appear in the new gridof an SC are the following:

A great increase in the complexity of the secondary distributiongrid.

A foreseeable increase in the number of micro-generators inthe secondary distribution grid.

The appearance of many generators in the LV grid that will haveto function in a coordinated manner.

The appearance of smart meters for the control of demand andresidential generation.

The first two already exist today. However, it is foreseeable thatthey will increase significantly in number and importance. Con-sequently, we will obtain a much more complex grid that willrequire safer and more efficient control mechanisms.

The third point is the most novel and it will require specialdesign from the perspective of stability, security, and operation.

The last point will also allow real-time control of distributionfor the final users. Its massive nature will require the utilization ofspecial maintenance and communication techniques.

Finally, it is important to emphasize again that all of thesesystems have a common meeting point at the transformationsubstations of the secondary distribution grid, the fundamentalpoint at which the three basic systems (ADA, AMI, and DER)naturally converge.

4.3. Communication and systems

To achieve an SC, it is necessary for information to flow andcommunication technologies to evolve [31]. To this end, one mustrely on a Power Line Communications (PLC) network to send ordersto devices and to receive information about them and each one ofthe indicators from the monitoring and control center. In this PLCnetwork, what we call Inodes and Isockets have been developed;these devices converse with different loads and equipmentconnected to the grid, thus allowing the grid to be managed.Finally, the smart meters for the remote management projectrepresent a special type of the above devices [32].

This integration initiative is distributed in various legs, such asefficient energy generation and storage, lighting infrastructure,mobility, remote management, and efficient control and manage-ment of buildings, all based on Smart Communication and Infor-mation Technologies (CIT), which is the true heart of the project.

Fig. 5 shows the integration scheme for Smart CIT.A proper integration approach will utilize a data bus in which

all of the applications can share information and that can growhorizontally without influencing the applications that are func-tioning [33].

4.4. Technology and equipment

The distribution grid of the future will consist of a combinationof multiple generators and storage elements [34] with some of thefollowing technologies and equipment that will appear and thatshould be treated statistically.

A distinction will be made between primary equipment (relatedto power infrastructures) and secondary equipment (infrastructuresrelated to electronic control devices and associated communications)

and the necessary information systems for the coordinated controlof both.

4.4.1. Primary equipment4.4.1.1. Primary equipment in the Advanced Meter Infrastructure(AMI) system. A smart meter is an electronic device that willentirely replace current electromechanical meters in the comingyears. This device participates in the functions of DER, AMI, andADA. The primary functions of the new residential smart metersare detailed below:

Metering according to hourly time slots (AMI). Power limitation on a contractual basis (AMI). Disconnection because of non-payment (and restoration) (AMI). Quantification of reverse power if there is a negative balance (DER). Sending information to the distributor (ADA and AMI). Measurement of wave quality (voltage dips) (ADA and AMI).

The special feature of this technology is volume, regarding boththe number of devices and the amount of information to beprocessed. Merely installing these devices involves installing thefunctionality of a consumer portal. This functionality involves theinstallation of a device at the transformer stations (which we shallcall remote measurement hubs), PLC communications through theLV grid between consumers and hubs, and communicationsbetween the hub and central systems.

4.4.1.2. Primary equipment in the Distributed Energy Resources andStorage (DER) system. This is undoubtedly one of the key pieces ofour SC. Multiple, small generators distributed geographically sothat they equilibrate consumption where it occurs.

We shall distinguish between two types of generators accord-ing to the voltage level of the grid to which they are connected:

MV: Generators connected to the MV grid. These are powergenerators with power 40.1 MW. They need a protectioninfrastructure similar to that used in the MV grid. They sharecommunications infrastructures and should interact with smartdevices installed in this grid. Their fundamental objective is toprovide power to the MV segment to which they are connected.They tend not to regulate, and when dealing with renewableenergy, all of the available energy is used. A significant numberin each MV segment (0ono10) does not frequently exist.Currently, they have an automated character that disconnects

Fig. 5. SC Smart CIT [32].

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them from the grid automatically at the instant when adisconnection of the main line occurs.

LV: Generators connected to the low-voltage network. Theyneed protection adapted to LV. They share infrastructure withthe AMI system. Their main purpose is to provide power to theLV segment. The fundamental characteristic of these generatorsis that a significant number can be present in each LV segment(0ono100). The ideal situation occurs when the power of theinstalled generator equals the required power consumption.

4.4.2. Secondary equipment: electronic control devicesThe first aspect to consider in a generation system is the control

of the generated power. The regulation system should considerother parameters besides the active and reactive powers, such asthe availability of generators.

Another very important aspect to consider is synchronization.A generator cannot be coupled to the grid if it does not fulfill thefollowing conditions:

It has the same frequency. It has the same phase. It has the same voltage.

Otherwise, connecting the generator can cause a short circuit.There are synchronization mechanisms for each type of generationto correct and ensure compliance with these three conditions.The mains voltage acts as a synchronization pilot, and when itdisappears, all of the generators disconnect from the grid. Theobjective is to constantly minimize the power consumed by themain power supply.

Each point of connection of a controllable load, a storage device,or a generator to the electricity grid is considered an energy point,which can consume or produce energy. An electronic controller isavailable, and it is modeled by the following:

1. Autonomy: The maximum energy that it can produce/consumeper unit time.

2. Load: The instantaneous power that it can produce/consume asa function of time.

3. Availability: This is given as a function of time (planning).4. Cost: This is according to the time slots and type of generation.5. Type of regulation: For example, the all-or-nothing allocation of

active power or reactive power.

4.4.3. Information systemInformation systems can be classified according to their func-

tion, but must work in a coordinated and integrated manner.

AGC: Automatic Generation Control. AMS: Asset Management System. WMS: Work Management System. OMS: Outage Management System. GIS: Geographic Information System. EMS: Energy Management System. AGC: Automatic Generation Control DSM: Demand Side Management. DMS: Distribution Management System. CIS: Customer Information System. NMS: Network Management System. Billing, Planning and Advanced Simulation

4.4.3.1. MV case. The secondary distribution grid is typically com-posed of rings connected to two primary distribution substationswith some antenna circuit ramifications. It is operated radially;

thus, there is always an intermediate open switch, by default theso-called boundary point. If there has been some self-healingoperation, this open switch might have changed and can be anyother one. That is, upon increasing the automation of this grid, aninitial problem occurs because the network topology can changeeasily. Therefore, the number of generators/consumers connectedin a section is not constant.

A typical model of the secondary distribution grid then consistsof a cluster of automated circuit-cutting elements, which willenable self-healing in coordination with the automatism of theheader re-connector, and a set of transformers and generatorsconnected to the grid.

The generators connected to the grid have limited or no regu-lation capacity; thus, they operate by on-off commands. Towardsthe primary distribution, transformer coupling can occasionally beconsidered a generator with a certain capacity for regulation.At this level, it can provide an allotment command for active andreactive power that will operate locally, thereby optimizing thenumber and types of generators used.

4.4.3.2. LV case. The transformers in the case of LV micro-gene-ration scenarios can occasionally turn into generators. In this case,they can indeed have a certain regulation capacity globally via on-off mechanisms for individual generators.

In the same manner, the LV distribution grid can be modeled asa star of load-connection busses and/or individual generators.

4.5. Electric vehicles

The rising price of fossil fuels and the need for transport that isincreasingly cleaner and more respectful towards the environmentmake it foreseeable that in the coming years, the fleet of electricvehicles (EV) [35,36] and plug-in hybrid vehicles (PHEV) will increasemarkedly [37]. This increase will have the following direct effects:

Increased energy efficiency. Increased penetration of RES in the transport sector. Reduced CO2 and NOx emissions [38].

In terms of the energy supplied to the vehicle, gasoline engineshave an efficiency of only 27%, and diesel engines have an effi-ciency of only 33%, because a large part of the energy is consumedas heat. In contrast, electric motors have an efficiency of 95%.

It is a demonstrated fact that 95% of the time, our vehicles areparked. During this time, millions of batteries can be at the service ofthe electric grid for utilization at moments of high demand, tostabilize the grid, to increase reliability, or for recharging duringexcess RES production; this system is referred to as Vehicle to Grid(V2G). In addition, these batteries can be used in a home with a PHEVas a power system in case of power-failure emergencies, for example,or to increase the power available to the residence at certain hours;with the battery fully charged and the gas tank full, a plug-in hybridcan provide energy to the average Japanese home (approximately10 kWh) for four days. This system is referred to as Vehicle to Home(V2H). This type of optimal energy flow can be controlled automa-tically via a Home Energy Management System (HEMS).

To achieve this comprehensive SC project, 12 working groups,or Work Packages (WPs), have been established. The first four areof a horizontal nature, i.e., they affect the entirety of the project,whereas the rest are of a vertical nature, i.e., they affect specificareas of development [25].

WP01 Project management and tracking. WP02 Operational deployment and communication plan. WP03 Harmonization through the DENISE (Safe and Efficient

Intelligent Energy Distribution) project [39].

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WP04 Telecommunications. WP05 Systems. WP06 Medium-voltage grid automation. WP07 Mini-generation and storage on the MV grid. WP08 Energy efficiency and active management of demand. WP09 Low-voltage grid automation. WP10 Micro-generation and storage in the LV grid. WP11 Remote-management infrastructure (AMI). WP12 Electric vehicles (V2G).

Thus, as result of this project, SC fundamentally relies ona highly reliable communications framework with sufficient band-width, and it entails a great technological advancement andsustainable development. It is necessary for information to flowand communication technologies to evolve.

This scenario of applications and the use cases that will bedescribed in the next part will contribute to the development of theglobal architecture of the INTEGRIS project [40]. The use cases that willbe defined cover all the project working groups and have involved allof the groups in their elaboration, thereby affecting the entire grid, andwill involve a guide to using the smart power distribution grid.

5. Use cases, SG functionalities

The exposition of these use cases (UCs) attempts to cover all thefunctionalities that should be supported in the SG, from the pointof view not only of communications but also of the system ingeneral [41,42].

The UCs are detailed in three large groups, UCs for MV, UCs forLV, and UCs that affect both (MV/LV). Within these three groups,various subdivisions into subgroups have been made: ADA, DER,AMI, and COM (communication).

The utilized communication protocol follows the IEC 61850norm [43]. This protocol permits different methods of informationaccess: polling, sampled measured values (SMV), or reporting [44].In this document, only the methods of polling and reporting havebeen used. The polling method allows requesting a variable fromthe destination and transmitting this information to the source. Incontrast, the reporting method allows storage of the values ofvariables in a local record with a time stamp until some elementrequests the record with all of the information.

5.1. Use cases for MV

The UCs have been grouped into ADA and DER. The AMI groupis not present because its UCs is only applied to the LV grid.

5.1.1. ADA MV use casesThe ADA UCs have been grouped into six sections:

General functionsThe general UCs affect or can be used by any MV acting elementthat must perform an ADA functionality. The UCs in this sectionare as follows: ADA data reading (MV). Alarms from the operations control center.

Grid managementThis refers to the UCs that describe the automation operationsthat must be commonly performed in the electric grid suchthat it can continue to function correctly.Given that the functions of this group involve a large number ofactions, the system has been divided into three subsystems andtheir different cases.1. Contingency analysis

To calculate contingency cases

Partial discharges State of communications

2. Voltage control Supervision of the grid voltage. Reconfiguration of the grid.

3. Load control Supervision of the grid load. Reconfiguration of the grid.

Grid self-healingThese are the UCs that are related to the detection and repair ofproblems in the electric grid. Failure detection (MV) Failure isolation (MV) Restoration of service after failure (MV) Local isolation of failures (MV)

Avoiding islandingGrid monitoring is necessary to detect whether the gridconfiguration is incorrect at a particular moment in time andto avoid islanding.The ADA control center must receive certain information fromthe distributed generators. A UC is presented.Monitoring of the ADA grid configuration

Discharge managementThis is the UC that applies when the power grid needsoccasional or periodic maintenance work, which is performedby the grid operators.Discharge management

Management of the distribution systemThe objective of this scenario is the reading, control, andvisualization by the distribution system of data from devicescontrolling the margins that can lead to failures by performingcomplex calculations and sending control signals. The UCs arethe following: Device control. Visualization of the state of the distribution grid.

5.1.2. MV DER use casesThis section presents the UCs related to the DG, which are

defined as the grid's ability to act on different types of generatorsdistributed over the MV grid. The purpose of these actions is toprovide the energy needed by the network with maximumefficiency and to integrate a large number of new resources thatmust be managed in an SG.

Management of MV distributed generatorsThe following UCs are considered: Activating the distributed generator Deactivating the distributed generator Monitoring the quality of the energy generated

Management of the MV storage systemsSuch systems will be considered as two types of systems:1. Controllable distributed generators (the generator).2. Controllable loads (the consumer).

The following UCs are given: Activating the storage system. Deactivating the storage system. Monitoring the quality of the energy generated/consumed. Regulating the generation/consumption parameters. Reactive-power control function.

5.2. Use cases for LV

The following section presents the UCs for the LV distributiongrid, which have been divided into ADA, DER, and AMI.

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234 231

5.2.1. LV ADA use casesThe ADA functionalities in LV are primarily centered on failure

detection. The following use cases are given:

Reading of ADA data; Failure detection via meters (AMI); Failure detection via fuse-box meters; UserLV box association procedure; and Harmonic filtering and correction.

5.2.2. LV DER use casesThe following UCs, which are grouped into six sections, are given:

Management of LV distributed generatorsThe following are the use cases: Activating the distributed generator. Deactivating the distributed generator. Monitoring the quality of the energy generated. Regulating the generation parameters. Reactive-power control function.

Electric vehicle UCs (PEV, plug-in electric vehicle) [45]There is a registry in the DER control center for grid connec-tions with different functionalities. Registration of the vehicle onto the grid. Deregistration of the vehicle off the grid. Charging the vehicle on the grid. The PEV enters the available reserve'. The PEV provides energy to the grid. The PEV receives energy from the grid.

Energy efficiency and demand management in homes and busi-nesses.The UCs defined in this section consist of generic uses forenergy efficiency and demand management in homes andbusinesses. For this functionality, it is necessary to conveyinformation and instructions to and from the customer andthe marketer or electricity distributor. Basic information services for the customer. Energy management services for the customer. Planned demand-management services (by price). Demand management services because of predicted grid

congestion.

The two remaining use cases center on the interaction with themeter. Data reading for energy management. Energy management because of predicted grid congestion.

DG managementIn this section, all the UCs related to DG energy managementare given. Activating the storage system. Deactivating the storage system. Monitoring the quality of the signal generated/consumed by

the storage system. Regulating the generation/consumption parameters.

Monitoring systems for the MCSThe objective of this scenario is the monitoring of grid data onthe part of the monitoring-system user. Visualization of the MV grid Visualization of the Microgrid

Avoiding islandingGrid monitoring is necessary to detect whether the gridconfiguration is incorrect at a particular moment in time andto avoid islanding. This monitoring is performed at the ADA andDER levels.Monitoring of the DER grid configuration

5.2.3. AMI use casesThe following UCs grouped into AMI management are given:

AMI managementThe use cases in this section center on type-5m (multifunctionelectronic meter for LV supply [46]). Power management Rate management Disconnection of the user from the grid Connection of the user to the grid Meter reading Load-curve reading

5.3. Generic use cases (MV/LV)

5.3.1. COM use cases

Management of communicationsThe following use cases are derived from the use of communi-cations: (Online) failure management (Offline) failure management

Performance managementThis goal of this scenario is to detect problems of performancein grid communications. (Online) performance management (Offline) performance management

Inventory managementThe goal of this scenario is to detect problems of performancein equipment installed on the grid.Management of component life cycle

Thus, the results show that it is possible to cover all the func-tionalities supported in the SG, it establishes a guide to using thesmart power distribution grid, and in this process, it optimizes theinfrastructure of the electrical industry.

Fig. 6 graphically shows the different UCs of the basic SG systems.

6. Conclusions

The obtained results show that the presence of DG in distribu-tion grids modifies their energy flows. These grids used to have apassive character with some design conditions and grid architec-ture under the assumption of unidirectional flows from thetransmission grid boundary points to the final consumers.

This work shows that DG installation affects power quality,among which the most important related events are voltage dipsinduced by failure defects.

Also, the injection of active power in distribution grids impliesan increase in the voltage in the entire grid and the increasing ofthe reactive power that must be absorbed to maintain the voltageat the grid; these effects depend linearly on the level of penetra-tion and the parameter k.

One of the conclusions of the analysis shows that with growinglevels of DG penetration, the actual values of grid voltage qualitycannot be ensured. Synchronizing voltage regulation is crucial forfacilitating DG development and guaranteeing the quality of thepower supply.

The fundamental key for this is the SG concept, an adequateinfrastructure with two-way communications and hierarchical,distributed architectures to perform different applications thatare needed [47].

Thus, developing based traffic models for the smart grid toevaluate the performance of communication networks is a neces-sary fundamental medium to make this structure of communicating

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234232

devices function as one and to perform adequate control andsupervision of the distribution grid so that the flows and voltagelevels in the grid are known at all times, thereby enabling guar-antees of the quality and security of the supply [48].

For this, devices for protection, control, regulation, and mea-surement should be interconnected in a hierarchical network withadequate levels of quality and reliability. The reuse of infrastruc-ture and the power grid topology is also an indispensable elementin this deployment [49,50,51].

The conclusions of this work, RES can be optimally integrated intothe distribution grid, as has been already achieved in the transmissionsystem with large-scale renewable plants [52,53]. For future trends,generation can approach consumption through the installation ofphotovoltaic panels and mini-wind generators in buildings [54], theuse of polygeneration systems in micro-power generation at thebusiness and public sectors [55,56,57], the installation of dispersedmicro-wind systems, sustainable hybrid energy systems, and the

presence of energy storage systems in vehicle batteries such thatpart of the energy can be consumed afterwards for the climate controlof buildings, street lighting, and electric transport [58,59].

Acknowledgments

The authors wish to express their gratitude to ENDESA for theircollaboration in providing documents related to the Smart CityMalaga and the INTEGRIS project.

References

[1] Luo Lei, Tai Nengling, Yang Guangliang. Wide-area protection research in thesmart grid. Energy Procedia 2012;16:16016.

[2] Kohsri Sompol, Plangklang Boonyang. Energy management and control systemfor smart, renewable energy remote power generation. Energy Procedia2011;9:198206.

Fig. 6. Schematic of UCs of the basic SG systems.Source: Author's work.

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234 233

http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref1http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref1http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref2http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref2http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref2

[3] Wolsink Maarten. The research agenda on social acceptance of distributedgeneration in smart grids: renewable as common pool resources. RenewSustain Energy Rev 2012;16:82235.

[4] Al-Agtash Salem. Electricity agents in smart grid markets. Comput Ind 2013;64(3):23541.

[5] Ancillotti Emilio, Bruno Raffaele, Conti Marco. The role of communicationsystems in smart grids: Architectures, technical solutions and researchchallenges. Comput Commun 2013;36:166597.

[6] Gaviano Antonello, Weber Karl. Christian dirmeier. Challenges and integrationof pv and wind energy facilities from a smart grid point of view. EnergyProcedia 2012;25:11825.

[7] Fotouhi Ghazvini MA, Morais Hugo, Vale Zita. Coordination between mid-termmaintenance outage decisions and short-term security-constrained schedul-ing in smart distribution systems. Appl Energy 2012;96:28191.

[8] Jrventausta Pertti, Repo Sami, Rautiainen Antti, Partanen Jarmo. Smart gridpower system control in distributed generation environment. Ann Rev Control2010;34:27786.

[9] Wang Wenye, Xu Yi, Khanna Mohit. A survey on the communicationarchitectures in smart grid. Comput Netw 2011;55:360429.

[10] Moreno-Munoz A, Jos Gonzlez de la Rosa Juan, Flores-Arias JM, Bellido-Outerino FJ, Gil-de-Castro A. Energy efficiency criteria in uninterruptiblepower supply selection. Appl Energy 2011;88:131221.

[11] Gmez JC, Amatti JC. Distributed generation power quality interaction,specifically referring to voltage dips. Argentina: School of Engineering, RioCuarto National University (Interaccin Generacin Distribuida Calidad dePotencia, especficamente referida a Huecos de Tensin. Facultad de Ingeniera.Universidad Nacional de Ro Cuarto); 2006.

[12] Piumetto M, Gmez Targarona JC. Characterisation of voltages dips and theirimpact on sensitive loads in an MV system with distributed generation duringa monophasic failure (Caracterizacin de Huecos de Tensin y su Impacto enCargas Sensibles en un Sistema de M.T. con Generacin Distribuida duranteFalla Monofsica). http://www.argencon.org.ar/sites/default/files/072.pdf;2012 [accessed 16.02.13].

[13] IEC (1000-2-2/4) Standard that defines the power quality.[14] UNE-IEC/TR 61000-2-8:2006. IN electromagnetic compatibility (EMC) Part 2-8:

environment voltage dips and short interruptions on public electric powersupply systems with statistical measurement results (IEC/TR 61000-2-8:2002).

[15] Benachaiba C, Haidar Ahmed MA, Habab M, Abdelkhalek O. Smart control ofUPCQ within microgrid energy system. Energy Procedia 2011;6:50312.

[16] Saldaa CR. Performance analysis of the anti-islanding relay in a distributedgenerator (Anlisis del desempeo del rel anti-isla de un generadordistribuido). http://iie.fing.edu.uy/epim2010/myreview/myPapers/p60.pdf; 2010[accessed 16.02.13].

[17] International Standard IEC 60038 Standard Voltages. http://212.175.131.171/IEC/iec60038%7Bed6.2%7Den_d.pdf [accessed 16.02.13].

[18] Standard EN 50160 (Voltage Characteristics of Public Distribution Systems,1999). http://www.copperinfo.co.uk/power-quality/downloads/pqug/542-standard-en-50160-voltage-characteristics-in.pdf [accessed 16.02.13].

[19] Grids Project [Proyecto Redes] 2025. Development of technological solutionsfor the Spanish power grid of 2025. (Desarrollo de soluciones tecnolgicaspara la red elctrica Espaola del 2025). (20092012). http://www.redes2025.es/ [accessed 16.02.13].

[20] Annals of Mechanics and Electricity. ICAI Engineers Association. CatholicInstitute of Arts and Industries (Revista Anales de Mecnica y Electricidad.Asociacin de Ingenieros del ICAI. Instituto Catlico de Artes e Industrias).http://www.revista-anales.es [accessed 16.02.13].

[21] Voltage control in distribution grids with Distributed Generation (I). Annals ofMechanics and Electricity. ICAI Engineers Association (Catholic Institute ofArts and Industries) 13th ICAI April 2012. (Revista Anales de la asociacin deingenieros del ICAI). http://www.revista-anales.es/web/n_13/seccion_3.html;13 April 2012 [accessed 16.02.13].

[22] Niknam Taher. A new HBMO algorithm for multiobjective daily Volt/Varcontrol in distribution systems considering Distributed Generators. AppliedEnergy 2011;88:77888.

[23] Voltage control in distribution grids with Distributed Generation (II). Journalof the association of engineers of the 14th ICAI June 2012. (El control detensin en redes de distribucin con Generacin Distribuida (II). Revista de laasociacin de ingenieros del ICAI). http://www.revista-anales.es/web/n_14/seccion_3.html; 14 Junio 2012 [accessed 16.02.13].

[24] Hossain MJ, Saha TK, Mithulananthan N, Pota HR. Robust control strategy forPV system integration in distribution systems. Appl Energy 2012;99:35562.

[25] Smart City Malaga. http://portalsmartcity.sadiel.es/; http://portalsmartcity.sadiel.es/EN/documentos/100204_%20Smartcity_ENDESA_Eng3.pdf [accessed16.02.13].

[26] FEDER: Fondo Europeo de Desarrollo Regional (ERDF) European RegionalDevelopment Fund. http://europa.eu/legislation_summaries/agriculture/general_framework/g24234_es.htm [accessed 16.02.13].

[27] Gao Jingcheng, Xiao Yang, Liu Jing, Liang Wei, Philip Chen CL. A survey ofcommunication/networking in smart grids. Future Gener Comput Syst2012;28:391404.

[28] NTP (Network Time Protocol), y PTP (Precision Time Protocol, IEEE 1588). http://www.en4tel.com/pdfs/NTPandPTP-A-Brief-Comparison.pdf [accessed 16.02.13].

[29] CIGRE (the Council on Large Electric Systems) D2 (Telecommunication andinformation systems [Sistemas de informacin y telecomunicacin]) PS2(Interconnected information systems to support competitive markets).http://www.cigre.org/ [accessed 16.02.13].

[30] John Justo Jackson, Mwasilu Francis, Lee Ju, Jung Jin-Woo. AC-microgridsversus DC-microgrids with distributed energy resources: a review. RenewSustain Energy Rev 2013;24:387405.

[31] Usman Ahmad, Shami Sajjad Haider. Evolution of communication technolo-gies for smart grid applications. Renew Sustain Energy Rev 2013;19:1919.

[32] Uciencia Scientific Journal (Uciencia revista cientfica) no. 10, RenewableEnergies. (Energas Renovables. Diciembre 2012). http://www.uciencia.uma.es/; December 2012 [accessed 16.02.13].

[33] Cunjiang Yu, Huaxun Zhang, Lei Zhao. Architecture design for smart grid.Energy Procedia 2012;17:15248.

[34] Wade NS, Taylor PC, Lang PD, Jones PR. Evaluating the benefits of an electricalenergy storage system in a future smart grid. Energy Policy 2010;38:71808.

[35] Siang Fui Tie, Chee Wei Tan. A review of energy sources and energy manage-ment system in electric vehicles. Renew Sustain Energy Rev 2013;20:82102.

[36] Richardson David B. Electric vehicles and the electric grid: a review ofmodelling approaches, impacts, and renewable energy integration. RenewSustain Energy Rev 2013;19:24754.

[37] Hannan MA, Azidin FA, Mohamed A. Hybrid electric vehicles and theirchallenges: a review. Renew Sustain Energy Rev 2014;29:13550.

[38] Foley Aoife, Tyther Barry, Calnan Patrick, Gallachir Brian . Impacts ofelectric vehicle charging under electricity market operations. Appl Energy2013;101:93102.

[39] DENISE Proyecto de Distribucin Energtica Inteligente, Segura y Eficiente.http://www.cedint.upm.es/es/proyecto/denise; 2010 [accessed 16.02.13].

[40] Global Architecture of the INTEGRIS project [Arquitectura Global del proyectoINTEGRIS]. http://fp7integris.eu/uploads/deliverables/100205_INTEGRIS_MGM_v0r2.pdf [accessed 16.02.13].

[41] Smart City technology fund project (Proyecto fondo tecnolgico Smart City).http://portalsmartcity.sadiel.es/noticias/20091210_nota_prensa.html;http://twenergy.com/arquitectura-sostenible/smartcity-malaga-un-modelo-de-gestion-sostenible-i-179 [accessed 16.02.13].

[42] INTEGRIS: INTelligent Electrical Grid Sensor communications. http://www.fp7integris.eu/index.php; http://library.abb.com/global/scot/scot271.nsf/veritydisplay/b90133b19bf48124c1256ec2004e08f8/$File/04-12m470.pdf[accessed 16.02.13].

[43] IEC 61850 Norm, communications protocol http://www.ruggedcom.com/applications/IEEE/IEC61850/ [accessed 16.02.13].

[44] Liang Yingyi, Campbell Roy H. Understanding and Simulating the IEC 61850Standard. Comput Sci Res Tech Rep 2009 ([accessed 16.02.13].).

[45] Dallinger David, Wietschel Martin. Grid integration of intermittent renewableenergy sources using price-responsive plug-in electric vehicles. Renew SustainEnergy Rev 2012;16:337082.

[46] Classification of measurement and border points. Unified regulation ofmeasurement points in the Spanish electricity GRID. Article 7. (Clasificacinde los puntos de medida y frontera. REGLAMENTO UNIFICADO DE PUNTOS DEMEDIDA DEL SISTEMA ELCTRICO ESPAOL. Articulo 7.) https://sede.cne.gob.es/c/document_library/get_file?uuid=6ef5072d-9c06-4dec-8db5-9f3934ecb7de&groupId=10136 [accessed 16.02.13].

[47] Samada Tariq, Kiliccote Sila. Smart grid technologies and applications for theindustrial sector. Comput Chem Eng 2012;47:7684.

[48] Khan Reduan H, Khan Jamil Y. A comprehensive review of the applicationcharacteristics and traffic requirements of a smart grid communicationsnetwork. Comput Netw 2013;57:82545.

[49] Aziz AFA, Khalid SN, Mustafa MW, Shareef H, Aliyu G. Artificial intelligentmeter development based on advanced metering infrastructure technology.Renew Sustain Energy Rev 2013;27:1917.

[50] Kaygusuza Asim, Kelesa Cemal, Alagoza Baris Baykant, Karabiber Abdulkerim.Renewable energy integration for smart sites. Energy Build 2013;64:45662.

[51] Ruiz-Romero Salvador, Colmenar-Santos Antonio, Gil-Ortego Rosario, Molina-Bonilla Antonio. Distributed generation: The definitive boost for renewableenergy in Spain. Renew Energy 2013;53:35464.

[52] Zhang Peng, Li Wenyuan, Li Sherwin, Wang Yang, Xiao Weidong. Reliabilityassessment of photovoltaic power systems: review of current status andfuture perspectives. Appl Energy 2013;104:82233.

[53] Ruiz Romero Salvador, Colmenar Santos Antonio, Gil Manuel Alonso Castro.EU plans for renewable energy. An application to the Spanish case. RenewEnergy 2012;43:32230.

[54] Parida Bhubaneswari, Iniyan S, Goic Ranko. A review of solar photovoltaictechnologies. Renew Sustain Energy Revi 2011;15:162536.

[55] Bracco Stefano, Delfino Federico, Pampararo Fabio, Robba Michela, RossiMansueto. The University of Genoa smart polygeneration microgrid test-bedfacility: The overall system, the technologies and the research challenges.Renew Sustain Energy Rev 2013;18:44259.

[56] Niemi R, Mikkola J, Lund PD. Urban energy systems with smart multi-carrierenergy networks and renewable energy generation. Renew Energy 2012;48:52436.

[57] Planas Estefana, Gil-de-Muro Asier, Andreu Jon, Kortabarria Iigo, Martnezde Alegra Iigo. General aspects, hierarchical controls and droop methods inmicrogrids: a review. Renew Sustain Energy Rev 2013;17:14759.

[58] Yanine Franco F, Sauma Enzo E. Review of grid-tie micro-generation systemswithout energy storage: Towards a new approach to sustainable hybrid energysystems linked to energy efficiency. Renew Sustain Energy Rev 2013;26:6095.

[59] Sinha Sunanda, Chandel SS. Review of software tools for hybrid renewableenergy systems. Renew Sustain Energy Rev 2014;32:192205.

S. Ruiz-Romero et al. / Renewable and Sustainable Energy Reviews 38 (2014) 223234234

http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref3http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref3http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref3http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref4http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref4http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref5http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref5http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref5http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref6http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref6http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref6http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref7http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref7http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref7http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref8http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref8http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref8http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref9http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref9http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref10http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref10http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref10http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref11http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref11http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref11http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref11http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref11http://www.argencon.org.ar/sites/default/files/072.pdfhttp://refhub.elsevier.com/S1364-0321(14)00416-X/sbref12http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref12http://www.iie.fing.edu.uy/epim2010/myreview/myPapers/p60.pdfhttp://www.212.175.131.171/IEC/iec60038%7Bed6.2%7Den_d.pdfhttp://www.212.175.131.171/IEC/iec60038%7Bed6.2%7Den_d.pdfhttp://www.copperinfo.co.uk/power-quality/downloads/pqug/http://www.copperinfo.co.uk/power-quality/downloads/pqug/http://www.redes2025.es/http://www.redes2025.es/http://www.revista-anales.eshttp://www.revista-anales.es/web/n_13/seccion_3.htmlhttp://refhub.elsevier.com/S1364-0321(14)00416-X/sbref13http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref13http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref13http://www.revista-anales.es/web/n_14/seccion_3.htmlhttp://www.revista-anales.es/web/n_14/seccion_3.htmlhttp://refhub.elsevier.com/S1364-0321(14)00416-X/sbref14http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref14http://www.portalsmartcity.sadiel.es/http://portalsmartcity.sadiel.es/EN/documentos/http://portalsmartcity.sadiel.es/EN/documentos/http://europa.eu/legislation_summaries/agriculture/http://europa.eu/legislation_summaries/agriculture/http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref15http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref15http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref15http://www.en4tel.com/pdfs/NTPandPTP-A-Brief-Comparison.pdfhttp://www.en4tel.com/pdfs/NTPandPTP-A-Brief-Comparison.pdfhttp://www.cigre.org/http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref16http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref16http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref16http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref17http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref17http://www.uciencia.uma.es/http://www.uciencia.uma.es/http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref18http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref18http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref19http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref19http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref20http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref20http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref21http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref21http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref21http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref22http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref22http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref23http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref23http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref23http://www.cedint.upm.es/es/proyecto/denisehttp://www.fp7integris.eu/uploads/deliverables/http://www.fp7integris.eu/uploads/deliverables/http://www.portalsmartcity.sadiel.es/noticias/20091210_nota_prensa.htmlhttp://www.twenergy.com/arquitectura-sostenible/http://www.twenergy.com/arquitectura-sostenible/http://www.fp7integris.eu/index.phphttp://www.fp7integris.eu/index.phphttp://www.library.abb.com/global/scot/scot271.nsf/http://www.library.abb.com/global/scot/scot271.nsf/http://www.ruggedcom.com/applications/IEEE/IEC61850/http://www.ruggedcom.com/applications/IEEE/IEC61850/http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref24http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref24http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref25http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref25http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref25https://sede.cne.gob.es/c/document_library/get_file?uuid=6ef5072d-9c06-4dec-8db5-9f3934ecb7de&groupId=10136https://sede.cne.gob.es/c/document_library/get_file?uuid=6ef5072d-9c06-4dec-8db5-9f3934ecb7de&groupId=10136https://sede.cne.gob.es/c/document_library/get_file?uuid=6ef5072d-9c06-4dec-8db5-9f3934ecb7de&groupId=10136https://sede.cne.gob.es/c/document_library/get_file?uuid=6ef5072d-9c06-4dec-8db5-9f3934ecb7de&groupId=10136http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref26http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref26http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref27http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref27http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref27http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref28http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref28http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref28http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref29http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref29http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref30http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref30http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref30http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref31http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref31http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref31http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref32http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref32http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref32http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref33http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref33http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref34http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref34http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref34http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref34http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref35http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref35http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref35http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref36http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref36http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref36http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref37http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref37http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref37http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref37http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref38http://refhub.elsevier.com/S1364-0321(14)00416-X/sbref38

Integration of distributed generation in the power distribution network: The need for smart grid control systems,...IntroductionDG and power quality: the problem of failure defects in networksPower re-supply of outages during reconnectionsExtending the power outage duration to reduce the area affectedPossibility of anti-phase reconnection

The effect on voltage control in distribution grids with DGInfluence of DG on voltage controlInfluence of DG on MV gridsInfluence of DG on LV grids

A viable architecture for a multi-service telecommunications networkConceptual architectureElectrical infrastructuresCommunication and systemsTechnology and equipmentPrimary equipmentPrimary equipment in the Advanced Meter Infrastructure (AMI) systemPrimary equipment in the Distributed Energy Resources and Storage (DER) system

Secondary equipment: electronic control devicesInformation systemMV caseLV case

Electric vehicles

Use cases, SG functionalitiesUse cases for MVADA MV use casesMV DER use cases

Use cases for LVLV ADA use casesLV DER use casesAMI use cases

Generic use cases (MV/LV)COM use cases

ConclusionsAcknowledgmentsReferences