Papers and Application Notes

  1. Improvements in Line Differential Relays – to be presented in PACWORLD 2019
  2. Teleprotection in the new WAN world
  3. MV High Impedance Faults Detection Based on LV Measurements
  4. CT Saturation and its Influence on Protective Relays
  5. Real Application of Protection Functions based on Goose messages
  6. Improvements in the Operation of a Distance Relay during Resistive Faults
  7. WAN Network Communications Architectures for Smartgrids: Case Study comparison
  8. The application of teleprotection systems in cogeneration plants
  9. IEC61850-9-2 Process Bus Implementation on IEDs. IEC 61850, applications and benefits
  10. Enhanced Operation of Electricity Distribution Grids through Smart Metering PLC Network Monitoring, Analysis and Grid Conditioning
  11. Comprehensive Cybersecurity strategy for Smartgrid equipment manufacturers
  12. Application of zero sequence filter on transformer differential protection
  13. Inrush currents and their effect on protective relays
  14. Analysis of OLTC Control of Parallel Transformers
  15. Performance Results from 100,000+ PRIME Smart Meters Deployment in Spain
  16. Smart meters enable synchrophasor applications in distribution grids
  17. Distributed IT architecture for deploying a secure Advanced Metering Infrastructure
  18. Implementing the Smartgrid in MV/LV Distribution
  19. Polyphase recharge point. Optimized integration of high power EV recharge into the distribution grid
  20. Advanced sensors for the Smart Grid: how to deal with existing switchgear in secondary substations
  21. Single integrated solution device for the SmartGrid
  22. Making the SmartGrid real, a case study
  23. Communication Architecture for IP- based Substation Applications
  24. Enabling Smartgrid Communications over MV lines. LAN/WAN Design for reliability and operability
  25. Quasi- synchronous noise interference cancellation techniques applied in low voltage PLC
  26. Field Techniques to overcome aggressive noise situations in PLC Networks
  27. Strategies for PLC signal injection in electricity distribution grid transformers
  28. Making Smart Metering real deploying prime based networks
  29. Implementation of Telecontrol Applications over GPRS Networks
  30. The impact of the electric vehicle on the Smart Distribution Grid
  31. MUGIELEC: A comprehensive approach to EV recharge infrastructure
  32. Adapting Protection to Frequency Changes

If you would like to receive any of he listed papers, please contact us. We would be happy to share them with you.

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Teleprotection in the new WAN world

  • Authors: David Gil Donate
  • Company: ZIV
  • Date: March 2019
  • Event: SEAPAC 2019, 19-20 MARCH, 2019, SIDNEY, AUSTRALIA
  • Keywords: MPLS, teleprotection, WAN, IEC 60834
Abstract

Today many electric companies rely on SDH/SONET networks as their transmission backbone. These TDM-based networks have proven reliable, resilient and secure over the years for delivering voice, video and data traffic, including SCADA. TDM equipment is being phased out, however, and newer applications are requiring more than TDM can give; the future of operator networks is undeniably MPLS, as it better serves geographic information systems, high resolution video protection, connectivity and machine-to-machine communications.

Utilities need reliable and systematic communications from their operation grid. On the other hand they also need that many applications or services work at the same time in complicated moments. Therefore, certain critical applications have strict requirements in the development of their communications channel and, logically, the solutions applied must be optimized for the technology of the utility’s communications network. The technology of the Communications network, as it is happening in the rest of the operators, is evolving towards packet switching solutions, which brings new challenges to maintain the initial requirements.

The performance of the protection system is only guaranteed if all subsystems contribute to the required part. Teleprotection equipments are within those services that demand more stringent requirements. Compliance with the IEC 60834 standard guarantees the correct operation of the teleprotection system.

This paper cover how teleprotection applications via packet switched wide area networks can be implemented guaranteeing required application specific performance parameters. It will be analyzed the results in different lab situation and confronted with real measurements.
And also we will add another applications that could be covered by a teleprotection like the measurements of remote amp and voltage.


MV High Impedance Faults Detection Based on LV Measurements

  • Authors: Iñaki OJANGUREN, Nerea RUIZ, Jesús GARCÍA Laura MARRON, Cristina MARTINEZ, Txetxu ARZUAGA
  • Company: Iberdrola, ZIV
  • Date: June 2017
  • Event: CIRED Conference 2017, Glasgow
  • Keywords: MV High Impedance Faults Detection, LV Measurements
Abstract

Smartgrids can offer real time knowledge of the state of the LV network. The advanced metering infrastructure (AMI) which is being deployed can provide useful information for optimum grid operation in addition to billing data. With a better knowledge of the LV segment, LV/MV grid maintenance processes can be improved. Therefore, real time information of the grid enables fault management, quality of supply monitoring, and efficient handling of customer complaints.

In this context, this paper will describe an innovative and field tested solution in order to remotely detect high impedance MV faults caused by broken conductors (and any MV open phase situation).

How are these faults detected? AMI developments include monitoring elements in the low voltage output of the transformer at each Secondary Substation. These elements include LV supervision devices that measure current and voltage in the LV side of the transformer. They also monitor the quality of supply, voltage level anomalies, voltage dips, harmonics, and every significant parameter in the voltage signal. This solution is easily integrated into existing AMI deployments as no specific extra devices are required.

A series of MV line fault types have been analysed, noting that they have a direct impact in the low voltage levels of the transformers near the fault, causing voltage unbalances. In the solution described, LV supervision devices will integrate a high impedance fault detection algorithm that monitors voltage unbalances at the secondary of the MV/LV transformer. These unbalances are notified as events to the backend information systems of the Distribution Companies. These events, once they are processed, will allow the grid distribution operator to detect MV high impedance faults. In Iberdrola this implementation is achieved thanks to the connection between the metering system which receives the events and the EMS/SCADA/DMS control systems. MV/LV Transformers that have signalled this event are highlighted in the schematic diagrams, allowing an easy identification by the operator of the faulty line segment. Other functionalities, like real time querying of transformer supervisors and customer meters connectivity checking (ping) are also implemented.

The described algorithm has been successfully validated in the field. Field experiences show how this solution optimizes MV grid operation, decreasing blackout times, improving customers’ perception and improving safety, as dangerous situations caused by faults in MV lines (loose conductors over resistive ground, etc.) can be identified


CT Saturation and its Influence on Protective Relays

  • Authors: Roberto Cimadevilla, Ainhoa Fernández
  • Company: ZIV
  • Date: October 2015
  • Event: PACWORLD Conference 2019
  • Keywords: CT saturation, CT dimensioning, DC offset, remanence, overcurrent, directional, differential, distance
Abstract

This paper reviews the phenomena of CT saturation and all the factors that affect it. It describes the influence CT saturation has on the different protection functions such as overcurrent, directional, differential and distance and explains the solutions applied by last generation relays to increase the security and dependability during CT saturation. The paper also shows how to dimension a CT based on the different standards used nowadays.

 


Real Application of Protection Functions based on Goose messages

  • Authors: Inigo Ferrero
  • Company: ZIV
  • Date: October 2015
  • Event: PACWORLD Conference 2019
  • Keywords: IEC61850, GOOSE, PRP, HSR, False Differential, Load Shedding, Breaker Failure, Logic Selectivity, Master-Slave, Circulating Current
Abstract

IEC61850 standard has been extended in a very general way worldwide and this Paper will be focused on real applications that are operating in several substations and which are based on, or at least depend on, one of the services that IEC61850 provides, this is, the GOOSE service. This service makes use of multicast messages and it is defined in IEC61850-8-1, allowing the direct communication of different kind of information between IEC61850 servers (digital signals as single points or double points, analogue values and integers). Along the last years, it has been successfully implemented at the substation bus level, being used to develop decentralized automatisms, protection functions that need information located in other devices and control blockings. Furthermore, the GOOSE service, provides several benefits such as a considerable reduction of the copper wiring and therefore a cost reduction, a simplification in the development of the engineering work, it contributes with an error detection method and a way to solve or at least notifying problems, it reduces the electrical risk, it supplies interoperability between the devices of different manufactures, etc.

All this, along with the thrust, know-how and good work of the protection relay manufactures, has encouraged that both the electrical companies and the private sector have chosen this technology, developing many applications based on the GOOSE service. As starting point, this Paper will describe not only the different real communication systems in which the applications that are going to be analyzed have been included but also the meaning of the GOOSE service itself together with its operation and the security methods that both the system itself and the IEC62439-3 standard (PRP and HSR redundancy protocols) provides in order to be able to see the reliability level of the systems. Afterwards, the following real applications that nowadays can be found operating in different substations will be analyzed in depth:

  • Protection
    – False line differential and busbar differential.
    –  Load shedding.
    –  Dynamic enabling of protection functions, logic selectivity.
    –  Breaker failure.
    – Transference and automatic restoration.
  • Control
    –  Automatic voltage regulators working in parallel conditions using the Master/Slave method and the Circulating Current method.
    – Control commands blocking and other control functionalities.

 


Improvements in the Operation of a Distance Relay during Resistive Faults

  • Authors: Roberto Cimadevilla, Izaskun García
  • Company: ZIV
  • Date: October 2015
  • Event:
  • Keywords: Distance Relay,  Fault resistance, ARC
Abstract

Distance relays provide good dependability for bolted faults but they can face problems detecting resistive faults, especially in short lines. The fault resistance can also affect the security of the relay.
This paper explains the concept of the apparent resistance. The influence of the remote infeed with load flow and non-homogeneity of the system on both Quadrilateral and Mho characteristics is described. The effect of the ground resistance on the phase to earth loops during a phase-phase-ground fault is also reviewed.

The paper describes the most common polarization methods used for the reactance line to compensate the load flow and non-homogeneity of the system. It describes an adaptive polarization method that provides good security and dependability for any type of resistive fault. Special conditions are considered: faults during open pole conditions, cross-country faults and evolving faults. Real events and RTDS cases are considered. The paper also provides a guide for setting the resistive reach of a distance relay, based on the line impedance, the VT and CT errors, the phase selector used, the type of load flow and non-homogeneity compensation, general reactance line tilting, load encroachment, resistive limiter algorithm (based on ohms / phase or ohms / loop), etc. Examples from real installations are included.


WAN Network Communications Architectures for Smartgrids: Case Study comparison

  • Authors: Aitor Arzuaga, Miguel Angel Alvarez, Sonia Martinez, Txetxu Arzuaga, Mikel Zamalloa, Hampesh T and J.R.Rao
  • Company: ZIV
  • Date: November 13-15, 2013
  • Event:CIGRÉ D2 (SC D2 Information systems and telecommunication), Mysore- Karnataka- India
  • Keywords: Communication, architecture, network, Smartgrid, WAN, distribution
Abstract

This article presents an analysis of three different WAN communication architectures used in big scale Smartgrid projects. Two case studies analyse typical configurations in real life European scenarios, with a different approach in terms of dependability and complexity. The third case study analyses a typical configuration used in India for distribution automation programmes. All of these communication architectures make use of third party network providers (mainly cellular networks) in order to implement the Smartgrid communication network. However they follow very different approaches, which are discussed in the article.
Finally, the three communication arhitectures are compared, and analysis is included, and the main conclusions are discussed.


The application of teleprotection systems in cogeneration plants

  • Authors: Fernando Castro, Jose Miguel Arzuaga and Aitor Arzuaga
  • Company: ZIV
  • Date: November 13-15, 2013
  • Event:CIGRÉ D2 (SC D2 Information systems and telecommunication), Mysore- Karnataka- India
  • Keywords: Cogeneration, Teleprotectionm Shannon’s Limit, Waveform Quality, Island Operation
Abstract

Cogeneration plants will increasingly play an important role in the supply of electricity. Because of efficiency reasons electricity utilities buy energy generated in cogeneration plants and sell it to their customers.
Though this is indeed a good idea from the point of view of efficiency, it poses a number of technical problems. For example the waveform quality has to be preserved (voltage stability, frequency stability and phase), and islands of generation have to be detected and carefully controlled.

These two goals require new concept of teleprotection systems

  • The breaker has to be tripped even if there is no fault on the line.
  • A permanent state has to send to the autoproducer permises to prevent accidental reclosure operation.
  • Analogue values regarding voltage, power, reactive power and others have to be measured, transmitted to the remote end for proper monitoring and the corresponding decision- making process.

A new generation of teleprotection systems for cogeneration plants is described, together with the performance that should be achieved.


IEC61850-9-2 Process Bus Implementation on IEDs. IEC 61850, applications and benefits

  • Authors: Roberto Cimadevilla, Iñigo Ferrero and Jose Miguel Yarza Narro.
  • Company: ZIV Grid Automation, S.L and ZIV R&D.
  • Date: March 12-13, 2013
  • Event:CIGRÉ Australia APB5, SEAPAC 2013, Brisbane- Australia.
  • Keywords: IEC61850-9-2, Process Bus, Sampled Values, Frequency Tracking, Resampling, Polynomial interpolation.
Abstract

The Process Bus implementation provides many advantages to the utilities: copper reduction- cost reduction, engineering simplification, better failure detection system, lower risk of electrical accidents, interoperability, etc. The process Bus is based on two types of multicast messages, the GOOSE (defined in IEC61850-8-1) and the Sampled Values (SV, defined in IEC61850-9-2). After the successful implementation of the GOOSE message in the Station Bus, utilities are starting to use it in the Process Bus, together with the SV message. Pilot projects are currently in operation.

This paper focuses on the SV messages and their influence on the IEDs. Devices working with SV, coming from the Merging Units (MU) or from the non- conventional CTs (NCCT), have to cope with issues not considered with conventional IEDs: resampling, frequency tracking, counter- measures to be taken during loss or delay of SV, etc.

The paper explains the issues found during the development of an IED based on SV, describing the adopted solutions. Interpolation algorithms are used for resampling and for lost SV estimation. The frequency tracking algorithm is reviewed. Test results for different conditions are included


Enhanced Operation of Electricity Distribution Grids through Smart Metering PLC Network Monitoring, Analysis and Grid Conditioning

  • Authors:Alberto Sendin, Iñigo Berganza, Aitor Arzuaga, Xabier Osorio, Iker Urrutia and Pablo Angueira.
  • Company: ZIV, Iberdrola and the Department of Communication Engineering of the University of the Basque Country.
  • Date:
  • Event:Multidisciplinary Digital Publishing Institute (a publisher of open- access journals).
  • Keywords:Smart Metering, Methodology, PLC, PRIME, Distribution Grid, Monitoring, LV line, LV phase, Detection.
Abstract

Low Voltage (LV) electricity distribution grid operations can be improved through a combination of new smart metering systems’ capabilities based on real time Power Line Communications (PLC) and LV grid topology mapping. This paper presents two novel contributions. The first one is a new methodology developed for smart metering PLC network monitoring and analysis. It can be used to obtain relevant information from the grid, thus adding value to existing smart metering deployments and facilitating utility operational activities. A second contribution describes grid conditioning used to obtain LV feeder and phase identification of all connected smart electric meters. Real time availavility of such information may help utilities with grid planning, fault location and a more accurate point of supply management


Comprehensive Cybersecurity strategy for Smartgrid equipment manufacturers

  • Authors: Miguel Angel Alvarez and Txetxu Arzuaga.
  • Company: ZIV.
  • Date: November 13-15, 2013.
  • Event:CIGRÉ D2 (SC D2 Information systems and telecommunication), Mysore- Karnataka- India.
  • Keywords:Smartgrid, Cybersecurity, risk analysis, CIA model, McCumber cube, SGAM, SGIS.
Abstract

The benefits in the evolution of traditional electrical grid into the Smartgrid, are more evident every day. However, this evolution is also offering more rewards to potential attackers as well as a wider range of potential attack vectors due to the increase in the use of communications and the integration of operational systems in the internet. This has led to an increased awareness of the need for implementation of Cibersecurity measures in the Smartgrid.

Cybersecurity field has not been part of the body of knowledge of electrical grid designers, though. So, even if equipment manufacturers are beginning to deal with the incluison of Cybersecurity features to their developments, they are not always following the best approach but trying to find and follow recommendations and best practices guides. However, there are no fixed rules that ensure the security of equipment yet.

The main aim of this paper is to use a pragmatic approach to create a reference guide for a first approach of equipment manufacturers to the world of cybersecurity. To achieve this, it is necessary to analyze very different aspects ranging from the work of public agencies such us NERC CIP or penetration testing techniques (such us those made by Digital Bond in S4), to international standards (IEC62351…), key management procedures. All of this should also be combined with the study of known Cybersecurity attacks such us Stuxnet.

This paper takes into account that the implementation of Cybersecurity is a quite different task compared with the ones usually tackled by manufacturers. On one hand, it must be considered that it is not a concrete and definite task, but a set of decision making and measurement implementation rules relatively unconnected to one another. However, they help in the prevention of a whole range of risks for equipment.

On the other hand, and, unlike what happens with other features, the implementation of security measures does not 100% guarantee the security of equipment, so the task does never end, and in addition to the prevention methods, detection methods should also be implemented to offer quick detection of new vulnerabilities. The combination of prevention and detection will sometimes fail, so a good Cybersecurity system must also consider mitigation and recovery techniques.

This paper proposes as a practical approach the descomposition of the system in use cases as concise and clear as possible. The different steps proposed for use cases are as follows:

  • Initial analysis based on abstract concepts such as confidentiality, integrity and availability (CIA model).
  • Analysys of risks and vulnerabilities, focusing primarily on scaled potential attacks.
  • Selection of generic methodologies for prevention, detection and response.
  • Selection of the security features both hardware (chip key storage, cryptographic coprocessors, biometric protection…) and software (security libraries, logs and event managers…).

Tracking a top-down methodology for writing use cases, favors Cybersecurity non based on “magic formulas”, but on common sense


Application of zero sequence filter on transformer differential protection

  • Authors: Roberto Cimadevilla
  • Company: ZIV
  • Date: March 12-13, 2013.
  • Event:CIGRÉ Australia APB5, SEAPAC 2013, Brisbane- Australia.
  • Keywords:Zero- sequence filter, phantom tertiary, three- legged transformer, differential unit, directional comparison unit, harmonic blocking.
Abstract

Delta- Wye transformer connections create discontinuities in the zero- sequence network as the zero- sequence current can flow at one side of the transformer without flowing at the other side. This effect generates a zero- sequence differential current that can make the differential unit trip. Traditional solutions applied to remove the zero sequence differential current where based on delta connected CTs. Zero- sequence filters in digital relays are software implemented.

In many digital relays the zero sequence filter can be enabled or disabled. On the other hand, some relays can remove the zero- sequence current calculated from the phase currents or from the ground currents (currents measured in the neutral grounding).

This paper reviews the transformer configurations that require the enabling of the zero- sequence filter by taking into account not only the connection group but also the construction of the magnetic core (this aspect is not always considered), explaining in detail the phantom or virtual tertiary effect of three- legged wye- wye transformers. Real false trips due to this effect are included.

The paper also explains the differences between both methods used for the zero- sequence current calculation (the one based on the phase currents and the one based on the ground current). The influence on the differential unit, harmonic restraint and common external fault detectors is analyzed. The first method can lead to a reduction of the differential current and to an erroneus phase selection during an internal fault. However, “2 out of 3” logics both for harmonic blocking and for a phase directional comparison unit can be implemented increasing the stability. The second method provides very good sensibility and phase selection but does not allow the implementation of the “2 out of 3” logics reducing the stability. Cases based on real events and RTDS simulations are reviewed


Inrush currents and their effect on protective relays

  • Authors: Roberto Cimadevilla
  • Company: ZIV
  • Date: 2013
  • Event:Texas A&M 2013
  • Keywords: Inrush, sympathetic inrush, harmonic blocking, harmonic restraint, cross-blocking, CT saturation.
Abstract

This paper explains in detail the phenomena of inrush in single- phase transformers during three conditions: transformer energization, external fault clearing and sympathetic inrush. It then focuses on the inrush in three- phase transformers, explaining the influence of a delta winding and analyzing the types of transformer configurations that allows the flow of zero- sequence current.

The paper describes the influence of the inrush current on different types of protection functions as transformer differential, overcurrent, distance, busbar and line differential. It focuses mainly on the transformer differential describing the most common methods used for maintain the security during the inrush condition: harmonic restraint and harmonic blocking. Their differences are explained. It then explains the different crossed logics used and selects the most appropriate one. It finally describes a logic to inhibit the harmonic restraint/ blocking based on external fault detector. This logic reduces the tripping time of the differential unit mainly during internal faults with CT saturation. Different cases are considered based on real events and RTDS simulations.


Analysis of OLTC Control of Parallel Transformers

  • Authors: Íñigo Ferrero Roberto Cimadevilla José Miguel Yarza Iñaki Solaun
  • Company: ZIV, EHU-UPV
  • Date: 2013
  • Event: WPR
  • Keywords: IEC 61850, GOOSE service, AVR, parallel transformers, master-follower method, circulating current method.
Abstract

Different cases are considered based on RTDS simulations and real connections to Intelligent Electronic Devices (IEDs), where one Automatic Voltage Regulator (AVR) device is associated with each transformer andthe piece of information shared between the IEDs, digital and analogical signals, is transmitted by IEC 61850 communications (GOOSE messaging). Even though the three automatisms are covered in depth, the tests
are going to be focused on the circulating current method.

The AVRs are going to control 45MVA, 138±13×5%/36 kV, YNd11 power transformers being subject to different situations:

  1. Two power transformers working in parallel conditions with the same electrical characteristics:
    a. Being supplied by the same source.
    b. Being supplied by different sources.
  2. Two power transformers working in parallel conditions with different electrical characteristics
  3. Five power transformers working in parallel conditions.
  4. Backup power transformers coming into the system when there is a trip in any of the main power transformers.

In all the above mentioned conditions, decisions are taken in each AVR to maintain the busbar voltage at a given setpoint, keeping also constant the load voltage and trying to reduce the circulating current that appears between the parallel transformers. Moreover, the AVR will keep track of the tap position. This paper will also describe the communication system due to the fact that using IEC 61850 and GOOSE messages requires no wiring between the transformers, which simplifies the installation of the IEDs, the engineering process, the troubleshooting and implies a reduction of cooper wiring


Performance Results from 100,000+ PRIME Smart Meters Deployment in Spain

  • Authors: Alberto Sendín, Iñigo Berganza, Aitor Arzuaga, Anssi Pulkkinen and Il Han Kim.
  • Company: ZIV, Iberdrola, Current Technologies and Texas Instruments.
  • Date: October 28-31, 2012
  • Event:IEEE Sensors 2012, Taipei- Taiwan
  • Keywords: narrowband Power Line Communications (PLC)
Abstract

PRIME (PoweRline Intelligent Metering Evolution) is a narrowband Power Line Communications (PLC) technology targeted for use in smart metering applications. It is standarized as part of international Recommendations ITU-T G.9955 and G.9956, and there are currently a number of deployments by utilities in different markets which use it for a cost- effective, technically proven solution.

This paper is a continuation of two previous ones presented in the first and second SmartGridComm Conferences, in which PRIME background and status were discussed, including interoperability tests and first results in multi- vendor deployments.

This final article describes the network architecture which has been thoroughly tested and is currently being used by Iberdrola for its SmartGrid deployment, PRIME network deployment selections, a proposed classification for secondary substations based on experience and finally the tools which are being used for analysis and acceptance tests, along with performance results.


Smart meters enable synchrophasor applications in distribution grids

  • Authors: Sergio Santos, Asier Llano, Aitor Arzuaga, Txetxu Arzuaga, Laura Marrón and Mikel Zamalloa
  • Company: ZIV Metering Solutions
  • Date: August 2012
  • Event: CIGRE (Conseil International des Grands Reseaux Electriques), Paris- France
  • Keywords: Smart, Meters, Synchrophasor, Applications, Distribution, Grids
Abstract

Synchrophasors are being used widely in HV/MV substation applications. In these facilities we have extensive synchronizing GPS receivers which are able to provide timestamping information to IEDs or other devices. However, up to now they are not being used in BT applications due to cost restrictions in the last section of the distribution grid.

PLC communication systems can be used to synchronize current and voltage measured by meters installed in the same circuit of a network. The above will provide advanced power network status information with no additional costs.

Power line communication systems are being nowadays widely used, and commonly we can find PLC modems either built-in or externally connected to the meter. It is possible to make smart meters on a network synchronized through a pattern based in PLC, to obtain simultaneous current and voltage measurements. This technology allows a wide range of new measurement options, such as overloaded neutral wires, voltage unbalances in different points, network instability due to uncertain loads (EV) or distributed generation (DER) including EVs with V2G capabilities, or calibration errors and tampering schemes.

This technology introduces an innovative methodology by which the measuring modules of the meters can take advantage of the PLC infrastructure obtaining additional useful information from the Low Voltage network and implicating smart meters, concentrators and basic PLC communication devices.

Normally, electrical input signals are measured by meters following an autonomous sample rate, based on their internal oscillator, and detecting zero crossings instants of the voltage as well. In this standard scheme, between two meters there is no interaction at all, and their sample instants are calculated based on their own measurements. In order to get the collaborative measurement, all the sample rates of both meters (and every meter involved in a specific algorithm), must be synchronized with a defined maximum time drift. This can be made by means of a PLC system. Regarding PRIME PLC technology we could get a synchronization error drift of near 5us, applying statistical and expert control systems, and 12 us by means of the standard preamble pattern.

In deployments of three phase systems, with only single phase meters, the power phase unbalance could be measured along the derivation points using this method, reading samples of every meter involved and applying the standard formulae for direct, reverse and homopolar sequences. Also neutral wire impedance and neutral current shape can be retrieved only applying basic Kirchoff rules.

Measurement results will be shown for a three- phase, for wires, and multiline deployment emulation. The real situation will be first tested in a laboratory. Error estimation comparisons for neutral current polyphase vector angles will be shown at different locations of the circuit, and also the time payload and maximum sampling frequency will be also studied. Device design issues are also being considered.

In summary, PLC infrastructure, apart from acting as a communication system for billing, event recording and other purposes, can be used to add new capabilities to the system, by making meters, placed in different locations of the power network, to operate in a synchronized manner. This paper will further analyze this technology and how they can be implemented for enhanced LV network monitoring applications, for instance in DER scenarios.

https://cigreindia.org/CIGRE%20Lib/Cigre%20Pairis%202012/C6/C6_110_2012.pdf


Distributed IT architecture for deploying a secure Advanced Metering Infrastructure

  • Authors: Txetxu Arzuaga and Aitor Arzuaga
  • Company: ZIV Metering Solutions and ZIV R&D
  • Date: August 2012
  • Event: CIGRE (Conseil International des Grands Reseaux Electriques), Paris- France
  • Keywords: IT, Architecture, Metering, Infrastructure
Abstract

When discussing about IT, everyone tends to think on centralized systems in a ‘cooled air conditioning’ Data Processing Center. This is possibly also true in most of the utility IT systems. But there are some other utility applications that require tailored solutions, such as Advanced Metering Infrastructure (AMI). This paper will discuss the challenges an AMI poses onto this type of information systems.

First of all, it should be noted than an AMI deployment is no longer a centralized IT system but a geographically spread IT solution. Many AMI deployments- mainly in urban environments, where distribution MV to LV transformers can service up to several hundred users- are based on the installation of data concentrators at the transforming station integrating the readings of all meters connected to that transformer. In this case, the information system cannot be reduced to the Meter Data Management System that runs in the DSO central office. The data concentrators are also a key part of the Distributed Information System. And there will be thousands of them all over a region/ nation.

This new Distributed Information System for AMI should account for:

  • Systematic Meter Data Collection.
  • Complex Event Processing. Several thousands of small IT systems may trigger events simultaneously. How can we transform this huge amount of events into useful information?
  • IED’s management (in terms of configuration, firmware upgrade). Operation will be more and more complex.

In addition to the previously stated requirements, all the IT system must be provisioned in a secure way. Note that data concentrators will be installed in different sites, where the DSOs may not have their own telecom infrastructure available. As a result of this they will have to rely on third party communication links, which raises aditional security concerns.

The information system must be also scalable, since AMI deployments start servicing thousands of customers, but they must be able to cope with millions. The mechanisms and architectures must be able to scale up accordingly and in this field the service arcitecture between the central DSO information system and the distributed concentrators is crucial.

This paper will propose a distributed IT solution for AMI based on an architecture oriented to services. Also the costs of deployment and operation will be analyzed and accounted for. Note that Telecommunications and information systems are the most significative elements in AMI deployments as far as the investments and the operational expenses are concerned,and consequently are a key element (sometimes the key element) for their approval

Implementing the Smartgrid in MV/LV Distribution

  • Authors:Aitor Arzuaga, Txetxu Arzuaga and Rafael Quintanilla.
  • Company: ZIV R&D Smart Metering Networks, ZIV Grid Automation and ZIV Metering Systems
  • Date:November 12-14, 2012
  • Event: GCC Power 2012 (Conference & Exhibition), Omán.
  • Keywords:Smartgrid, Intelligence, Distribution, Operation, MV, LV, Automation, Communications, Metering
Abstract

The introduction of the Smartgrids in electricity distribution networks is modernizing the infrastructure and adding an unprecedented set of technologies to the distribution substations. It derives from the need to enhance the grid with intelligence in order to gain efficiency, reduce CO2 emissions, integrate renewable energy generation, improve quality of supply and manage demand.

All these innovations are being put in place in new infrastructure, in sections where the assets are new. In many sections of the grid such as city centres, most of the MV/LV distribution grid is already in place, and a big challenge for the electricity distribution company is how to modernize and implement the benefits of the Smartgrid in those parts of the grid that are already in operations, for some years. Distribution assets are expensive and their lifespan ranges may be in order of years or decades, so it is just out of the questions to substitute secondary substations that are just 5 or 10 years old. Additionally, this infrastructure is diverse, coming from different periods, and they were not conceived to be upgraded in the future. Additionally, the MV/LV grid has not received a significant level of attention or investment in many places, just to keep it working.

This article will highlight the most important aspects that must be taken into account when tackling an existing (operating) distribution grid modernization project. And it will deal with the specific limitations for MV/LV grid supervision and automation, and how to overcome them.


Polyphase recharge point. Optimized integration of high power EV recharge into the distribution grid

  • Authors: A. Arzuaga, T. Arzuaga, D. García- Pardo, A. Gonzalez, E. Keller and M. Zamalloa
  • Company: ZIV and Iberdrola
  • Date: August 2012
  • Event: CIGRE (Conseil International des Grands Reseaux Electriques), Paris- France
  • Keywords: Polyphase, Recharge Point, Integration, Power, EV, Distribution, Grid
Abstract

The new wave of Electric Vehicles has already arrived to our streets and highways. This kind of vehicles not only mean a change of propelling technology, but they also open the door for a new mobility paradigm by allowing new forms of customized energy supply that will let the user decide where, how, when and how much to charge thus easing two of the main drawbacks of EVs: reduced range and long charging time. This is feasible thanks to the ubiquity of the energy that is to be supplied (electricity), which, contrary to gas stations, is available anywhere in the urban areas of developed countries.

How will the electric grid face the challenge of integrating a large number of EVs while keeping the highest standards of quality of service and safety?. Public regulators claim that night- time low- power charges are the preferred solution if full profits from renewable sources (thus CO2- free) are to be obtained. Also this approach fits with the load profile flattening objectives, reducing peak power demand. This is obviusly the less challenging solution for EV recharge because it can be done with very little investment in charging spots and it does not require new generation facilities. But EV drivers require alternative ways of recharging their EVs, especially when they are on a long road trip or need to urgently refill their batteries, which will require fast charging capability.

There is a lot of talk about slow, quick, rapid and fast charging, but what does this really mean?. The time spent to charge a battery depends on several factors that are controlled by different industries:

  • The power that the charging station and the line that feeds it can provide. The electric equipment industry and electricity utilities are the main actors controlling this factor.
  • The charging power that on- board battery chargers support (for AC charging) and the charging power and charge curve that each type of battery supports. This depends on the automotive industry and battery manufacturers.
  • The energy storage capability of the battery and the state of charge, which depend on the battery manufacturer, use of the battery, temperature, etc.

The only factor of this list depends of the electric industry is the power that the charging station can provide so it makes more sense to focus the discussion on the power than on the time spent for the recharge, which as we just mentioned, depends on more factors that may substantially vary for each EV.

Is this high- power opportunity charging scenario a problem for the electric grid?. What are the problems involved?. Is it just a matter of power or are there some other factors to take into account such as the size of the charging station, flexibility of the charging cable, type of plug, etc, that set important restrictions for the design of a charging station?.

This paper will provide an overview of factors such as the availability of one to three phase low voltage power grids and their voltage ratings for some reference countries. This overview will set a framework to present a cost- benefit analysis for different alternatives ranging from low power AC charging to high power AC or DC charging, comparing pros and cons for each of the possible modes.This analysis will consider factors such as the supported powers for different types of IEC62196 plugs, the usability of different cables, possibility of residential installation of each type of charge spot, cost, impact on the electric grid, etc.


Advanced sensors for the Smart Grid: how to deal with existing switchgear in secondary substations

  • Authors: Aitor Arzuaga, Jose Antonio Moreno and Covadonga Coca
  • Company: ZIV
  • Date: 6-9 June 2011
  • Event: CIRED (21st International Conference on Electricity Distribution), Frankfurt- Germany
  • Keywords: Sensors, SmartGrid, Switchgear, Substations
Abstract

The recent interest of the utilities for the automation of the electrical distribution in medium voltage grid, with the aim of improving service, while reducing operation costs, and at the same time managing the grid in real time, requires the installation of electronic equipment inside the secondary substations. These electronic equipment need sensors to measure the most important electrical parameters such as the voltages, currents and phases. At the same time, the necessary communications between equipment, located in the secondary substations that compose the medium voltage network, need, when using PLC (Power Line Carrier) technology, capacitive or inductive couplers, in order to inject the high frequency signals in the conductors.

The sensors and couplers installed in secondary substations must fulfil all the standards and existing regulations which apply to elements subject to high voltages and currents. They must be adapted in each situation to the available space, which differs greatly from one secondary substation to another, depending on its type, such as those of masonry, metalic air cabins or SF6 gas cells. However, there is currently no sensor solution for many of the existing swithgear in the distribution grid. As a result of this, a careful analysis of the requirements and existing scenarios, and available sound technology must lead us to the development of the required sensors.


Single integrated solution device for the SmartGrid

  • Authors: Aitor Arzuaga, Javier Arriola, Zigor Ojinaga, Txetxu Arzuaga and Mikel Zamalloa
  • Company: ZIV and Iberdrola
  • Date:  June 2011
  • Event: PAC (Protection, Automation & Control) World Conference, Dublin – Ireland
  • Keywords: Single, Integrated, Solution, Device, SmartGrid
Abstract

The introduction of SmartGrids in Secondary Substations, with the goal of automating the distribution grid, requires the addition of several different functions to the existing infrastructure, such as Smart metering Concentrators, LV/MV monitoring functions, automation functions, Communications Equipment, and sometimes ancillary devices, such as power back- up systems. These functions are very innovative and currently implemented by suppliers in separate boxes (products). These products are still young in their lifecycles, as the technology and applications are being developed right now.

But if the SmartGrid is going to succeed, and the existing electricty distribution installations upgraded in big numbers, all the functions mentioned above must be integrated in a single box solution, to drive down costs, ease the installation, improve asset and inventory management, and just make the process simpler. It is just a matter of economics and simplicity.

This paper will discuss the problem of integrating Smartgrid functionalities in existing secondary substations, which are already in operation. Most of secondary substations at a certain moment will be of this type. For new secondary substations, electronics and sensors can be custom built and integrated into the switchgear or transformer, so the issue of the single solution affects primarily the upgrading of the existing grid. We will introduce such integrated “Smart Grid for Secondary Substation” device concept and rationale, and analyze its key requirements, applications and challenges


Making the SmartGrid real, a case study

  • Authors: Rafael Quintanilla and Jose Miguel Yarza
  • Company: ZIV
  • Date:10-11 March, 2011
  • Event: CIGRE SEAPAC (South East Asia Protection & Automation Conference), Sydney – Australia
  • Keywords: SmartGrid, Distribution, Automation, Sensors, RTU, Meters, PRIME, PLC
Abstract

It is a well- known fact that things are changing for the electrical network; during the last years, due to several factors:

  • Climate change
  • Fuel prices
  • Intensive use of electricity in the digital economy
  • Increased deployment of Distributed Energy Resources (DER) at different voltage levels
  • Evolution of traditional consumers of electricity that have become also producers, changing their role of users of electricity to users of the network

As a consequence of that, it is necessary:

  • To improve the quality of service and the quality of energy.
  • To be more efficient on the use of the energy.
  • To manage the demand actively to optimize the use of the network.
  • To incorporate the end users as active agents in the market of energy and services.
  • To be able to integrate effectively the DER.

All above requires increasing the smartness of the electrical gridm especially at distribution level, incorporating intelligence into the secondary substations, making them visible and capable of giving information about the state of the medium and low voltage network. That means installing sensors, measurement capability, communications, actuators, IEDs…And all this while the system continues working, coping with old installations that were not designed taking into account the new requirements.

This paper describes the experience obtained during the deployment of a supervision system in a real network in a medium size city located in the Mediterranean coast of Spain. It was necessary to develop different solutions that look into account the diversity of installations derived from the technical history of the utility owner of the network. A wide range of technologies were used to get an optimized application: electromagnetic sensors, materials engineering, Ethernet, power line communications, IEC 61850…

Finally, a glance into the future is provided, examining where the authors think the technology is going to, helping the network to achieve a revolution by evolution


Communication Architecture for IP- based Substation Applications

  • Authors: Henrik Riis and Aitor Arzuaga
  • Company: Energinet.dk and ZIV
  • Date: October 19-20, 2011
  • Event: CIGRÉ (Conseil International des Grands Reseaux Electriques), Paris- France
  • Keywords: IP, Survey, Case Study, Substation, Communications Architecture
Abstract

IP communication is being extensively introduced into the operation of the Electrical Power Utility. The substation IP network environment has evolved from acting as an extension of the office LAN to a state, where it is carrying multiple services, including the transport of critical and sensitive data.

Working Group D2.28 is currently developing a Technical Brochure which contains:

  • A compilation of user requirements and expectations cencerning existing and envisaged services in the new networked environment of the substation. This information was gathered by conducting a survey among Cigré members, major vendors and consultants.
  • A description of possible network migration processes.
  • Guidelines on how to choose an optium network architecture, covering services which require connectivity beyond the substation perimeter. The guidelines are intended to be in line with the ones given for substations in IEC61850-90-4.
  • A description of important parameters to be considered for each relevant technology. The description is not centered around specific applications and is therefore open to the usage of IP in different areas.
  • Five case studies, aiming at describing project and process experiences, rather than technicalties.

This is an extract which deals with the results of the user survey as well as giving an overview of the technical contents of our Technical Brochure. In addition, one of the six network case studies contained in our Brochure is reproduced


Enabling Smartgrid Communications over MV lines. LAN/WAN Design for reliability and operability

  • Authors: Aitor Arzuaga, Txetxu Arzuaga and Josep Salat;
  • Company: ZIV
  • Date: October 19-20, 2011
  • Event: CIGRÉ (Conseil International Des Grands Reseaux Electriques), Paris- France
  • Keywords: MV, PLC, Secondary Substation Communications, WAN, OFDM, Spread Spectrum
Abstract

Smartgrid functionality in distribution grids relies heavily in communications functions. This is a challenge because many existing distribution grid facilities such as secondary substation lack communications links. Sometimes there are existing fiber links, but most of the facilities are not connected.

As a result of this, every time that Smartgrids are deployed in a secondary substation, communications means must be added in order to connect the premises to the utility’s network, and this network must be able to deliver the required data rate and latency requirements.

Then there are some alternatives to choose from, but most of them rely on communications means which are not owned by the utility, if available, such as GPRS/3G, Satellite links or ADSL. Sometimes there are not any options to choose from, depending on the physical location of the substation. The consequence is that these communication links have operation costs and the availability of the communications network is outside the control of the utility.

In order to overcome these limitations, some utilities try to rely on traditional technologies already used in telecontrol applications such as VHF radio links. However, this technology cannot be used in most urban environments.

One way of solving the problem would be to use a communications technology which uses the existing infrastructure, and there is actually infrastructure which is available in existing secondary substations and which may be used: MV lines. However, it is a very noisy and lossy medium, and in order to establish links with the required bandwith and distance coverage deep analysis and test are required, both at the physical and MAC layers, and at the couplings.

This paper will describe new techniques to implement a layer two network device over MV lines, using different modulation techniques such as OFDM and Spread Spectrum.


Quasi- synchronous noise interference cancellation techniques applied in low voltage PLC

  • Authors: Asier Llano, Alberto Sendin, Aitor Arzuaga and Sergio Santos
  • Company: ZIV  and Iberdrola
  • Date:   April 2011
  • Event: IEEE ISPLC (International Symposium on Power Line Communications and its Applications), Udine – Italy
  • Keywords: PLC, DSP, Signal, Processing, Synchronous, Noise, Cancellation, PRIME, LV.
Abstract

Low voltage power lines are attractive for communications in smart metering, but they are subject to many kinds of interferences. One important source of interference is the one which is synchronous with the power network frequency. This noise shares the mean periodicity with the mains, but it also ususally has some sort of time drift or jitter that shifts the position and phase of the signal from period to period. This paper refers to this particular kind of noise, which this paper will label as “quasi- synchronous”.  Several processing techniques have been used to cancel this component of a signal. The core of the algorithm is the predictor and its learning mechanism, which is able to provide a predicted version of the quasi- synchronous noise adjusted to the variations of the input phase, ready to perform the cancellation. The results of these cancelation technologies are described, applied to both, synthetic and real input signals, to demonstrate that quasi- periodic noise can be cancelled with affordable processing power consumption.


Field Techniques to overcome aggressive noise situations in PLC Networks

  • Authors: Alberto Sendin, Asier Llano, Aitor Arzuaga and Iñigo Berganza
  • Company: ZIV and Iberdrola
  • Date:   April 2011
  • Event: IEEE ISPLC (International Symposium on Power Line Communications and its Applications), Udine – Italy
  • Keywords: PLC, PRIME, Repetition, Noise, Three Phase, Cyclic, Switch
Abstract

Power Line Communications (PLC) technologies and systems use state- of- the- art technical solutions to provide communication means for Smart Grid applications. PRIME is one of those systems, with a comprehensive Physical and Media Access Control (MAC) Layer specification for CENELEC A- band, used today in Smart Metering deployments.

PRIME systems have demonstarted to be capable of working in normal scenarios (urban, suburban and rural) covering long distances in typical noise conditions. However, there are locations where noise is harsher than the regular conditions. This kind of noise is usually found close to the premises where meters are located. It often shows a periodic nature, both in its origin and external effects (e.g. daytime and nighttime cycles).

This paper proposes a way to overcome the noise situation mentioned above, based on field deployable solutions. These solutions are based on the development of devices which, using the switching concept inherent to PRIME systems, can help affected meters to overcome noisy situations. Results from field experiments are provided, and the conclusions may be used to further develop products to overcome aggressive noise situations on field.


Strategies for PLC signal injection in electricity distribution grid transformers

  • Authors: Alberto Sendin, Asier Llano, Aitor Arzuaga and Iñigo Berganza
  • Company: ZIV  and Iberdrola
  • Date: April 2011
  • Event: IEEE ISPLC (International Symposium on Power Line Communications and its Applications), Udine -Italy
  • Keywords:PLC, PRIME, Repetition, Three Phase, Distribution, Transformer, Substation, Base Node, Smart Metering
Abstract

Distribution transformers are found in secondary substations, and connect to three phase low voltage lines that deliver electricity to points of supply. Electricity customers are charged for their consumptiom based in the measurements registered in meters present at the pint of supply.

Power Line Communication (PLC) signal injection in distribution transformers is a key element in PLC signal propagation in distribution grids. PRIME is a narrowband PLC technology in CENELEC A band, used by utilities to communicate with meters at maximum data rates of 122,9 kbps. PRIME technology establishes subnetworks rooting at distribution transformers in secondary substations, where the so called Base Nodes are installed, to communicate with Service Nodes present at meters in Smart Metering environments.

This paper analyzes the alternatives for PLC signal injection, either single phase or three phase, through different field tests, in order to improve overall network constitution and performance of meters. The results and conclusions may be extrapolated to any other low voltage PLC technology in the same frequency band.

The conclusions of the paper make recommendations to use specific PLC injection configurations, depending on the topologies under study, and provide guidance for product development in this area which has fundamental influence in the results obtained for the PLC communication system.


Making Smart Metering real deploying prime based networks

  • Authors: Txetxu Arzuaga Canls and Aitor Arzuaga Munsuri
  • Company: ZIV Metering Solutions and ZIV R&D
  • Date:26- 27 October 2011
  • Event: JIEEC(International Electrical Equipment Conference), Bilbao- Spain
  • Keywords: Smart, Metering, Prime, Networks
Abstract

This paper describes the main challenges a Utility needs to face in order to succesfully deploy an advanced metering infraestructure. We will focus on a PRIME based AMI. The first question to answer, prior to any technical analysis, is why should we base an AMI deployment on PRIME technology?.

We think that several arguments can be placed explaining the reasons for which most of Spanish Utilities have decided to deploy PRIME based AMI’s. Nevertheless, we would like to hightlight the most important ones:

  • It works. This may seem quite evident, but when discussing of a complex architecture, where multiple technologies (telecom, information systems, metering) need to work together for the AMI system to success, is not so evident. PRIME allows the customer to fulfill its business requirements, making it feasible to gather billing & consumption data every day from all smart meters, to operate the AMI and to appropriately respond to events generated in smart meters on time
  • Product interchangeability. This PRIME feature fulfills the ambition of any purchaser, i.e. to have multiple provision sources. This makes the Utility’s logistics procedures ligthter as any approved smart meter can be used at customer premises.
  • Future proof. Finally, PRIME technology is maintained inside an Alliance of more than 35 technology companies that represent the most important players in the AMI value chain. This fact assures its evolution.

As stated in the first paragraph, this paper will focus on just one aspect of the AMI challenge: The one related to PLC communications. In fact, we will focus on urban/semi- urban areas. In these areas, due to the distribution network nature, it makes sense to deploy AMI based on LV PLC technologies.

This paper is organized in several sections. The first one introduces an AMI architecture, so prior to focusing on the PLC part, we understand the full picture. Next section details the main challenges a LV grid poses to design an appropriate telecom technology, and the powerline injection problem. A third section provides the reader a brief summary of PRIME technology. A fourth section shows some figures and facts obtained with PRIME.


Implementation of Telecontrol Applications over GPRS Networks

  • Authors: Aitor Arzuaga Munsuri, Jose Miguel Arzuaga Canals and Mikel Zamalloa Aiartzaguena
  • Company: ZIV
  • Date:   December 2010
  • Publication:  PAC (Protection, Automation & Control)  World Magazine, Winter 2011
  • Keywords: Telecontrol, GPRS, Networks
Abstract

This paper introduces GPRS (General Packet Radio Service) technology and examines its applicability to the sphere of telecontrol communications in an electric utility. In order to do so we will perform an analysis of the technology and its possibilities, telecontrol protocols, and give specific examples of why traditional telecontrol applications which function correctly over point- to- point serial links require a reformulation which optimises their function over a communications technology such as GPRS. It will also be analyzed wether this technology fulfils the reliability requirements expected by utility communications.


The impact of the electric vehicle on the Smart Distribution Grid

  • Authors: M.G.Zamalloa, A.Gonzalez, A.Arzuaga and T. Arzuaga
  • Company: ZIV and Iberdrola
  • Date: October 2011
  • Event: OTTI SmartGrids & eMobility, Munich&nbsp- Germany
  • Keywords: Electric Vehicle, Smart, Distribution, Grid
Abstract

This paper analyzes the challenges, risks and opportunities related with the introduction of the EV such as the positive impact of overnight charging for the demand curve and the risks of daytime charging depending on the grade of penetration.

An overview of the most important factors that infrastructure managers (both utilities and new market players such as EV charging infratestructure managers) should address is given: Grade of penetration, concentration of charge spots and the grade of intelligence of the infrastructure.


MUGIELEC: A comprehensive approach to EV recharge infrastructure

  • Authors: Aitor Arzuaga, Eduardo Zabala, Ana Gonzalez Bordagaray, David García Pardo, Mikel Rentería and Mikel Zamalloa
  • Company: ZIV, Tecnalia, Iberdrola and Semantic Systems.
  • Date:  October 2011
  • Event: OTTI Smart Grids & eMobility, Munich- Germany
  • Keywords: Comprehensive, Approach, EV, Recharge, Infrastructure
Abstract

MUGIELEC is a publicly funded R&D project initiative in the Basque area which gathers many important players in the energy sector in order to collaborate on EV related technology and applications, with a strong focus in the infrastructure side. The project covers from system- level grid operation, to the infrastructure- to- vehicle communication, including critical subsystems such as recharge infratestructure scenarios, impact on the grid, V2G technical feasibility, customer behavior analysis…The project has a strong focus on promoting standarization activities in the areas related to the research results obtained in the project by the partners.

The project began in September 2010, and will run until the end of 2012. It has a budget of over 10M euros and a participation of 12 companies and 5 R&D institutions. It is now (as of June 2011) finishing the specification and requirement analysis phase in order to go into R&D activities. Later in the project schedule, two testbeds will be developed: a parking lot system solution and a fast recharge station, in order to validate the developments carried out during the project.

The MUGIELEC initiative, sponsored by the Basque Government, under the administrative lead of ZIV and technology coordination by TECNALIA, is formed by: AEG, CEMENTOS LEMONA, FAGOR, GAMESA, IBERDROLA, INCOESA, INDRA, INGETEAM, ORMAZABAL and SENANTIC SYSTEMS.

This paper will introduce MUGIELEC’s approach and objectives and will describe some of its first results for a business model and approach for the exploitation of the infrastructure for EV charging, the information and data base management in order to provide adequate services, and the communication and protocols among the different systems from the EV and charging point to the System Operator, considering also the charging point management system and the stationary management in the secondary substation

 


Adapting Protection to Frequency Changes

  • Authors: Roberto Cimadevilla (ZIV), Rafael Quintanilla (ZIV ), S. Ward (RFL Electronics Inc.).
  • Company: ZIV & RFL Electronics Inc
  • Date:    October 25 – 27, 2005
  • Event: Presented to the 32nd Annual Western Protective Relay Conference Spokane, WA
  • Keywords:
Abstract

Electric power systems are susceptible to frequency variations. While the US grid generally exhibits a very stable frequency during all but emergency conditions (such as cascading black-outs) there are regions in some countries in which such variations are extremely notable and recurrent and experience from these applications provide very good data for improving protection design.

Proper protective relay behavior is of key importance to minimize system degradation and to stabilize the system as quickly as possible. Incorrect relay response during frequency excursions is bound to aggravate an already deteriorating situation.

This paper describes how conventional distance protections are affected by frequency variations and how digital technology allows designing reliable protective relays that will behave correctly under such conditions.

Real cases are used for illustration, showing distance protection operations without any provisions for frequency changes. The cases are reevaluated with the same distance protection after adding adaptive algorithms to track system frequency.

The paper includes a description of the problems encountered when implementing the adaptive frequency tracking algorithms and the solutions chosen to ensure reliability independent of system conditions.

 

Application Notes

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