CIRED                            20th International Conference on Electricity Distribution                   Prague, 8-11 ...
CIRED                                                                                              20th International Conf...
CIRED                       20th International Conference on Electricity Distribution                  Prague, 8-11 June 2...
CIRED                       20th International Conference on Electricity Distribution                    Prague, 8-11 June...
CIRED                      20th International Conference on Electricity Distribution                Prague, 8-11 June 2009...
CIRED                       20th International Conference on Electricity Distribution                  Prague, 8-11 June 2...
CIRED                       20th International Conference on Electricity Distribution                   Prague, 8-11 June ...
CIRED                      20th International Conference on Electricity Distribution                   Prague, 8-11 June 2...
CIRED                      20th International Conference on Electricity Distribution                  Prague, 8-11 June 20...
CIRED                      20th International Conference on Electricity Distribution                    Prague, 8-11 June ...
CIRED                      20th International Conference on Electricity Distribution                   Prague, 8-11 June 2...
CIRED                      20th International Conference on Electricity Distribution                   Prague, 8-11 June 2...
CIRED                      20th International Conference on Electricity Distribution                   Prague, 8-11 June 2...
CIRED                      20th International Conference on Electricity Distribution                  Prague, 8-11 June 20...
CIRED                      20th International Conference on Electricity Distribution                  Prague, 8-11 June 20...
CIRED                      20th International Conference on Electricity Distribution                   Prague, 8-11 June 2...
CIRED                      20th International Conference on Electricity Distribution                   Prague, 8-11 June 2...
CIRED                      20th International Conference on Electricity Distribution                Prague, 8-11 June 2009...
CIRED                      20th International Conference on Electricity Distribution               Prague, 8-11 June 2009 ...
CIRED                      20th International Conference on Electricity Distribution               Prague, 8-11 June 2009 ...
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Special report-s3

  1. 1. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Special Report - Session 3 OPERATION, CONTROL AND PROTECTION Theodor CONNOR Chairman - Germany Markus ZDRALLEK Special Rapporteur - Germany Ignaz HÜBL Special Rapporteur - Austria Block 1 OperationIntroduction − Condition AssessmentThe interest in Session 3 -like the interest in Cired at all- is − Distribution Managementstill and constantly growing. The number of 261 abstractsreceived for Session 3 underlines this growing interest Block 2 Controlimpressively. Since the number of different countriessubmitting papers is increasing, too, Session 3 is even − Distribution Management Systems / SCADAgetting more international as it already was. Due to the − Distribution Automationextreme high number of abstracts received for Session 3Chairman and Rapporteurs had to be once again quite strict − Communication/ IEC 61850in rejecting papers in order to keep quality and a − Cyber Securitymanageable number of papers during the conference. Block 3 ProtectionTherefore 142 abstracts were accepted by NationalCommittees and Technical Committee (TC) and the authors − Fault Locationwere called to submit a full paper. Finally 124 full papers − Neutral Groundinghave been accepted for Session 3. An overview of thereview process gives Figure 1. − Distributed Generation / Simulation Abstracts received − Practical Implementation In the area of grid operation lots of papers have been Abstracts accepted received dealing with the problem how to derive the Full papers accepted technical condition of grid components correctly. This task still seems not solved sufficiently enough, although it is a Poster Session major problem since many maintenance and renewal strategies are fundamentally based on a correct assessment Main Session of the equipment condition. All papers dealing with this matter are discussed in a separate block. RIF In the area of grid control two trends can still and clearly be 0 50 100 150 200 250 300 observed: Firstly –in most cases driven by the quality standards of grid regulators- more and more automation ofFig. 1: Overview of the review process MV-grids or even of LV-grids can be considered. ThisAll authors are asked for a poster presentation, 28 of them comes along with a higher demand on communication andwill be additionally present their paper in the Main Session corresponding techniques and infrastructure. Since there is aand 16 more academic papers are allocated to two Research lot of work spent on this tasks it was addressed especially inand Innovation Forums (RIF). the call for papers and 14 papers covering communication matters are finally accepted.Traditionally and according to the topics of the paperssubmitted Session 3 is still structured into three blocks: Secondly grid control is increasing its efficiency due to more and more powerful SCADA-Systems. These systems can handle much larger grids than in the past and offerCIRED2009 Session 3: Operation, Control and Protection Page 1 / 20
  2. 2. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009additional possibilities. Furthermore systems which in the Paper 403 from the U.S. focuses especially on the conditionpast have been solely used for SCADA-purposes develop assessment of XLPE-insulated Cables. The proposedtowards integrated Distribution Management Systems method is based on the analyses of radio frequency pulses.(DMS). Paper 234 shows a very practical application of a specialNew in the control part is cyber security task. Including inspection program in Brazil for the condition assessment ofSCADA-systems more into the office IT-infrastructure of MV porcelain pin insulators in order to replace the badgrid operators leads to an increasing risk for cyber threats. ones. Due to this program the number of outages could be reduced significantly. In contrast to this the theoreticalThe main focus of protection is the location of several paper 466 (Russia) confirms a life time model of technicaltypes of faults and the neutral grounding in MV networks. components to answer the still unsolved question of theBoth theoretical examination and practical application are ageing of grid components. Unfortunately only the theory isshown. A lot of papers being a part of protection are presented without showing any calculation results.examining the location of earth faults in isolated andcompensated networks. Of course there exists no universal Another practical application is given in paper 525 (U.K.)method which would be applicable to all types of networks about condition assessment of the foundation of stealand ground faults and would be able to localize the ground towers. As an enhancement to the measurement offaults in MV network safely. polarisation current a transient dynamic response method is used.Practical experiments try to attest the function of newalgorithm and fault detectors implemented in protecting Still on experimental stage is a laser based scanning systemsystems. for high voltage power lines from Italy presented in paper 784. The measuring system given in Figure 3 is adequate toAn overview of the number of papers related to the different monitor the ice accretion on conductors as well asblocks and sub blocks is given in Figure 2. conductors’ sags. 25 20 Number of papers 15 10 5 0 DM-Systems / SCADA Condition Assessment Cyber security Distribution Fault Location Neutral Grounding Generation/Simulation Management Practical Communication / IEC Automation Distribution Distributed Fig. 3: Schematic description of the measuring system 61850 Paper 540 from Italy introduces a condition based maintenance strategy of MV circuit breakers. Depending on Operation Control Protection several failure models from different concrete measurements like opening/closing duration conditionFig. 2: Overview of the accepted papers information of the circuit breaker is derived.The majority of papers is prepared by groups of authors. In Paper 448 (Italy) touches a security problem faced by manysome cases these groups are composed of authors from grid operators that is protection against housebreaking anddifferent countries and even continents. The authors are vandalism. A video monitoring application developed andfrom grid operating companies, vendors, universities and installed in many 110-kV-substations of Enel Distribuzioneother research associations. So Session 3 of Cired 2009 is presented.truly reflects the ‘state of art’ of the grid operationcommunity in case of Operation, Control and Protection. A concrete and practically used condition assessment method of MV-transformes is given in paper 686 from Malaysia. Different diagnostic techniques as well as theirOperation influence on the calculation of the overall condition index are presented.Condition AssessmentAll papers of this sub-block describe methods or casestudies to determine the condition of the grid–equipment asexact as possible. Some methods are more theoretical or inexperimental stage, while others are well used andimplemented in grid operating companies.The papers 146, 530 (both U.K.) and 195 (Netherlands)present the experiences with different condition assessmentsystems based on partial discharge monitoring systems.CIRED2009 Session 3 : Operation, Control and Protection Page 2 / 20
  3. 3. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Paper 874 from the Netherlands is about organizational changes which are necessary since the lifecycles of substation automation systems are getting and shorter and shorter and the systems themselves are getting more and more integrated. Two papers deal with risk assessment in distribution grids: A technical assessment management systems developed at EDP in Portugal based on risk assessment and condition assessment is presented in paper 914, while paper 171 (Norway) shows maintenance strategies based on qualitative and quantitative risk assessment. Beside the papers presented in the condition assessmentFig. 4: Transformer health index according to age block two more papers deal with new, more sophisticated maintenance or refurbishment strategies: Paper 611 givesFigure 4 actually shows the condition assessment results for the experience of replacing Static Var compensators (SVC)a population of about 700 transformers and Figure 5 gives feeding a coal train haulage grid in Australia before theythe according mitigation decisions for transformers in bad reach the end of their service lifetime. Paper 472 presents acondition. practical approach of an Austrian Grid operator to support the decision of maintaining MV- and LV- Overhead lines or replacing them by cables.Fig. 5: Mitigating actions on problematic transformers Fig. 6: Cost drivers of low voltage overhead linesDistribution Management The different cost drivers of overhead line maintenance arePaper 45 from a Romanian grid operator discusses the analyzed in detail (Figure 6) and aerial views showing forreliability of substation equipment during its lifetime example the vegetation (Figure 7) are used to support thefocused on transmission level. The goal is to take sufficient concrete planning decisions.decisions for operation and modernisation of substationsPaper 65 from U.K. proposes to use lithium-ion batteries forthe back up power of substations in order to overcome thedrawbacks of conventional lead-aced batteries. These are tobig and require to much regular maintenance according tothe paper.In Cired 2009 only three papers deal with introduction ofworkforce management (WFM) systems although this is amajor task for many grid operating companies worldwide.Paper 691 presents the implementation of a WFM-system ata large German grid operating company. An overview of theproject and the new WFM-processes as well as the principal Fig. 7: Visualized result for the low voltage gridIT-architecture, the central and mobile equipment is given.Paper 326 from Sweden gives the results of a study about Paper 1036 gives details of an interruption reporting systemstructure and robustness of the IT-architecture of WFM- developed and implemented in a Malaysian grid operatingsystems. The last WFM-paper (559, Portugal) describes a company.system configured specially to optimize grid management The quit impressive paper 119 is about the icing catastrophyand operation in the very dense distribution grid of Lisbon.CIRED2009 Session 3 : Operation, Control and Protection Page 3 / 20
  4. 4. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009in China in the beginning of 2008, causing a lot of large Paper 697 (U.K.) describes the features of modern reclosersblackouts (see Figures 8 und 9). designed for self-controlled switching of load and fault current. Paper 331 from China presents an analysis of switching time and capacities to compensate the reactive power of substations in a 35-kV-grid more accurate. Another analysis of reactive power compensation is given in paper 179 from Brazil. In Paper 68 a method to plan and optimise own resources of a grid operating company (field service personnel, agency staff, tools etc.) and to define an optimal outsourcing strategy is introduced. An example of the optimisation ofFig. 8: 110kV central conductor icing scene the operation of a high voltage grid is given. A similar model is presented in paper 818 in Session 6.It is shown, how the weather conditions could damage thegrid so much and therefore affect the power supply so Paper 408 from Austria deals with the problem of stableextensive. Finally countermeasures to prevent such black island operation of grids. Grid restoration strategies in aouts in the future are given. 110-kV-grid are proved with dynamic simulations taking grid and feeding power stations into account. Potential scope of discussion − Condition assessment of grid components: Why is it so difficult to solve the problem? Is there a general solution trend? How about the ageing phenomenon? − WFM-systems: Are they well introduced in the companies or are they still an experiment? How do they affect the whole processes of a grid operation company? − Maintenance strategies: To simple or to sophisticated? How to manage the balance between data collectionFig. 9: Icing phenomena on a pole of distribution line afford benefits?Many customers facing longer lasting interruptions of − Can large blackouts due to extreme weather conditionssupply complain about a lack of information about the re- be prevented? Will the frequency increase in the future?supply process. To overcome this problem in Finland (paper478) and Germany (paper 919) information platforms for3rd-parties like police and fire-service and of course for thecustomers concerned have been developed.Table 1: Papers of Block 1 Operation assigned to Session 3 Paper No. Title MS MS RIF PS a.m. p.m. No.: 0045 Use of Information Generated by Remotely Controlled Medium-Voltage X Distribution System Components No.: 0065 The Utilisation of Lithium-Ion Batteries in Substations X No.: 0068 Reducing Network Operation Costs by Optimal Resource Planning X X No.: 0119 Analysis of Icing Accident in South China Power Grids in 2008 and Its X X Countermeasures No.: 0146 Experience of Mobile Web-Based Condition-Monitoring Technology for X Partial Discharge Detection and Analysis No.: 0171 Experiences Using Quantitative Risk Assessment in Distribution System X Maintenance ManagementCIRED2009 Session 3 : Operation, Control and Protection Page 4 / 20
  5. 5. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Paper No. Title MS MS RIF PS a.m. p.m. No.: 0179 Determination of Optimal Point for Reactive Power Compensation in X X Distribution Systems No.: 0195 Partial Discharge On-Line Measurements with Continuous Monitoring as X Invaluable Tool for Assessing Insulation Quality and Maintenance Planning No.: 0234 The Influence of the Weather Parameters on the Results of the Inspection of X Pin Insulators in Distribution Medium Voltage Lines No.: 0326 Assessing the Quality of Service of Workforce Management Tools X X No.: 0331 The Reactive Power Compensation Analysis System of Substation Based on X X Typical Day Load Curve No.: 0403 Condition Based Maintenance Strategy Tools for Power Cable Systems X No.: 0408 Dynamic Simulation of a 110-kV-Network During Grid Restoration X X No.: 0448 Video Monitoring Application to Primary Power Stations X X No.: 0466 Operation of Electrical Equipment in Distribution Networks on the Basis of X its Technical Life Assessment No.: 0472 Developing a Maintenance and Replacement Cabling Strategy for Medium X X and Low Voltage Overhead Lines - A Practical Approach No.: 0478 Innovative System Integration for Outage Communication X X No.: 0525 Non Intrusive Assessment of Steel Tower Foundations X No.: 0530 Use of Web Based Partial Discharge Monitoring to Extend Asset Life X No.: 0540 Condition Based Maintenance on MV Circuit Breakers X No.: 0559 Optimizing Management and Operation in very High Density Distribution X X Networks No.: 0611 SVC Refurbishment Experience for Critical Coal Train Haulage Network X No.: 0686 TNB Experience in Condition Assessment and Life Management of X X Distribution Power Transformers No.: 0691 Benefits of Highly Integrated Workforce Management Concepts X No.: 0697 Application of Recloser for Reliable Supply in Rural Overhead Distribution X X Networks No.: 0784 Laser Based Scanning System for Voltage Power Lines Conductors X Monitoring No.: 0874 Challenge of Managing the change Imposed on the Organisation by Digital X Secondary Technology No.: 0914 M2M - Developing and Implementing a Technical Asset Management X System in EDP Distribuição (Portugal) No.: 0919 Information and Communication Platform for Crisis Management (IKK) X No.: 1036 Development of Distribution Outage and Interruption Reporting System on X the Intranet to Facilitate Asset Management Block 2 Control Distribution Management Systems / SCADA All eight papers of this sub-block deal with theCIRED2009 Session 3 : Operation, Control and Protection Page 5 / 20
  6. 6. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009improvement or refurbishment of existing Distribution Paper 328 from China promotes a new state estimationManagement Systems (DMS). Paper 142 presents the method for distribution grids which combines historical(long) way from a stand alone HV-SCADA-System in and remote data using six data rules to improve dataSerbia to an enhanced and integrated DMS for HV- and quality.MV-grids. A similar project is given Paper 519 from Four more prospective papers deal with futureSlovenia ending up in the system configuration shown in requirements for DMS of all voltage levels which have toFigure 10. manage more and more ‘smart’ components. In paper 76 (U.K.) the idea of a ‘third generation DMS’ is introduced to cover these future requirements including the management of Smart Grids. Likewise papers 722 and 841 both from Germany focus on the growing needs for new, more intelligent DMS caused by more and more smart components connected to the grid. Paper 770 gives a 3- phases path (see Fig. 12) from today’s DMS towards future ‘Smart Grid’-DMS.Fig. 10: SCADA/DMS system configurationEven more management and control information isaggregated in the ‘vision’ of new control centres inSwitzerland (paper 587) and Italy. In paper 365 a so called‘supervision dashboard’ is presented which gives anoverview of the supply situation of the whole Enel-distribution grid. As shown in Figure 11 the user can zoominto each local control system to see its daily operationactivities. Fig. 12: Path towards DMS for Smart Grids Paper 636 from Sweden is about integration of the different IT-system which are used in an grid operating company which special regard to the SCADA-systems Distribution Automation Several papers in this block deal with more or less automatic re-supply switching actions carried through in MV-grids. While the goal is always the same –to reduce customers duration of supply interruptions- the methods to achieve this goal are different. First papers 453 (Denmark) and 635 (France) introduce the ‘self healing MV- distribution grid’. In case of a MV-fault, several main switching and re-supply actions are carried though automatically by local automated MV-substations (Figure 13) before field staff arrives.Fig. 11: Local and national ‘supervision dashboard’Paper 73 from Egypt is abaut a practical project to increasethe life time of the DMS of the city of Alexandria whilepaper 687 (Finland) presents Helsinki’s new DMS for theMV grid and in paper 699 an existing DMS in Serbia isimproved by including optimal voltage control. Paper 396gives another SCADA-application to control the 110-kV-grid for railway power grid in Germany.CIRED2009 Session 3 : Operation, Control and Protection Page 6 / 20
  7. 7. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 to compare various levels of automation for distribution grids relating the improvements in customers reliability of supply and the corresponding costs. Paper 681 from the Czech Republic deals with the advantages of Phasor Measurement Units (PMU) to improve power systems performance and reliability.Fig. 13: Local automated MV-substation – general architectureA similar target is presented by French grid operator ERDFin paper 496, who decided to add a set of advanceddistribution management functions to its MV-remote Fig. 15: Coupling of MV-gridscontrol system with the ultimate aim to achieve anautomatic network restoration. Paper 558 presents Paper 739 (the Netherlands) handles the problem of safecomparable ideas developed in the U.S. Paper 744 (Czech coupling of MV-grids fed by different 110-kV/MV-Republic) deals with several methods of utilization of data substations (Figure 15). It discusses several aspects oftransmitted from remote-controlled components to the equalizing currents and describes the system that has beencontrol centre. built for predicting these currents reliable. Communication/ IEC 61850 In this sub-block several papers deal with the utilisation of modern communication methods or standards for distribution grids. Three papers propose Ethernet communication: Paper 47 compares four ways of implementing an Ethernet/IP WAN network, with the aim of assuring the delivery of all the new generation services with Ethernet interfaces, with adequate quality of service and bandwidth, using the existing fibre optic network of EDP, the distribution company in Portugal. In paper 242 (Canada) key issues andFig. 14: ‘Pulse closer’ for overheadline protection considerations when designing hybrid networks involving serial and Ethernet Networks are defined and theFinally paper 1028 from the U.S. introduces ‘pulse closing’ characteristics of an environmentally robust hybridas a new technology for overhead distribution system network for substation automation applications areprotection. It uses a new method for verifying that a power described. Paper 244 (Canada) looks at considerationsline has cleared a fault before initiating a closing operation. when designing an Ethernet network for substationThe authors state that pulse closing is an alternative to automation applications which may include IEC61850conventional re-closing. It is expected to significantly station or process bus or a combination of both, with focusreduce stress on system components as well as improve on redundancy.power quality experienced by customers upstream of a Three papers investigate how wireless communication canfault (equipment see Figure 14). be used in distribution grids: Paper 619 from SpainIn some countries automation of LV-grids is in the scope discusses the state of art as well as advantages andof the grid operators, too. For example paper 439 from disadvantages of using wireless communication. Paper 856Italy presents a pilot project of Enel Distibuzione for the (U.K.) proposes the ‘WiMax-technology’ to deliver aremote control of LV-grids. The goal is to reduce the wireless internet protocol service for distribution gridsduration of customer supply interruptions and number of automation. A coverage study for Northern Ireland andworkmen interventions in case of LV-faults. About 1000 border countries of Republic of Ireland is presented. Inremote controlled LV-circuit breakers have already been paper 174 (U.K.) the influence of characteristic radioinstalled successfully. frequency impulsive noises with a view to assess its impactPaper 942 (Canada) describes a simulation tool that allows on wireless network technologies is investigated. Therefore the measurement equipment shown in Figure 16 is installedCIRED2009 Session 3 : Operation, Control and Protection Page 7 / 20
  8. 8. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009in a typical HV-substation. to intrude a substation’ and of course gives answers how to establish a practical and secure IT-architecture in grid operating companies protecting all principal domains given in Figure 17.Fig. 16: Measurement of radio frequency impulse noisesAnd many papers deal with the implementation of the(new) communication standards IEC 60870-5 (forSCADA-systems) and IEC 61850 (for substationcommunication): Paper 322 from Portugal states, thatEngineering of substation automation systems according to Fig. 17: Logical domains dealing with information securityIEC 61850 is a non-trivial task and describes differentapproaches to overcome the difficulties. Paper 372 presents Paper 650 (Italy) presents results from real experimentalthe new design of the communication network of a Belgian cyber attacks on grid control systems. Attack processes aregrid operating company implemented to improve control simulated and deployed in a laboratory test bed given inand protection stepping into the new generation protocols Figure 18. and their impact is evaluated by observing theIEC 60870-5-104 and IEC 61850. Paper 356 describes how application behaviour during ordinary maintenance andthe communication standard IEC 60870-5-104, which operation activities, as well as during the execution ofcovers transmission over TCP/IP, is implemented at EDP highly critical defence actions.Distribution a Portuguese distribution grid operator. Inpaper 421 from Sweden the use of a waveguide forIEC61850 communication with particular attention on thecommunication latency is studied. Paper 741 (Finland)looks in particular at how horizontal communication withinIEC 61850, commonly known as GOOSE communication,between protection and control devices can be used toimprove the reliability and performance of the system.Paper 843 from Germany gives requirements and accuracydefinitions for a digital interface according to IEC 61850.The goal of paper 368 (Spain) is to define and build a newcommunication architecture, in parallel to the electricalgrid especially to support the demand management.Finally Paper 641 (Spain) presents some general rules andcriteria necessary to design a communication network overdistributions grids correctly. The paper also collects maincommunication requirements needed for Smart Grids. Fig. 18: Attacked SCADA-system configurationCyber SecurityThe lack of cyber security resilience endangers the Paper 838 defines zoning principles for electricityreliability of the overall energy supply which is part of the distribution and energy production environments based oncritical infrastructure. So the protection of the IT-systems a Zone model given in Figure 19 designed to mitigate thebut in particular of the SCADA-systems against cyber risk of cyber attacks and to enable the secure integrationattacks becomes more and more important for gridoperators.Paper 247 (Germany) describes the new cyber securitychallenges for energy automation systems from the vendorspoint of view and proposes solutions on how to resolvethem. Fig. 19: Zone model for protection against cyber attacksPaper 473 from Austria asks the provocative question ‘how Paper 917 explores the evolution of SCADA-systems andCIRED2009 Session 3 : Operation, Control and Protection Page 8 / 20
  9. 9. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009of critical infrastructures management under the − More MV and even LV-equipment means moreperspective of the growing concerns with information secondary equipment to be maintained in the grids. Areassurance, security and reliability at EDP in Portugal. the pros and cons really balanced?Paper 969 (Sweden) tries to understand the weaknesses of − How much and which kind of communication isSCADA-systems by analyses based on appropriate required by Smart Grids?graphical models of the system architecture. − Are cyber attacks on SCADA-systems a real danger orPotential scope of discussion just a hip subject?− SCADA-systems are getting larger and larger and more complicated. Is their a natural dead end for the systems and their operators?Table 2: Papers of Block 2 Control assigned to Session 3 Paper No. Title MS MS RIF PS a.m. p.m. No.: 0047 Implementation Models of an IP/Ethernet Network to Allow the Delivery of X New Generation Services in Substations No.: 0073 Strategy and Planning to Improve Distribution Automation Assets X Performance No.: 0076 Third Generation Monitoring Systems for Electric Power Distribution X Networks Lay the Foundation for Future Smartgrids No.: 0142 Evolutions in the Elektrovojvodina Scada System for MV Network X No.: 0144 Process of Simulating Novel Control Room Scenarios for Future Active X Networks No.: 0174 Detection of Ultra-Wide-Band Impulsive Noise in 400 kV Air Insulated X Substation No.: 0242 The Migration of Serial to Ethernet Communications – Why bother? X No.: 0244 Ethernet Networks Redundancy with Focus on IEC 61850 Applications X X No.: 0247 Cyber Security for Energy Automation Systems - New Challenges for X Vendors No.: 0322 Advanced Engineering Tools for Next Generation Substation Automation X Systems – The Added Value of IEC 61850 and the Inpact Project No.: 0328 A Novel State Estimation Method Based on Quality Tag for Distribution X Networks No.: 0356 IEC 60870-5-104 as a Driver to Evolution of Substation and Distribution X Automation at EDP No.: 0365 Supervision Dashboards to Monitor System and Network Performances at X Local and National Level No.: 0368 Demand Management Communications Architecture X No.: 0372 Belgian Walloon Electricity Distribution Network : Turning Control and X Protection into the Future No.: 0396 New Technological Challenges Operating the 110 kV, 16.7 Hz Grid for X Railway Power Supply in Germany No.: 0421 Evaluation of a Waveguide System for IEC61850 Communication X No.: 0439 Reduction of Supply Interruptions Duration by Means of Low Voltage X X Network Remote Control: First Results of Enel Distribuzione Experimentation No.: 0453 A Real Case of Self Healing Distribution Network X XCIRED2009 Session 3 : Operation, Control and Protection Page 9 / 20
  10. 10. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Paper No. Title MS MS RIF PS a.m. p.m. No.: 0473 Intruding a Substation? - IT Network Security in Power Systems / Guide for X Practical IT Based Architectures No.: 0496 Towards MV Networks Automation X X No.: 0519 Revitalization of Remote Control Centre at Elektro Primorska (Slovenia) X No.: 0558 Distribution Automation for Back-Feed Network Power Restoration X No.: 0587 Facing Challenges for Energy & Network Control Center X No.: 0619 Applicability of Wireless Communication Technologies to Measurement on X DENISE Electrical Distribution Network No.: 0635 On the Field Autonomous Automatism: A Complementary Way for Network X Automation No.: 0636 Analysis of Asset Management System Integration Maturity at Distribution X X System Operators No.: 0641 How to Design a Communication Network over Distribution Networks X X No.: 0650 Assessment of Power Control Systems Communications through Testbed X X Experiments No.: 0681 The Monitoring of Power System Events on Transmission and Distribution X Level by the use of Phasor Measurement Units (PMU) No.: 0687 A Comprehensive Secondary Substation Monitoring System X No.: 0699 Real-Time Voltage Control Integrated in DMS X X No.: 0722 Smart Substation and Feeder Automation for a Smart Distribution Grid X No.: 0739 Safe Sitching in the Medium Voltage Grid between Substations X No.: 0741 Utilizing Possibilities of IEC 61850 and Goose X No.: 0744 Use of Information Generated by Remotely Controlled Medium-Voltage X Distribution System Components No.: 0770 From DA to SmartGrids - Evolution or Revolution? A Path to Improve the X Utility Efficiency No.: 0838 Zoning Principles in Distribution and Energy Production Enviroments X No.: 0841 New Principles of Operating Electrical Distribution Networks with a High X Degree of Decentralized Generation No.: 0843 Digital Interface for IEC 61850. Requirements and Accuracy Definitions X X No.: 0856 Wireless Telecoms for Distribution Networks based on WiMax X X No.: 0912 Electric Grid Versus Data Network Architectures and Standards – Smartgrid X as Plug&Play No.: 0917 Security and Reliability over Critical Utility Infrastructures X No.: 0942 Justifying Distribution Automation X X No.: 0969 Issues of Cyber Security in Scada-Systems - On the Importance of X X Awareness No.: 1028 Applications Assessment of Pulse Closing Technology X The submitted papers deal with the fault location in case ofBlock 3 Protection short circuit as well as in case of earth fault. There exists no universal method which would be applicable to all typesFault Location of networks and ground faults and would be able to localize the ground faults in MV network safely.CIRED2009 Session 3 : Operation, Control and Protection Page 10 / 20
  11. 11. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009In Paper 161 from France a new generation of directionalfault indicators used in MV underground networks ispresented. The upgrade of the neutral point system in theMV system of ERDF demands a new detection algorithm.Paper 293 from Spain describes a PLC Fault LocationSystem used in underground cables of a MV network. TheCommunication is supported by a narrow Band PLC builtin modems that couples the signal to the ground shield ofthe power cable. In case of short circuit and trip by theprotective relay the master detector send the status of eachdetector in the system to the SCADA System.Paper 299 from CZ discusses the detection of individualtypes of ground faults according to the analysis ofelectromagnetic fields of MV Lines using statical anddynamical methods. By using the telecommunication it willread out the data from individual indicators automaticallyand collect them into a database according to therequirements of the operator. When a complex data basewill be available, it will be possible to evaluate the placeswith the most frequent occurrence of failures.Paper 398 from Italy presents new developments inoutdoor fault detectors. Fig. 21: Installation of cable fault detector Paper 464 from China describes transient current based earth fault locations in non-effectively earthed distribution networks. It is based on comparing the similarities of zero mode transient currents of faulty feeder, which is measured by the correlation coefficient. It does not require the measurement of zero mode voltage. The algorithm was tested in simulation using field data from an artificial fault with DAS of a 10 kV railway distribution network in Ganzhou, Jiangxi province, China. Paper 527 from The Netherlands derives from practical experience with fault location in MV networks. The DutchFig. 20: Fault detector complete equipment grid operator Alliander puts effort in faster location of faults in this network. A fault location system wasThis detector for outdoor applications has been tested and implemented in 10 substations equipped with the SASensoris showing excellent results applied to both isolated and protection and control system. The search algorithm usescompensated distribution networks. the momentary samples instead of FFT signals. PreliminaryIn Paper 447 from Italy another outdoor fault detector with tests of this algorithm show promising results as is shownintegrated current and voltage sensor is described. in Figure 22.Including Overcurrent, cross country faults detectionbeside a directional phase to earth fault detection forinsulated MV networks. Many thousands have beenpurchased by ENEL and are being installed, both in Italyand in Romania.CIRED2009 Session 3 : Operation, Control and Protection Page 11 / 20
  12. 12. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009Fig. 22: Calculation of the fault impedance Paper 973 from USA provides an update on the work performed to date with various utilities and fault locationAnother way of detecting low- and high ohmic faults is systems. Several different systems were evaluated. Thepresented in Paper 631 from Germany. The basics of the Hydro Quebec system results indicate that the voltage-onlyqu-algorithm where presented at CIRED 2003. There are fault location is also possible.some disadvantages of the standard qu-algorithm thereforethe new qu2-algorithm was developed. The sensitivity Paper 193 from China describes the simulation of a newagainst phase-splitting and the crosstalk from parallel method of single phase grounding fault location ofsystems are general problems of all protection relay. Field distribution networks which are proven through lots ofresults show the effectiveness of this new concept for simulation results.transient relays based on the qu2-algorithm.In Paper 642 from Norway an efficient fault management Neutral Groundingusing remote fault indicators is shown. The review in bothtraditional Fault Passage Indicators (FPIs) and the new This part starts with paper 132 from China. Determiningmethods supports the advantages by going from local the 10 kV power grid developed rapidly in Shanghaiindication to a remote indication. The interpretation of Shinan. Based on the actual grid situation and theresults is moved to the system operator who gets the measured capacitive current of nine substations, a basiccomplete overview during the fault situation. criterion has been concluded for adjusting the neutral point grounding mode from grounding through arc suppression coil to grounding through low resistance after having it analyzed technically. The criterion is instructive for selecting the neutral point grounding mode of newly built substations and the rebuilt ones. Paper 305 from Austria describes a new improved algorithm which has been developed. Earth fault distance protection with distance protection relays is common practice in solidly grounded networks. The simulation shows, that this improved distance calculation provides very good accuracy up to earth fault transitions impedances of 1 kOhm and can be used in 2-phase networks as well. In Paper 345 from Austria the effects of the capacitive and inductive interference between parallel high voltage power lines depending on the neural point treatment of this grid is presented. Examples are given, practical investigations andFig. 23: Downed conductor detection an approach for optimization in a typical 220/110 kV gridPaper 675 from Croatia with the theme “Determination of is faulted line with transient method” is a proven Paper 375 from Finland has studied earth fault protectionmethod based on the qu-algorithm. This paper shows based on neutral admittance. The results show that Y0examples based on earth fault tests that have been protection is a respectable alternative to traditional earthconducted in resonant grounded networks. This method fault protection functions.can detect lowohmic earth faults selectively without anyspecial demands on measuring transducers but its notreliable for highohmic and restriking earth faults. Fig. 24: Evaluation of the I0 cos(φ) criterionCIRED2009 Session 3 : Operation, Control and Protection Page 12 / 20
  13. 13. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009Based on the theory and field tests, the admittancecalculation should be based on changes in the zero-sequence quantities due to a fault, the novel Y0characteristic should be used and the parallel resistorshould be permanently connected.Paper 397 from China describes an experimental study onextinguishing arc performance in different types of ArcSuppression Coils (ASC). The experiments show that thefour kinds of ASC have are better able to extinct thegrounding arc compared to that of electric network withoutASC. In Paper 554 from Italy the neutral compensation andnetwork monitoring is discussed. The latest experiences inthe test application of the pulse injection techniques fordetermining the tuning conditioning compensatednetworks. This technique allows very simple andperforming implementation for Petersen coil systems, Fig. 26: 15 kV zigzag reactor with straight tank wallsindependent from the coil type. The last paper in this sub block paper 1034 from CzechPaper 620 from Croatia evaluates a system on protection Republic, the influence of fault type on fault current in MVperformance in resonantly earthed MV networks. An compensated network is discussed. There were damagedoverview of the procedure implemented before putting concrete towers in E.ON Czech Republic distributionPeterson coils in operation is given, with emphasis on the network; the aim of an experiment was to measureearthing system evaluation, which has proved to be rather electrical values during the fault. The first results of faultimportant. current and voltage analysis show that the longer operation of earth fault on unearthed console of concrete tower is very dangerous for the lifecycle of the towers. Distributed Generation / Simulation This sub block contains four papers. Paper 649 from Finland describes the effects of the distributed generation on the earth fault protection of a MV feeder and protection coordination. Neutral isolated and compensated systems were considered.Fig. 25: Recorded transmission lines and transformerphase currents during single phase earth fault testPaper 1004 from Portugal shows Artificial Neutral Points(ANPs) made by oil-immersed reactors which can beoverstressed both mechanically and thermally. A numberof failures have been reported, particularly in overhead linenetworks. Fig. 27: Model of MV system and DG unit The behaviour of the generator during the high speed automatic reclosing of the feeder is an important matter relating to electrical safety and protection coordination. In the second Paper 759 from Finland applications of modern communication technology to loss-of-mains (LOM) protection are discussed. In applications where the communication infrastructure and primary circuit lay-out supports the use of line differential protection of the interconnecting feeder, LOM protection can be realised inCIRED2009 Session 3 : Operation, Control and Protection Page 13 / 20
  14. 14. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009a fast, reliable and selective way by utilizing thecommunication link of the line differential protectionscheme for binary signal transfer signalling. Theconventional passive techniques for LOM protection canbe utilized as back-up or stand-by protection in case anyabnormalities should be detected in the communicationchain.In Paper 257 from UK the impact of wind farms onelectromagnetic transients in 132 kV network, withparticular reference to fault detection, was simulated in a Fig. 29: Current Transformer Connection to Relaysnumber of cases. Results show that adaptive autoreclosingschemes may need particular attention when designed forDFIG connected lines, although the traditional approach ofsignal processing and AI is validated since the effect offault parameters have far more significance then thegenerating technology concerned. In Paper 746 from UKthe Prony method for the estimation of dominant inter-areaoscillations modes in large power systems is presented.The main goal of this paper is to compare the dominantoscillations modes extracted by the Prony method withthose obtained by Eigen-value analysis. Fig. 30: Rogowski Coil Connections to Relays Paper 56 from Egypt assesses the performance of over- current protective relays when a decaying DC component exists in the current signal. The Paper depicts how the characteristics of the relay can deviate more than expected. From those characteristics, three new performance indices are proposed. The method used for the assessment could be used in an analysis of protective system performance during system faults and also for selecting the proper relay for a specific application that requires the relay operation to be more independent of decaying DC components. Paper 100 from India presents a fiber optics based sensing network applicable for fault detection in power systemFig. 28: Inter-area oscillation modes in a large system with using PLC/SCADA technology. Paper 104 from Portugala FSWF presents a distributed generation protection scheme to permit “ride-through fault”.Practical ImplementationThe sub block practical implementation contains 23 Papersand show a big variety of practical experience.Paper 36 from the USA compares operating characteristicsof non-conventional current sensors, Rogowski Coils, andconventional iron-core current transformers for protectiverelaying applications. Fig. 31: Voltage versus time profileCIRED2009 Session 3 : Operation, Control and Protection Page 14 / 20
  15. 15. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Autonomous Demand Area Power System (ADAPS). In this paper an uninterrupted power supply method of 6,6 kV non-fault section using the LPC targeting 6,6 kV distribution line is proposed and demonstrates the fault operation method of the protection system for ADAPS.Fig. 32: Phase-to-Phase Voltage recordedThe main conclusions are that Distribution Utilities have toreduce their fault clearance time under 500 milliseconds atleast when phase-to-phase voltage drops to 20% of thenominal voltage. This ride-through fault voltage profile has Fig. 34: Expected future power systemto substitute the current under voltage relay settings. In Paper 360 from Italy describes the integration of DSOorder to be user friendly the ride-through fault voltage control system and TSO automatic load shedding system toprofile must be included onto the digital protective relay. improve the security of the national grid.Paper 168 from Czech Republic describes protectionstructures in MV networks, mainly the connection ofinstrument transformers (both inductive and electronic) andthe measuring equipment used to analyze their signals. Itsummarizes the current situation and explains the way inwhich this structure could be optimized and the design ofits components simplified.Paper 199 from Brazil shows a protection system for theCo-Generation of methane gas connected to COPEL´sDistribution grid. Fig. 35: Integrated remote and control systemFig. 33: Phase-Ground short-circuit test The maximal delay time between a critical event on the national grid and the real load reduction is lower than 800After lab test results were approved, a panel with milliseconds. The positive results of the pilot project leadprotection equipment was installed at Granja Colombari to an application plan to extend the application over theand short-circuit tests as real simulations were done on whole Italian territory.COPEL´s distribution system at the point of connection, asshown in Figure 33. Paper 504 from Austria describes the measurement of line impedance and mutual coupling of parallel lines to improvePaper 320 from France describes a modern SF6 RMU with the protection system. Power lines are far from beingcircuit-breakers and integral self powered electronic relays. symmetrical. The logical consequence of this seems to beThe main advantage for using RMU with fixed integral CB that upcoming generations of protective relays will havefunction is that it allows improved transformer protection. individual impedance setting for all possible fault loops.Paper 347 from Japan shows a protection system for In Paper 623 from Czech Republic the interaction ofCIRED2009 Session 3 : Operation, Control and Protection Page 15 / 20
  16. 16. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009transmission and distribution systems is presented. Thediscussion points are protection settings and voltagecontrol. The comparison between measurement andsimulation shows the correctness of the used dynamicmodels.Korea Electric Power Corporation (KEPCO) covers allpower distribution lines in Korea. In Paper 629 from Koreathe distribution protection coordination program using GISschematics diagram is presented.Paper 728 from Germany presents a network protectionsecurity assessment. This becomes particular necessary incase of networks with DG infeeds. The systematicprotection security assessment includes variants of networkand protection configuration and is feasible with restrictedoperating expenses.Paper 729 from China describes an application of an inservice setting of Micro-Processor based relays in China.The supporting system of in service settings for different Fig. 37: Overview of weather station measurementskinds of substations is introduced. The technical and A protection relay has been developed which co-ordinatesmanagement measures to ensure the security of in service with E.ON Central Networks´ control system and providessetting are presented. backup in case the latter fails.Paper 733 from the UK describes how dynamic line rating Paper 743 from Norway deals with the localization ofis applied for load management and protection of the phase-to-phase short circuits on a medium voltage feeder132kV double-circuit line Skegness and Boston (North with distributed generation (DG). The methods are notEast of England) thereby enabling a larger penetration of meant for protection, only for fault localization. Thus,wind generation. The rating of the line is calculated communication speed is not critical. Only current anddynamically from local weather measurements. voltage magnitudes need to be communicated. Measurements from the DG-node during fault can be utilized for deciding the most probable fault location when more than one candidate location is found.Fig. 36: Measuring the conductor temperature Fig. 38: Two fault locations 20 km from the substation Paper 764 from Finland describes the increasing cost- efficiency of substation automation systems by centralized protection functions. Technology developed and prototyped by ABB facilitates new centralized protection and control functionality for substations. Paper 769 from Germany gives the criteria to operate the 20 kV networks of East Bavaria (Germany) with arc suppression coils according to standards. The investigation showed that for the tolerable touch voltage as well as for the earthing conditions at the sites, the decisive current has to be considered.CIRED2009 Session 3 : Operation, Control and Protection Page 16 / 20
  17. 17. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009Paper 774 from the UK describes a new, economic and determination of protection settings and help to improvemodernized version of the well known Cleveland the documentation quality in the complete / Time Limited Fuse (TLF) principle. The The Paper 993 from Brazil presents performance analysesprotection diagram has been redesigned and can now be of distance protection and differential protection applied onused on all modern types of Medium Voltage Ring Main 4 short transmission lines of ISA CTEEP, a BrazilianUnit switchgears with far less energy needed compared to power transmission utility. The use of the Real Timethe conventional TLF scheme. Digital Simulation to evaluate the performance of distance protection and differential protection applied to short transmission lines demonstrates to be a very powerful tool, making the simulation of several situations on the power transmission system possible. Paper 1064 from the USA presents the testing of multifunctional distribution protection relays. Testing of these devices requires good understanding of their functionality, the available tools and the purpose of the test.Fig. 39: The new TLF protection scheme Fig. 41: Distribution protection block diagram IEC 61850 introduces new requirements for the testing tools – ability to simulate GOOSE messages from IEDs in a distribution protection scheme and to subscribe and monitor GOOSE messages published by the tested devises.Fig. 40: TLF protection accessible behind the front coverUtility customers in the UK are working with TLFprotection for several technical and economical reasonsand are having good experience with this principle sincethe 1970´s. A modern version based on state-of-the-artcomponents has been developed to improve the TLFprotection.Paper 903 from Germany describes a practicaldetermination of protection settings for the utility Hof. Inthis paper the steps to perform a full revision of theprotection settings of all protection devices in the medium Fig. 42: IEC 61850 GSSE based IED functional testingvoltage network from the utility Hof are detailed. This Paper 1065 from India examines the process of replacingrevision was caused by the change of the neutral treatment. the conventional high impedance (HiZ) busbar protectionBecause of the complexity of the problem it is illustrated systems in substations with modern low impedance (LI)how software tools can support the planners during the numeric busbar protection schemes. The study draws onCIRED2009 Session 3 : Operation, Control and Protection Page 17 / 20
  18. 18. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009IEEE and CIGRE reports on deployment of numeric busbar − Protection systems are interconnected with operationprotection, manufacturers´ literature, and National Grid´s and control systems. How do the protection devicesown reliability studies, assessment of their policy for depend on the other systems?deployment of numeric busbar protection and operationalexperience of the operating personal. The paper also − Combining protection, control and communication is ahighlights some of the key issues, resulting from this study, very powerful technique. What happens if one of thesewhich should be considered by National Grid before full units is faulty?commissioning of the modern busbar protection. − Distributed generation become more important in the future. How must DG and protection system workPotential scope of discussion together?− New algorithms and new generations of fault detectors are designed. Is a new generation of protection systems required?Table 3: Papers of Block 3 Protection assigned to Session 3 Paper No. Title MS MS RIF PS a.m. p.m. No.: 36 Comparative Performance Characteristics of Current X Transformers and Non-Conventional Current Sensors No.: 56 Impact of Decaying DC Component on the Characteristics of Over- X X Current Protective Relays No.: 100 Detection and Signalling System of High Impedance Faults in X Transmission Lines Using Fiber Optic Sensing Network and PLC/SCADA Technology No.: 104 Wind Park Protection Scheme to Permit “Ride-Through Fault” X X No.: 132 Neutral Point Grounding Modes for 10 kV Grids in Shanghai X X Shinnan Area No.: 161 A New Generation of Directional Fault Passage Indicators for the X ERDF Distribution Network No.: 168 Protection of MV Networks Using Electronic Instrument X Transformers No.: 193 A New Method about Location for Line-to-Ground Fault in Small X Current Neutral Grounding System No.: 199 Protection System for the Co-Generation of Methane Gas X X Connected to Copel’s Distribution System Network – Tests and Procedures No.: 257 Impact of Wind Farms on Electro-Magnetic Transients on 132kV X Network, with Particular Reference to Fault Detection No.: 293 Underground Network Fault Location System Through Narrow X Band PLC Technology No.: 299 Identification of Ground Faults According to the Analysis of X Electromagnetic Fields of MV Lines No.: 305 Earth Fault Distance Protection X No.: 320 Circuit-Breaker RMU Improves MV/LV Transformer Protection X No.: 345 Displacement Voltages in Resonant Grounded Grids Caused by X Capacitive Coupling No.: 347 Development of Protection System for Autonomous Demand Area X Power System - Demonstration Test of Isolated Operation Methods for Non-fault Section in Distribution Line FaultCIRED2009 Session 3 : Operation, Control and Protection Page 18 / 20
  19. 19. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Paper No. Title MS MS RIF PS a.m. p.m. No.: 360 Integration of DSO Control Systems and TSO Automatic Load X X Shedding System to Improve the Security of the National Grid No.: 375 Performance of Novel Neutral Admittance Criterion in MV-Feeder X Earth Fault Protection No.: 397 Experimental Study on Extinguishing Arc Performance in Different X X Types of Arc Suppressing Coil No.: 398 Fault Isolation in Overhead Distribution Networks: New X Developments in Outdoor Fault Detectors No.: 447 An Innovative Integrated Current/Voltage Sensor for Outdoor Fault X X Detectors No.: 464 Earth Fault Location for Distribution Automation X X Based on Zero Mode Transient Current Correlation No.: 504 Measurement of Line Impedance and Mutual Coupling of Parallel X Lines to Improve the Protection System No.: 527 Practical Experience with Fault Location in MV Cable Networks X No.: 554 Neutral Compensation and Network Monitoring – Test Field X Experience in Determining Resonant Point and Homopolar Parameters with Active and Passive Pulse Injection No.: 620 Earthing System Evaluation and Influence on Protection X X Performance in Resonantly Earthed MV Networks No.: 623 Interaction of Transmission and Distribution Systems from Voltage X Control and Protection Settings Point of View No.: 629 Distribution Protection Coordination Program using GIS X X No.: 631 New Adaptive Algorithm for Detecting Low- and High Ohmic X X Faults in Meshed Networks No.: 642 Efficient Fault Management using Remote Fault Indicators X X No.: 649 Improving the Operational Reliability of MV Distribution Network X X including DG Units applying different Protection Applications No.: 675 Determination of Earth Faulted Line with Transient Method X No.: 728 Network Security Assessment – An important task in Distribution X X Systems with Dispersed Generation No.: 729 Application of in Service Setting of Micro-Processor Based Relays X in China No.: 733 Dynamic Line Rating Protection for Wind Farm Connections X X No.: 743 Location of Short-Circuit Faults on a Medium Voltage Feeder with X X Distributed Generation No.: 746 Monitoring of Inter-Area Oscillations in Power Systems with X X Renewable Energy Resources Using Prony Method No.: 759 Applying Modern Communication Technology on the Loss-of- X Mains Protection No.: 764 Increasing Cost-Efficiency of Substation Automation Systems by X Centralised Protection Functions No.: 769 Definition of Criteria to Operate 20kv-Networks with Arc X X Suppression Coils According to StandardsCIRED2009 Session 3 : Operation, Control and Protection Page 19 / 20
  20. 20. CIRED 20th International Conference on Electricity Distribution Prague, 8-11 June 2009 Paper No. Title MS MS RIF PS a.m. p.m. No.: 774 Modern Redesigned Time limit Fuse Protection for Medium X Voltage Distribution Circuit-Breakers in Ring Main Units No.: 903 Protection Setting Simuation and Documentation within the X Network Planning Tool PSS(R)Sincal No.: 973 Update on Distribution System Fault Location Technologies and X X Effectiveness No.: 993 The use of Real Time Digital Simulation for Performance Analysis X of Distance Protection and Differential Protection in Short Transmission Lines No.: 1004 Neutral Earthing Through Reactors in Aerial Distribution Networks X X No.: 1034 The Influence of Affected Phase on Fault Current in MV X X Compensated Networks No.: 1064 Testing of Multifunctional Distribution Protection Relays X No.: 1065 A Survey on Performance Evaluation of Low Impedance Numeric X X and High Impedance Busbar Protection SchemesCIRED2009 Session 3 : Operation, Control and Protection Page 20 / 20