3 luglio 2006 Dove Auditorium CESI via Rubattino 54 - Milano Qualità della tensione nelle reti elettriche in Italia: il sistema italiano di monitoraggio delle reti MT PROSPETTIVE DI RICERCA SULLA QUALITA’ DELLA TENSIONE C.A. Nucci CIGRE ST C4 Autorità per l’energia elettrica e il gas FORUM

Update on Activities of CIGRE C4 (System Technical Performance) Power Quality Working Groups Si ringrazia Robert Koch Convener Advisory Group AG C4.1. AG C4.1. Power Quality

Cigré AG C4.1. Scope Continuity of supply and voltage quality (magnitude, waveform, frequency, symmetry). – measurement and simulation methods – identification of quality indices and – study of acceptable/achievable limits / performance objectives – monitoring techniques – emission from disturbing installations, – immunity of sensitive installations, – mitigation techniques – economic aspects AG C4.1. Power Quality

Existing and New WG’s/TF’s (as at April 2005 SC 4 Meeting) Active Completed Scope & proposed convener reviewed and approved by Study Committee C4 Scope under preparation AG C4.1. Power Quality

Recently Completed WG’s/TF’s JWG C4.1.04: Power Quality Indices and Objectives - Key deliverable: TB 261 & Electra paper published in October Review existing indices and objectives. - Review of international measurement data. - Recommendations for quality indices. - Recommendations for quality objectives. WG disbanded Aug 2004

JWG C4.1.01: Power Quality General Aspects - Key deliverable (2005): Flickermeter test protocol (Electra paper) - Decision to terminate in 2006 due to TC limit of 3 years - Proposed scanning function to be continued as TG under AG C4.1 TF C4.1.02: Voltage Dip Evaluation and Prediction Tools - Key deliverable (2006): Cigré broshure: simulation & analysis methods - Draft completed, extensive background provided JWG C4.1.03: Emission Limits for Disturbing Loads - Key deliverables (2005/6): Reports to IEC 77A/WG8, Electra paper - Draft 10 of IEC revision (harmonics) completed, provided to IEC - Drafts 2 IEC revision (flicker), new doc on unbalance completed - Work on emission limits from LV installations started - Review of WG progress on CIRED Apha 2 session (Mark McGranaghan) AG C4.1. Power Quality Existing WG’s/TF’s

AG C4.1. Power Quality JWG C4.1.05: Technical Performance Benchmarking Guidelines - Transmission & Sub-transmission systems - Practical application of TB261 recommendations - Internal indices (e.g. availability / line fault rates) - Peer group selection - Guidelines not actual benchmarking JWG C4.1.06: PQ Instrument Test Protocols - Test protocol for IEC instrument (mainly Class A) - Practical application JWG C4.1.07: Economic Framework for Voltage Quality - Voltage quality (including dips & short interruptions) - Methodology - Indicative costs were possible New WG’s/TF’s

ECONOMIC FRAMEWORK FOR VOLTAGE QUALITY Scope  To estimate the cost of power quality to companies and their customers.  Review and document the economic implications of the PQ parameters: voltage dips, short interrupt., and voltage waveform quality  Review and document methods of assessing these costs that have been used to date, including aspects such as:  Direct and indirect costs to customers (e.g. production losses and plant damage).  Energy losses associated with poor PQ.  Cost of energy not supplied  Methods of collecting customer costs.  Actual customer costs collected to date for various industry sectors.  Propose a standardized method of collecting the above information, based on the experience of various international studies.  Recommend a methodology of using this data to cost and motivate PQ interventions on the power system or within the customer plant.  Provide indicative costs for specific industry sectors, where possible.

AG C4.1. Power Quality TF C4.1.08: Review Of Flicker Objectives - HV,MV&LV Systems - Review international measurements - Review propagation of flicker - Recommendation of revised objectives JTF C4.1.09: Emission Assessment Techniques - Review practical application of CCU2 guidelines published a few yrs ago - Introduction of guidelines for unbalance emission assessment WG C4.1.10: Dip Immunity of Equipment - Customer Installations - Classes of dip performance for various equipment types - Based on data collected on test conducted around the world - Specification guidelines New WG’s/TF’s

REVIEW OF FLICKER OBJECTIVES FOR HV,MV & LV SYSTEMS Reason for such a TF  In practice, many companies report significantly higher flicker levels at some sites in their power systems with no associated customer complaints. At the same time, customers supplied by these power systems are concerned about the significant costs associated with meeting flicker limits based on these objectives. This raises questions on the compatibility levels used, particularly on EHV, HV and MV systems, where LV customers are not directly connected. Past work of C4, reported in TB 261 (Power Quality Indices and Objectives), as well as present work in both JWG C (Emission Limits for Disturbing Installations) and IEC 77A/WG8 have highlighted the need for these flicker objectives to be studied further. Several specific considerations have been highlighted which may explain the lack of complaints. These should be considered in more detail by this TF. The proposed scope of the task force is to:  Document a careful review of international experiences with measured flicker levels and corresponding complaints, taking into consideration key technical issues such as:  Where the flicker levels were measured (LV, MV, HV, or EHV – as well as the “upstream” v.s. “meshed” point in the network defined in TB 261)  Possible errors in the flicker measurement itself (e.g. flagging of dip events that may not have been excluded from the flicker measurement)  Information on customer complaints – what was the methodology for collecting this?  The time of day that the flicker source was operating v.s. the time at which most customers would have been sensitive to flicker levels  Document the results of the latest studies on flicker propagation, taking into consideration factors such as:  Actual measurements of transfer factors from EHV to HV to MV to LV.  The impact of different types of loads on the LV and MV systems  Impact of the type of flicker source and sequence components on the propagation of flicker (e.g. the lower negative sequence impedance of motors)  Summarise the findings of international studies on flicker impacts on new lighting technologies.  Based on the above, to recommend revised LV compatibility levels, characteristic levels (MV,HV,and EHV), and HV/MV/LV transfer ratios.

temporali  fulmini ma anche  vento  rami spezzati  … Anche in ambito CIGRE

Meinberg GPS 168-PCI:  accuracy of ±250 ns NI DAQ 5112 digitizer:  12-bit  sampling frequency of 100 MS/s  accuracy of ±1%  storage capability of 16 MB Pearson VD-305A:  300 kV peak  nominal ratio 10 kV / 1 V  bandwidth 30 Hz ÷ 4 MHz (-3 dB)  rising time 100 ns  accuracy ±1% Progetto FULCOR Obiettivo: correlare eventi atmosferici rilevati dal CESI-SIRF a guasti o disturbi all’interno di sistemi elettrici di distribuzione tramite l’utilizzo di sistemi distribuiti di misura e accurati codici di calcolo (LIOV-EMTP). Progetto FULCOR Obiettivo: correlare eventi atmosferici rilevati dal CESI-SIRF a guasti o disturbi all’interno di sistemi elettrici di distribuzione tramite l’utilizzo di sistemi distribuiti di misura e accurati codici di calcolo (LIOV-EMTP).