Supply Reliability Statistics in Austria / Germany

Supply Reliability Statistics in Austria / Germany

Question 12.1What are the actual practices in order to collect reliability data and compute the reliability indices? What are the most frequently used indices? What are generally the requirements of the regulating authorities?

Both in Austria and in Germany, the statistical schemes for the collection of reliability data are oriented at the results of the DISQUAL working group. In both countries (starting in Germany in 2004 with an updated scheme), all three DISQUAL indices – frequency of interruption, mean duration of interruptions and non-availability – can be calculated from the recorded data.

In Germany, as there is currently no regulator (which will be installed by July 2004), the only available statistic is the voluntary statistic of incidents of the Association of German network operators (VDN – Verband der Netzbetreiber). The recording scheme will be updated to include a detailed description of supply interruptions in MV and LV networks starting 2004.

In Austria, the data has to be delivered by all network operators to the regulator (E-Control GmbH). Additionally, the Austrian Association of Electricity Utilities (VEÖ – Verband der Elektrizitätsunternehmen Österreichs) maintains an voluntary and more detailed statistic. An additional index, the energy not delivered in time, was characterized as the most comprehensive indicator by the regulator (E-Control GmbH). It will be used as the basis for a monetary evaluation of supply interruptions which will be developed in the future.

However, in the recent and ongoing activities concerning supply reliability statistics, several key aspects have been identified which pose problems:

• Many indices are customer-oriented, but the detailed definition of “customers” is difficult and not at all comparable between different network operators or even internationally,
• as a basis, the rated power of transformers is used, which leads to several problems in recording the data (e.g. with customer stations) and to systematic distortions for special operating situations (e.g. cable cars which do not operate in summer),
• monetary evaluation requires a very detailed documentation of the network structures, the customer-specific registration of supply interruptions and an agreed assessment of interruption costs,
• there is a strong need for more detailed definitions on a European level in order to allow the international comparison of reliability data.

Question 12.2Do DNO use some dedicated software to analyse and predict the reliability of their network and study the influence of the network structure, planning and development strategy? Which software is used?

There are several dedicated software tools for different tasks in the field of supply reliability. For the recording and analysis of reliability data, e.g. the tool INTERASS is used with many DNOs in Austria and Germany. For probabilistic reliability analysis, especially the tools RAMSES and ZUBER, which are available as modules with several network calculation platforms, are used.