PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 1 A Pre-Study Towards Investigating the Art of Choosing Right Level of Input Data Paper 125, PMAPS 2012, Istanbul June 12, Session 24 Carl Johan Wallnerström 1, Sabina Stenberg 2, Patrik Hilber 1, 1 Royal Institute of Technology – KTH, Stockholm, Sweden 2 Uppsala University / Svenska Kraftnät (Swedish national grid)

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 2 Background In many countries there is a tendency towards both an increased demand of cost-effectiveness and at the same time high reliability, e.g. as a consequence of quality regulations and/or mandatory customer compensations Important to investigate if the introduction of more comprehensive analysis methods are needed or not

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 3 Overall issue Collecting and using comprehensive input data in analyses is expensive, but using to rough methods could however give inaccurate results The aim of this paper is to provide a minor contribution (pre-study) to this major issue: – Highlight the potential problem of using mean values – Provide a method to evaluate existing methods used by DSOs to see if more detailed input data gives different results

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 4 Problem of using mean values Traditional reliability analysis applied to power distribution often use mean values All outages are not about mean length. Some outages are due to switching possibilities short, while some major outages can last >12 hours. This can be a problem if: – The mean consequence from all outages is not equal to the consequence of a mean outage, i.e. if the consequences are not linear dependent with outage length

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 5 Consequences of outages Overall economic consequence categories due to regulation/laws – current situation in Sweden: 1.Outages <0.05 hours: Currently no legal cost for the DSO, but should be reported separately (perhaps included in future version of tariff regulation) 2.Outages hours: Input to tariff regulations (SAIFI and SAIDI), can collectively affect tariff framework despite each customers individual reliability

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 6 Consequences of outages 3.Outages >12 hours: Mandatory individual customer compensation witch increases with time a)12-24 hours: First compensation level, 12.5 % of annual tariff (or min ~100 Euro) b)>24 hours: Higher customer compensation levels, but also since 2011 possible additional consequences followed by a 24 hour functional requirement due to the law An alternative strategy to only using mean values, that relatively easy can be implemented, is to divide outages into length categories

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 7 Consequences of outages

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 8 Evaluate methods at a DSO Current method at this DSO: – Quantitative, but with major simplifications – Measure the decresment of outages minutes, i.e. ~SAIDI*[num. of cust.] for each investment – Looking at a feeder at time, not consider dependences, only consider lines at MV level – Neglect contribution from underground cables – This methods gives an action list of project sorted by [cost]/[reliability improvement]

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 9 Evaluate method at a DSO Will a more comprehensive reliability analysis method give: 1.Another project priority? 2.Other kind of investments preferred? E.g. less focus on replacing OH lines with cables? 3.More or less investments that are profitable? 1 st question easiest to test

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 10 Approach to evaluate new methods Method idea: – Compare an existing analysis method with new methods without perform any sharp or expensive changes in the organization – The approach is to study already performed investments and then perform a hypothetical investment planning process based on more comprehensive reliability analysis and compare the outcomes – The next step, if positive outcome, can be a sharp pilot study of analysis method(s) and after that consider permanent changes

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 11 Closure Important issues are highlighted: – A tendency towards increased demand of cost-effectiveness on the one hand, and high reliability on the other more important to chose good analysis methods – The problem of using average values – The difficulty to chose right level of input data A method to investigate whether a more comprehensive analysis method give different outcome, without perform any sharp changes

PMAPS 2012, Istanbul June C. J. Wallnerström, KTH - Royal Insitue of Technology 12 Thank you for your attention!