Question 14.5

A well known recent CIGRE report [1] provides a wide comparative analysis of the customer's costs that in various countries worldwide are typically assigned to power supply interruptions. In particular, costs in currency/kW of interruptions of duration lasting from 1 min to 8 hours are analyzed in the report. The results are interesting and mainly show a not negligible variability of the costs reported for the different countries.The costs, obviously, much vary in function of the end-use segment as investigated. Concerning the industrial sector, the cost assigned in the majority of the investigated Countries to a 1 hour-interruption ranges between about 5 USD/kW and about 18 USD/kW. The cost referred for a 8 hours-interruption ranges between about 22 USD/kW and 58 USD/kW. Furthermore, some recent surveys performed in Italy [2] have evidenced costs of long interruptions that vary between 20 and 40 USD/kW.For what concerns short interruptions, an interesting report by EPRI [3] regarding costs as obtained from a wide survey performed in industrial customers in US, reports an average net cost (for the wide investigated sample) per outage of 1477 USD for a 1 second-interruption and of 2107 USD for a 3 minute-interruption.A recent survey performed in North Eastern Italy has evidenced that an approximate cost of about 0.5-1 €/kW can be attributed to PQ problems related to voltage dips [2].

Question 14.6

The limited experiences so far performed in investigating customer’s satisfaction concerning power quality issues evidence that adequate tutorial activities should be planned in advance of every initiative aimed at including customer’s satisfaction in practical initiatives of either regulators or distributors.

Question 14.7

In [2] some results of a questionnaire based survey enquiring customer’s satisfaction are reported. An overall quite good satisfaction has been obtained from the large majority of the customers as investigated. Outages remain the most visible problem but a high, and ever increasing with the automation level in the customers’ premises, sensitivity level has been found also for voltage dips. Still low is the customers’ perception of disturbances like harmonics that do not have any direct effects on the industrial process or supply continuity.

References

[1] R. Billinton et al., Methods to Consider Customer Interruption Costs in Power Systems Analysis, CIGRE Task Force 38.06.01Report, Paris, 2001.

[2] A. Prudenzi, S. Quaia, D. Zaninelli, Surveying PQ Aspects in Italian Industrial Customers, to appear in Proc. of 2003 IEEE/PES Transmission and Distribution Conference & Exposition, Dallas, Sept. 7-12, 2003.

[3] “The Cost of Power Disturbances to Industrial and Digital Economy Companies”, EPRI (CEIDS) Report, Palo Alto, CA, June 2001.