# Power Quality Impact and Its Assessment: A Review and a Survey of Lithuanian Industrial Companies
## 2 Literature Review
### Economic Impact  
The economic impact of PQ can be direct and indirect: (1) direct cost includes loss of production during continuous operation, loss of resources and time, waste in semi-finished production, restart of process, equipment damage, costs associated with human safety and health, environmental financial penalties, as well as utility costs due to interruptions; (2) indirect cost includes the costs due to production delay and the financial cost of loss of market share [19; 20; 21]. Each factor depends on the user and its technological process and has a different weight. It also depends on the PQ phenomenon. For example, according to the information reported by [22] (2007), in the case of the annual energy consumption of 1-5 GWh, the total annual loss experienced by the three Slovenian industrial companies due to voltage sags was EUR 180,000 (i.e., on average EUR 60,000 per company) at the prices of either 2007 or earlier year, EUR 800,000 by the eight companies due to short interruptions, EUR 40,000 by the one company due to harmonics, EUR 100,000 by the two companies due to voltage transients, in the case of the annual consumption of 5-25 GWh, EUR 1,380,000 by the four companies due to short interruptions, in the case of the annual  
Figure 2: A look at PQ through the prism of sustainable development. consumption exceeding 25 GWh, EUR 760,000 by the five companies due to voltage sags, EUR 950,000 by the eight companies due to short interruptions, etc. According to [23] (2012), the financial losses per voltage sag event suffered by nine United Kingdom industrial consumers at prices of either 2010 or earlier year were GBP 18,300 by the pulp and paper plant, GBP 152,500 by the metalworking plant, GBP 4366 by the food processing plant, GBP 15,250 by the textile plant, GBP 3,344,000 by the semiconductor fabrication plant, GBP 45,750 by the automotive assembly plant, GBP 30,500 by the chemical plant, GBP 61,000 by the equipment manufacturing plant, and GBP 18,300 by the plastic extrusion plant, and it was mentioned that the most sensitive equipment is AC contractors, variable-frequency drives, programmable logic controllers and personal computers. Other information from two sources about the economic impact of voltage sags at the prices of 2001 or earlier year is available in [24] (2022, p. 163): (1) until 2001, typical financial loss per voltage sag event suffered by semiconductor production business was EUR 3,800,000, EUR 6,000,000 per hour by financial trading, EUR 750,000 by computer centers, EUR 30,000 per minute by the telecommunications industry, EUR 350,000 by steelworks, and EUR 250,000 by the glass industry; (2) in the United States until 2001, the financial impact of one voltage sag event in paper manufacturing was USD 30,000, USD 50,000 in the chemical industry, USD 75,000 in the automobile industry, USD 100,000 in equipment manufacturing, USD 250,000 in credit card processing, USD 2,500,000 in the semiconductor industry, and the annual impact was over USD 20 billion. Perhaps it can be guessed that such losses nowadays should be lower due to higher industrial flexibility, a higher level of both grid automation and distributed generation penetration, and various other factors--this topic remains for further research. Let us compare the equations for estimating the financial impact of voltage sags and harmonics given in [19]. Although they both at first glance seem to be quite simple, their application in practice by evaluating all the technical and economic variables is not an easy task (which is one of the reasons for the lack of scientific literature on this topic). In the case of voltage sags, total financial losses for a consumer can be calculated by the following equation:  
\[TL=MV-CM-CE+AC, \tag{1}\]  
where \(MV\)--market value of products that could have been produced during downtime; \(CM\)--material cost that could have been used in production process; \(CE\)--energy cost that could have been used in production process; \(AC\)--additional costs suffered due to supply interruption.