# Power Quality Impact and Its Assessment: A Review and a Survey of Lithuanian Industrial Companies
## 2 Literature Review
### Environmental Impact
the family _Christitika_ are also regularly observed in Lithuan: stock down (Columbic consis), Eurasian collured above (Strategpitka facancis), European turtle drove (Strategpitka facancis). 11 The only species within the genus _Christika_ probably observed in Lithuan. It was previously placed in the genus _Larus_. 15 Further, the following species of the family _Rallistic_ are also regularly observed in Lithuan: coma craka (_Cra cry_), common momentum (Gottlma christipa), spotted craka (_Vorana pretrans_), water (_Iallistic_ (_Sut  
Moreover, there is also the reverse effect, when animals are not responsible for PQ events but nevertheless are killed. In addition, carcasses of killed animals attract the others, which obviously can and will touch a fallen wire as well [64; 65; 66]: for example, [64] describes the electrocution of both a fox and a bear by a fallen power transmission line in the Russian taiga [65], describes the electrocution of six animals (a rhino, a giraffe, two lions, and two hyenas) in South Africa after storms toppled a power cable, and [66], which is based on the video material of [67], describes the electrocution of foxes (Figure 5b) and other mammals (Figure 5c). Figure 5: Fauna of Lithuania in the spring of 2024. (**a**) White stork (_Ciconia ciconia_); (**b**) Red fox (_Vulpes vulpes_); (**c**) European moose (_A. alces alces_). by a fallen power line due to Russo-Ukrainian War. As mentioned in [1; 2; 8], in Lithuania, such electrocution is possible even under more ordinary conditions: a single-phase fault of an overhead power line of the MV grid can last several hours (until the fault node is physically detected by the electrician brigade, because the resulting voltage unbalance do not propagate through the power transformers [2]), and the contact with such a fallen wire is fatal not only for humans but also for local fauna (Figure 5). One more aspect to discuss is wildfires. Power grid faults can generate sparks and thus initiate wildfires [68; 69; 70; 71], and even though these faults are not the main cause, this does not devaluate its significance. According to [68], in the Australian State of Victoria, \"powerlines cause only 2-3% of all rural fires\" under normal conditions, but under extreme fire risk conditions, \"this contribution increases dramatically to up to 40-50%\". According to [69], in 2011-2015, electrical power or utility lines caused 14% of all wildfires in the United States, and in 2017-2022, electrical power caused 9% of all wildfires in California (which cannot be directly compared to the aforementioned 14% due to different evaluation practices) but their financial impact was equal to 67%. Probability of ignition depends on such factors as arc duration, wind speed, fuel type (organic matter), and fuel moisture content [72]. Potential causes of fire, not to mention lightning strikes, include many primary causes of PQ events examined in [2], which first cause RMS variations and then other related phenomena--voltage transients and voltage unbalance. From our point of view, these causes can be divided into two groups:  
1. Vegetation-related faults. These faults are caused by the interaction of wires with trees and bushes. It is not a secret that among the measures to reduce the impact of vegetation are condition monitoring and surveillance of electricity grid infrastructure, vegetation clearing, as well as replacing overhead power lines with underground cables. In Lithuania, according to the statistical data of 2015-2018 provided by [2], the expected annual rate of interaction between the 10 kV grid and a tree outside the safety zone is 845, the interaction with a tree inside the safety zone--95, shrub grow-in events--117, and tree branch drop events--160.