# Power Quality Impact and Its Assessment: A Review and a Survey of Lithuanian Industrial Companies
## 5 Discussion
### Survey as a Scientific Method
#### 5.2.1 Surveys Conducted on the Subject of PQ
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**Question** & **Result and Discussion** \\ \hline \multirow{4}{*}{Are you monitoring PQ in your network? Why do you do the monitoring?} & More than 90\% of respondents carry out monitoring due to customer complaints/requests, in second place is to maintain and prove standard compliance. In Lithuania, an important reason was also pressure from the National Energy Regulatory Council due to complaints from the Lithuanian Confederation of Industrialists \\ \hline \multirow{2}{*}{How many PQ monitors do you have?} & This question has already been discussed in [1]. An excessive number of PQ monitors is not cost-effective, and it is impossible to monitor every power grid node. Operators use both fixed and portable monitors \\ \hline \multirow{2}{*}{How do you choose which type of monitor to use?} & More than 80\% of respondents answered that PQ monitor must meet the standard requirements, and more than 50\% marked number of monitored channels, data output compatibility, cost, and ease of use (including both monitor and software) \\ \hline \multirow{2}{*}{What is important when you choose where to install permanent monitors?} & This topic is studied in detail by [1]. Most votes were for PQ polluting (57\%) and PQ sensitive (50\%) customers. Some respondents mentioned their aspiration to install monitors at all HV/MV substations, or at all points of common coupling \\ \hline \multirow{4}{*}{How many different manufacturers and types of PQ monitor do you use?} & The mode of answers is 2–3. The equipment (software) of different manufacturers has quite different functionality, but in essence must comply with EN 50160:2010: for instance, two different software are used in [8], and only one is able to display the entire voltage profile during the entire measurement period (but on the other hand, such functionality requires more computer resources) \\ \hline \multirow{4}{*}{What electrical parameters you mostly monitor?} & Long-duration RMS voltage variations received the most votes (89\%), followed by voltage sags and swells (82\%), harmonics (76\%), interruptions (68\%), etc. \\ \hline \multirow{4}{*}{What electrical parameters do you mostly monitor?} & In approximately 90\% of cases, all three phases are monitored: system current is monitored by 55\% of respondents, current of individual customers by 41\%, phase-to-ground voltage by 85\%, and phase-to-phase voltage by 50\%. According to [2,8], at the moment, there is not enough experience for making sophisticated decisions from few parameters, hence it is very beneficial to have a complete picture, despite the fact that EN 50160:2010 does not require to monitor current and both voltages \\ \hline \multirow{4}{*}{How do you store the output from your monitors?} & Despite the fact that computer progress over the past decade has been significantly higher than that of the PQ field, this question does not lose its relevance. Central PQ databases are used in 62\% of cases, but other options, such as to store the information in separate files and distributed storage, are used as well. In most cases, the monitor-bundled software is used for PQ data analysis, but sometimes there are another but not necessarily easier options, for example, to use MS Excel. In Lithuania, manually gathered PQ data are analyzed in the bundled software and is stored in files. Further questions are related to remote data collection, duration of storage, memory size of PQ monitors—some of them have already been discussed in [1] \\ \hline \hline \end{tabular}
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Table 31: Highlights and analysis of the international survey of [118].