Lysenko V. Using the zero sequence voltage statistical frequency characteristic for Petersen coil tuning

The objective of this work is improvement of the adjustment methods of capacitive current compensation device by considering impact of noise and interference in zero-phase sequence voltage. In this thesis actual theoretical and practical problem of increasing efficiency of the 6 - 10 kV electric networks by improvement adjustment methods of capacitive current compensation device (Petersen coil) was solved. The method of Petersen coil inductance adjustment was improved using new informational parameter - distribution of spectral density of zero-phase sequence voltage and frequency of maximum level of this spectral density, that made this method "passive" and allowed to avoid negative impact of artificial zero-phase sequence excitation. Artificial excitation of zero-phase sequence loop hastens the wearing of insulation and can lead to increased levels of overvoltage in the network, and thus leads to reduced durability and efficiency of electric network usage. As a result of experiments it was determined that in distributed networks with open-wire lines weather conditions e.g. strong wind may create significant interference with frequency 50 Hz. This interference may have negative impact on work of automatic Petersen coil adjustment devices, that are using phase or voltage amplitude of zero-phase sequence loop at 50 Hz frequency as informational parameter. Such interference may also affect on relay shield devices (like protection from one-phase to ground shorting). The efficiency of automatic adjustment device that is using new informational parameter - frequency of maximum level of spectral density of noise power in zero-phase sequence loop was confirmed by experiments and in practice by deployment on Kirov Electric Networks company.