%0 Generic %1 papneja2015measurement %A Papneja, G.S. %A Pikisch, Moritz %D 2015 %K & Compensation Coupling Earth Factor Fault Impedances Mutual Positive Sequence Zero factor %T Measurement of Line Impedance and Mutual Coupling of Parallel Lines to Improve the Reliability of Protection System %X The impedances of overhead transmission lines and cables are needed for distance protection, fault locators and power system calculation. Inaccurate line impedances can cause malfunctions of distance protection, wrong displayed fault locations and faulty calculation results. The required values in symmetrical components are the positive sequence impedance, the zero sequence impedance and the zero sequence coupling impedance (only for double circuit lines). These parameters can be determined by measurement or by calculation. The calculation of line impedances is based on ideal geometrical assumptions like homogeneous ground resistivity and continuous line geometry. Varying ground resistivity, buried conductors and a missing earth conductor between two towers are not considered in the idealized impedance calculation, although they have a strong impact on the real line impedance. Therefore, the calculation method does normally not provide capable and accurate results which allow reliable protection settings and fault location. A high accuracy of line impedance values can be received by measuring line impedances instead of calculating them. Accurately measured zero sequence impedances allow reliable and correct operation of distance protection and fault locators. Measurements have shown that in a significant number of cases the k factor of the measured lines is deviating more than 20% from its actual value. This can result in zone under- or overreach and consequently, the selectivity is lost. This paper presents an advanced method for measuring the transmission line impedance. Based on these measurements, the relevant parameters for distance relays are calculated like the positive sequence and zero sequence impedance values, as well as the grounding (K) factor.

@conference{papneja2015measurement, abstract = {The impedances of overhead transmission lines and cables are needed for distance protection, fault locators and power system calculation. Inaccurate line impedances can cause malfunctions of distance protection, wrong displayed fault locations and faulty calculation results. The required values in symmetrical components are the positive sequence impedance, the zero sequence impedance and the zero sequence coupling impedance (only for double circuit lines). These parameters can be determined by measurement or by calculation. The calculation of line impedances is based on ideal geometrical assumptions like homogeneous ground resistivity and continuous line geometry. Varying ground resistivity, buried conductors and a missing earth conductor between two towers are not considered in the idealized impedance calculation, although they have a strong impact on the real line impedance. Therefore, the calculation method does normally not provide capable and accurate results which allow reliable protection settings and fault location. A high accuracy of line impedance values can be received by measuring line impedances instead of calculating them. Accurately measured zero sequence impedances allow reliable and correct operation of distance protection and fault locators. Measurements have shown that in a significant number of cases the k factor of the measured lines is deviating more than 20% from its actual value. This can result in zone under- or overreach and consequently, the selectivity is lost. This paper presents an advanced method for measuring the transmission line impedance. Based on these measurements, the relevant parameters for distance relays are calculated like the positive sequence and zero sequence impedance values, as well as the grounding (K) factor.}, added-at = {2021-02-10T14:59:38.000+0100}, author = {Papneja, G.S. and Pikisch, Moritz}, biburl = {https://www.bibsonomy.org/bibtex/2c6ba119504dbd314afbe2162ce2489f2/ceps}, interhash = {a7f19d6b1dcacc76b67a6bb2bb2afd9f}, intrahash = {c6ba119504dbd314afbe2162ce2489f2}, keywords = {& Compensation Coupling Earth Factor Fault Impedances Mutual Positive Sequence Zero factor}, timestamp = {2023-12-20T14:33:31.000+0100}, title = {Measurement of Line Impedance and Mutual Coupling of Parallel Lines to Improve the Reliability of Protection System}, year = 2015 }