Current mapping strategy for improving two-terminal series-compensated line current differential protection

• Published in: Electric power systems research 2021-07, Vol.196, p.107243, Article 107243
• Main Authors: Bainy, Rômulo G., Silva, Kleber M., Johnson, Brian K.
• Format: Article
• Language: English
• Subjects: Differential protection; Generalized alpha plane; Power system; Protection; Series compensation; Transmission line
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2021.107243

•The current mapping strategy (CMS) can improve the performance of differential protection of series-compensated transmission lines compared to the regular alpha plane.•The protection engineer can adjust the CMS according to the desired emphasis (i.e., sensitivity or security).•The CMS operates correctly even under severe outfeed conditions or subsynchronous oscillations.•Transient studies and 1340 simulations with different pre-fault and fault conditions proved the effectiveness of the CMS. This paper presents a particular case of the generalized alpha plane called current mapping strategy (CMS) formulation applied to differential protection of series-compensated transmission lines. The proposed formulation presents two unique features, control over the internal fault settlement region (FSR) and the use of an operation characteristic (OC). The FSR and the OC are two concentric circles defined on the alpha plane. Additionally, the proposed CMS allows the user to adjust the center and radius of the FSR and OC, according to the desired sensitivity and security of the protection. To validate and test the performance of the improved CMS, numerous computer simulations have been carried out using the Alternative Transients Program (ATP) on a 400 km long series-compensated, 500-kV transmission line. Furthermore, analysis of an extensive database of cases is conducted to highlight the CMS’s sensitivity. The obtained results demonstrate the effectiveness of the settings of the CMS and a smooth trajectory to the FSR. The CMS also proved to be stable and reliable even under severe subsynchronous oscillations and outfeed conditions.