Setting Free Fault Location for Three-Terminal Hybrid Transmission Lines Connected With Conventional and Renewable Resources

Abstract

Three-terminal hybrid transmission lines (TTHTLs) are attractive from both environmental and commercial view. Hybrid transmission lines are growing due to urbanization, connecting an industrial load and renewable integration. A TTHTL comprises sections of both overhead lines and underground/subsea cables or overhead lines with different X/R ratios. Faulted section identification (FSI) is key for defining the adaptive/selective auto-reclosing scheme and estimation of the fault location for TTHTLs. In this paper, FSI and fault location algorithms are proposed without using the parameters of any line section. Novelty of the methodology lies in a two-stage approach to the problem. In the first stage, series impedance parameters of all the sections are calculated using closed loop formulae. These parameters are then utilized in identifying the faulted section. In the second stage, the above calculated line section parameters and faulted section are used to estimate complete line parameters including shunt capacitance and subsequently the fault location. The advantage of the proposed method is that it does not require an initial guess of the line section parameters, is non-iterative in the first stage, and provides correct fault section identification for TTHTLs. These features make it suitable for designing the selective auto-reclosing protection scheme for the TTHTLs within traditional protection relaying hardware. More importantly, the series impedance parameters calculated in the first stage constitute good initialization values for the non-linear problem of estimating the complete line parameters. This results in better convergence of the algorithm and accurate parameter estimation. The developed solution is verified using the PSCAD/EMTDC simulations for TTHTLs connected with conventional and different inverter-based renewable resources. The performance of the proposed solution is compared with commercially available solutions, and it is found to be accurate. This solution is amenable for implementation in line differential protection relays without additional infrastructural changes.INDEX TERMS Adaptive auto-reclosing protection scheme, inverter-based renewable resources, faulted section identification, fault location, parameter estimation, three-terminal hybrid transmission lines NOMENCLATURE A. VARIABLES

A ground fault location algorithm in double‐circuit transmission lines with T‐off connection to an industrial microgrid by using current and voltage phasors information of a single terminal

“…References [3][4][5][6][7][8][9] have addressed the issue of fault location in three-or more terminal transmission lines based on the impedance method in phasor domain using the synchronous data of terminals in different topologies. The studies proposed in this section can be divided into two separate categories based on the nature of the power sources connected to the terminals.…”

“…The designs presented in [3][4][5][6] neglect the effect of the nature of the power sources connected to the terminals. On the other hand, references [7][8][9] have considered this effect and model of power supplies connected to the terminals.…”

“…It uses the equations of positive-, negative-, and zero-sequence phasors governing the fault circuit and the boundary conditions of asymmetric and symmetric faults to find the distance of the fault from the terminals. And in continuation of these researches, reference [9] discussed a fault location algorithm in hybrid three-terminal transmission lines connected to an industrial microgrid containing distributed renewable generations. The proposed plan uses the synchronous information of the terminals and the distributed line model as well as the phasor equations governing the fault circuit to find the fault location.…”

Time-Domain-Based Distance Protection for Transmission Networks: Secure and Reliable Solution for Complex Networks

“…11(c)). modeling details are available in [43,44], in comparison with the performance of the existing phasor-based distance protection. Case 5: In-zone AB fault at 2% of the line: Consider a phase A to phase B fault at 2% of the line PQ from P, with 𝑅 𝑓 5Ω.…”

“…The wind generator control is modelled to follow Danish Grid Code [13], including reactive power injection during voltage dips according to the fault ride-through (FRT) characteristics. The complete modeling details are available in [43,44]. The proposed method operates reliably by issuing a trip signal for the in-zone fault and restraining for the out-of-zone fault.…”