Abstract
An appropriate method is proposed for identifying permanent faults from transient faults in double-circuit transmission lines. This method could be used in adaptive single phase auto-reclosures in order to diagnose between permanent and transient faults, determine extinguishing time of the secondary arc, and calculate issuing time of reclosing commands during the occurrence of transient single phase to ground faults. The proposed method is based on harmonic analysis of the adjacent healthy circuit and could be an effective solution for blocking permanent disconnection of the power flow, improving stability, and maintaining the power network synchronism. In this paper, transient and permanent faults are simulated on a typical power system, and then current harmonics of the healthy circuit terminal are extracted and finally the proposed index for identifying the fault type is applied. In the case of transient faults, this method determines the minimum time needed for a fast successful adaptive reclosing in the network and thus prevents instability and nonsynchronism in both sides of the transmission line. Results of the various simulations run in EMTP-RV verifies accurate performance of the proposed approach.
Highlights
Single line to ground (SLG) faults in transmission lines (TLs) are classified into two types: permanent and transient
The authors in [27] differentiated between arcs and categorized them into two types: 1) primary arcs occurring during the short circuit SLG fault and 2) secondary arcs resulting from capacitive coupling between healthy and faulty phases
In this paper, a new approach is proposed for recognizing permanent faults from transient faults
Summary
Single line to ground (SLG) faults in transmission lines (TLs) are classified into two types: permanent and transient. Another strategy for adaptive single phase auto-reclosure in TLs equipped with a shunt reactor is presented in [12] This approach is based on the difference between the current calculated through the transient fault model and the real current measured in the faulty phase of the shunt reactor. An accurate solution for detecting the fault type and estimating the secondary arc extinguishing time is proposed These two operations are based on a new index using the harmonics of healthy TL current. In addition to its high accuracy and speed, the proposed method does not require any threshold level, neither for fault type detection nor for determining the extinguishing moment of the secondary arc (the moment of issuing the successful reclosing command), and it is suitable for any type of double-circuit TL.
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