An Iterative Two-Terminal Fault-Location Method Based on Unsynchronized Phasors

The railway distribution system is a neutral noneffectively grounded medium-voltage network. An advanced fault-location system for this distribution network, called the railway distribution network fault location system, is proposed in this paper. This fault-location system is based on tracing the superimposed signal and the work principle, simulation results, and field tests of the location system are presented. It is able to identify the fault location in a fast and accurate way. Compared with other conventional superimposed signal-based schemes, the system's performance is improved by employing the inject and fault-current detect sensor (IFCDS) to trace the fault signal and wireless to transmit detect information. The IFCDS, which permanently hangs on feeders, is based on the wireless sensor networks technology, so it can network automatically in a certain range, and improve the flexibility of the communication subsystem. Through analyzing the uploaded information by the fault-location computer in the substation, the fault point can be located. Issues of superimposed signals, such as optimal frequency choice, impact of tapped load, fault distance, and fault resistance, and so on are of concern. Through simulation in PSCAD/EMTDC, these issues are fully discussed. At last, the tests in the field show that the system has simple principle, high reliability, fast location speed (usually less than 15 min), and high accuracy (location error is less than 0.5 km).Index Terms-Fault location, neutral noneffectively grounded system, railway continuous transmission line (CTL), S-injection method, wireless-sensor networks (WSNs).

Section: Two Key Problems In S-injection Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved Fault-Location System for Railway Distribution System Using Superimposed Signal

Jun

et al. 2010

“…In marine power systems which have no exposed distribution cables it is difficult to remove or restore the faulted line sections without accurately knowing the fault position. Generally fault location schemes can be classified into two categories: based on impedance estimation [14]- [20] and based on traveling waves [21] [22]. Fault location schemes based on system impedance estimation have been developed for many years.…”

Section: Introductionmentioning

confidence: 99%

“…Double-ended schemes as described in [16], [17] present simple and robust fault location methods but a GPS based synchronization is required to produce accurate fault location results. In [18]- [20] fault location methods were investigated based on a system distributed parameter model which provided a higher accuracy compared with traditional impedance models (ignoring the shunt capacitance). However, the iteration calculation may bring more errors to the result considering the system noise and distortion and moreover a system with a non-linear load may not be suitable for this method.…”

Section: Introductionmentioning

confidence: 99%

Marine Power Distribution System Fault Location Using a Portable Injection Unit

Jia

Liu

Christopher

et al. 2015

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 1  Abstract--A portable injection unit for Active Impedance Estimation (AIE) is built and tested in a DC zonal marine power distribution system to provide useful information for system protection and restoration. The portable unit generates current "spikes" and injects them into the system once short circuit faults are detected (by measuring the system voltage drop). The faulted system impedance can be estimated by AIE and comparing the estimated impedance with the pre-calibrated value, the fault location can be determined. The proposed method does not rely on system fault transient information or communication from the remote-end measurement and offers fast and accurate fault location in DC marine distribution systems. The proposed method has been tested and validated on a 750V, 2 MW twin bus DC Commercial Test Facility with the system both de-energised and energised.

“…A two-terminal method by using unsynchronized voltage and current phasors based on the distributed parameter model is discussed by Johns et al [16]. The authors in [17] have proposed an iterative approach to improve the accuracy of the fault distance estimate and it does not require synchronization of measurements. Reference [18] relates the synchronized voltage and current phasors of the sending end and receiving end with parameters, from which the fault location is derived.…”

Section: Introductionmentioning

confidence: 99%

Double-Circuit Transmission-Line Fault Location With the Availability of Limited Voltage Measurements

Kang

Liao

2012

This paper presents a new approach for locating short-circuit faults on a double-circuit transmission line. Various algorithms have been proposed previously that usually require measurements recorded from one or two buses of the faulted line. However, such measurements may not always be available in some scenarios, rendering inapplicability of existing methods. To complement existing methods, this paper proposes a novel, general fault-location method by harnessing voltage measurements at one or more buses, which may not be taken from the faulted line. The bus impedance matrix of each sequence network with the addition of a fictitious bus at the fault point can be derived as a function of the fault location. The fault location can then be obtained based on the bus impedance matrix and voltage measurements. The distributed parameter line model is utilized. The network data are assumed to be available so that the bus impedance matrix can be constructed. When multiple voltage measurements are available, an optimal estimator capable of identifying bad measurement data is also proposed for enhanced fault location. Since field data are not available at this time, simulated data are utilized for evaluation studies, and quite accurate results have been achieved.Index Terms-Bus impedance matrix, distributed parameter line model, double-circuit transmission line, fault location, optimal estimator.