Fault‐location accuracy in resonant‐earthed medium voltage systems swegrids-logo

SweGRIDS research area CIPOWER Controllable Power Components
SweGRIDS project code CP23
Project type PhD
Status running
Researcher Md Zakaria Habib   (webpage)
University KTH (EME)
Project period 2017-03-24 to 2021-09-30   
Project supervisor Nathaniel Taylor   (webpage)
Industrial sponsors Vattenfall, Ellevio, ABB

back to project index

Project abstract

Challenge: Characterize the accuracy of present methods for location of earth faults in resonant-earthed MV networks. Define what features of the present networks and location methods (in Sweden) are the main limitations to this accuracy, so that improvements can be made in the most efficient way. Design a method that take advantage of modern sensors and communications: the main criterion is accuracy, but other important properties are robustness, cost of implementation, sensitivity, and speed. Resonant earthing systems have been studied and refined for a long time, but recent “game-changing” developments open new scope: time-stamped measurements from small, self-powered sensors can now be obtained and transmitted at low cost. It is therefore of interest to determine the type and position of measurements that most efficiently improve fault location, and thus whether accuracy could now be improved at modest cost.

Summary of work

Different operation philosophies of resonant-earthed distribution systems, as well as the fault location principles, have been studied in the first stage of the project in order to identify the limitations of the existing solutions. The existing fault location strategies can be broadly divided into two categories. In one category, the strategy is to calculate the distance of the fault location from the primary substation. It requires comparatively less number of device installations which is economically attractive. However, the fault location accuracy is highly sensitive to fault resistances, measurement errors and network parameters. In the second category, the strategy is to segmentize the whole feeder and locate the faulty section. This strategy requires the installation of several devices in the network. Most of the cases, the length of the faulty section depends on the positioning of the installed devices. Any improvement in the location accuracy requires the installation of more devices which makes the strategy economically less attractive.

The influence of these two major fault location strategies on the SAIDI of a network has been studied. The study shows that installing costly devices (using the second category) can provide better improvement in SAIDI than a cheap fault locator with very poor accuracy (the first category). The requirements of voltage measurements, high-frequency measurements, time synchronization etc. are few reasons behind the increased cost of the devices that are used in the second fault location strategy.

In this project, two current based location methods are proposed that locate the faulty section through segmentation of the faulty feeder. The first method uses the faulty phase as the reference to remotely calculate the current-phasors and determines the direction of the fault current. The method shows good performance for resistive faults, highly loaded conditions, undercompensated networks but a weakness for the feeders with a large charging current. Therefore, this method is good for the feeders with overhead lines but not promising for the feeders with underground cables.

The second proposed method works on the incremental values of the phase currents. It checks the change in phase current magnitudes of the three phases due to earth-faults and compares them to determine whether the measurement location is on the fault passage or not. This method shows promising results in various difficult conditions. Its performance has been tested for network asymmetry, measurement errors, high fault resistances, zero active current from the transformer neutral etc. A decision-making algorithm is under study that the device would be able to take decision independently and remotely (i,e, no need of transferring large data for central analysis to determine the fault passage). Further study will be done to check the transient behaviour of the proposed solution.

Event log

2017: Presented an overview of the project at the Nordic Workshop in Power System Protection at NTNU, Norway

2018: Presented a summary of the existing fault location methods at the Nordic Workshop in Power System Protection at KTH, Sweden

2019: Presented a potential phasor based solution of the earth-fault location at the Nordic Workshop in Power System Protection at University of Vaasa, Finland

2019: Attended the 25th International Conference on Electricity Distribution (CIRED), at Madrid, Spain

2020: A current based proposed solution was presented at the IET 15th International Conference on Developments in Power System Protection (DPSP) at Liverpool, United Kingdom

2020: Impact of two major fault location types on the SAIDI of a network was presented at the IEEE International Conference on Power System Technology (POWERCON) at Bangalore, India (Virtual Conference)

2020: Submitted a journal article at ELSEVIER-EPSR (Electric Power System Research)

Project reference-group

Daniel Wall,  Vattenfall
Andrew Kitimbo,  Vattenfall
Erik Lejerskog,  Ellevio

Publications by this researcher

See alternatively the researcher's full DiVA list of publications, with options for sorting.
Publications in journals and conferences usually will not show until a while after they are published.

Cross-Country faults in resonant-grounded networks : Mathematical modelling, simulations and field recordings
Gabriel Miguel Gomes Guerreiro,   Z. Gajic,   S. Zubic,   Nathaniel Taylor,   Md Zakaria Habib.
2021,   Electric power systems research, vol. 196

Impact of the fault location methods on SAIDI of a resonant-earthed distribution system
Md Zakaria Habib,   Md Tanbhir Hoq,   Sanja Duvnjak Zarkovic,   Nathaniel Taylor.
2020,   2020 IEEE International Conference on Power Systems Technology, POWERCON 2020, 14 September 2020 through 16 September 2020

A Current-based Solution for Earth-fault Location in Resonant-earthed Medium-voltage Distribution Systems
Md Zakaria Habib,   Mohamed F. Abdel-Fattah,   Nathaniel Taylor.
2020,   The IET 15th International Conference on Developments in Power System Protection (DPSP)

Reliability Assessment of Protection Schemes for Series Compensated Transmission Lines
Md Tanbhir Hoq,   Md Zakaria Habib,   Ebrahim Shayesteh,   Nathaniel Taylor.
2019,   4th International Conference on System Reliability and Safety (ICSRS), Rome, Italy, November 20-22, 2019

Phase Shift Compensation Method for the Line Differential Protection on UHV-AC Transmission Lines
Md Zakaria Habib,   Jianping Wang,   YouYi Li,   Nathaniel Taylor.
2018,   The IET 14th International Conference on Developments in Power System Protection

Distributed Secondary Frequency Control Considering Rapid Start Units Using Alternating Direction Method of Multipliers
Muhammad Talal Khan,   Md Zakaria Habib,   Elin Karlsson,   Davood Babazadeh,   Lars Nordström.
2016,   Workshop on Modeling and Simulation of Cyber-Physical Energy Systems, MSCPES 2016, Hofburg PalaceJosefsplatz 3Vienna, Austria, 11 April 2016 through

Publication list last updated from DiVA on 2021-09-18 22:00.

back to project index

Page started: 2016-12-01
Last generated: 2021-09-18