Determination of Proper Angle Settings in Resistance Grounded Distribution Systems for Directional Earth Fault Relays (original) (raw)
Related papers
International Journal of Electrical Power & Energy Systems , 2012
Differential protection scheme is based on comparison of measured variables such as current and voltage at the two ends of a line via a communication channel such as pilot wire. This scheme is preferred and extensively used in distribution feeder protection system in Malaysia due to its fast operation. However pilot-wire differential scheme has its own drawbacks especially on the maintenance of the pilot-wire. Once the plot-wire is out of service, the feeder protection is jeopardised. One of the options to overcome such maintenance issue is to adopt directional relay as the feeder protection. This paper investigates a suitable relay connection and the maximum torque angle for the directional relay for 33 kV underground network. In this study, a section of 33 kV underground network in Kuala Lumpur (KL) city has been analysed. All faults types have been simulated at all possible location in the network. The obtained voltage and current were then used to determine the operation of directional overcurrent and earth-fault relay. The simulation results indicate that 30° relay connection with 0° maximum torque angle (30°/0°) is the most suitable setting to be applied for 33 kV underground network in KL, as against the best general and most versatile setting, 45°/90°. © 2012 Elsevier Ltd. All rights reserved. http://www.sciencedirect.com/science/article/pii/S0142061512000385
Optimal operational characteristics of directional earth fault protection
2017
The function of the directional earth ground fault protection is to protect against ground faults by selecting the output at the substation. Nowadays, ground faults are covered by this function protection, that may have low sensitivity. Given the large number of variables that influence the system, it is necessary to analyze their impact in order to reach an optimal setting. Highly resistive ground faults result in very low residual voltages and currents, but also an angle between them for different ground connections. This results in a drawback in the normal exploration of the MV network. The measuring devices’ errors and their electrical schemes used in the calculation of residual voltage and currents were the subject of study in this work. Moreover, a protection unit was tested in the laboratory to measure the loads of the voltage and current analog inputs. The adopted neutral regime and the variations between its characteristics overhead, underground and mixed lines were analyze...
2007
The purpose of this study is to asses the influence of current harmonic components (mainly third-order components) on the operation of a three-phase subtransmission system at 34.5kV, which employs as predominant load Single-Wire Earth Return (SWER) Systems, the detailed analysis of which is observed in some of Copel’s feeders. The disconnection of feeders ensuing from neutral overcurrent caused by opening the automatic reclosers that protect circuits that predominantly feed SWER systems has occurred at a certain frequency. Normally, this occurs due to the difficult load balance between the phases of the three-phase system. Thus, neutral trip adjustments have reached high stages, which affect the sensitivity and reliability of the protection system. The attempt to discover the cause of the aforementioned disconnection occurrences led to performing field tests and measuring endeavors, whereby it was possible to observe an extremely high third harmonic current, which is addressed in th...
Directional Earth Fault Protection for Transmission Lines – Need and Operational Experiences
— This paper attempts to bring out the necessity of activating directional earth fault protection in numerical distance relays and also highlights an operational problem with this protection in double circuit lines. These aspects are discussed with specific reference to two incidents taken place in 400 kV and 220 kV transmission lines emanating from Gas Insulated Switchgear (GIS) of 540 MWe Nuclear Power Plant and from 220 kV Out door Switchyard of 220 MWe Nuclear Power Plant respectively.
2016
This paper presents a new selective and non-directional protection method to detect ground faults in neutral isolated power systems. The new proposed method is based on the comparison of the rms value of the residual current of all the lines connected to a bus, and it is able to determine the line with ground defect. Additionally, this method can be used for the protection of secondary substation. This protection method avoids the unwanted trips produced by wrong settings or wiring errors, which sometimes occur in the existing directional ground fault protections. This new method has been validated through computer simulations and experimental laboratory tests.
Energies, 2015
This paper presents a new selective and non-directional protection method to detect ground faults in neutral isolated power systems. The new proposed method is based on the comparison of the rms value of the residual current of all the lines connected to a bus, and it is able to determine the line with ground defect. Additionally, this method can be used for the protection of secondary substation. This protection method avoids the unwanted trips produced by wrong settings or wiring errors, which sometimes occur in the existing directional ground fault protections. This new method has been validated through computer simulations and experimental laboratory tests.
Impact of GCSC on IDMT directional overcurrent relay in the presence of phase to earth fault
Serbian Journal of Electrical Engineering, 2013
This paper presents the impact of GTO Controlled Series Capacitor (GCSC) parameters on the Inverse Definite Minimum Time (IDMT) Directional Overcurrent Relay (DOCR) based on the International Electrotechnical Commission (IEC) standards. The DOCR is used to protect a single 400 kV transmission line of the Algerian transmission network which belongs to the Algerian Company of Electrical and Gas (Group Sonelgaz). The effects of GCSC on transmission line protected parameters as well as fault current and DOCR operation time in the presence of phase to earth fault with fault resistance are investigated considering three scenarios.
Effect of single phase to ground fault with arc resistance on the performance of distance relay
2011
Distance relay is the main protection of power transmission lines and make an important role in power system stabilization if it operates selective and instantaneous. In this paper, the trajectory of the fault impedance is determined. It is shown that in the end of the first zone or in the middle of the second zone, distance relay could not make a correct decision for operating if the fault occurs with arc. So to overcome this problem, in this paper a novel technique using total harmonic distortion (THD) is proposed. The proposed method makes the distance relay more selective and instantaneous.