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Locating high-resistance grounding faults poses a tough and challenging problem for the safety of DC railway systems. High-resistance grounding fault current isn't sufficient to trigger switches, which may expand the accident or turn into potential hazards. In order to overcome the limits of the existing methods (such as signal injecting method, resistance method and so), developing a novel fault...
Pantograph of an en-energized train may never run through n neutral section. As it does so, the arc generated across the pantograph will likely short the two feeding lines together at both sides of the neutral section where two phases are separated, The fault is called out-of-phase short-circuit fault for which short two out-of-phase feeding lines. Traditional feeder distance protection and current...
Modern power supplies must provide reliable, high-quality power. Therefore, it is important that a transmission line fault be identified accurately, reliably and corrected as soon as possible. A method for classifying fault type based on short time Fourier transform (STFT) is provided in this paper. STFT is a means of signal processing in which a Fourier transform (FT) is performed by setting a window...
Most of current arc suppression coil compensation system works based on the magnitude of post-fault distributed capacitance. This system can not offer compensation before fault, so in power system with large distributed capacitance current, short circuit shock is inevitable. This paper proposes an automatic arc suppression coil compensation technology based on fixed-frequency signal injection, it...
Historically, the distribution network has been planned in order to operate in radial configuration. Protective relays are adopted to detect system abnormalities and to execute appropriate commands to isolate swiftly only the faulty component from the healthy system. Nowadays, the regulation schemes implemented by Regulators require that Distribution Companies reduce number and duration of supply...
A new method for detection occurrences of CT saturation is presented in this paper. The presented algorithm applies only first order derivatives of signals which is possible it has been designed in a new innovative methodology in which phase current signals are considered as coordinates of a 3D vector. The proposed algorithm is compared with standard one applying secondary current signal combined...
Although there has been a practice of transposition of transmission lines, most of the real life EHV/UHV lines are untransposed. The distance protection of such lines becomes very complicated. With the advent of Global Positioning System (GPS) and Fiber optics technology, current differential protection can be a better choice for such lines. This paper proposes current differential protection scheme...
A transient fault information based IED integrating protection fault location, fault record, measurement and control functions for transmission line is proposed in this paper. IED hardware scheme adopts multiple CPU distributed structure, and includes mainly the following modules: process level communication module, protection module, fault location and record module, measurement and control module,...
A large-scale implementation of distributed generation (DG) for households involves each house generating its energy from photovoltaic (PV) cells. This approach is particularly suitable in rural electrification projects where demand is relatively low and yet grid connection is costly. A meshed microgrid is an attractive solution for energy generation and sharing in domestic electrification projects...
This paper proposed a new power grid fault diagnosis model combining Petri nets and grid computing. It includes the power grid computing system's structure, software service and algorithm. The model can use the high performance computing method and distributed environment of grid computing. At the same time, Data grid system can offer table, efficient and unified information resources for the power...
This paper presents a combined method for discrimination between inrush current and internal fault current of power transformers. The mentioned method is based on wavelet analysis of power system frequency which is estimated by Prony method. The Prony method is utilized to estimate power system frequency with three consecutive samples rapidly and also Daubechies wavelet family uses the estimated frequency...
This paper presents the measured impedance at the relaying point in the presence of Static Var Compensator (SVC), one of the shunt connected Flexible Alternating Current Transmission System (FACTS) devices; in the case of inter phase, phase to phase and three phase, faults. The presence of SVC on a transmission line has a great influence on the measured impedance at the relaying point. In the presence...
This paper describes how increased functionality of the Network Rail Integrated Protection and Control (IPC) extended IEC 61850 station bus solution unlocks the ability to rationalise the electrification system design, and hence achieve a substantial reduction in primary plant requirements when delivering the new railway electrification schemes committed by the Government.
The project to install new cables in the Woodhead Tunnel forming part of National Grid's (NGET) 400kV transmission system running across the Pennines, requires a state of the art cable monitoring and protection system. The availability of IEC61850 offers the opportunity to provide a simple but effective system in an early long haul application.
This paper presents the results of the analysis of a vast fault records database. The fault records were obtained during numerous experiments performed from 2005 to 2011 in real resonant-earthed distribution networks. The purpose of these experiments was to provide data either for verifying distribution network safety during earth faults or for testing methods of earth fault location or elimination...
Autoreclosure provides a means of improving power transmitting ability and system stability. The conventional reclosure adopts the fixed dead time interval strategy, that is, the reclosure is activated after a time delay to restore the system to normal as quickly as possible without regard to the system conditions; however, these simple techniques cannot give the optimal operating performance. For...
This paper deals with line protection challenges experienced in system having substantial wind generation penetration. Two types of WTGU: Doubly Fed (DFIG) and Squirrel Cage (SCIG) Induction Generators are simulated and connected to grid with single circuit transmission line. The paper summarizes analytical investigations carried out on the impedance seen by distance relays by varying fault resistances...
This paper presents a new multi-criteria stabilization algorithm of transformer differential protection. Proposed scheme bases on new criteria signals and appropriate operation thresholds. New algorithm employs fuzzy reasoning technique for better discrimination of inrush conditions. The developed stabilization algorithm has been tested with ATP-EMTP generated signals, proving to be reliable and much...
The new generation of current sensors, such as Rogowski coils, have performance characteristics that can improve design and operation of modern power systems. This paper presents novel solutions that integrate protection, control, and metering functions for power transformers and cables by sharing signals from the same Rogowski coils.
Decentralized Energy Resources (DER) and especially wind farms became a challenge for protection, automation and control in the grids. Transmission system operators as well as distribution system operators require tests of Loss of Mains and other decoupling protection functions. In some countries certification of these functions is required. The units are equipped with a huge amount of internal protection...
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