Faults In Distribution Systems Research Articles

Faulty feeder detection based on the composite factors in resonant grounding distribution system

Faulty feeder detection of the single-phase-to-ground fault in resonant grounding distribution system (GRDS) is faced with huge challenge due to weak fault current, and the existing methods indicate low reliability in some situations. For improvement, a new method based on composite factors is proposed in this paper. The composite factor is composed of transient factor and steady-state factor which are defined respectively according to transient process and steady-state component in the fault zero-sequence equivalent network. The transient factor of faulty feeder is much greater than those of healthy feeders, and the steady-state factor of faulty feeder is a constant and also much larger than those of healthy feeders when the series resistance of Peterson coil exists. However, the steady-state factors of all feeders are equal to 0 when the series resistance is short-circuited. Thus, a threshold value is constructed. By comparing the composite factors and the setting threshold, the faulty feeder can be detected. The correctness and adaptability of the proposed method are verified by simulations under various fault situations, such as different transition resistances, fault initial angles, fault distances, Gaussian white noises and compensated degrees. The tested results of experiment platform based on RTDS prove the correctness and feasibility of the proposed method.

A two-level ANN-based method using synchronized measurements to locate high-impedance fault in distribution systems

This paper describes a new method for locating and identifying high-impedance fault in medium-voltage networks of unbalanced distribution systems, considering: load variation, reconfiguration, distributed generation, fault resistance variation, inaccuracy in feeders data, and protection devices operations. The method is based on artificial neural networks (ANN) and considers data from synchronized measurement units. Two sets of ANNs are created. The first set has the objective to identify the faulty area and the second set has the objective to indicate the distance between the fault point and the first meter of the area. The IEEE 123 Node Test System is used to validate the proposed method.

Event-Based Simulation of a Decentralized Protection System Based on Secured GOOSE Messages

A new simulation library is developed on OMNeT++ to model faults in distribution systems. The proposed library makes it possible to calculate the status of lines and busbars from the point of view of a protection system, enabling the modeling of overcurrents, power outages and fault passage indicators. The library is applied to model a decentralized protection system based on the exchange of IEC 61850 Generic Object Oriented Substation Events (GOOSE) messages between intelligent electronic devices responsible for the operation of circuit breakers and disconnectors. The time needed to secure and transmit GOOSE messages over the Internet is characterized and included in the model. Several studies are carried out to analyze the effect of different parameters, such as GOOSE retransmission times and failure rates of switching devices and communication channels, on the performance of the protection system.

Single-phase-to-ground fault section location in flexible resonant grounding distribution networks using soft open points

Resonant grounding (RG) distribution networks operate with low fault currents during single-phase-to-ground (SPG) faults. This mode offers a continuous power supply but causes intensifying fault location problems. Overcurrent relays fail to work, and most of the existing location methods are inapplicable. This paper proposes a method based on low-frequency signal superposition to locate SPG faults in RG distribution systems. In this method, a soft open point (SOP), a high-profile power electronic device applied in flexible distribution networks, is used as a signal superposition device, which enhances its existing functions of power and voltage regulation. It superimposes a 25 Hz symmetrical three-phase voltage onto the network after SPG faults occur. The 25 Hz zero-sequence currents along lines are subsequently gathered to determine the fault section. The main feature of the method lies in the adaptive current criterion for fault section location. The analysis of the zero-sequence currents in the low-frequency RG subsystem indicates that the criterion is not sensitive to line parameters, network structure, fault resistance or distributed generation. Comparative simulation tests with the S-injection method in PSCAD confirmed the validity and superiority of the proposed method.

Method for Protection of Single-Line-Ground Fault of Distribution System with DG Using Distance Relay and Directional Relay

When large scales DG are connected to the distribution system of unidirectional power currents, bi-directional power currents are formed, making it impossible to use conventional overcurrent protection methods alone to detect and isolate fault sections for ground and short-circuit faults. To solve these problems, this study proposed the method of protection against single-line-ground fault of common neutral line multi-contact local power distribution system using distance relay and directional relay. The proposed protection method was applied to the common neutral multi-ground distribution system to validate the protection against single-line-ground fault through the PSCAD/EMTDC software package and effectively detect and isolate only the zone of single-line-ground fault without malfunctions.

LWT Based ANN with Ant Lion Optimizer for Detection and Classification of High Impedance Faults in Distribution System

LWT Based ANN with Ant Lion Optimizer for Detection and Classification of High Impedance Faults in Distribution System

Research on Islanding Strategy for Fault Recovery of Distribution System with Micro-grid

In order to adapt to the actual situation of power distribution system fault recovery with micro-grid, a recovery strategy for micro-grid to operate on island with important system load at first under fault conditions is hereby studied. Due to the weak overload capacity, large fluctuation and obvious influence of weather and time period of renewable energy in micro-grid, the dynamic changes of distribution generation and loads in non-fault power loss areas should be considered as much as possible when generating islands. According to historical data, the daily random fitting functions of photovoltaic power generation, fans and various loads are respectively generated by using respective optimization models. For judging the start and duration of the fault, using the fitting function to set the fitting power value of each unit in the distribution system and other information, and calculating the dynamic importance information of each load node as the heuristic condition for subsequent island search. The search strategy in this paper is to guide the load added to the island according to the dynamic importance of the load, and to analyze the reliability of island operation. This method controls the direction of island search, and gives priority to ensuring the recovery of important loads. At the same time, it can ensure the balance between the stability of island generation and the maximum utilization of renewable energy.

Single-phase flexible arc suppression device based on BSC-SOGI-PLL method for distribution networks

The single line-to-ground (SLG) fault is a research focus, considering it is amongst the top frequent occurrences of faults in distribution systems. The neutral point treatment is crucial for continuous safe operation of distribution systems. However, the traditional arc suppression coil cannot compensate for the active component in ground current. Therefore, we present a single-phase flexible arc suppression device (SFASD) based on backstepping control and second-order generalized integrator phase-locked loop (BSC-SOGI-PLL) method. The SFASD with a cascaded H-bridge (CHB) topology is connected to the neutral point of distribution systems for eliminating the ground current. The comparisons between the BSC-SOGI-PLL and the BSC method concerning the effect of arc suppression are discussed. The effectiveness of the proposed SFASD based on the BSC-SOGI-PLL components for arc suppression is verified on the scale-down experimental platform.

The Differential Protection Scheme for Microgrid Using S-Transform

The micro-grids with distributed generators enhance the aggregate power supply to the increasing load demand. However, the conventional over current relay protection may fail to operate when magnitude and direction of current differs significantly in grid connected mode and islanded mode depending upon DGs types and generating capacity. This paper presents a differential protection scheme using S-transform for detection and phase identification of faults in distribution systems integrated with different types of DGs. A radial distribution system with photovoltaic and synchronous distributed generators is simulated for data generation in PSCAD/EMTDC software. The proposed technique is tested on various fault cases and confirms accurate detection of faults and correct identification of faulty phases within a cycle for a 50 Hz grid nominal frequency.

Development of a new methodology for detection of high impedance faults for using in distribution automatic reclosers

This paper presents the preliminary results of a new methodology for detecting high impedance faults in distribution systems based on interharmonic signatures. The methodology involves incorporation of an interharmonic current analysis system into a conventional protection system, such as automatic reclosers. To check the functionality of the proposed methodology, the authors carried out field tests on different types of soil, involving instantaneous current waveform measurements during the occurrence of faults. The results suggest that the methodology, based on interharmonic currents produced by variations in electric arc length during the occurrence of high-impedance faults, shows great promise when it comes to detection of the disturbance.

Application of Optimized Technique for Identification of Location and Recognition of Fault in Distribution System

Distribution network is the group of connected loads with number of buses and feeders. The different facial appearance is present in distribution system which makes it somewhat arduous and dissimilar to examine as estimated to a transmission system. Due to load uncertainties, the system effected with losses, faults, quality and discrepancies in power supply at distribution level. Now a days the identification of fault and its type as of conventional approaches is very complicated and calibrated dynamically is proposed in this work. This work narrates impedance-based fault calculation for its location and its type based on feeder distance between bus to bus for 3-phase 4-wire distribution system. The paper mix faults section detection with impedance-based method in order to address non-homogeneity of feeder parameters and power quality issues in distribution system. The 15-Bus and 33-Bus distribution test system is examined and estimated the fault and its type using Fuzzy logic using MATLAB.

Numerical method for islanding the location of ground fault in the material based distribution system

Nowadays the location of a ground fault and separating the fault segments are very complicated in the material based distribution networks because the reality to facilitate the fault current is really minute to be calculated. Considering the smart digital meters are installed in the distribution side voltage (11 kV) of the radial distribution systems through the advancement of the smart-grid. This paper presented an identification of fault location and islanding of fault segments using smart digital metering unit on the distribution network side. Generally, superior method is used to locate the faulted segments and the faulted negative sequence by connecting the association between measurement sets and distance of the fault. The proposed technology is experienced in India, a real-time 40-bus radial distribution system and the results provide that it is appropriate for a system with both inactive load demands. This technology does not need any management methods but it uses the wide-area measured data. Together with the breakers, the proposed methodology can locate and island the fault segments without disrupting the healthy distribution network process.

Temporary Fault Ride-Through Method in Power Distribution Systems with Distributed Generations Based on PCS

The current practice of Distributed Generation (DG) disconnection for every fault in distribution systems has an adverse effect on utility and stable power trading when the penetration level of DGs is high. That is, in the process of fault detecting and Circuit Breaker (CB) reclosing when a temporary fault occurs, DGs should be disconnected from the Point of Common Coupling (PCC) before CB reclosing. Then all DGs should wait at least 5 minutes after restoration for reconnection and cannot supply the pre-bid power in power market during that period. To solve this problem, this paper proposes a control method that can keep operating without disconnection of DG. This control method is verified through modeling and simulation by the PSCAD/EMTDC software package for distribution systems with DGs based on PCS (Power Conditioning Systems) and CB reclosing protection.

THE ANALYSIS ON HYBRID SUPERCONDUCTING FAULT CURRENT LIMITER (SFCL) USAGE TO LIMIT SHORT CIRCUIT FAULT CURRENT OF 20 KV ELECTRIC POWER DISTRIBUTION IN SENGKALING SUBSTATION

Abstract —The occurrence of fault in electrical power system operation is inevitable. The causes of fault in electrical power transmission and distribution system for instances are lighting strikes on transmission canal, tree collapses, or short circuit inter-phases to the ground. In order to protect the equipment and the whole electrical system in Sengkaling Substation and to reduce the short circuit fault current quickly within timeframe of ½ cycle, it requires Superconducting Fault Current Limiter (SFCL) which is going to be placed on the bus that comes close to a critical point. The designing and analysis on the system of before and after hybrid SCFL installment utilize PSCAD software. The simulation result obtained by installing hybrid SFCL in incoming bus 2 (20 kV) was that hybrid SFCL was able to reduce short circuit fault current in ½ initial cycle with L-G fault of 16.77 kA changed to 5.9 kA, L-L-G fault of 35.38 kA changed to 9.15 kA, L-L-L-G fault of 38.36 kA changed to 9.8 kA, and L-L fault of 28.89 kA changed to 4.35 kA. The average percentage of short circuit fault current that was reduced by hybrid SFCL was 74.12%.

Modelling of high impedance faults in distribution systems and validation based on multiresolution techniques

The electric arc phenomenon associated with high impedance faults (HIFs) in distribution systems is an exciting subject that directly impacts over the reliability of electrical utilities, because fault currents are very small and present non-linearity and asymmetrical waveforms. Therefore, HIFs may be an undetectable phenomenon by overcurrent protections like fuses, re-closers, and relays. A HIF entails a challenge for its detection and location. In this sense, more realistic high impedance models, as well as reliable signal processing techniques, are needed to extract all transient characteristics aiming to detect HIFs in distribution networks. In this work, an efficient Resistive-HIF model is proposed and implemented into the Alternative Transients Program of the Electromagnetic Transients Program (ATP/EMTP) software to represent the main characteristics of HIFs. The model is compared against well-prove models by using two multiresolution approaches based on the Hermite transform and the Wavelet transform considering different frequency bands.

Fault detection in smart grids with time-varying distributed generation using wavelet energy and evolving neural networks

Online monitoring systems have been developed for real-time detection of high impedance faults in power distribution networks. Sources of distributed generation are usually ignored in the analyses. Distributed generation imposes great challenges to monitoring systems. This paper proposes a wavelet transform-based feature-extraction method combined with evolving neural networks to detect and locate high impedance faults in time-varying distributed generation systems. Empirically validated IEEE models, simulated in the ATPDraw and Matlab environments, were used to generate data streams containing faulty and normal occurrences. The energy of detail coefficients obtained from different wavelet families such as Symlet, Daubechies, and Biorthogonal are evaluated as feature extraction method. The proposed evolving neural network approach is particularly supplied with a recursive algorithm for learning from online data stream. Online learning allows the neural models to capture novelties and, therefore, deal with nonstationary behavior. This is a unique characteristic of this type of neural network, which differentiate it from other types of neural models. Comparative results considering feed-forward, radial-basis, and recurrent neural networks as well as the proposed hybrid wavelet-evolving neural network approach are shown. The proposed approach has provided encouraging results in terms of accuracy and robustness to changing environment using the energy of detail coefficients of a Symlet-2 wavelet. Robustness to the effect of distributed generation and to transient events is achieved through the ability of the neural model to update parameters, number of hidden neurons, and connection weights recursively. New conditions could be captured on the fly, during the online operation of the system.

Safety impacts of electric potential and electromagnetic fields as result of faults in electric distribution system

ABSTRACTThis article investigates the impacts of electric potential (EP) and electromagnetic fields (EMF) on human health, especially for those living or working near a distribution system, as a consequence of faults inside the distribution system supplied by an outdoor substation. A case study was carried out using a 115/22 kV substation and a 22 kV distribution system of Thailand’s Provincial Electricity Authority (PEA), with simulated faults injected at the top of a pole of distribution lines located at three different locations. Two methods were proposed for EP and EMF reduction: 1) bonding the ground grid of the substation and the ground rod of the riser pole, and 2) connecting the overhead ground wires of the substation and that of the distribution system. The study results confirm that the two proposed methods offer practically effective problem-solving solutions for reducing EP, and they are therefore able to mitigate the risk of equipment damage. The spatial distribution of EMF measured in the vicinity of the distribution system was found to comply with the threshold set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the International Radiation Protection Association (IRPA), indicating that those living or working outside the substation were safe.

High Impedance Fault Detection using Advanced Distortion Detection Technique

A High Impedance Fault (HIF) in the power distribution systems remains mostly undetected by conventional protection schemes due to low fault currents. Apart from degrading the reliability of power supply to customers, HIF can impose a high cost on the utilities due to technical damages. The nonlinear and asymmetric nature of HIF makes its detection and identification very challenging. HIF signatures are in the form of minute-level distortions in the observable AC sinusoidal voltage and current waveforms but these signatures do not follow a clear pattern. In this paper, we present Advanced Distortion Detection Technique (ADDT), based on waveform analytics to distinguish and detect HIF. In addition, the ADDT analysis provides a fair assessment about the location and severity of HIF for efficient decision-making at the DSO level. ADDT is computationally lightweight and can be implemented in actual relays, hence it is enabled to provide an easy and cost-effective solution to HIF detection issues. ADDT robustness is tested in several simulation cases of interest using the IEEE-34 and IEEE-13 distribution test feeder systems in RTDS power system simulator. The test results successfully demonstrate the effectiveness and robustness of ADDT.

One-Class Classifier Based Fault Detection in Distribution Systems With Varying Penetration Levels of Distributed Energy Resources

The integration of Distributed Energy Resources (DERs) into distribution systems greatly increases the system complexity and introduces two-way power flow. Conventional protection schemes are based upon local measurements and simple linear system models, and are thus not capable of handling the new complexity and power flow patterns in systems with high DER penetration. In this paper, we propose a data-driven protection framework to address the challenges introduced by DERs. Firstly, considering the limited available data under fault conditions, we adopt the Support Vector Data Description (SVDD) method, a commonly used one-class classifier, for distribution system fault detection, which only requires the normal data for its training process. Secondly, incremental learning is incorporated into the proposed SVDD-based protection framework to accommodate variations of the integration level of DERs in distribution systems over time. In particular, the artificial uniform-hyperspherical data generation model is incorporated into the incremental SVDD to boost the training speed. Finally, we validate the proposed method under the IEEE 123-node test feeder. Simulation results demonstrate that our proposed SVDD-based fault detection framework significantly improves the robustness and resilience against DERs in comparison with conventional protection systems. Meanwhile, the proposed online updating model outperforms the existing incremental SVDD models in terms of successful training speed.

Transformer for Single-phase Line Break Fault in Low Voltage Three-phase Distribution System

Single-phase line break fault is becoming more and more frequent in low voltage three-phase distribution system. Therefore, once the single-phase line break fault occurs, three-phase loads cannot work, which will cause unnecessary economic loss. This paper proposed a transformer that can transfer power from two-phase to three-phase for single-phase line break fault in low voltage three-phase distribution system. The proposed transformer can solve the problem that these three-phase loads cannot work due to single-phase line break fault. At the same time, the principle that the transformer transfers power from two-phase to three-phase is analyzed. Finally, simulation results verify that the proposed transformer can transfer power from two-phase to three-phase.