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Fault detection in transmission lines plays an important role in maintaining the dependability and steadiness of power networks. Traditional methods for identifying faults often struggle to handle the diverse nature of real-world fault situations. Machine learning (ML) algorithms offer a data-centered approach that can adjust and learn from datasets, potentially overcoming the limitations of traditional approaches. This paper presents a review of progress in using ML for detecting faults in transmission lines. By drawing insights from lots of studies, explores the paper how ML algorithms have evolved in fault detection, including techniques like networks, recurrent neural networks featuring long short-term memory (LSTM) and convolutional neural networks (CNN). The paper delves into the spectrum of applications where ML is used for fault detection across fault scenarios and operational settings. Additionally, it discuss the obstacles and prospects linked to putting ML-based fault detection systems into practice, such as challenges with data quality, model interpretability and integration with existing grid monitoring systems. Finally, the paper outlines future research paths focused on pushing forward the boundaries of fault detection in power transmission systems through approaches and collaborative endeavors involving academia, industry players and policymakers. In general, this review highlights how ML has the power to revolutionize fault detection methods, enhancing the resilience and dependability of power systems. [ABSTRACT FROM AUTHOR]

The integration of remote renewable energy sources located near the long‐distance HVDC transmission corridor to the HVDC system is an active area of research. This study presents a new fault‐tolerant scheme using a modular soft‐switched DC–DC converter with high‐voltage gain to integrate renewable energy sources to LCC‐based HVDC systems. The configuration, operating principle and mathematical modelling of the new DC–DC converter are described in this study. As both the charging and discharging processes takes place through resonant circuits, zero current switching of all the switches used in the converter is achieved. The proposed scheme has the inherent fault‐tolerant capability and enables fast recovery from commutation failures in the main LCC HVDC system. The operation of the proposed scheme during various fault scenarios is analysed and explained in this study. The performance of the proposed scheme and its fault ride though the capability is verified using a simulation model built in PSCAD/EMTDC and an experimental prototype. [ABSTRACT FROM AUTHOR]

Considering both environmental and commercial aspects, mixed three-terminal transmission lines are attractive. Mixed three-terminal lines consist of two sections of the overhead line and one section of underground cable. In this work, a selective auto-reclosing, fault location, and parameter estimation technique for mixed three-terminal lines using synchronised data from all three terminals are proposed. The proposed method uses the pre and during-fault data recorded at the three ends of the line. Using the recorded sampled data, pre-fault and during-fault phasors are estimated. Four functions are formulated from the pre-fault equivalent network of the system. Additionally, three sets of four functions each are formulated after assuming the fault to be on each of the three sections. Subsequently, the faulted section, fault location, and three sets of line parameters are simultaneously calculated by solving each set of equations. Finally, the correct faulted section, location, and parameters are identified based on the characteristics of obtained line parameters and fault location. Furthermore, the identified faulted section information is applied to enable or block the auto-reclosing function. The simulations and analysis are carried out using PSCAD/EMTDC and MATLAB scripts, respectively. The accuracy, capabilities, applications, and limitations are discussed for different fault scenarios. [ABSTRACT FROM AUTHOR]

This study presents a novel algorithm based on dq-components, which has been effectively used for bus zone protection. The analogue current transformer (CT) secondary signals are acquired and converted into sampled values. Then, the fundamentals of an instantaneous current-based differential protection scheme (87B) have been considered to establish the trip logic of the proposed scheme. Its performance has been validated by simulating faults on an existing 400-kV substation with a double-bus-single-breaker configuration. Moreover, a laboratory test bench has been developed to test the authenticity of the proposed scheme for various fault scenarios. The obtained results from the simulation model and laboratory prototype testify the claims of higher sensitivity during internal faults and better stability during external faults with CT saturation. The proposed scheme has been able to provide high-speed busbar protection against a wide range of internal faults. Comparative evaluation with contemporary busbar protection schemes clearly indicates its superiority. [ABSTRACT FROM AUTHOR]

Fault mode and effects analysis (FMEA) has been used during decades for analysing the effects of faults in different applications. Initially, FMEA based on risk priority numbers provided information about the effects in the system, but during the last years different approaches have been developed to obtain a more robust risk evaluation. The proposed enhanced FMEA can provide the quantitative effects of sensor faults in a railway traction drive, in variables such as torque, current and voltages. In addition to the previous work, quantitative effects on overall performance indicators, such as energy efficiency and comfort, are obtained too. Hardware-in-the-loop (HIL)-based fault injection approach has been used to generate fault scenarios. The test platform is composed of a real-time simulator and a commercial traction control unit for a railway application.

This paper reports an experimental feasibility study of the potential for using Fibre Bragg Grating (FBG) thermal sensing technology for electrical fault detection in random wound coils. The study is performed on prototype test coils housed in a purpose built steel core section. The FBG thermal sensors are embedded between copper conductors in multiple positions within the coil structure and in close proximity of the known hot spots of interest. The examined coils are designed to enable emulation of hot spots representative of those that would be expected at the outset of winding fault events. A series of experiments were separately conducted in order to characterise the potential of coil internal thermal stress monitoring to provide recognition of a developing winding fault. To this end, winding fault scenarios with different severity levels of inter-turn fault are experimentally examined. The reported findings demonstrate the potential of the proposed in-situ thermal sensing scheme to enable monitoring and recognition of coil internal thermal stress induced at various stages of emulated electrical fault.

This paper presents a fault‐tolerant secondary and adaptive primary microgrid control scheme using a hybrid multi‐agent system (MAS), capable of operating either in a semi‐centralised or distributed manner. The proposed scheme includes a droop‐based primary level that considers the microgrid energy reserves in production and storage. The secondary level is responsible for: a) the microgrid units' coordination, b) voltage and frequency restoration and c) calculation of the droop/ reversed‐droop coefficients. The suggested architecture is arranged upon a group of dedicated asset agents that collect local measurements, take decisions independently and, collaborate in order to achieve more complex control objectives. Additionally, a supervising agent is added to fulfill secondary level objectives. The hybrid MAS can operate either with or without the supervising agent operational, manifesting fast redistribution of the supervising agent tasks. The proposed hybrid scheme is tested in simulation upon two separate physical microgrids using three scenarios. Additionally, a comparison with conventional control methodologies is performed in order to illustrate further the operation of a hybrid approach. Overall, results show that the proposed control framework exhibits unique characteristics regarding reconfigurability and fault‐tolerance, while power quality and improved load sharing are ensured even in case of critical component failure. [ABSTRACT FROM AUTHOR]

Fault mode and effects analysis (FMEA) has been used during decades for analysing the effects of faults in different applications. Initially, FMEA based on risk priority numbers provided information about the effects in the system, but during the last years different approaches have been developed to obtain a more robust risk evaluation. The proposed enhanced FMEA can provide the quantitative effects of sensor faults in a railway traction drive, in variables such as torque, current and voltages. In addition to the previous work, quantitative effects on overall performance indicators, such as energy efficiency and comfort, are obtained too. Hardware-in-the-loop (HIL)-based fault injection approach has been used to generate fault scenarios. The test platform is composed of a real-time simulator and a commercial traction control unit for a railway application. [ABSTRACT FROM AUTHOR]

This paper reports an experimental feasibility study of the potential for using Fibre Bragg Grating (FBG) thermal sensing technology for electrical fault detection in random wound coils. The study is performed on prototype test coils housed in a purpose built steel core section. The FBG thermal sensors are embedded between copper conductors in multiple positions within the coil structure and in close proximity of the known hot spots of interest. The examined coils are designed to enable emulation of hot spots representative of those that would be expected at the outset of winding fault events. A series of experiments were separately conducted in order to characterise the potential of coil internal thermal stress monitoring to provide recognition of a developing winding fault. To this end, winding fault scenarios with different severity levels of inter-turn fault are experimentally examined. The reported findings demonstrate the potential of the proposed in-situ thermal sensing scheme to enable monitoring and recognition of coil internal thermal stress induced at various stages of emulated electrical fault. [ABSTRACT FROM AUTHOR]

The intrinsic safety type of protection significantly increased in complexity during the last decades. Thus, it even provides the opportunity to use highly complex electronic circuits without involving a significant explosion risk within the oil industry or in power plants, but not limited to those two. In order to achieve this performance, the type of protection is based on three pillars: limiting of energy, heat and also fault tolerance. The potential failure of components, connections, and separations are taken into consideration for intrinsic safety evaluations. This paper focuses on scenarios of separation faults in intrinsic safety circuits. The introduction part of the paper provides a summary of requirements for the intrinsic safety type of protection. The separation requirements are also highlighted. This part also explains the „countable" concept regarding the separation faults. The second part of the paper is dedicated to the fault scenarios assessment. Also, this part shows the theoretical model which yields the magnitude of the fault scenarios group. The built-up algorithm for effective localization of the separation faults on a real electronic board is presented in the second part of the paper. This algorithm was implemented using Visual Basic for Applications script and National Instruments Ultiboard software. In the third part of the article, the obtained results are reported and discussed. In order to have a comprehensive image, there was proposed a graph in which links are considered separation distances and elements conductive tracks. Another tool proposed and used was separation distances histogram. The influence of increased finesse on the number of non-countable separation faults was also discussed. The main outcome of the paper is represented by the high impact of non-countable separation faults number over the number of separation failure scenarios. For example, the circuit analysis showed the potential for over sixteen million failure scenarios. [ABSTRACT FROM AUTHOR]

To evaluate and optimise insulation coordination concepts for state of the art high-voltage direct current (HVDC) transmission systems, appropriate test voltage shapes are required for laboratory imitation of occurring stresses. While especially transient voltages in the monopolar modular multilevel converter (MMC)–HVDC links show an extensive deviation from commonly applied switching impulse shapes, this study focusses on the analysis of over-voltages subsequent to direct current pole to ground faults. Additionally, novel methods for synthetic laboratory test voltage generation are proposed. Based on simulated transients occurring during fault scenarios in different symmetrical monopolar ±320 kV MMC–HVDC schemes, curve fitting, and related analysis techniques are used in order to compare simulated over-voltages with standard test voltage shapes. Moreover, these techniques further allow the identification of novel relevant impulse characteristics. Subsequently, design considerations for the generation of non-standard impulses based on single-stage circuits are derived and discussed. Those synthetically generated voltages may, later on, provide the basis for future investigations on related dielectric effects caused by those non-normative over-voltages.

Abstract Global primary energy consumption will continue to increase with a high rate to 2050, which will be a big challenge for countries to meet both global and regional energy demand. Pumped storage stations (PSS) integrated to a hybrid power system (HPS) with solar and wind power for China are under construction to tussle with this challenge. Historically, modeling of a PSS integrated HPS has been ignored the interaction effect between the shaft vibration and the governing strategies, which will increase the dynamic risk of PSS disconnected immediately to HPS. Here we unify the models of the hydro-turbine governing system and hydro-turbine generator units with a novel expression of hydraulic forces. We quantize all the parameter's interaction contributions of PSS integration to HPS and validate this model with the existing models. Finally, we show the feasibility of PSS's model in integrating of a HPS under steady and fault scenarios. [ABSTRACT FROM AUTHOR]

In the last years several numerical codes have been developed to analyse tsunami waves. Most of these codes use a finite difference numerical approach giving good results for tsunami wave propagation, but with limitations in modelling inundation processes. The HyFlux2 model has been developed to simulate inundation scenario due to dam break, flash flood and tsunami-wave run-up. The model solves the conservative form of the two-dimensional shallow water equations using a finite volume method. The implementation of a shoreline-tracking method provides reliable results. HyFlux2 robustness has been tested using several tsunami events. The main aim of this study is code validation by means of comparing different code results with available measurements. Another objective of the study is to evaluate how the different fault models could generate different results that should be considered for coastal planning. Several simulations have been performed to compare HyFlux2 code with SWAN-JRC code and the TUNAMI-N2. HyFlux2 has been validated taking advantage of the extensive seismic, geodetic measurements and post-tsunami field surveys performed after the Nias March 28th tsunami. Although more detailed shallow bathymetry is needed to assess the inundation, diverse results in the wave heights have been revealed when comparing the different fault mechanism. Many challenges still exist for tsunami researchers especially when concern to early warning systems as shown in this Nias March 28th tsunami.

In the last years several numerical codes have been developed to analyse tsunami waves. Most of these codes use a finite difference numerical approach giving good results for tsunami wave propagation, but with limitations in modelling inundation processes. The HyFlux2 model has been developed to simulate inundation scenario due to dam break, flash flood and tsunami-wave run-up. The model solves the conservative form of the two-dimensional shallow water equations using a finite volume method. The implementation of a shoreline-tracking method provides reliable results. HyFlux2 robustness has been tested using several tsunami events. The main aim of this study is code validation by means of comparing different code results with available measurements. Another objective of the study is to evaluate how the different fault models could generate different results that should be considered for coastal planning. Several simulations have been performed to compare HyFlux2 code with SWAN-JRC code and the TUNAMI-N2. HyFlux2 has been validated taking advantage of the extensive seismic, geodetic measurements and post-tsunami field surveys performed after the Nias March 28th tsunami. Although more detailed shallow bathymetry is needed to assess the inundation, diverse results in the wave heights have been revealed when comparing the different fault mechanism. Many challenges still exist for tsunami researchers especially when concern to early warning systems as shown in this Nias March 28th tsunami. [ABSTRACT FROM AUTHOR]

A bond graph representation of switching devices known for a long time has been a modulated transformer with a modulus b(t)∈(0,1)∀t≥0 in conjunction with a resistor R:Ron accounting for the ON-resistance of a switch considered non-ideal. Besides other representations, this simple model has been used in bond graphs for simulation of the dynamic behaviour of hybrid systems. A previous article of the author has proposed to use the transformer–resistor pair in bond graphs for fault diagnosis in hybrid systems. Advantages are a unique bond graph for all system modes, the application of the unmodified standard Sequential Causality Assignment Procedure, fixed computational causalities and the derivation of analytical redundancy relations incorporating ‘Boolean’ transformer moduli so that they hold for all system modes. Switches temporarily connect and disconnect model parts. As a result, some independent storage elements may temporarily become dependent, so that the number of state variables is not time-invariant. This article addresses this problem in the context of modelling and simulation of fault scenarios in hybrid systems. In order to keep time-invariant preferred integral causality at storage ports, residual sinks previously introduced by the author are used. When two storage elements become dependent at a switching time instance ts, a residual sink is activated. It enforces that the outputs of two dependent storage elements become immediately equal by imposing the conjugate3 power variable of appropriate value on their inputs. The approach is illustrated by the bond graph modelling and simulation of some fault scenarios in a standard three-phase switched power inverter supplying power into an RL-load in a delta configuration. A well-developed approach to model-based fault detection and isolation is to evaluate the residual of analytical redundancy relations. In this article, analytical redundancy relation residuals have been computed numerically by coupling a bond graph of the faulty system to one of the non-faulty systems by means of residual sinks. The presented approach is not confined to power electronic systems but can be used for hybrid systems in other domains as well. In further work, the RL-load may be replaced by a bond graph model of an alternating current motor in order to study the effect of switch failures in the power inverter on to the dynamic behaviour of the motor. [ABSTRACT FROM AUTHOR]