Fault Recorder Research Articles

Holocene earthquake history and slip rate of the southern Teton fault, Wyoming, USA

AbstractThe 72-km-long Teton normal fault bounds the eastern base of the Teton Range in northwestern Wyoming, USA. Although geomorphic surfaces along the fault record latest Pleistocene to Holocene fault movement, the postglacial earthquake history of the fault has remained enigmatic. We excavated a paleoseismic trench at the Buffalo Bowl site along the southernmost part of the fault to determine its Holocene rupture history and slip rate. At the site, ∼6.3 m of displacement postdates an early Holocene (ca. 10.5 ka) alluvial-fan surface. We document evidence of three surface-faulting earthquakes based on packages of scarp-derived colluvium that postdate the alluvial-fan units. Bayesian modeling of radiocarbon and luminescence ages yields earthquake times of ca. 9.9 ka, ca. 7.1 ka, and ca. 4.6 ka, forming the longest, most complete paleoseismic record of the Teton fault. We integrate these data with a displaced deglacial surface 4 km NE at Granite Canyon to calculate a postglacial to mid-Holocene (14.4–4.6 ka) slip rate of ∼1.1 mm/yr. Our analysis also suggests that the postglacial to early Holocene (14.4–9.9 ka) slip rate exceeds the Holocene (9.9–4.6 ka) rate by a factor of ∼2 (maximum of 3); however, a uniform rate for the fault is possible considering the 95% slip-rate errors. The ∼5 k.y. elapsed time since the last rupture of the southernmost Teton fault implies a current slip deficit of ∼4–5 m, which is possibly explained by spatially/temporally incomplete paleoseismic data, irregular earthquake recurrence, and/or variable per-event displacement. Our study emphasizes the importance of minimizing slip-rate uncertainties by integrating paleoseismic and geomorphic data sets and capturing multiple earthquake cycles.

Transmission Line Fault Resistance Values Based on Field Data

Systematic deployment of digital fault recorders has made considerable amounts of field data available and raised the interest to compute fault resistance values from large sets of power system faults and analyze the results statistically. Published results are valuable, however scarce. The present paper gives further contributions by showing results obtained from 89 fault records, for the 400 kV, 220 kV, and 150 kV voltage levels, comparing these with recently published data. Furthermore, the present paper addresses the fundamental question on the existence of a theoretical distribution capable to describe the fault resistance value. For such purpose, an exploratory data analysis is applied to the new results, and a comparison between the exponential and the Weibull distribution is carried out. Results show that both distributions can describe the field data based distributions, the Weibull being more adequate for low resistance values.

Low-angle normal faults record Early Permian extensional tectonics in the Orobic Basin (Southern Alps, N Italy)

Well-preserved SSE-dipping low-angle normal faults (LANF) active during the Early Permian (Cisuralian) were recognized along the northern margin of the Orobic Basin (central Southern Alps, N Italy). These faults, which escaped most of the Alpine deformations, exhumed the Variscan basement during the deposition of the upperpart of the Lower Permian succession (Pizzo del Diavolo Formation).Fault planes show evidence of frictional processes typical of the upper crust associated with hydrothermal circulation, responsible for the deposition of cm to m thick tourmalinite and Uranium mineralization.The recognized LANFs interacted with high-angle normal faults producing half grabens that stored the Lower Permian deposits, where synsedimentary fault activity in their hangingwall is testified by abrupt vertical and lateral facies changes, thickness variations and by soft-sediment deformations. Mesoscopic structures, exposed in the hangingwall of a major LANF (the Aga-Vedello Fault system) along a synthetic high-angle normal fault, include conjugate normal faults, horst-and-graben, domino-style planar and listric faults, which clearly record synsedimentary deformations testified by liquefaction and dewatering structures, typical of pre-consolidation hydroplastic conditions. This exceptional record indicates deformations at shallow crustal level which occurred during the Early Permian along high-angle normal faults soling into the LANFs, forming the northern boundary of the Orobic Basin.The outcrop continuity, the perfectly preserved relationships among high- and low-angle normal faults together with the synsedimentary record of fault activity and the occurrence of mesoscopic faults developed during the deposition of the sediments, make this case-study an excellent reference for the analysis of extensional tectonics in synsedimentary conditions.In addition, the occurrence of large LANF systems, typical of a stress regime characterized by a vertical s1, suggests that the Lower Permian Orobic Basin was dominated by pure extension at least in the study area, alternatively to existing interpretations, which favor a transtensional origin of the basin. Strike-slip tectonics can be responsible for a later partial tectonic inversion of the basin, as testified by the angular unconformity with the overlying Upper Permian succession (Verrucano Lombardo), marking a Middle Permian stratigraphic gap.

A High Efficient Approach for Power Disturbance Waveform Compression in the View of Heisenberg Uncertainty

This paper proposes a highly efficient approach for power disturbance waveform (PDW) compression in the view of Heisenberg uncertainty. The key idea is to represent each signal component of PDW using as few nonzero coefficients as possible by the uncertainty principle restriction. PDWs are projected in a union of bases (UB), and each signal component of the PDWs can be represented very sparsely. The UB decomposition is solved by orthogonal matching pursuit. The features and cross correlation of subbases of the UB guarantee the PDW compression with high a compression ratio and recovered accuracy. With various simulated and field PDWs tests, the compressed data size of the new method is proven with good characteristics such as low sensitivity to sampling frequency increment and types of signal components contained in PDWs. Moreover, it is found that the new method and methods that employ wavelet techniques share the similar effect of noise for PDW compression. The proposed method is also applied at a 220-kV power substation for field PDW compression from fault recorders. The comparisons, analyses, and experiments indicate that the proposed method has a high PDW compression efficiency for future power grid monitoring.

Fault causes identification for transmission lines based on HHT and PNN

In this paper, Hilbert-Huang transform(HHT) is introduced into the application of fault cause identification for transmission lines. This method is composed of empirical mode decomposition (EMD) and Hilbert transform. It can analyze the characteristics of signal frequency quantitatively and accurately[1]. By analyzing the information of four common faults from fault recorder, the Hilbert marginal spectrum and the Hilbert time-frequency spectrum can be considered as the feature of different fault causes which can be classified by a probability neural network (PNN). The results show that the method can effectively identify the cause of the fault and has a high accuracy.

Application Research of Multi-source Information Fusion Technology in Power Network Fault Diagnosis

In this paper, a power grid fault diagnosis method based on multi-source information fusion technology is proposed for grid faults. Firstly, the wavelet transform is used to analyze the electrical quantity information of the fault recorder and PMU, and the three fault reliability characterizations of the components are obtained. Secondly, the information fusion based on the improved D-S evidence theory is carried out for each fault characterization, and the comprehensive fault credibility of the components is obtained, and the fault criterion is given. Finally, the fuzzy C-means method is used to make the diagnosis decision of the faulty component, and the final diagnosis result is obtained. The simulation results show that the method combines the electrical quantities of the fault recorder and the PMU to obtain accurate fault diagnosis results, which can effectively reduce the impact of protection and switch refusal misoperation on power grid fault diagnosis. This method has a good application prospect in power system fault diagnosis.

Flashover characteristics of plastic cloth on ±800 kV HVDC transmission line

In order to study the reasons for the restart failure after locking of the ±800kV HVDC transmission lines caused by the plastic cloth of the greenhouse, combined with a bipolar closure fault example of the ±800kV HVDC transmission line caused by a plastic cloth, the voltage and current time characteristics of the ±800 kV HVDC transmission line after failure are obtained through fault field investigation and fault recording analysis. Through plastic cloth contamination detection and linear equivalent test of ±800kV DC tolerance voltage, the necessary conditions for flashover and the time level of local burning to whole cloth breakage are obtained. The flashover, combustion and deionization process of plastic cloth are showed through linear equivalent 800kV DC voltage flashover test, which proves the possibility of three restart failure owing to the insufficient deionization as a result of the fact that fault current is large, the discharge channel is dispersed and the restart interval is short. Meanwhile, the flashover characteristics of plastic cloth of ±800kV HVDC transmission lines are obtained.

Fault Waveform Regenerator and Its Digital Closed-Loop Modification Technique

In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed in this paper, together with its hardware structure and software flow chart. Fault waveform regenerator mainly depends on its power amplifiers (PAs) to regenerate the fault waveforms recorded by digital fault recorder (DFR). To counteract the PA’s inherent nonlinear distortions, a digital closed-loop modification technique that is different from the predistortion technique is conceived. And the experimental results verify the effectiveness of the fault waveform regenerator based on the digital closed-loop modification technique.

Characteristics of commutation failure based on fault recording

Commutation failure of the high-voltage direct current (HVDC) transmission system is common fault in a converter station. The fault recording in one converter station when commutation failure caused by the disturbance of the AC system was collected, and the turn-off angle of valves, zero-crossing offset, and landing amplitude of bus voltage were calculated and statistically analysed. The results suggested that, in the case of commutation failure, the turn-off angle of the 82% of cases was 90% cases, and the average was ∼4.6%. The number of cases, whose zero sequence voltage peaks was <50 kV, accounted for 97% of the total. The results will provide basic data for analysing the main influencing factors of commutation failure and setting up countermeasures for the HVDC system.

Helium Isotope Ratios in Spring Waters of the Tunka–Oka–Sayan Rift (East Sayan Area): Correlation with Heat Flow

Abstract —Studies of helium isotope ratios in groundwaters discharging as springs within the Tunka–Oka–Sayan rift in the East Sayan area reveal an anomaly extending for 350 km along the East Sayan fault on the extension of the Tunka anomaly in the southwestern flank of the Baikal rift system. The calculated heat flow values (qR) agree with the measured ones (qT), and the heat flow anomalies correlate with those in the 3He/4He ratios throughout the Oka–Sayan and Bilin–Busiyn-Gol rifts. The correlation of the geophysical and geochemical parameters confirms that both are controlled by heat and mass transfer. Both mantle helium and heat apparently originate from a mantle plume beneath the South Baikal volcanic province (SBVP). The concordant 3He/4He and heat flow patterns in the Oka–Sayan fault record ongoing rifting and magmatism along the East Sayan Fault zone. The helium isotope and heat flow anomalies are consistent with the presence of low-velocity zones in the upper 200 km beneath the southwestern Baikal rift zone as far as the southern edge of the Siberian craton, which are detectable in seismic tomography images. Magmatism in the extreme southwest of the Baikal rift zone was maintained by active tectonic movements in the Pliocene and by the activity of the SBVP mantle plume. The obtained helium isotope data and high heat flow values indicate that rifting and magmatism propagate northwestward along the East Sayan Fault zone. This pattern fits the geothermal model for continental rifts implying that magmatic activity in the western end of BRS has been controlled by lithospheric deformation. The geothermal model for the Baikal–Mongolia region covers the area northwest of the system of three rift basins along the East Sayan faults.

An Automated Technique for Extracting Phasors from Protective Relay’s Event Reports

Post-fault event report analysis is a crucial skill set for electric power engineers in the protection industry. This paper serves as a reference which elucidates the preprocessing procedures involved in transforming data present in event reports to phasors that can be used in various post-fault analysis application algorithms. The paper discusses key elements of this process such as interpreting the data and calculating voltage and current phasors from instantaneous sample values present in a fault record. A crucial component of event report analysis is choosing the appropriate time instant for calculating phasors for event report analysis. Conventionally, protection engineers manually perform event report analysis and arbitrarily select time instants after certain cycles of fault inception for this purpose. This approach prevents the process from being successfully automated. Furthermore, arbitrary selection of time instant does not utilize the entire fault data and may fail in several cases such as short time fault scenario and evolving fault scenario. For this purpose, this paper proposes an adaptive novel technique which utilizes the entire data present in the event report to select the most suitable time instant for event report analysis. The superiority of the proposed algorithm over conventional methods is demonstrated using three real-world scenarios.

Optimization Method With Prediction-Based Maintenance Strategy for Traction Power Supply Equipment Based on Risk Quantification

A prediction-based maintenance (PBM) strategy can save resources while simultaneously guaranteeing the traction power supply system (TPSS) operates in a stable and reliable condition. Based on risk quantification, this paper presents a method to assess maintenance needs and optimize the PBM strategy for traction power supply equipment (TPSE). This method utilizes historical maintenance information and the fault record of the TPSE as inputs to a fault prediction model based on a Bayesian classifier. By comparing the prediction results with the actual equipment operation state, statistical parameters are obtained to calculate the reliability and economic indices for the maintenance strategies. The comprehensive maintenance risk is then quantified by integrating the dynamic inspection and fault risk costs for the TPSE. The minimum comprehensive risk is selected as the optimization objective, and the criterion for fault prediction spurs from the optimization results are used to form the PBM strategy. Practical maintenance information and fault record data of 27.5-kV vacuum circuit breakers for a TPSS are used to verify the proposed method. The results show that, by fully utilizing the current data, this method can predict equipment faults by considering multiple factors, and it can quantify the risk for a particular PBM strategy, which is also applicable to similar large-scale traction power supply facilities. To improve the PBM strategy, the approach optimizes fault prediction criteria to achieve a minimum comprehensive maintenance risk. The proposed method can provide effective data and confidence for decision makers in implementing PBM for TPSS.

Location and sinistral displacement of the eastern Liaoyuan Accretionary Belt along the Tan–Lu Fault Zone, NE China

The NE- to NNE-striking, continental-scale Tan–Lu Fault Zone (TLFZ) in NE China is subdivided into the ∼900 km long Yilan–Yitong Fault (YYF) in the west and the ∼1000 km long Dunhua–Mishan Fault (DMF) in the east. Both faults record sinistral displacement during the earliest Cretaceous, leading to an obvious offset of the boundary between the Liaoyuan Accretionary Belt (LAB) and the North China Craton (NCC). Previous studies have demonstrated that the LAB in the south of the eastern Central Asian Orogenic Belt (CAOB) extends eastwards into an area between the YYF and the DMF. The boundaries between the LAB and NCC indicate a 35 km sinistral displacement upon the YYF. However, it remains unclear whether the LAB extends to the east of the DMF, and the amount of sinistral displacement on the DMF is poorly constrained. Here we present lithological observations and U–Pb and Hf isotopic data from zircon to constrain the age and position of the LAB to the east of the DMF. The data indicate an eastward extension of the LAB across the DMF, suggesting the continuous presence of the LAB east of the TLFZ in NE China. The U–Pb ages, εHf(t) values, and two-stage model ages of zircons from the study area constrain the boundary between the LAB and NCC to an extension of the NE-dipping Chifeng–Kaiyuan Fault to the east of the DMF. The geological boundaries on both sides of the DMF indicate a 170 km sinistral displacement along the fault. Thus, the TLFZ has a total sinistral displacement of 205 km in NE China. The eastern branch of the TLFZ records significantly more movement due to its proximity to the Pacific Ocean, where subduction of oceanic crust might have caused sinistral faulting along the TLFZ.

Rule extraction for tram faults via data mining for safe transportation

The demand to travel by rail is ever increasing because it benefits passengers. Also it is important for railway administrators to carry passengers safely to their destinations. One of the parameters that cause unsafety transportation is faults in railway transportation. Undergoing safety procedures and developing safety systems require awareness of what is causing unsafe conditions. This can be obtained by learning from the past. Data mining is a tool to extract information from historical data. One of the most common fields of transportation to apply data mining is fault analysis. In the present study the data set of 4-year record of tram faults from a railway transportation company in Turkey was obtained to carry out rule extraction from the occurrence of faults that cause delays in tram services. For this purpose, we used a rough set tool Rosetta as well as Weka for rule extraction. As a result, we obtained meaningful and useful rules, and these rules were interpreted.

Relay performance verification using fault event records

IntroductionEvent reports recorded by intelligent electronic devices (IEDs) such as digital relays and fault recorders during disturbances depict the status and system parameters of the power system. Incorrect relay settings and unknown system parameters can lead to relay misoperation but information regarding these are available by performing a comprehensive analysis of fault records. Hence, it is necessary to regularly make a comprehensive assessment of the functioning of the relay to ensure reliable operation.Case descriptionThe objective of this paper is to demonstrate various aspects of evaluating relay performance and verifying circuit parameters which are used in relay settings using field data in two case studies.Discussion and EvaluationWhile scrutinizing the relay’s operation, this paper also presents key insights on verifying circuit parameters using the same relay event records.ConclusionsThe lessons learned from the case studies presented in this paper will equip a protection engineer to inspect the operation of a relay during a transmission line fault, help gain a better understanding of the fault event and take possible actions to prevent future occurrence of similar events.

Method for Realizing On-Line Condition Monitoring of Protective Device Based on Data of Information Processing System

At present, the evaluation of relay status maintenance depends on a great deal of manpower, while the data source of relay protection device and fault recorder information system (hereinafter referred to as the guarantee system) has reached the basic requirement for online monitoring status evaluation. Based on the analysis of the internal structure of the system, the automatic extraction of abnormal operation information of the protection device is realized. According to the failure mode and reliability analysis method FMEA, the evaluation index of the risk of on-line status of the protection device is proposed. In the real-time status of relay protection devices and systems quantitative assessment, the final selection of actual operating data protection device as an example to show the effect of the method.

A Novel Fault Elements Location Algorithm Based on Wide Area Fault Recorder Data for HV Transmission System

After a large-scale grid failure, it is important for dispatchers to know the faulty components and causes and to develop the correct scheduling strategy. In this paper, a new fault diagnosis scheme is presented based on widely configured fault recorders. The proceeded algorithm using the wide-area recorder data to locate the fault components such as transmission lines, busbars and transformers. Different indicators are given for different components on the grid. A variety of criterion indexes are deduced for the transmission line using the distributed parameter model. The credibility of the judgment is improved by using multiple criteria. A search scheme based on the initial adjacency matrix is used to locate fault component on the grid. The fault area is defined according to the uploaded recorder data. The fault components are searched in the wide defined fault area according to the proposed scheme. The element with the greatest probability of failure is found. The three faulty elements simulation models based on PSCAD/EMDTC are established and studied, what’s more, the power system model is also established to test the algorithm. The simulation results verify the effectiveness of the proposed method.

Sampling Rate Impact on Estimation of Untransposed Transmission Line Parameters Based on Fault Records

This paper highlights the sampling rate impact over an estimation method based on modal analysis techniques applied on untransposed three-phase transmission line. The analysed method represents a transmission system in the modal domain as three independent propagation modes that are modelled as three single-phase transmission lines using a suitable $$\pi $$ equivalent. The estimation procedure is carried out in the modal domain, without the explicit modelling of the phase mutual parameters, which means a significant simplification on the calculation process using the least-square solution method. Since the modal parameters are identified, the self- and mutual parameters can be calculated using the same modal transformation matrix during the line decoupling. The method estimation accuracy is evaluated for a range of sampling rate associated with the relays records.

Investigation of transformer failure in Indonesia

Transformer failure investigation is important to obtain necessary actions which prevent similar failure from happening in the future. An investigation was conducted upon the failure of a transformer in Indonesia which damaged substation apparatuses nearby. To determine possible cause of the failure, the investigation was performed by doing visual inspection after failure, further analysis on related historical assessment result data and simulation using related nameplate and actual configuration. Most historical assessment result data showed no early failure indication of the transformer, while sweep frequency response analysis (SFRA) test result showed severe deformation on both primary and secondary winding. A simulation using Transient Analysis Program for internal short circuit between winding and ground was conducted and the output waveform was identical to Digital Fault Recorder (DFR) waveform data during transformer failure. Therefore, the possible cause of transformer failure was internal arcing on primary winding to ground which could not be interrupted by the protection system. According to visual inspection after failure, the possible cause of protection system malfunction was accidental open circuit in Current Transformer (CT) secondary circuit which damaged whole CT wiring.

Vacuum circuit breaker modelling for the assessment of transient recovery voltages: Application to various network configurations

Vacuum circuit breakers (VCBs) are widely used for medium voltage applications when low maintenance, long operating life, and large number of allowable switching cycles are required. The accurate estimation of the transient recovery voltages (TRVs) associated with their switching operation is indispensable for both VCB sizing and insulation coordination studies of the components nearby the switching device. In this respect, their accurate modelling, which is the object of the paper, becomes crucial. In particular, the paper illustrates two applications of a VCB model, which show the model capabilities of simulating TRVs due to opening/closing operation, namely the switching of large electrical motors and the switching of cables collecting offshore wind farms (OWFs). Data from digital fault recorder (DFR) in a water-pumping plant and from a measurement campaign in an OWF using a high-bandwidth GPS-synchronised measurement system, respectively, are used for model validation. It is shown that the inclusion of detailed VCB models significantly improves the agreement between the measurements related to both pre- and restrikes and the corresponding simulation results obtained by using two well-known electromagnetic transient simulation environments, namely, EMTP-RV and PSCAD/EMTDC. The procedure adopted for the identification of the VCB model parameters is described.