High Voltage Circuit Breaker Research Articles

Toward an Integrated Approach of HV and MV Circuit-Breakers Optimization Maintenance Planning and Reliability Assessment: A Case Study

This paper investigates technical and organizational tools to improve maintenance planning performances. Indeed, maintaining a high level of reliability and availability of a Medium Voltage electrical network protection system such as the Medium Voltage and High Voltage circuit-breaker and its numerical protection relay at a low operating expenses cost is one of the most critical and challenging tasks for MV electrical distribution network operators. This work has mainly two goals. Firstly, to propose an operating expenses budget function that evaluates the Planned Scheduled Preventive Maintenance Policy combined with a Condition-based maintenance fora real series-parallel multi-assets MV electrical distribution system with active redundancy under the reliability and the maintenance frequency visits of these components. Secondly, to implement an integrated genetic algorithm approach in order to look for the optimal perfect and planned preventive maintenance scheduling policy and condition-based maintenance that minimizes the maximum operating expenses cost of the entire system.The method determines the optimal schedule of preventive maintenance actions based on minimization both reliabilty and operating expenses costs. Conclusions and recommendations for practice are made on the basis of obtained results.

Spectroscopic On-Line Monitoring of Cu/W Contacts Erosion in HVCBs Using Optical-Fibre Based Sensor and Chromatic Methodology.

Contact erosion is one of the most crucial factors affecting the electrical service lifetime of high-voltage circuit breakers (HVCBs). On-line monitoring the contacts’ erosion degree is increasingly in demand for the sake of condition based maintenance to guarantee the functional operation of HVCBs. A spectroscopic monitoring system has been designed based upon a commercial 245 kV/40 kA live tank circuit breaker with copper–tungsten (28 wt % and 72 wt %) arcing contacts at atmospheric pressure. Three optical-fibre based sensors are used to capture the time-resolved spectra of arcs. A novel approach using chromatic methods to process the time-resolved spectral signal has been proposed. The processed chromatic parameters have been interpreted to show that the time variation of spectral emission from the contact material and quenching gas are closely correlated to the mass loss and surface degradation of the plug arcing contact. The feasibility of applying this method to online monitoring of contact erosion is indicated.

Transient circuit implementation of arc models with particular focus on arcs in low-voltage power cables

Accurate and detailed fault arc models are increasingly important for development of modern power system protection algorithms which demand very granular and realistic time domain simulation. While the literature spans several decades, few contributions specifically address arcing in low voltage (LV) power cables. Such cables are usually installed underground, underwater, or even in space, making them difficult to access in the field. Real world fault studies on LV power systems are difficult and disruptive so existing fault data is scarce. Therefore to generate reliable and extensive data on the influence of fault arcing on power networks, electromagnetic transient (EMT) timescale simulations of the grid are required at circuit level, together with a commensurate circuit model of the arc itself. This paper therefore assesses existing arc models for their suitability for implementation in a circuit simulator and, for the first time, presents universal electrical circuits that solve existing arc model equations. Although the existing models have mostly been developed for arcs in high voltage overhead lines and circuit breakers, circuit simulations are presented here to evaluate their suitability for LV power cables. Particular emphasis is therefore given to the model inspired by the ablation process as the arc propagates through the cable dielectric. Following the circuital implementation of existing models, a novel Low Impedance Arc Model (LIAM) is presented that computes the time varying “ablation” conductance with a reduced number of parameters. Quantitative analysis of the arc conductance as a function of time (for the models considered in this study) was performed to show the important influence of the electrical environment to the development and the shape of the arc. It was found that the resistance of the source driving the arc is of crucial importance. Furthermore, in order to create a more realistic simulation tool, a model of the high frequency component of the arc conductance is demonstrated for the first time.

Development of a multiperspective optical measuring system for investigating decaying switching arcs at the nozzle exit of circuit breakers.

High-voltage gas circuit breakers, which play an important role in the operation and protection of the power grid, function by drawing an arc between two contacts and then extinguishing it by cooling it using a transonic gas flow. Improving the design of circuit breakers requires an understanding of the physical processes in the interruption of the arc, particularly during the zero crossing of the alternating current (the point in time when the arc can be interrupted). Most diagnostic techniques currently available focus on measurement of current, voltage, and gas pressure at defined locations. However, these integral properties do not give sufficient insight into the arc physics. To understand the current interruption process, spatially resolved information about the density, temperature, and conductivity of the arc and surrounding gas flow is needed. Owing to the three-dimensional, unstable nature of the arc in a circuit breaker, especially near current zero, a spatially resolved, tomographic diagnostic technique is required that is capable of freezing the rapid, transient behavior and that is insensitive to the vibrations and electromagnetic interference inherent in the interruption of short-circuit current arcs. Here a new measurement system, based on background-oriented schlieren (BOS) imaging, is presented and assessed. BOS imaging using four beams consisting of white light sources, a background pattern, imaging optics, and a camera permits measurement of the line-of-sight integrated refractive index. Tomographic reconstruction is used to determine the three-dimensional, spatially resolved index of refraction distribution that in turn is used to calculate the density. The quantitative accuracy of a single beam of the BOS setup is verified by using a calibration lens with a known focal length. The ability of the tomographic reconstruction to detect asymmetric features of the arc and surrounding gas flow is assessed semiquantitatively using a nozzle that generates two gas jets, as described in [Exp. Fluids43, 241 (2007)EXFLDU0723-486410.1007/s00348-007-0331-1]. Experiments using a simple model of a circuit breaker, which provides optical access to an ∼1 kA arc that burns between two contacts and is blown through a nozzle system by synthetic air from a high pressure reservoir, are also described. The density in the decaying arc and surrounding gas flow is reconstructed, and the limitations of the technique, which are related to the temporal and spatial resolution, are addressed.

Adaptive fault diagnosis of HVCBs based on P-SVDD and P-KFCM

High voltage circuit breakers (HVCBs) are among most important pieces of equipment in the power system, and thus its fault diagnosis is quite essential for efficient operation. Most related research can only diagnose the known fault. However, the diagnosis may fail to work when an unknown fault occurs. Aimed to address the lack of new knowledge acquisition and real-time model classification updating, a novel method based on particle swarm optimization-support vector domain description (P-SVDD) and particle swarm optimization-kernel-based fuzzy c-means (P-KFCM) is proposed for adaptive fault diagnosis of HVCBs in this paper. In the proposed method, P-SVDD can detect the unknown fault sample by particle swarm optimization (PSO) parameter optimization while P-KFCM is used in known sample category recognition and its modified partition coefficient (MPC) cluster validity is used in unknown fault category search. The proposed method's operation process is introduced in detail, and the principles underlying the adaptive fault diagnosis model are discussed as well. In engineering application of an online monitoring system with fault diagnosis, the simulation results based on the measured HVCB closing coil current show that the proposed adaptive model can acquire new knowledge and update model classification in real-time with a higher diagnostic accuracy, compared with the existing algorithms.

A data-driven prognostic approach based on statistical similarity: An application to industrial circuit breakers

In this paper, a data-driven prognostic algorithm for the estimation of the Remaining Useful Life (RUL) of a product is proposed. It is based on the acquisition and exploitation of run-to-failure data of homogeneous products, in the followings referred as fleet of products. The algorithm is able to detect the set of products (sub-fleet of products) showing highest degradation pattern similarity with the one under study and exploits the related monitoring data for a reliable prediction of the RUL. In particular, a novel methodology for the sub-fleet identification is presented and compared with other solution found in literature. The results obtained for a real application case as Medium and High Voltage Circuit Breaker, have shown a high prognostic power for the algorithm, which therefore represents a potential tool for an effective Predictive Maintenance (PdM) strategy.

CFD Simulation of Temperature Rise in High Voltage Circuit Breakers

High-voltage circuit breakers (HVCB) interrupt short-circuit currents to protect electrical networks and act as electric conductor carrying the nominal current without producing impermissible temperature rise in any of its components. In the present work, the coupling of computational fluid dynamics with computational electromagnetics is presented for predicting the temperature rise in HVCB. Predictions are compared with measurement and design changes for the improvement are discussed.

Modelling and Simulation of SF6 High-Voltage Circuit-Breakers - an Overview on Basics and Application of CFD Arc Simulation Tools

The paper gives an overview on the basics of CFD arc simulation tools with respect to the simulation of the fluid mechanical processes in the interrupter unit of SF<sub>6</sub> high-voltage circuit-breakers at no-load and short-circuit switching-off processes. On the example of SF<sub>6</sub> self-blast circuit-breakers the complete process from the analysis of the switching-off process to the creation of a modular simulation model consisting of several sub models is illustrated. Details to the modelling in the particular sub modules and to the implementation are given. The capability of a CFD arc simulation tool based on the program package ANSYS/FLUENT is demonstrated on the basis of selected simulation results. Furthermore case examples for the application of the presented CFD arc simulation tool in the development process of high-voltage circuit-breakers are given.

高電圧遮断器の設置環境と環境負荷低減技術の動向

高電圧遮断器の設置環境と環境負荷低減技術の動向

Improved Arc Interruption of High Voltage SF<sub>6</sub> Circuit Breakers Using Modified Mayr’s Differential Equation

The study of arc interruption is very essential in high voltage circuit breakers since arc extinction must be achieved in the shortest possible time for effective protection of the power system. This paper presents some conventional arc models used in the research of interaction between switching arc and circuit during the interruption process of high voltage circuit breakers. It goes ahead to develop a model that is current dependent with a constant time parameter that helps to improve the process of arc interruption in high voltage SF6 circuit breaker. The simulation results show that the model has the capability of reducing the arc interruption time by completely extinguishing the arc current almost instantaneously.

Recent Trends in Development of High Voltage Circuit Breakers with SF6 Alternative Gases

The available knowledge of state-of-the-art of SF6 alternative gases in switching applications was collected and evaluated in an initiative of the Current Zero Club together with CIGRE. The present contribution summarizes the main results of this activity and will also include the latest trends. The main properties and switching performance of new gases are compared to SF6. The most promising new gases are at the moment perfluoroketones and perfluoronitriles. Due to the high boiling point of these gases, in HV applications mixtures with CO2 are used. For MV insulation perfluoroketones are mixed with air, but also other combinations might be possible. The dielectric and switching performance of the mixtures, with mixing ratios that allow sufficiently low operating temperatures, is reported to be only slightly below SF6. Minor design changes or de-rating of switchgear are therefore necessary. Differences between the gas mixtures are mainly in the boiling point and the GWP.

Предотвращение повреждений трансформаторов на электростанциях с укрупненными энергоблоками, подключенными к комплектному распределительному устройству через высоковольтные кабели

Many hydro power plants (HPP) in various countries are being operated with double generating units (DGU) where each unit generator-transformer has its own generator circuit breaker (CB) and both units are connected to a high voltage (HV) network via two common CBs installed in an air-insulated switchgear (AIS). Such circuitry was designed to halve the number of rather expensive HV CBs and to save on the space necessary for their installation. The necessary flexibility of HPP is continued as DGUs allow keeping one unit transformer in idle mode and putting into operation a unit generator via generator CB very rapidly if necessary. Long-term experience has demonstrated the high reliability of operation of HPPs with such circuitries, nevertheless due many reasons the AISs in HPPs are replacing now with more compact and convenient in operation gas-insulated switchgears (GIS). This replacement is taking place in many countries, and everywhere, the existing DGUs are connected to GISs via HV cables. It shall also be noted that each GIS circuitry is generally designed identically to previous AIS circuitry. But cases of damage of some unit transformers working in idle mode have been observed in a number of countries after such replacement. This paper reports the results of investigating one of these cases of damage, discusses the possible causes of this incident and elaborates some measures to prevent such damages in the future.

Analysis of Last Development Results for High Voltage Circuit-breakers Using New G3 Gas

Among many alternative gases proposed to replace SF6 as insulating gas, g<sup>3</sup> (green gas for grid), fluoronitril based component officially introduced at CIGRE 2014, can be now used for insulation projects and new environmental friendly circuit breakers. This gas mixture g<sup>3</sup>, presents a reduction of the global warming potential by 98% compared to SF<sub>6</sub> gas and shows quite good dielectric withstand capability. Many new investigations about thermal and chemical behavior have been done and are precised in this paper. Last switching test campaigns will be presented for 145 kV applications. Simulation tools should be updated to be applicable to these projects. Developments and comparisons with last test results will be analyzed.

Model-based fault analysis of a high-voltage circuit breaker operating mechanism

Model-based fault analysis of a high-voltage circuit breaker operating mechanism

Расчет переходных восстанавливающихся напряжений при выборе выключателей для электроустановок напряжением 110 кВ и выше

In clearing short-circuit faults, a transient recovery voltage (TRV) arises between the circuit breaker contacts, which may initiate repeated ignition of electric arc. For modern circuit breakers, including SF6 and vacuum ones, the maximum permissible TRV peak and rate of rise values are given in the GOST(State Standard) R 52565-2006. Earlier editions of the relevant standards contained the requirements only for air blast and oil circuit breakers. The use of modern electrical installations with circuit breakers selected without paying proper attention to TRV may lead to accidents with severe consequences. The article presents a theoretical and calculated comparison of the regulatory documents applicable to circuit breakers for rated voltages of 110 kV and higher and contains recommendations on calculating the TRV parameters that can be used as reference ones in checking the breaking capacity of high-voltage circuit breakers. Methods for calculating the parameters of TRVs with exponential, single-frequency and sawtooth waveforms are considered and compared with one another. Examples of calculating transients involving different TRV waveforms are given. The necessity of calculating TRV with a sawtooth waveform for SF6 and vacuum circuit breakers is pointed out. For updating the design conditions under which the maximum TRV rate of rise and peak values may occur, it is recommended to continue the study. In particular, it is advisable to determine the critical remoteness of a short circuit fault on the line side determined by the combined effect of power line parameters and short-circuit current values on the TRV.

Sulfur hexafluoride joins the fluorination tool box

In the ongoing quest for developing milder, safer, and more versatile fluorinating reagents, chemists at Massachusetts Institute of Technology have developed the first general strategy for using sulfur hexafluoride in organic synthesis (Angew. Chem. Int. Ed. 2016, DOI: 10.1002/anie.201608792). Sulfur hexafluoride, SF6, is a colorless, odorless, inert gas that is widely used as an insulator in electrical equipment such as high-voltage circuit breakers and as a tracer gas to check ventilation systems. But because SF6 has the highest known global warming potential for any compound, these applications are being phased out. The cheap gas could still be used to an advantage in large-scale syntheses in which SF6 is destroyed. MIT’s T. Andrew McTeague and Timothy F. Jamison may have found one option. The team created a process in which an iridium photocatalyst transfers an electron to SF6 to create a reactive radical species. The radical subsequently disintegrates, providing a source

Mechanical Fault Diagnosis of High Voltage Circuit Breakers Based on Variational Mode Decomposition and Multi-Layer Classifier.

Mechanical fault diagnosis of high-voltage circuit breakers (HVCBs) based on vibration signal analysis is one of the most significant issues in improving the reliability and reducing the outage cost for power systems. The limitation of training samples and types of machine faults in HVCBs causes the existing mechanical fault diagnostic methods to recognize new types of machine faults easily without training samples as either a normal condition or a wrong fault type. A new mechanical fault diagnosis method for HVCBs based on variational mode decomposition (VMD) and multi-layer classifier (MLC) is proposed to improve the accuracy of fault diagnosis. First, HVCB vibration signals during operation are measured using an acceleration sensor. Second, a VMD algorithm is used to decompose the vibration signals into several intrinsic mode functions (IMFs). The IMF matrix is divided into submatrices to compute the local singular values (LSV). The maximum singular values of each submatrix are selected as the feature vectors for fault diagnosis. Finally, a MLC composed of two one-class support vector machines (OCSVMs) and a support vector machine (SVM) is constructed to identify the fault type. Two layers of independent OCSVM are adopted to distinguish normal or fault conditions with known or unknown fault types, respectively. On this basis, SVM recognizes the specific fault type. Real diagnostic experiments are conducted with a real SF6 HVCB with normal and fault states. Three different faults (i.e., jam fault of the iron core, looseness of the base screw, and poor lubrication of the connecting lever) are simulated in a field experiment on a real HVCB to test the feasibility of the proposed method. Results show that the classification accuracy of the new method is superior to other traditional methods.

ИНТЕЛЛЕКТУАЛЬНЫЕ МОДЕЛИ КОМПЛЕКСНОЙ ОЦЕНКИ ТЕХНИЧЕСКОГО СОСТОЯНИЯ ВЫСОКОВОЛЬТНЫХ ВЫКЛЮЧАТЕЛЕЙ

ИНТЕЛЛЕКТУАЛЬНЫЕ МОДЕЛИ КОМПЛЕКСНОЙ ОЦЕНКИ ТЕХНИЧЕСКОГО СОСТОЯНИЯ ВЫСОКОВОЛЬТНЫХ ВЫКЛЮЧАТЕЛЕЙ

Performance Evaluation of Circuit Breaker Electrical Contact Based on Dynamic Resistance Signature and Using Health Index

High-voltage circuit breakers (CBs) are extremely important components for the function of power supply system. The need to predict proper function of CB has increased over the years. Dynamic resistance measurement (DRM) is an effective method to evaluate the condition of CB’s contact. This paper aims to predict the correlation between the various levels of contact degradation and characteristics of dynamic resistance waveform. Five diagnosis parameters are extracted from DRM curve. Using scoring and weighting techniques, heath index is applied to clearly identify the condition of CB as healthy, need caution, and risky. The proposed method is implemented with ten healthy and ten faulty electrical contacts as examples for illustrating the effectiveness of the method in assessing the CB condition.

Mechanical Fault Diagnosis of High Voltage Circuit Breakers with Unknown Fault Type Using Hybrid Classifier Based on LMD and Time Segmentation Energy Entropy

In order to improve the identification accuracy of the high voltage circuit breakers’ (HVCBs) mechanical fault types without training samples, a novel mechanical fault diagnosis method of HVCBs using a hybrid classifier constructed with Support Vector Data Description (SVDD) and fuzzy c-means (FCM) clustering method based on Local Mean Decomposition (LMD) and time segmentation energy entropy (TSEE) is proposed. Firstly, LMD is used to decompose nonlinear and non-stationary vibration signals of HVCBs into a series of product functions (PFs). Secondly, TSEE is chosen as feature vectors with the superiority of energy entropy and characteristics of time-delay faults of HVCBs. Then, SVDD trained with normal samples is applied to judge mechanical faults of HVCBs. If the mechanical fault is confirmed, the new fault sample and all known fault samples are clustered by FCM with the cluster number of known fault types. Finally, another SVDD trained by the specific fault samples is used to judge whether the fault sample belongs to an unknown type or not. The results of experiments carried on a real SF6 HVCB validate that the proposed fault-detection method is effective for the known faults with training samples and unknown faults without training samples.