Performance Of Protection System Research Articles

Utilization of thermoelectric technology in converting waste heat into electrical power required by an impressed current cathodic protection system

Supplying an energy source for impressed current cathodic protection is considered as the main challenge for pipelines corrosion protection in remote areas. The purpose of this study is to construct and evaluate the performance of an impressed current cathodic protection system using waste heat to replace the external electrical power supply. The system consists of four thermoelectric modules producing the electrical power from the hot combusted gas stream. Mathematical modeling and Buckingham Pi theorem were applied to obtain five dimensionless parameters and several models to estimate the system performance. According to the experimental results, the generated voltage, electrical current, and temperature difference have been increased rapidly during the experiment up to 201 mV, 44 mA, and 20 K, respectively. Moreover, mathematical modeling and Buckingham Pi theorem were also utilized to obtain three equations, two nonlinear and one dimensionless equation, to calculate the generated electrical voltage with the maximum error of 1.22%, 9.11%, and 10%, respectively. The results indicate that the temperature difference (between inlet gas and environment) and the figure of merit have a direct effect, and heat sink thermal resistance has an inverse effect on the generated electrical voltage.

Influence of process bus on performance of power system protection

The development of substation operations under open standards has ensured interoperability among technology manufacturers and has led to system management evolution. Implementing a Process Bus (PB) and its related technologies represents the future of power systems protection. The release of the IEC61850-9-2 sampled values protocol has allowed the replacement of the conventional measurement method by an ethernet-based system at substation yards. This study focuses on the PB implementation effects such as the trip time delay and possible time shift over the protection system performance. The paper points out aspects that should be considered through the engineering process and design, considering the two PB standards, IEC61850-9-2LE and IEC61869-9. A test architecture was composed of a conventional relay, and two PB relays synchronized using the IEEE-1588-Precision Time Protocol (PTP). Four tests were carried out, including a software simulation and field-collection data. The two PB standards presented similar results during the tests. The relay signal resampling results in time shifts that should be properly compensated, and the digitalization delays found can occasionally add more than 9 ms in the final trip time and must be considered in protection studies prior to implementation. Otherwise, it can significantly impact on the project of the power system.

Measuring performance and identifying metrics of machine protection systems for particle accelerators

AbstractMachine protection systems are used at high power particle accelerators in order to prevent long downtimes due to equipment damage. No systematic way to measure their success at reaching this goal exists (the performance of machine protection systems). This paper briefly goes through the history of particle accelerators and gives an introduction to machine protection for particle accelerators. Two metrics to measure the performance of machine protection systems are suggested and discussed. This paper is part of the work to define the problem from the perspective of a recently initiated PhD‐student project.

Performance assessment of cathodically protected reinforced concrete structure based on alternative performance criterion: a case study

Performance of cathodic protection system in reinforced concrete structures is generally evaluated using 100 mV decay criterion. This approach is widely used, however has its own limitations. Recently, a new approach by determining the actual corrosion rate using the Butler Volmer equation has become an ‘alternative’ criterion for assessing the performance of cathodic protection system. This paper deals with critical examination and practical application of Butler-Volmer Equation to judge the effectiveness of cathodic protection system. Sensitivity analysis of various input parameters through numerical modelling by parametric studies showed significant dependence of corrosion rate on cathodic Tafel slope. One-year field data from a cathodic protection monitoring site in UK was collected and variability in the two approaches was assessed.

Design of an Ionic Conductor as Permanent Electrode for Monitoring Cathodic Protection System performance.

The most dominant used method for protecting the bottom of a tank is impressing a current cathodic protection (ICCP). Monitoring the CP system is critical to maintain and extend the service life of the exterior bottom of the storage tank. The bottom of the tank usually located on or near the surface of the ground and in contact with materials used to support the tank and so presents a corrosion challenge. This work presents a successful design of an ionic conductor that can be used as a monitor procedure of ICCP system for ground storage tanks bottom. The new ionic conductor system offers an accurate and efficient performance compared with old copper/ copper sulphate electrode monitoring system. The risks failure of permanent electrodes including cables disconnection and electrode dryness are increasing. Ionic conductors were used to insure proper potential monitoring. The new ionic conductor system scheme has the features of lower cost and less installation time over conventional methods.

Performance Assessment of Magnesium Anodes Manufactured by Sintering Process

This work shows the performance of cathodic protection systems formed by an API (American Petroleum Institute) X52 steel exposed to seawater and coupled with galvanic anodes of Mg, Mg-1Cr, and Mg-1Nb fabricate by sintering technique at a temperature of 500 °C. Potential monitoring indicates that X52 steel of the three systems remained in the protection zone. Mg-Nb/X52 system showed the more stable potentials since the first day; the recorded values remained between −1.0 and −1.1 V vs. SCE (saturated calomel electrode) during the seven days of exposure time. Current density records show that Mg/X52 system had the most stable values, while the other two systems (Mg-Cr/X52 Mg-Nb/X52,) had current fluctuations. The Mg-X52 system recorded the most negative potential values, which can be attributed to a greater magnitude and a better distribution of the cathodic protection current. However, the Mg-Nb/X52 system had a better result because the current drained by the system was constant throughout the experiment.

Investigation of an IEC 61850 standard-based process bus implementation of a protection and control scheme for parallelly connected transformers

PurposeThis paper aims to focus on the implementation of the International Electrotechnical Commission (IEC) 61850–9-2 standard based process bus with merging units (MUs) and sampled values (SV) to improve the protection and control systems. The digital process interface is important to be included on the process bus level.Design/methodology/approachThe IEC 61850–9-2 process bus standard is not extensively used in regard to SV when the IEC 61850 standard is implemented by power utilities. Many protection and control intelligent electronic devices (IEDs) are connected to a substation communication network, routers and switches using fibre-optic linked Ethernet. However, inductive current transformers (CTs) and voltage transformers (VTs) secondary circuits are still hardwired to the IEDs. The paper highlight issues with the copper wires for currents signals and how these issues can be eliminated by using the MUs and the SV protocol. The voltage regulator control IED of each transformer is required to regulate the voltage level of the secondary side bus bar it is connected to. All the regulating IEDs of parallel-connected transformers are required to communicate with each other to share information. They collectively control the bus bar voltage depending on the switching configuration of the parallel transformers.FindingsIt is shown that process bus information such as the high voltage switchgear status information of primary plant in the yard, can be used to improve the substation protection and control systems. The power transformer protection and voltage regulator control are focused on.Research limitations/implicationsThe deliverables of the research work can be applied in: The Centre for Substation Automation and Energy Management systems of the Department of Electrical Engineering, power utilities and other establishments using power systems and digital substations in the electrical supply industry. The research work on the thesis led to the development of a laboratory test-bench where students can learn and understand the basics of the IEC 61850–9-2 SVs principles. The test-bench components such as the IEDs, real-time digital simulator, standalone MUs and Ethernet equipment can be used for future research applications. The test-bench can be used to demonstrate during course work for students at the University, the basics of digital substations using a process bus network with IEDs, MUs and Ethernet equipment.Practical implicationsThe research work showed where lab equipment is getting outdated and future equipment will be required for research work in IEC 61850–9-2 process bus.Originality/valuePower utilities can benefit from implementing the IEC 61850 part 9–2 of the standard and by using MUs and other process interface information in substations. A cost reduction in high voltage equipment, substation installation and commissioning costs and better performance of protection and control system can be achieved.

In situ estimation of effective liquid water content on a wind turbine using a thermal based sensor

To correctly assess the performance of wind turbine ice protection systems (IPS), a complete overview of the meteorological conditions is needed. The same would prove helpful in the usage of the alternative operational control strategies during icing events. A crucial factor to consider is the estimation of the liquid water content (LWC). This parameter has a significant impact on the thermal behavior of IPS and therefore their efficiency. Finding a reliable, robust and accessible method for estimating the LWC on wind farms is a challenge that has yet to be solved. Wind farm operators frequently have to rely on visual observations to guide their decisions. This paper proposes a method for estimating the effective LWC in wind farms using a thermal based ice sensor. This proposed method was calibrated using the equivalent effective LWC obtained from image analysis of ice accretion on a reference cylinder. Over the winter of 2018–2019, on a Canadian site, 8 icing events were retained to provide calibration data. An increase of more than 10 mm of ice frontal thickness was observed during the daylight for all the events. The thermal based ice sensor proved to be coherent with the camera observations while presenting a more robust method with better sensitivity and accuracy. Having a reliable LWC estimation method not only presents an advantage for wind turbine operation but could also potentially help the site assessment process where the numerical weather predictions are not able to capture intra-site variations of the icing severity.

Thermal protection of electronic devices based on thermochemical energy storage

With the widespread use of electronic devices, heat dissipation and thermal protection issues have attracted attention. High temperatures can lead to failure or even burnout of the circuit boards, which are key parts of electronic devices. Most of the current research uses passive thermal protection based on phase change materials. In this study, a thermochemical energy storage material, boric acid, is applied as the thermal protection layer of electronic devices, and a thermal protection system that integrates heat insulation, heat storage, and heat reflection is proposed. The characterization results reveal that the decomposition temperature of boric acid is 112.9 °C, which is close to the thermal protection temperature of the circuit board, and the decomposition enthalpy of boric acid is as high as 1173.7 J/g, indicating that it has a relatively high heat storage capacity. In the experiments performed at 300 °C, the thermal decomposition of boric acid provides a 108.1 °C constant-temperature platform for 1800 s for the circuit board, proving that boric acid can effectively prevent heat input from the external high-temperature environment and extend the thermal protection time. In addition, as the water vapor produced by thermal decomposition evaporates, the boric acid does not release heat like phase change materials during the cooling process, which can prevent secondary heat damage to the circuit board. The performance of the boric acid-based thermal protection system can be further improved by adding heat insulation and heat reflection materials to it.

Lightning Protection of Photovoltaic Systems: Computation of the Developed Potentials

In this paper, the performance of a lightning protection system (LPS) on a grid-connected photovoltaic (PV) park is studied by simulating different scenarios with the use of an appropriate software tool. The aim of this paper is to highlight the importance of an LPS and optimize its design for the protection of equipment and personnel in case of a direct lightning strike. In particular, developed potential due to lightning strikes is examined considering isolated and non-isolated external LPS. Moreover, the effect of the separation distance on the lightning performance of the PV installation is investigated for different soil structures and grounding systems. The extracted results are expected to support the design and implementation of a secure PV park and endorse its uninterrupted operation considering techno-economically balanced protection measures.

Long-Term Performance of Anti-Freeze Protection System of a Solar Thermal System

In a moderate, transitory climate, to prevent freezing of outdoor pipes and collectors in solar thermal systems, anti-freezing fluids are commonly used. There is little experience of using water without any additives as a solar thermal fluid in such a climate. Based on these findings, to fill the knowledge gap this article presents the long-term results of thermal performance and anti-freeze protection of a solar heating system with heat pipe evacuated tube collectors with water as a solar thermal fluid. The operation of this system under real conditions was analysed for five years in southern Poland. The annual value of solar insolation ranged from 839 to almost 1000 kWh/m2. The monthly efficiency of the solar collectors from March to October was usually higher than 25%, and the lowest was between November and January. The anti-freeze protection system consumed annually from 7 to 13% of the heat generated by the collectors in the installation. Supporting the operation of the central heating system in the building during the winter season highly improved the efficiency of the solar collectors. Results show that it is possible to use water without any additives as a solar thermal fluid in a moderate, transitory climate.

A new-intelligent method for evaluating the lightning protection system performance of complex and asymmetric structures

- In order to model and visualize the performance of lightning and its protection system, several analytical methods such as the rolling sphere method (RSM) have been developed in which protected and unprotected areas are separated. However, in none of these methods, the scale and severity of the damage can be quantified numerically. In this paper, by using the leader progression model (LPM) in 3D space along with an intelligent algorithm named Teaching-Learning-Based optimization (TLBO), a new method is proposed to identify the vulnerable areas with the highest probability of lightning strikes. In using the TLBO algorithm, a new method for determining the critical range of current is defined and the most vulnerable points on the structure are determined, so that, based on the simulation results, the best positions of the lightning rods can be specified respectively. A sample asymmetric structure of height less than 60 meters is analyzed as a case study, and the optimal locations and heights of lightning rods are determined using the rolling sphere method and the proposed method, respectively. The simulation results validate the effectiveness of the proposed method which makes it suitable for other complex structures.

Single and combined use of friction-damped and base-isolated systems in ordinary buildings

This study addresses the nonlinear seismic responses of ordinary moment frame building upgraded with a series of passive protective systems. To this, friction damper (FD) as an energy dissipation device and lead rubber bearing (LRB), friction pendulum bearing (FPB), and high damping rubber bearing (HDRB) as base isolators were considered. The effectiveness of the isolation systems together with the dampers was investigated comparatively. For this purpose, eight different cases were taken into account. The first case contains a five storey steel ordinary moment frame considered as fixed-base (FB), the other four cases are the single use of FD, LRB, FPB, and HDRB in such frame, and the last three cases include the upgrading of the frame with the combination of FD with each of the base isolation systems. They are modelled using a finite element program, and evaluated by the nonlinear time history analyses in which seven ground motion records were adopted. The seismic performance of the passive protective systems was evaluated by the engineering demand parameters such as storey displacement, bearing displacement, relative displacement, roof drift ratio, interstorey-drift ratio, absolute acceleration, base shear, base moment, hysteretic curve, and energy dissipation. One of the main outcomes of this study was that single protective system could not always satisfy fully operational performance level, while the combined systems of the base isolation with friction damper effectively achieved for the case study frame. Furthermore, the results showed that the combined systems were capable of limiting the inter-storey drift without increasing the absolute accelerations.

Influence of angle of attack on a combined opposing jet and platelet transpiration cooling blunt nose in hypersonic vehicle

Flying condition with angle of attack is inevitable in a hypersonic vehicle, and it may influence the thermal protection system (TPS) performance of opposing jet and its combinations. A 3D Navier-Stokes equation and shear stress transfer (SST) k-ω model with compressible correction are employed to simulate the angle of attack characteristics of a blunt body with opposing jet and platelet transpiration TPS. The flowfield and heat flux transfer for angles of attack 0°, 3°, 6° with jet pressure ratio PR=0.1 and 0°, 6°, 12° with PR=0.2 are obtained. Numerical results show that the flowfield is no longer symmetrical with the effect of the angle of attack. The flowfield and heat transfer in windward and leeward performed adversely. The recompression shock wave in windward is strengthened, which increases local temperature and strengthens heat transfer. The opposing jet fails in thermal protection when the angle of attack reaches critical value; however, the critical angle of attack can be promoted by increasing PR. Finally, the transpiration gas can strengthen the cooling efficiency of windward, thereby, increasing the critical angle of attack.

Improvement of structures seismic response based on pendulum systems with double sliding surface

The seismic isolation of the construction structures is of particular importance because the optimum stability premises of the structures during the seismic events are ensured. There are different isolation methods but based on the structure base isolation principle, the friction pendulum bearing systems (FPBS) have been used with good results in equipping new structures and also in rehabilitating of the old buildings that had to be consolidated. The double surface friction Pendulum (DSFP) bearing is an improved version of the well-known single concave friction pendulum bearing (FPBS). The principal benefit of the DSFP bearing is represented by its capacity to accommodate substantially larger displacements compared to a traditional FPBS of identical plan dimensions. Moreover, there is the capability to use sliding surfaces with different radius of curvature and friction coefficients, offering the designer greater flexibility to optimize the protective system performance. Through these systems good seismic isolation results are achieved for the building structures where mounted interposed between the foundation and the superstructure realizing the disconnection between the two structural elements. The disconnection is important because the insulated structure vibration period is modified in the sense of its significant increase, also with the increase of structure lateral flexibility, ultimately reducing the ground acceleration and avoiding the efforts vertical transmission to the isolated structure upper levels. The double surface friction pendulum system ensures an important modification of the isolated structure behavior materialized through the seismic response mitigation. This paper describes the double surface friction bearing (DSFP) constructive details with operation principles and also presents some numerical analysis results related to force–displacement relation considering different values of curvature radius and friction coefficients of the two friction surfaces used

Mitigation performance of the process protection system on the accident consequences of H2S-containing natural gas release and explosion

Toxic loads and explosion overpressure loads pose grave threats to the offshore oil and gas industry. Many safety measures are adopted to prevent and mitigate the adverse impacts caused by toxic loads and explosion overpressure loads. As a general safety barrier, the process protection system has been widely used but rarely evaluated. In order to assess the barrier ability, the mitigation performance of the process protection system is concerned in this study. Firstly, several chain accidents of H2S-containing natural gas leakage and explosion are simulated by varying the response time of the process protection system with CFD code FLACS. Qualitative assessment is conducted based on the variation of the dangerous load profiles. Furthermore, the quantitative assessment of the mitigation performance is accomplished by considering its ability in reducing the probability of fatality. Emergency evacuation and no emergency evacuation are considered respectively in the quantitative assessment. The results prove that the process protection system takes effect on mitigating the toxic impact and explosion overpressure impact. The results also demonstrate that although the emergency evacuation may result in a severer explosion load to the operator, the process protection system can mitigate the adverse impacts regardless of whether the emergency evacuation is conducted or not.

Distribution systems protection considering aspects of coordination and time-dependent response for reliability evaluation

A detailed representation of the time-dependent characteristics of a protection system requires a more complex modelling of two elements that are typically outside of the reliability evaluation scope: short circuit current and response given by protection devices. The first requires that aspects such as fault type, affected phases, location and fault resistance are modelled, while the second depends on a proper representation of protection time-current curves. The proposed methodology creates a simulation model where the up and down cycle of components is merged with the operation of protection devices and the fault characteristics using sequential Monte Carlo Simulation. A comparison between the classical approach and a more representative protection modelling highlights the benefits of a time-dependent representation of the performance of protection systems.

A PROPOSED MODEL FOR DIMENSIONALITY REDUCTION TO IMPROVE THE CLASSIFICATION CAPABILITY OF INTRUSION PROTECTION SYSTEMS

Over the past few years, intrusion protection systems have drawn a mature research area in the field of computer networks. The problem of excessive and unrelated features has a significant impact on the rate of intrusion detection performance. To classify network traffic, whether harmful or normal, the use of machine learning algorithms has been applied in many previous researches. Therefore, to obtain the accuracy, we must reduce the dimensionality of the data used. An improved model for feature selection is proposed in this paper to increase the accuracy of intrusion detection systems, hence improve the performance of an intrusion protection system. We evaluate the performance of our developed model based on a comparison of several known algorithms as well as other algorithms that use of deep learning with a multi-layered perception algorithm. The NSL-KDD dataset is used for examining classification. The proposed model outperformed the other learning approaches.

Investigation of Galileo Probe Entry Heating with Coupled Radiation and Ablation

This paper presents a trajectory-based heating and ablation study of the Galileo probe forebody flow and thermal protection system performance. The validity of modeling assumptions regarding diffusion, radiative heating, and ablation made in previous work, including preflight predictions, are addressed. The Navier–Stokes equations are solved assuming a one-temperature chemical nonequilibrium flowfield with coupled radiation and ablation. Geometric changes in the forebody due to ablation are accounted for. Solving the Stefan–Maxwell equations to compute the species mass diffusion in the flowfield, instead of assuming a constant Schmidt number as was done in previous studies, was found to significantly increase total predicted recession by about 10% on the flank, due to increased convective heating. Application of the high-fidelity ray-tracing approach resulted in a 10% reduction in the radiative heating along the forebody when compared with the heritage tangent-slab approximation. Additional modeling approaches, such as state-specific H modeling, application of ray-tracing for coupled flowfield radiative source terms, and including precursor absorption were considered but found to have a minimal impact on recession. The resulting nominal prediction was found to be nearly within the uncertainty of the flight data along the entire surface of the probe. This improved agreement relative to past studies is due to the notable impact of shape change, multicomponent diffusion, and ray-tracing radiative heating, most of which were not included in previous models. To provide uncertainty bounds for the present simulations, an uncertainty analysis was performed. Sources of uncertainty were identified in the ablation modeling, radiation modeling, flowfield kinetics, turbulence modeling, and thermodynamic properties of select species. When the impact of all considered uncertainties are combined, the stagnation point recession varies between and of the nominal value while a near constant uncertainty band exists on the flank.

Estimation performance of the lightning protection system in an urban 110 ​kV grounding grid substation

A lightning protection system (LPS) of an urban 110 ​kV substation is designed and analyzed according to NFPA 780 and IEC 62305-3 standards. The analysis of the LPS is established on the value of risk assessment. The total area of the substation has been described based on the modern designs represented by the real operational efficiency of the facility. This study aims to improve the understanding of the unexpected manner of the grounding system beneath lightning currents by clarifying the basic concepts of the lightning protection level. The mode was represented by the CDEGS software package, which provides effective geometrical modeling with object and result visualization. Furthermore, module and automated Fast Fourier Transform (FFT) is implemented in this study to simulate electromagnetic fields in the time and high-frequency domains. These current values are compared to the desired protection levels within the standards. The study results show that for the improved protection of the primary system against lightning, the total power grid must be considered as a source of improvement for studying shielding influence and the protection levels provided inside this substation. The lightning behavior of overhead transmission lines is associated with line flashover protection consequent to lightning strokes.