Dial Setting Research Articles

Development and validation of a model to calculate anesthetic agent consumption from inspired and end-expired concentrations, minute ventilation, fresh gas flow and dead space ventilation.

Anesthetic agent consumption is often calculated as the product of fresh gas flow (FGF) and vaporizer dial setting (FVAP). Because FVAP of conventional vaporizers is not registered in automated anesthesia records, retrospective agent consumption studies are hampered. The current study examines how FVAP can be retrospectively calculated from the agent's inspired (FIN) and end-expired concentration (FET), FGF, and minute ventilation (MV). Theoretical analysis of agent mass balances in the circle breathing reveals FVAP = [FIN - (dead space fraction * FIN + (1 - dead space fraction) * FET) * (1 - FGF/MV)]/(1-(1 - FGF/MV)). FIN, FET, FGF and MV are routinely monitored, but dead space fraction is unknown. Dead space fraction for sevoflurane, desflurane, and isoflurane was therefore determined empirically from an unpublished data set of 161 patient containing FVAP, FIN, FET, MV and FGF ranging from 0.25 to 8 L/min delivered via an ADU® (GE, Madison, WI, USA). Dead space fraction for each agent was determined empirically by having Excel's solver function calculate the value of dead space fraction that minimized the sum of the squared differences between dialed FVAP and predicted FVAP. With dead space fraction known, the model was then prospectively tested for sevoflurane in O2/air using data collected over the course of two weeks with one FLOW-i (Getinge, Solna, Sweden) and one Zeus workstation (Dräger, Lübeck, Germany). Because both workstations use an electronically controlled vaporizer/injector, the dialed FVAP were available to allow the calculation of median performance error (MDPE) and median absolute performance error (MDAPE). MDPE and MDAP are reported as median and interquartiles. The empirical dead space fraction for isoflurane, sevoflurane, and desflurane were 0.59, 0.49, and 0.66, respectively. For prospective testing, a total of 149.4h of useful data were collected from 78 patient with the Zeus and Flow-i combined, with FGF ranging from 0.18 to 8 L/min. The model predicted dialed FVAP well, with a MDPE of -1 (-11, 6) % and MDAPE of 8 (4, 17) %. FVAP can be retrospectively calculated from FIN, FET, FGF, and MV plus an agent specific dead space fraction factor with a degree of error that we believe suffices for retrospective sevoflurane consumption analyses. Performance with other agents and N2O awaits further validation.

Koordinasi Proteksi Relai Arus Lebih pada Sistem Distribusi Radial Menggunakan Jaringan Syaraf Tiruan Perambatan Balik

<p><em>To reduce damage to electrical power equipment, protective equipment is needed that is designed as well as possible, so that the protection relay can isolate faults in parts of the distribution network as fast as possible. This backup protection need appropriate relay coordination, so that could protect, if it happens of a primary protection failure. To provide the best service to customers, it is necessary to coordinate the protection relay in the electric power system. To provide protection, the protection relay in the electric power system must be properly coordinated. In this study, we will make a simulation to calculate the TDS and Ipickup values of the overcurrent relay using a artificial neural network backpropagation with software Matlab R2016a. The results of this study can determine the value of TDS (Time Dial Setting) and Ipickup (Current pickup) by overcome the main problem of overcurrent relay protection coordination at the Ammurea II Factory PT. Petrokimia Gresik using a method artificial neural network backpropagation. And, also obtained the results of the minimum value of MSE (Mean Square Error) with the process using the method artificial neural network backpropagation.</em></p><p><em><br /></em></p>

Effect of Low Dose Intravenous Dexmedetomidine with 4% Sevoflurane on Haemodynamic Response during Laryngoscopy and Tracheal Intubation: A Randomised Controlled Study

Introduction: Over the last decade, the use of dexmedetomidine has found favour in obtunding the haemodynamic response during laryngoscopy and tracheal intubation but the use of higher doses has lead to a number of adverse effects. Aim: To compare the effect of low dose dexmedetomidine (0.5 µg/kg) and 4% sevoflurane (dial setting) with, Normal Saline (NS) and 4% sevoflurane (dial setting) on haemodynamic response to laryngoscopy and intubation. Materials and Methods: This randomised double blind controlled study was carried out in 60 patients of American Society of Anaesthesiologists (ASA) class I, undergoing elective surgery under general anaesthesia. The patients were allocated to group DX (n=30) and group NS (n=30), who received dexmedetomidine 0.5 µg/kg infusion and NS infusion intravenous (i.v.) respectively, in equal volume over 10 minutes before anaesthesia induction. They were evaluated for the requirement of thiopentone sodium, vecuronium bromide and sevoflurane, total i.v. fluids transfused haemodynamic parameters intraoperatively (pre and post induction) and postoperatively at regular intervals, and side effects. Results: On statistical comparison, Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Arterial Pressure (MAP) were found to be significantly less in group DX than in group NS with a p-value of <0.05. The total i.v. fluids infused in group NS and DX expressed as mean±Standard Deviation (SD) were 1145.00±228.21 and 1325.00±359.64, respectively. This was statistically significant. Thiopentone requirement was statistically more in group NS with a mean±standard deviation of 249.17±37.99 than in group DX (225.00±38.84). Similarly, sevoflurane requirement was statistically less in the DX group at various time intervals. Ten patients (33%) in group DX required antiemesis, compared to 13 patients (43%) in group NS. Two patients in group NS and three patients in group DX required injection (inj.) atropine to treat bradycardia. Conclusion: On comparison, a combination of 4% sevoflurane with 0.5 µg/kg dexmedetomidine was more effective in attenuating pressor response than 4% sevoflurane (dial setting) alone, but is associated with minor and manageable risk of bradycardia and hypotension.

Optimal restoration of directional overcurrent protection coordination for meshed distribution system integrated with DGs based on FCLs and adaptive relays

Integrating DGs in Distribution Networks (DNs) leads to miscoordination problems in Directional Overcurrent Relays (DOCRs). Optimization techniques and Fault Current Limiters (FCLs) are methods applied for restoring the coordination between protective relays. This paper proposes a new approach to solve the miscoordination problem between the DOCRs caused by the DGs into a looped DN. The Whale Optimization Algorithm (WOA) is used to obtain the optimum values of the pickup currents (Ip), and Time Dial Setting (TDS) of the DOCRs. The approach is applied to overcome the DOCRs miscoordination problem in the case of connecting FCL in series with the DG integrated with DN. The approach computes the minimum impedance value of FCL needed to be installed in series with the DGs to restore the DOCRs coordination. In the case of DN implies adaptive relays, the approach is modified to achieve the optimum combination between the FCL impedance values and the number and locations of adaptive relays to restore the coordination of the DOCRs at a minimum cost. The proposed and modified approaches are tested on 9-bus looped DN connected to DGs at different buses to prove their applicability. Moreover, several simulations are implemented to test the proposed methods for different fault locations.

Optimal coordination of over-current relay in a power distribution network using opposition based learning fractional order class topper optimization (OBL-FOCTO) algorithm

For the appropriate service of the power system network, the protection system which is equipped with relays and circuit breakers must operate in proper and efficient manner. In the power protection system, relays act as the brain of the circuit breaker which sense the fault situation and send the command to trip the circuit breaker to isolate the faulty part for reliable operation of rest part of the power system network. The relay performance may be affected by the Plug Setting (PS) and Time Dial Setting (TDS) due to the complex distribution network. The performance of the relay operation can be improved by proper tuning of TDS and PS. Therefore, to optimize the PS and TDS and to improve the performance of relay operating time, an opposition based learning fractional order class topper optimization algorithm called (OBL-FOCTO) is presented. The proposed method is a modified version of classical Class Topper Optimization (CTO, in which an Opposition Based Learning (OBL) concept as well as Fractional Order (FO) updating concept is introduced to improve the explorative and exploitive properties. The exploitation, exploration and convergence behavior of OBL-FOCTO is validated using CEC-2020 benchmark functions. The performance of the proposed method is evaluated using six test systems like IEEE 3 Bus, IEEE 4 Bus and IEEE 30 Bus system respectively. The superiority of the proposed method is shown by comparing the obtained results with some other existing results obtained using some existing methods. The results of the presented method for the relay coordination problem shows that the total operating time of the relays is minimized ( taking 0.037 to 10.432 percent less operating time to perform the relay operation for different cases) while compared to existing results for all six test systems with maintaining coordinations between each relays and also fulfill other constraints. Further, a non-parametric statistical hypothesis test has been applied to all test systems of the simulation results to show their significance.

An Optimized Adaptive Protection Scheme for Numerical and Directional Overcurrent Relay Coordination Using Harris Hawk Optimization

The relay coordination problem is of dire importance as it is critical to isolate the faulty portion in a timely way and thus ensure electrical network security and reliability. Meanwhile a relay protection optimization problem is highly constraint and complicated problem to be addressed. To fulfill this purpose, Harris Hawk Optimization (HHO) is adapted to solve the optimization problem for Directional Over-current Relays (DOCRs) and numerical relays. As it is inspired by the intelligent and collegial chasing and preying behavior of hawks for capturing the prey, it shows quite an impressive result for finding the global optimum values. Two decision variables; Time Dial Settings (TDS) and Plug Settings (PS) are chosen as the decision variables for minimization of overall operating time of relays. The proposed algorithm is implemented on three IEEE test systems. In comparison to other state-of-the-art nature inspired and traditional algorithms, the results demonstrate the superiority of HHO.

Optimal setting of DOC relay in distribution system in presence of D-FACTS

The process of selecting optimal settings for directional over-current relays (DOC relays) is a selection of time dial setting (TDS) and IP (backup current), So that changes in the system of electrical power distribution. In this work, a breeder genetic algorithm (BGA) has been applied to optimal settings of DOC relays with multisystem D-FACTS devices. The simulation consists of two network operation scenarios, scenario without D-FACTS which consisting of coordination of DOC relays against three phase faults, and the second scenarios with multi TCSC. In general, had been verified on optimal settings of relays that the impacts of TCSC insertion in 33-bus distribution system on DOC relays.

고침투율의 분산전원이 배전계통 보호 시스템에 미치는 영향을 고려한 과전류 계전기 정정값 최적화에 관한 연구

Recently, the research on hosting capacity (HC) calculation has become important due to the high interconnection of Renewable Energy Sources (RESs). The existing research on the maximum HC calculation is mainly focused on power quality. However, if the distributed generation is connected based on the HC calculation, there is a risk that the protection system could be affected and create some problems such as Sympathetic Tripping and Protection Blinding (protection device malfunction). Although this problem can be overcome by changing the relay correction value, the problems might still occur due to the limitation of the protection device setting. Therefore to solve this problem, an algorithm that can simultaneously optimize the Time Dial Setting of the overcurrent relay and the HC of the distributed generation without causing a protection system problem is proposed in this paper. The proposed algorithm was optimized through the most widely used genetic algorithm (GA), and the simulation was done using MATLAB and DigSLINET PowerFactory. The simulation was tested in IEE 37 bus system and from the simulation, the optimal overcurrent relay setting and HC value are obtained.

Application of PSO for optimal coordination of directional over-current relays in distribution system with distributed renewable energy sources

<p>The use of Distributed Renewable Energy Sources in the electrical network has expanded greatly. But, integration of these resources into distribution systems caused more problems in protection related issues such as mis-coordination, and changes the direction and value of fault currents. When connecting new D-RES to electrical power distribution networks, it is required to re-coordinate Directional Over-CurrentRelays (DOC-Relays) to ensure the continuity of the power transmission when the short circuits take place. This work presented a Particle Swarm Optimization (PSO) algorithm to determine two independent variables called Pickup current (Ip) and Time Dial Setting (TDS) for optimal setting of relays. From analysis result, the impacts of RES location in the distribution system on DOCRs had been observed on the optimal relays settings</p>

Per-Phase and 3-Phase Optimal Coordination of Directional Overcurrent Relays Using Genetic Algorithm

Penetration of the power grid by renewable energy sources, distributed storage, and distributed generators is becoming increasingly common. Increased utilization of these distributed energy resources (DERs) has given rise to additional protection coordination concerns, particularly where they are utilized in an unbalanced manner or where loading among phases is unbalanced. Digital relays such as the SEL-751 (produced by Schweitzer Engineering Laboratories, Pullman, WA, USA) series have the capability of being set on a per-phase basis. This capability is underutilized in common practice. Additionally, in optimization algorithms for determining relay settings, the time-overcurrent characteristics (TOCs) of relays are generally not treated as variables and are assigned before running the optimization algorithm. In this paper, TOC options themselves are treated as discrete variables to be considered in the optimization algorithm. A mixed integer nonlinear programming problem (MINLP) is set up where the goal is to minimize relay operating times. A genetic algorithm (GA) approach is implemented in MATLAB where two cases are considered. In the first case, the TOC and Time dial setting (TDS) of each relay is set on a three-phase basis. In the second case, per-phase settings are considered. Relay TDSs and TOCs are both considered as simultaneous discrete control variables. Despite the stochastic nature of using per-phase settings for unbalanced systems is found to generally allow for shorter operating times. However, for relatively balanced systems, it is best to use three-phase settings if computation time is of importance.

Optimal coordination of over current relay using opposition learning-based gravitational search algorithm

In this paper, the optimum coordination of over current relay in distribution system has been performed. The time dial setting (TDS) of over current relay is optimized by minimizing total operating time of relays. As the power system is a complex and highly interconnected, the complexity may be occurred in calculating optimum relay coordination time (TDS, phase setting etc.) by conventional or analytical methods. Therefore, an opposition learning-based gravitational search algorithm (OLGSA) is proposed for relay coordination optimization problem. The proposed optimization method can search the optimum solution for relay coordination problem from both the direction (initial populations and their opposite direction populations) in search space to reach global solution as early as possible. Three different distribution power systems are considered to verify the performance of the proposed algorithm for optimum relay coordination problem. The simulation results for all three cases have been compared with existing results. The outcome of the proposed method for relay coordination problem shows that the total relay operating time is minimized (20–40 % improvement in relay total operating time for different cases) comparably than available results for all three cases by maintaining coordinations among relays and satisfying different constraints.

Protection Coordination of Bidirectional Overcurrent Relays Using Developed Particle Swarm Optimization Approach Considering Distribution Generation Penetration and Fault Current Limiter Placement

This article is treated with the protection coordination of bidirectional overcurrent relays (OCRs) in distribution power systems to obtain the best performance at a minimum total time dial setting (TDS). High penetration of distribution generation (DG) into distribution systems may significantly affect the protective system; since they increase the short-circuit level by injecting an extra share of fault current, it results in changes in the power/current flow direction. Accordingly, the fault current limiter (FCL) devices should be utilized to mitigate the short-circuit current. FCLs and DGs both will disturb the protection settings of protective equipment. The characteristics and the set point of inverse time relays depend on the fault clearing time (FCT) and the pick-up current. Therefore, an optimization approach is required to minimize the FCTs and TDSs of main relays and backup ones to protect all equipment. Moreover, this strategy selects the optimal placement of the FCL cooperatively according to the cost minimization. The optimization approach is implemented based on the particle swarm optimization (PSO) method within an extra parameter to improve the convergence speed and find the global solution, especially at initial iterations. The proposed optimization approach named developed PSO (DPSO) is tested on the IEEE 14-bus system and compared with some existing methods. Finally, the analysis and evaluations present the effectiveness of the best current transformer (CT) settings with the minimum response time.

Optimal Coordination of Directional Overcurrent Relays in Meshed Active Distribution Network Using Imperialistic Competition Algorithm

The optimal setting of directional overcurrent relays (DOCRs) ensures the fault detection and clearing in the minimum possible operation time. Directional protective relaying is carried out to coordinate relay settings in a meshed network in the presence of distributed generation. The main goal of DOCR coordination is to find the optimal time dial setting (TDS) and pickup multiplier setting (PMS) to reach the minimum total operation time of all primary relays in the presence of coordination constraints. Due to the complexity of mixed integer non-linear programming (MINLP) problem, imperialistic competition algorithm (ICA) as a powerful evolutionary algorithm is used to solve the coordination problem of DOCRs. The proposed DOCR coordination formulation is implemented in three different test cases. The results are compared with the standard branch-and-bound algorithm and other meta-heuristic optimization algorithms, which demonstrates the effectiveness of the proposed algorithm.

An Improved Inverse-Time Over-Current Protection Method for a Microgrid with Optimized Acceleration and Coordination

This paper presents an improved inverse-time over-current protection method based on the compound fault acceleration factor and the beetle antennae search (BAS) optimization method for a microgrid. The proposed method can not only significantly increase the operation speed of the inverse-time over-current protection but also improve the protection coordination by considering the possible influential factors in terms of microgrid operation modes, distributed generation (DG) integration status, fault types, and positions, which are marked as the most challenging problems for over-current protection of a microgrid. In this paper, a new Time Dial Setting (TDS) of inverse-time protection is developed by applying a compound fault acceleration factor, which can notably accelerate the speed of protection by using low-voltage and short-circuit impedance during the fault. In order to improve the protection coordination, the BAS algorithm is then used to optimize the protection parameters of the pick-up current, TDS, and the inverse time curve shape coefficient. Finally, case studies and various evaluations based on DIgSILENT/Power Factory are carried out to illustrate the effectiveness of the proposed method.

An application of evaporation-rate-based water cycle algorithm for coordination of over-current relays in microgrid

Relay coordination is reliable and crucial to guarantee that healthy feeders are properly isolated from the defective areas in a microgrid network. An appropriate protection scheme must be properly planned during the design of the microgrid to ensure safety for the power components in the event of a failure. The implementation of distributed generators in the microgrid changes the total network’s Load-Flow and often impacts the magnitude and direction of the fault current. Using the nature-inspired novel evaporation-rate-based water cycle algorithm (ERWCA), the enhancement in microgrid protection is accomplished in this work by optimizing the relay settings, reducing their operation time and time dial setting of each relay. The approach proposed is validated with the IEC microgrid benchmark system and the findings are contrasted with current techniques. It is found that the proposed strategy produces substantial improvement for the microgrid in the application of over-current relays and greatly reduces the relays’ overall net operating time.

Absolute standardisation and determination of the half-life and gamma emission intensities of 89Zr

An absolute standardisation of 89Zr was performed alongside determination of gamma emission intensities and half-life. The collected data were evaluated alongside complementary works from previous publications and new recommended nuclear data values are presented including a new evaluated T1/2 = 78.361(25) h and new absolute intensities for gamma transitions resulting from its decay to 89Y. Dial settings for commercially available radionuclide calibrators are also presented and show a relative difference of approximately 3% compared to previously published values.

Optimal Overcurrent protection for industrial medium voltage network (Dept. E)

Abnormal condition and faults in power systems can cause power supply interruption and sometimes equipment damage. Hence, there is an increasing need for an effective protection scheme. In order to obtain a secure and reliable protection system, an effective coordination has to be satisfied between backup and primary protection devices. The main objective of this paper is to select the optimal settings of overcurrent relays that achieve the minimum operating time for relays when subjected to abnormal conditions or faults. The coordination process between overcurrent relays inside the network is accomplished considering detecting the fault and tripping the nearest circuit breaker to disconnect the affected area without affecting other areas. This paper investigates the protection requirement of switchgears in a practical power plant and design a coordination set for all circuit breakers and overcurrent relays in the low and medium voltage areas. In addition, both linear programming and genetic-algorithm methodologies are used to optimize the values of time dial setting for different operating scenarios of power plants so as to achieve the minimum operating times of overcurrent relays.

Desarrollo del algoritmo genético heurístico para la coordinación de protecciones

The coordination of overcurrent relays is an easy task when dealing with a radial distribution line. However, when directional units are in place to protect meshed networks, the problem becomes very complex. This is because the protection device must offer primary and backup operation for the same or multiple lines using the same protection setting. Moreover, considering two parameters namely the time dial setting and the current pickup setting make the coordination problem even more complex to be achieved manually. Therefore, in this article, the protection coordination study is formulated as an optimization problem to be solved using a heuristic Genetic Algorithm. This not only saves time for the protection engineer; it also transfers the burden to a computer using artificial intelligence and guarantee that the results are close to optimal.

Primary activity standardization of 177Lu for calibrating commercial dose calibrator

Primary activity standardization of 177Lu has been conducted at the Center for Technology of Radiation Safety and Metrology-National Nuclear Energy Agency (PTKMR-BATAN) to establish a national reference standard for 177Lu measurements. The standardization was performed using a 47i(3(LS)-y coincidence counting system with digital coincidence counting (DCC) technique. The activity standardization of 177Lu gave a result of 148 kBq/g + 1.78 kBq/g at a reference time with uncertainty value evaluated at k = 2. The result was then used to establish a secondary standard by calibrating the reference ionization chamber using the ‘dialing-in’ method. A dial setting value of 024 was obtained on the standard reference IC. The new dial setting will be used in the routine calibration services of commercial dose calibrator to ensure all measurements of 177Lu are traceable to the national standards.

Low powered variable voltage E-Cigarette batteries under perform at higher power settings

Objective: Electronic Cigarettes (EC) use continues to increase with many efforts underway to develop dose-response relationships for clinical and sub-clinical purposes. This study investigated the battery performance of several variable voltage (VV) ECs capable of varied voltage outputs.Materials and Methods: Six brands of VV EC batteries were tested for dial setting accuracy (voltage) and power supplied during simulated vaping. All measurements were conducted using a single atomizer with two different resistance coils at four voltage settings in a blocked randomized structure. Battery dial settings were accurate when disconnected from an atomizer.Results: When powering an atomizer during simulated vaping, all batteries supplied power linearly up to approximately 8.5 watts. Beyond 8.5 watts all batteries began to undersupply power, plateauing around 9-10 watts, depending on the specific battery.Discussion: This behavior was not consistent with battery internal resistance. Undersupply of power at higher device settings will result in lower-than-expected nicotine (or THC) delivery and potentially lower pyrolysis products such as aldehydes.Conclusion: Studies seeking to associate VV EC power with psychological, physiological or toxicological effects should measure the actual power supplied or else a negative bias is likely to be observed in trials above 8.5 watts.