Dial Setting Research Articles

Melaka Network Overcurrent Protection & Coordination Analysis Using PSCAD Software

This paper presents a study on the modeling of the 132/33/11kV PMU Pulau Gadong network and the Melaka radial distribution feeder. The study proposes a protection scheme by providing the appropriate relay Pickup current/Plug Setting (PS) and Time Multiplier Setting (TMS )/Time Dial Setting (TDS) for the discrimination process and evaluating the effect of parallel transformers during faults. For this study, the IEC std 255-3 standard inverse IDMT curve characteristic was chosen for the simulation using the Power System Computer Aided Design (PSCAD). The results show that these values were trustworthy, which provide adequate and reliable protection for the whole network.

Optimizing DOCRs coordination when synergizing energy management with V2G using innovative optimization algorithms

This manuscript proposes an optimal coordination approach for directional overcurrent relays (DOCRs) within electric vehicle charging stations (EVCS), considering energy management and Vehicle-to-Grid (V2G) integration. The study focuses on maximizing efficiency and grid interaction in charging stations by addressing the challenge of DOCRs coordination. Three innovative optimization algorithms, namely the Hunger Games Search (HGS), Hunter Prey Optimization (HPO), and Sparrow Search algorithm (SSA), are employed to determine the optimal coordination for the DOCRs and get the time dial setting (TDS) and pickup current (IP) targeting minimum operating time for all DOCRs, considering factors such as load balancing, fault detection, and power quality in three different scenarios. EVSC has two types of charges DC and AC with two modes: V2G mode when EV is discharged into the grid, and G2V mode when EV is charged from the grid. Fast chargers are used to proceed as it can work in two modes V2G and G2V. Through extensive simulations and performance evaluations, the results demonstrate the effectiveness of the proposed approach. The three scenarios are simulated by using ETAP and MATLAB software according to fault location and to achieve voltage regulation and sufficient power for loads to achieved continuity of service for up to 1960.7 kW loads that kept fed. The proposed approach achieved the target of protecting the EVCS in minimum operating time of relays using the three algorithms and SSA introduces the best result more than other algorithms for the relay operating time with reduction up to 21 %.

Integration of Artificial Intelligence for Enhanced Coordination of DOCR Protection in Distributed Generation Systems

Distributed generation (DG) is an approach that involves adding decentralized power generation within a distribution network. Distributed generation systems can reduce transmission losses, increase the reliability of energy supply, minimize carbon emissions, and enable the active participation of consumers in energy production. However, with the increase in distributed generation, electric power systems face new challenges in maintaining operational reliability and safety. Disruptions such as short circuits or overcurrent can occur in the system, and appropriate protective responses are required to protect the power grid from more significant damage. The addition of DG also causes the short circuit current to vary and results in system protection coordination having to be redone. Carrying out coordination will take a long time. This research uses modeling and simulation of a distributed generation system with various operating conditions and works adaptively according to changes in the system due to the addition of DG. The results obtained from the simulation are used in neural network training to study the relationship patterns between directional overcurrent relays (DOCR) parameters and system operating conditions. The backpropagation algorithm is used in the Artificial Neural Network (ANN) training process. The training process utilizes the maximum Short Circuit Current (ISC) input obtained through generation, fault location, and fault type. Time Dial Setting (TDS) and Ipickup values are used as ANN training targets. After testing, the results obtained are in accordance with the target data. The efficacy of this method is further demonstrated through ETAP simulations, which confirm that ANN is a suitable approach for modeling adaptive and optimal relay coordination systems.

An adaptive protection coordination for microgrids utilizing an improved optimization technique for user-defined DOCRs characteristics with different groups of settings considering N-1 contingency

Due to the increased integration of distributed generation (DG) in electric power systems, optimal coordination of overcurrent relays has become a key problem in power distribution systems. However, there is a lack of expertise in the creation of optimum microgrid coordination that takes into account all N-1 scenarios through the nonstandard relay characteristics. This work presents a novel technique for optimal coordination of directional overcurrent relays (DOCRs) in terms of relay curve settings (A and B), time dial setting (TDS) and plug setting (PS) to achieve the shortest running time and attain optimal settings. The optimization is carried out using a modified version of the Hanger Games Search algorithm (MHGS). The performance of the proposed method is assessed using the 14 bus distribution system while considering all the N-1 contingencies. DIgSILENT software was utilized to perform the required power system analysis, such as power flow and short circuit analysis. The MHGS method is used to determine the best settings for the DOCRs problem. The results are compared to the traditional HGS as well as those obtained by other current optimization approaches provided in the literature in order to demonstrate the effectiveness and superiority of the proposed MHGS in lowering relay operation time for optimum DOCRs coordination.

Dose accuracy of the follitropin alfa pen injector 2.0, the follitropin alfa:lutropin alfa 2:1 combination pen injector 2.0 and the choriogonadotropin alfa pen injector 1.0 used for fertility treatment

ABSTRACT Background This study aimed to confirm that the incremental dose/clicks system dispenses accurate doses for the Merck family of fertility pen injectors. Research design and methods Set doses (Vset) for three dose dial settings (minimum dose [Vmin], midpoint dose [Vmid] and maximum dose [Vmax] for the follitropin alfa, choriogonadotropin alfa [D2 classification: single use/variable dose], and follitropin alfa:lutropin-alfa 2:1 combination pen injectors) or a single Vset for the choriogonadotropin alfa (D1 classification: single use/single dose) were assessed. Last dose administered by the multi-dose device was assessed for the 900 IU, 450 IU, 300 IU and 150 IU follitropin alfa, and the 900:450 IU, 450:225 IU and 300:150 IU follitropin alfa:lutropin-alfa 2:1 combination pen presentations. Results Dose accuracy tests for Vmin, Vmid and Vmax for the follitropin alfa and the follitropin alfa:lutropin-alfa 2:1 combination pen injectors, and last dose administered, were within acceptable limits according to ISO 11,608-1:2012/2014. Dose accuracy tests for the single use/single dose device classification and the single use/variable dose device classification of the choriogonadotropin alfa pen injector were also within the acceptable limits, according to ISO 11608-1:2000/2014. Conclusions The Merck family of fertility pen injectors functions reliably and the incremental dose/clicks system dispenses accurate doses.

Traceable calibration with 177Lu and comparison of activity meters at hospitals in Norway and Sweden

IntroductionThe activity meter is used to determine the activity of delivered radiopharmaceuticals, administered activity to patients and reference activity when gamma-cameras are calibrated prior to imaged-based dosimetry. The aim is to describe a procedure for cross-calibration of activity meters at different clinical sites, and report on 177Lu activity results when using factory-set calibration factors compared to when calibration is performed with traceability to a primary standard. MethodsThirty activity meters placed at seven hospitals in Norway and Sweden from four manufacturers: Capintec, Commecer, NuviaTech and Veenstra were included. A stock solution with 177Lu was prepared at the local sites and measured in each activity meter with factory settings. The solution was shipped to the reference site at Lund University for measurements in a secondary standard activity meter. Deviations between local and reference activity measurements were determined for three geometries: 25-mL vial, 10-mL syringe and 1-mL syringe. ResultsThe median of the deviations was 6.4 % for the 25 mL vial, 5.9 % for the 10 mL syringe and 6.8 % for the 1 mL syringe. The median of the deviations for the 25 mL vial, was 1.5 % for activity meters from Capintec, 7.0 % for Comecer, 11.0 % for NuviaTech and 2.4 % for Veenstra. The majority of the deviations were positive and the maximum deviation was 14.5 %. ConclusionThe activity of 177Lu measured in an activity meter with factory-set dial settings may yield deviations up to 14.5%, compared to activities measured with traceability to a primary standard. This would imply an undertreatment of patients.

Optimal coordination of directional overcurrent relays in complex networks using the Elite marine predators algorithm

The integration of renewable energy sources in the distribution network (DN) has had a significant influence by reducing power loss and enhancing network dependability. Aside from that, the protection system has met coordination issues as a result of bidirectional power flow and variations in fault levels. Therefore, an optimal coordination strategy is required to deal with relays coordination problem. The coordination problem of the directional overcurrent relays (DOCRs) is a restricted optimization issue that involves determining appropriate time dial settings (TDS) and plug setting (PS) to reduce relays operating time. Currently, a various nontraditional optimization strategies have been presented to overcome this challenge. In this paper, a modified version of the marine predators algorithm (MPA) referred to as Elite marine predator (EMPA) is developed for the optimal coordination of DOCRs. Therefore, the EMPA method is used to find out the optimal settings for the DOCRs problem. The suggested algorithm's performance is evaluated using standard test systems, including 3-bus, 8-bus, 9-bus, and 15-bus. The findings are compared with the traditional MPA and with other recent optimization methods presented in the literature to prove the efficiency and superiority of the proposed EMPA in reducing relay operation time for optimal DOCRs coordination.

Artificial intelligence based optimal coordination of directional overcurrent relay in distribution systems considering vehicle to grid technology

Optimal coordination of overcurrent relays has become a major challenge in power distribution systems due to the increasing participation of distributed generation (DG) and electric vehicle (EV) charging stations, especially vehicle-to-grid (V2G) technology. This paper proposes a novel approach for optimal coordination of directional overcurrent relays (DOCRs) to achieve the minimum operating time and obtain optimal tuning in terms of time dial setting (TDS) and pick-up current (IP) considering V2G integration. The optimization was conducted using three different Artificial Intelligence (AI) techniques: grey wolf optimization (GWO), cuckoo search (CS), and Hunger Games Search (HGS), and was performed on two systems: IEEE 33-bus system and a local grid located in El-Shorouk City–district#8 (ShC-D8), Cairo, Egypt. The proposed methodology is constructed and validated on ETAP and MATLAB software packages. The simulation results demonstrate that the proposed optimization techniques provide high dynamic performance and accurate coordination of DOCRs. The results show that HGS achieves the minimum operating time of all overcurrent relays as compared with GWO and CS. The effect of V2G integration on the coordination methodology is also considered. The proposed approach provides a significant contribution to the field of power system protection and can help improve the reliability and efficiency of power distribution systems with V2G integration.

Optimizers for optimal coordination of distance relays and non-standard characteristics of directional overcurrent relays

In this paper, different methods are utilized to solve the coordination issue involving directional overcurrent relays (DOCRs) and distance relays. The proper coordination of DOCRs and distance relays is a critical issue for system security in electrical networks. Finding the DOCRs setting, pickup current(Ip) and timed dial setting (TDS), and operating time for zone-2 of distance relays is the primary objective of solving the coordination problem. The constant parameters A & B of the directional overcurrent relay that are responsible to control the form of the relay´s characteristics as well as the Ip and TDS have been regarded as variables in this problem. The optimal value for these four DOCR settings has been determined using different optimization techniques. The primary and backup relays must operate sequentially and without any violations, and this must be guaranteed by optimization techniques. In order to determine the operation time for zone-2 and DOCRs setting, optimization methods are examined utilizing the 8-bus and IEEE 30-bus networks. Different optimization algorithms, including recent and traditional techniques, are compared. The obtained results show the superiority of the genetic algorithm (GA) in solving the coordination problem of distance relays and DOCRs. Also, the obtained results prove the ability of the GA method compared to the particle swarm algorithm (PSO), grey wolf optimization (GWO), water cycle technique (WCA), equilibrium optimizer (EO), African vultures optimization algorithm (AVOA), flow direction algorithm (FDA), and gorilla troops optimizer (GTO) techniques.

Selection of TCC Curve and Protection Cooperation Method of Distribution Line Using Linear Optimization

Distribution systems are mostly composed of radial structures, which are susceptible to an increased variability and complexity of system operation due to frequent line changes during operation. When multiple changes in distribution lines occur simultaneously, the relative positions of protective devices also change. The existing protection coordination method of distribution lines is configured by considering the operation characteristics and coordination time interval (CTI) of all protective devices in series from the substation to the terminal load. Therefore, the protection coordination algorithm needs to be redesigned whenever a line is changed or a protective device is added to the distribution line for which the existing protection coordination algorithm has been set. In addition, existing protection coordination methods require complex calculations and procedures, which are subject to human errors and are less feasible for responding in real-time to changes in the distribution system. In this paper, we propose the adaptive time–current curve (TCC) method by selecting the time dial setting (TDS) and minimum response time (MRT) of individual protective devices in accordance with the relative distance based on the linear optimization technique. Using PSCAD/EMTDC, a power system analysis program, the minimum operating current and the fault current of each protective device are obtained, and the proposed protection coordination algorithm is verified according to the series configuration relationship of the protective devices. Finally, the proposed method is applied to an actual distribution line to verify the improvement over the existing protection coordination.

Optimal coordination of directional overcurrent relays and distance relays using different optimization algorithms

The focus of this study is on solving the coordination problem between distance relays (DISRs) and directional overcurrent relays (DOCRs), which is a complex nonlinear problem with various constraints. Ensuring proper coordination between DOCRs and distance relays is critical for maintaining the security of electrical networks. The primary objective of employing optimization algorithms is to determine the optimal operating time for zone-2 of distance relays, as well as the DOCRs setting, time dial setting (TDS), and pickup current (Ipickup). The optimization techniques must also guarantee that the primary and backup relays operate in sequence without any violation. To this end, both recent and well-established optimization algorithms are evaluated using an 8-bus network, with the aim of determining the DOCRs setting and the optimal operating time for zone-2 of distance relays. Furthermore, a comparative analysis of different optimization algorithms, including both traditional and recent techniques, is conducted.

Low Computational Burden Adaptive Overcurrent Protection for Active Distribution Networks

Conventional distribution networks have evolved into active distribution networks due to the high penetration of distributed energy resources. These new networks have several protection issues; some are related to the high fault and load current variations due to the various operating conditions. This situation is faced by adaptive protection development, as proposed in this study, where variations among active distribution network operating conditions are considered to estimate the adaptive pickup current. This is used to estimate the overcurrent relay’s time dial setting, avoiding miscoordination. The proposed protection approach uses fast calculations and local measurements; consequently, a low computational burden is required to update the adaptive relay parameters for each operating condition without using communication infrastructure. The obtained results in the IEEE 34-nodes test feeder demonstrate the advantages of the proposed approach, accomplishing the coordinating time interval for phase and ground faults. These results show a high performance of primary and backup protection at different operating conditions of the proposed test system compared to the performance of the conventional protection approach. The proposed approach’s high performance, low computational burden, and communicationless characteristics make it suitable for immediate real-field implementation.

Optimum relay coordination for reliability evaluation of distribution system with allocation of wind turbine generators

ABSTRACT In this work, a method of optimal relay coordination for improving system reliability has been presented in association with the Wind Energy Conversion System (WECS). The graphical method as well as changes in Plug Setting Multiplier (PSM) and Time Dial Setting (TDS) have been used to test the system’s reliability with the help of ETAP. Load flow analysis, short circuit testing under different fault conditions, reliability assessment, and relay coordination have been performed on the proposed WECS. In this research work, a test system with relay coordination is proposed that is used for transformer protection using over-current relays (OCR) and ground-fault relays (GFR) devices with a wind energy induction generator. It is shown that coordination is off when WECS is added to the system. Therefore, maximum values of the circuit breaker’s trip device setting, the relay’s pickup, and the time dial settings are desirable to increase the coordination. Further, it has been revealed that the comprehensive analysis of load flow analysis, short circuit analysis, and reliability assessment play vital roles in achieving suitable relay coordination. Also, the use of ETAP software in this analysis improves the accuracy and speed of the circuit breaker operation at a reduced cost.

Application of Equilibrium Optimizer Algorithm for Solving Linear and non Linear Coordination of Directional Overcurrent Relays

The safety and reliability of an electrical network depend on the performance of the protections utilized. Therefore, the optimal coordination of the protective devices plays an essential role. In this paper, a new algorithm, Equilibrium Optimizer (EO), which is based on the physical equation of the mass balance, is implemented in the problem of the Optimal Coordination of Directional Overcurrent Relays (DOCRs). Moreover, the proposed method uses Linear Programming (LP), Nonlinear Programming (NLP) and Mixed-Integer Nonlinear Programming (MINLP) in order to optimize the Time Dial Setting (TDS), as well as the Plug Setting (PS), satisfying all possible constraints. Additionally, the performance of EO is evaluated using several benchmarks with different topologies. The results demonstrated the applicability and efficacy of the proposed approach. A comparison with other studies reported in specialized literature is provided to demonstrate the benefits of the proposed approach.

Protection Challenges of Green Technology in Power Distribution System

The mitigation of future electricity demand is highly dependent upon the integration of green energy technology. Most countries realise the importance of green energy and are given support policies for the encouragement of power integration from green energy sources (GES). The effect of bulk power integration from GES causes stability issues in the power system. The solar and wind energy technologies have been discussed in this paper. Issues relating to integration of GES in the distribution system have also been highlighted. It also describes the desired protection of the distribution network with GES. The coordination issue of auto recloser has been explained in depth. The paper narrates the challenges to green energy technology implementation in the distribution system. Finally, a solution for protection coordination is formulated and solved using a genetic algorithm between auto recloser and fuse using test system. Also, coordination with grid-side relay and fuse is validated. The results give optimised values of plug setting multiplier (PSM), time dial settings (TDS), and constants such as A, B, and x. The optimised values give the correct operating times of auto recloser (t 1) and fuse (t 2) and a coordinated time interval (CTI).

Methodology to assess performance indexes for sensitivity, selectivity, and speed of coordination of directional overcurrent protections

Many algorithms for the coordination of directional overcurrent protections (DOCP) have been proposed in literature claiming that optimal solutions are reached, even though there are different reported solutions for the same problem. A new method to evaluate the quality of solutions for the coordination of DOCP is proposed. Three indexes are defined for selectivity, sensitivity, and speed, as desirable features of the coordination of protections. The use of performance indexes to evaluate the response of DOCP systems has not been previously considered in the literature. Given time dial and pick-up settings provided by any program or algorithm, uniformly distributed fault locations are simulated in each transmission line in order to determine the operation times as well as the separation times between main and backup relays. For each fault, the trip sequence of each relay pair is identified and classified according to 15 possible outcomes. To illustrate the method, indexes were computed from seven different coordination solutions reported in literature over the same test system. Results show interesting trade-offs among the three indexes, suitable to be presented as three independent axes; consequently, a given solution could be better in one feature (e.g., speed) but worse in others (e.g., selectivity and/or sensitivity). • There was no method to evaluate the quality of protection coordination solutions. • A novel and integral assessment of sensitivity, selectivity, and speed of solutions is shown. • The assessment is performed using an exhaustive analysis of possible fault locations. • Seven existing coordination solutions over the same case study are impartially assessed. • Conflicts among resulting sensitivity, selectivity and speed indexes are analyzed.

Optimisasi Setting Directional Overcurrent Relay Dengan Menggunakan Hybrid Algoritma (DE – PSO)

To prevent interference and damage to equipment in the electric power system, the role of a protection system is needed. An unreliable protection system has the impact of economic losses, this is the basis for engineers to conduct research on the optimization of protection coordination in the electric power system. This study aims to ensure that the protection system can run properly in the event of a short circuit fault in the system. In addition, this research is to facilitate engineers in the calculation of the Directional Overcurrent Relay (DOCR) coordination study. In contrast to previous studies, this research implements a hybrid algorithm method on a real electrical system by considering the generator operating scheme. Due to the generator operating conditions that are always changing, it affect DOCR working time. To overcome these problems, it is necessary to set an optimal DOCR using the meta-heuristic method. This is the basis for researchers to conduct research on optimization of protection coordination settings. Each meta-heuristic method such as Differential Evolution Algorithm and Particle Swarm Optimization has its own advantages and disadvantages in the process of searching the optimization. Therefore, this research implements a hybrid strategy of Differential Evolution Algorithm – Particle Swarm Optimization (DE-PSO) to get the DOCR Time Dial Setting (TDS) value. From the results of the study, it can be concluded that using a hybrid algorithm is 83% more efficient than the non-hybrid method.

SURG-01. DEVELOPMENT OF MURINE MODEL OF LASER INTERSTITIAL THERMOTHERAPY (LITT) FOR BRAIN TUMORS

Abstract The objective of this study was to develop and test a murine system for delivery of laser interstitial thermotherapy (LITT). A system was built that allows for stereotactic placement of the laser into a mouse brain and real-time thermometry with a custom-made thermometer holder. Tissue heating curves for Laserglow Technologies 1064nm laser experiments testing tissue heating were performed by placing the laser in tissue and temperature monitoring via thermal probe. The laser was adapted for use with a stereotactic frame utilizing a system with a Hamilton syringe and a holder for consistent and precise placement of the thermal probe. The murine experiments were performed with C57BL/6 mice and samples were analyzed with H&E staining. First, ideal laser output was established using chicken breast. Laser dial setting of 4.38 successfully achieved slow tissue heating while a setting of 4.43 and 4.50 accomplished it rapidly, reaching a thermal ablative temperature of 43C in three and a half minutes. Next, a system for laser placement into the murine brain using the stereotactic frame was built revealing that the thermometer probe would require a separate system for consistent and precise measurements of heating. A thermometer probe holder was designed and fashioned via trigonometric calculations that allowed for thermal monitoring within 3mm spacing during laser ablation. Mice were anesthetized and treated with laser ablation at laser output of 4.38 and 4.43. H&E staining of the brain tissue demonstrated clear evidence of localized ablation identifiable by visible lesions on the H&E slides. The successful development of the stereotactic system for acquisition of tissue heating data coupled with evidence of successful live brain tissue ablation in a murine model via LITT proves that our protocol is ready for research of therapeutic combinatorial effects on live tumor bearing mice.

Least Restrictive Adaptation Model: Anything You Need You Can Find in the Kitchen Drawer (First printed inRE:view, 36(2), 63–69.)

Least Restrictive Adaptation Model: Anything You Need You Can Find in the Kitchen Drawer (First printed in<i>RE:view</i>, 36(2), 63–69.)

P-598 Dose accuracy of the follitropin-alfa, follitropin-alfa/lutropin-alfa and choriogonadotropin-alfa pen injectors used for fertility treatment

Abstract Study question Do the Merck family of fertility pen injectors (follitropin-alfa, follitropin-alfa/lutropin-alfa, choriogonadotropin-alfa) meet the International Organization for Standardization (ISO 11608-1:2000/2012/2014) product-validation requirements? Summary answer Each presentation of the family of fertility pen injectors performed as per the state-of-the-art product-validation specifications for dose accuracy in ISO 11608-1:2000/2012/2014 under atmospheric conditions. What is known already Pen injectors for medically assisted reproduction must comply with ISO 11608-1:2000/2012/2014, which specifies essential performance requirements, including dose accuracy, and represent a benchmark for product reliability. Product-validation studies of the follitropin-alfa pen injector showed that three presentations (300 IU, 450 IU, and 900 IU) reliably dispensed accurate doses under a range of conditions, but no information was available for the follitropin-alfa/lutropin-alfa and choriogonadotropin-alfa pen injectors. This study was done to confirm that the incremental dose/clicks system was accurate for equivalence of volume (dose) delivered at standard atmospheric conditions for the complete Merck family of fertility pen injectors (follitropin-alfa, follitropin-alfa/lutropin-alfa, choriogonadotropin-alfa). Study design, size, duration Laboratory-based dose accuracy measurement testing was carried out under standard atmospheric conditions, as specified in ISO 11608-1:2000/2012/2014, between 2015 and 2020. Participants/materials, setting, methods Set doses (Vset) for three dose dial settings (minimum dose [Vmin], midpoint dose [Vmid] and maximum dose [Vmax] [follitropin-alfa, choriogonadotropin-alfa, and follitropin-alfa/lutropin-alfa]) or a single Vset (choriogonadotropin-alfa) were assessed, as appropriate. The last dose administered by the multi-dose device and cartridge and total extractable dose were assessed on the 900 IU and 300 IU follitropin-alfa and the 900 IU/450IU and 300/150 IU follitropin-alfa/lutropin-alfa-pen presentations. Sixty measurements per assessment were made for each Vset. Main results and the role of chance Measurements were performed at two manufacturing sites. Dose accuracy tests for Vmin, Vmid and Vmax (dose dial settings of 12.5 IU, 87.5 IU and 150 IU, respectively, for the 150 IU pen [n = 2,226 (one site)]; dose dial settings of 12.5 IU, 162.5 IU and 300 IU, respectively, for the 300 IU pen [n = 742 per site]; and dose dial settings of 12.5 IU, 237.5 IU and 450 IU, respectively, for the 450 IU [n = 180 per site] and 900 IU pens [n = 410 per site]) for the follitropin-alfa and the follitropin-alfa/lutropin-alfa pen injectors were within the acceptable limits defined in ISO 11608-1:2000/2012/2014. The results of further assessments of last dose and total extracted volume for each presentation of these devices were also within acceptable limits. Dose accuracy tests for the single use/single dose device classification (D1) of the choriogonadotropin-alfa pen injector (n = 210 [one site]) showed that the Vset (6,500 IU) was within the acceptable limits according to ISO 11608-1:2000/2012/2014. Furthermore, dose accuracy tests for the single use/variable dose device classification (D2) of the choriogonadotropin-alfa pen injector (n = 180 [one site]) showed that the Vmin (260 IU), Vmid (3,380 IU) and Vmax (6,500 IU) values were also the within acceptable limits. Limitations, reasons for caution These assessments were carried out by laboratory scientists, who are not the intended users of the pen injectors, and were not delivered into human tissue; therefore, although these conditions meet the international standards, they do not reflect the real-world use of the pen injectors by patients. Wider implications of the findings The Merck family of fertility pen injectors functions reliably and the incremental dose/clicks system dispenses accurate doses, providing users with confidence that they can accurately administer the prescribed dose and minimize drug wastage outside of a clinic environment, which is more important than ever in light of the COVID pandemic. Trial registration number not applicable