The article discusses the selection of cables for power lines connecting wind turbine generators at the wind power plant. The screen cross-section of these cables should be selected considering the value of the screen current at double line-to-earth fault. To calculate this current, the dimensions of the cable should be known. However, these parameters are hidden and cannot be used during designing. Therefore, a highly simplified method is currently used in practice. It is shown that the errors from the highly simplified method are up to 33%. Authors propose a simplified method based on open data of cable manufacturers. The proposed method is compared with simulation results of a common model of cable power line and takes into account self and mutual inductances of the cores and screens. It is shown that the error of the proposed method is smaller than 4.0% for real cable power lines at wind power plants. However, for a long section of cable power line (2.5 km) the error of calculation might increase up to 6.3%. This allows us to use the proposed method for designing. In addition, the authors show how the results of the highly simplified method can be corrected to improve accuracy.
The method of operative determination of active power losses (both loading and crown) in alternating current lines has been improved. The proposed technique allows monitoring of active power losses in lines. Based on the comparative analysis of different approximation methods, the most effective method of analytical representation of regression dependences of active power losses on the corona on voltage for different weather conditions is proposed. The validity and reliability of scientific statements, conclusions, and recommendations given in the dissertation are confirmed by the analysis of the results of comparative calculations performed for different models. The efficiency of the developed algorithms and programs was tested on control examples with reference source data, where the results of the calculations were compared with the results obtained by standard programs. The developed technique of operative determination of losses of active power (loading and on a crown) allows one to carry out current monitoring of losses and passive parameters of high-voltage power lines of alternating current. The phenomena of self-excitation of generators connected to unloaded power lines are considered at great length. A physical analysis of the ongoing processes is given, and calculation methods are proposed that have been experimentally tested on a dynamic model. The paper takes into account the effect of the wire corona on the conditions of self-excitation of generators with the necessary developments to prevent this negative phenomenon in the main electrical network. Models and methods have been developed for evaluating the effect of the wire corona on the conditions for the occurrence of self-excitation in ultra-high voltage transmission lines.
1 November 2019 in IOP Conference Series: Earth and Environmental Science
An energy audit was conducted on a university building located within the main campus of Universiti Teknikal Malaysia Melaka (UTeM), Melaka, Malaysia. Some of the physical parameters particularly energy consumption, air velocity, airflow, operating temperature, relative humidity and lighting intensity were compared to the Malaysian Standards 1525:2014. This work aims at understanding the comfort level of the occupants and investigates the impact of lighting changes to the overall energy consumption. Based on the data collected, the team could estimate the current energy consumption for all floors. As expected, the air conditioning recorded the highest rate consumption at 72% of electricity usage in the building, followed by the consumption of lighting at 18% and other equipment only 10%. The average operating temperature was recorded at 22.758°C, which is less than that of the recommended range of 24°C - 26°C The average humidity was about 68.31% while the average lighting intensity was recorded at 461.422 lux. Additionally, the Building Energy Index (BEI) for the 2016-2017 period is 128.53 kWh/m²/year and 137.55 kWh/m²/year for 2017/2018. BEI values in 2017-2018 were a little higher than that specified in MS 1525:2014 Standards, which is 135 kWh/m²/year.
1 June 2022 in Indonesian Journal of Electrical Engineering and Computer Science
The medical staff is the first part which is affected in the COVID-19 pandemic, then the workers, whether in the hospital or quarantine hotels who are responsible for cleanliness and sterilization. The goal is to reduce the number of injured and preserve human safety. This led us to think deeply to solve this problem and make the life healthier and to reduce the spread of the virus by using internet of things (IoT). The goal of the research is to develop a special robot to sterilize quarantine rooms and hospitals, measure the patient’s temperature and heart rate, in addition to transporting medicines to patients in order to preserve the safety of the medical staff. So, in order to accomplish this purpose, we will create a proof of concept for the robot. Our robot will have a system capable of performing pre-programmed acts, either under direct human control or under the control of computer programs. This paper can be the basic for future research in the same field.
Temperature transducers are commonly used to monitor process parameters that are controlled by various types of industrial controllers. The purpose of this study is to design and model a simple microcontroller-based acoustic temperature transducer based on the variations of resonance conditions in a cylindrical resonance tube. The transducer’s operation is based on the generation of an acoustic standing wave in the free resonance mode of generation within a cylindrical resonance tube which is converted into a train of pulses using Schmitt trigger circuit. The frequency of the generated standing wave (i.e., the train of pulses) is measured by the Arduino Uno microcontroller, where a digital pin is used to acquire pulses that are counted using a build-in software function in an Arduino IDE environment. Experimental results are performed for three sizes of diameters to investigate the effect of the diameter of resonance tube on the obtained results. The maximum nonlinearity error according to Full-Scale Deflection (FSD) is about 2.3 percent, and the relative error of the transducer is evaluated using experimental findings and the regression model. The circuit simplicity and design of the suggested transducer, as well as the linearity of its measurements, are notable.
A Fast Flux Service Network (FFSN) domain name system method is a technique used on botnet that bot herders used to support malicious botnet actions to rapidly change the domain name IP addresses and to increase the life of malicious servers. While several methods for the detection of FFSN domains are suggested, they are still suffering from relatively low accuracy with the zero-day domain in particular. Throughout the current research, a system that’s deemed new is proposed. The latter system is called (the Fast Flux Killer System) and is abbreviated as (FFKS)). It allows one to have the FF-Domains “zero-day”, via a deployment built on (ADeSNN). It is a hybrid, which consists of two stages. The online phase according to the learning outcomes from the offline phase works on detecting the zero-day domains while the offline phase helps in enhancing the classification performance of the system in the online phase. This system will be compared to a previously published work that was based on a supervised detection method using the same ADeSNN algorithm to have the FFSNs domains detected, also to show better performance in detecting malicious domains. A public data set for the impacts of the hybrid ADeSNN algorithm is employed in the experiment. When hybrid ADeSNN was used over the supervised one, the experiments showed better accuracy. The detection of zero-day fast-flux domains is highly accurate (99.54%) in a mode considered as an online one.