Browsing by Author "Dobi, A.M"

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    Electricity theft detection framework based on universal prediction algorithm
    (Indonesian Journal of Electrical Engineering and Computer Science, 2019-08) Otuoze, Abdulrahaman; Mustafa, M.W.; Sofimieari, I.E.; Dobi, A.M; Sule, A.H; Abioye, A.E.; Saeed, M.S.
    Electricity theft has caused huge losses over the globe and the trend of its perpetuation constantly evolve even as smart technologies such as smart meters are being deployed. Although the smart meters have come under some attacks, they provide sufficient data which can be analysed by an intelligent strategy for effective monitoring and detection of compromised situations. So many techniques have been employed but satisfactory result is yet to be obtained for a real-time detection of this electrical fraud. This work suggests a framework based on Universal Anomaly Detection (UAD) utilizing Lempel-Ziv universal compression algorithm, aimed at achieving a real-time detection in a smart grid environment. A number of the network parameters can be monitored to detect anomalies, but this framework monitors the energy consumption data, rate of change of the energy consumption data, its date stamp and time signatures. To classify the data based on normal and abnormal behaviour, Lempel-Ziv algorithm is used to assign probability of occurrence to the compressed data of the monitored parameters. This framework can learn normal behaviours of smart meter data and give alerts during any detected anomaly based on deviation from this probability. A forced aggressivemeasure is also suggested in the framework as means of applying fines to fraudulent customers.
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    Field loss calculation of a wind‐powered axial flux alternator by analytical equations
    (Engineering Reports, 2021) Otuoze, Abdulrahaman; Mohammed, OO; Ibrahim, Oladimeji; Salisu, S; A.A, Emmanuel; Usman, A.M.; Dobi, A.M
    Various techniques have been investigated and proposed for core loss minimiza-tion in electrical machines. Nevertheless, many of such methods are mostlycomplicated and not suitable for consideration at a preliminary design stage. Inthiswork,asimplifiedprocedurewhichusesananalyticalapproachtominimiz-ing the field’s losses of an Axial Flux Permanent Magnet Alternator (AFPMA),is presented. First, the output equation of an AFPMA is referred, and then theminimization of the losses is investigated by analytical differential equations.The result of the derived-specific magnetic loading is investigated using threedifferent core materials, namely 35RM300, 50JN350, and 65JN800, and is foundto reduce with increased frequencies. The 35RM300 core material gives themaximum specific magnetic loading and minimum power loss at investigatedfrequencies of 50 to 500Hz. Although the 35RM300 core material gives the bestperformance, the optimal values are only determined as suitable by the manu-facturer’s design criteria. This study is a key indicator for a simple and efficientcore material selection in the design of a Wind-Powered AFPMA without theneed for complicated analyses at the preliminary design stage