Özet Elektrik şebekesinin en önemli elemanlarından biri olan güç transformatörünün mekanik bütünlüğünü değerlendirmek için çeşitli teşhis yöntemleri vardır. Tarama Frekans Cevap Metodu (TFCM) ile transformatörler yerinde analiz edilmekte ve arızalı durumlar tespit edilerek gerekirse yerinde yapılan müdahaleler ile giderilebilmektedir. TFCM transformatör empedansını etkileyen mekanik arızaların ve sargılarda oluşan kaymaların tespiti için etkili teşhis yöntemlerinden birisidir. Diğer arıza teşhis yöntemleri ile karşılaştırılan TFCM'nin üstün noktaları, önceki referans ölçümlerine bağımlılığının daha az olması ve mekanik arızaların çeşitliliğine yönelik kanıtlanmış duyarlılığının bulunmasıdır. Örnek çalışmalarda TFCM'nin ayrıntıları, üretim ve ulaşım aşamalarında gerçekleştirilen diğer testler sunulmuştur. Detaylı analiz ve bulgular ayrıntılı olarak ele alınmıştır. Abstract There are various diagnostic methods to assess the mechanical integrity of power transformers which are one of the most substantial elements of the power network. Sweep Frequency Response Method (SFRM) enables us to analyze transformers in situation, detect faulty cases and if necessary, faults can be repaired. SFRM is an effective diagnostic tool for detection of winding movement and other mechanical faults which affects the power transformer impedance. Key advantages of SFRM compared to other diagnostics are its proven sensitivity towards variety of mechanical faults and a lesser dependency on previous reference measurements. In case studies, the details of SFRM and other tests performed during manufacturing and transportation stages are presented. Elaborative analyses and findings are discussed in detail.

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Harvesting energy from the sun makes the photovoltaic (PV) power generation a promising technology. To obtain a consistent state of charge (SOC), consistent energy must be harvested and efficiently directed to the battery. Overcharging or undercharging phenomena decreases the lifetime of the battery. Besides, the effect of irradiance toward solar in term of sunlight intensity effects the efficiency and hence, sluggish the SOC. The main problem of the solar panel revealed when the temperature has increased, the efficiency of solar panel will also be decreased. This manuscript reports the finding of developing an automatic active cooling system for a solar panel with a real time energy monitoring system with internet-of-things (IoT) facility. The IoT technology assists user to measure the efficiency of the solar panel and SOC of the battery in real time from any locations. The automatic active cooling system is designed to improve the efficiency of the solar panel. The effectiveness of the proposed system is proven via the analysis of the effect of active cooling toward efficiency and SOC of photovoltaic system. The results also tabulate the comparative studies of active-to-passive cooling system, as well as the effect of cooling towards SOC and efficiency of the solar panel.

<span>An isolated electrical network with an independent local distributed generator is very sensitive towards the contingencies between load demand and supply. Although the network system has less complexity in term of structure, its stability condition is crucial due to its stand-alone operating condition. The total power deficit in the network gives the important information related to the dynamical frequency responses which may directly affect the system’s stability level. In this paper, the approach to estimate the total power deficiency for the isolated electrical network was presented by utilized the Luenberger observer method. Although the power deficit is not the state variable in the network mathematical model, the solution of estimation problem was feasible by introducing the new variable using additional dummy system. The simulation was carried out by using MATLAB/Simulink environment and the designed estimator was verified using multifarious load demand changes. The results show that the estimated signal was successfully tracked the expected actual signal with minimum error.</span>

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