Oktay Arikan

Harmonic Effects of Power System Loads: An Experimental Study

Especially with the developing semi-conductor technology, harmonics have become one of the most popular issues in power system. In this study, the measurements for the harmonic effects of the loads in power system were carried out and also contribution of these loads to harmonic distortion was exhibited. Moreover, the effect of harmonics existing in power sys‐ tem on the performance of some equipment was analyzed experimentally. The obtained re‐ sults were discussed and suggestions were given.

Reliability analysis of hybrid energy systems: Case study of Davutpasa Campus

In recent years, sustainable and clean renewable energy resources are widely used instead of fossil fuel energy resources in electrical energy generation systems. Especially, wind and solar energy conversion systems are utilized together in stand-alone systems. In this study, reliability analysis of a hybrid system installed in Davutpasa Campus of Yildiz Technical University is investigated. The system includes a wind turbine, PV panels, a hybrid charge regulator, a MPPT charge controller, an inverter, battery group and loads. Reliability indexes are calculated for analyzed system. The obtained results are examined and presented in this paper.

Electric field measurement and analysis around a line model at different voltage levels

The aim of this work is the experimental study of the electric field distribution around a line model in high voltage laboratory. Thereby study and knowledge of the electric field around a line at different voltage levels can be purposive for safety, settlements and design procedures of power lines. The measurements were carried out by using HOLADAY/HI-3604 electromagnetic field survey meter. Additionally, to compare the results obtained from the measurements, Finite Element Method Magnetics (FEMM) packaged program is used. The results show that the electric field intensity around a distribution line is changing with the distance in any direction. The electric field under and also near the distribution line is influenced with the increasing voltage levels.

Breakdown voltage analysis of insulating oils under different conditions

The dielectric performance of insulating oils used in high voltage equipment is very important for the power system continuity and reliability. In this study, breakdown voltage measurements of mineral insulating oil were carried at different temperatures and water quantity rates were researched. Additionally, the effect of water content inside the oil sample, approximately 2.5 percent, on the breakdown voltage was analyzed for particular temperatures. In the experimental study, the breakdown voltage behavior of mineral oil which is widely used in power transformers was acquired according to the ASTM D877 standard for different service conditions and the obtained results were presented.

The influence of voltage and frequency variations on insulation quality of a high voltage cable

Insulation quality issue has had a significant place in high voltage systems for long years. Especially for high voltage cables, which is one of the most crucial elements in power systems, the measurements of dissipation factor or tan delta has a great importance on the insulation life time. Besides, when the power system parameters such as frequency and voltage level are not steady, tan delta measurement values will also be changed. Therefore, tan delta and dielectric loss measurement should be realized in case of unsteady power system conditions to get more exact results. In this study, tan delta measurement of a 20,1/34,5 kV, single core high voltage cable is carried out. By changing the frequency and voltage level, dissipation factor, capacitance (Cs), insulation resistance (Rs) and dielectric losses (Pk) measurement values are obtained.

Introduction to hybrid systems — Yildiz Technical University

Energy has always been an important factor for socio-economic development of humans. Most of the energy is generated from fossil fuels in the world. Nevertheless, environmental aspects and depleting of fossil fuels causes increase of renewable energy utilization. The produced energy from renewable energy resources are transferred to grid or used in stand-alone systems. As energy generation depends on environmental conditions, efficiency and energy potential of renewable energy systems changes according to region of installation. In this study, introduction of the solar-wind-battery hybrid system constructed in Davutpasa Campus, Yildiz Technical University, and future work for the system are presented.

Measurement of the dielectric performance of an instrument transformer at different voltage and frequencies

In this study, the capacity, tan delta and dielectric loss of an IVT are measured for different voltage levels and frequency values. The measurement process is realized for the isolation between the primary and secondary windings of a 10kV/0,1 kV nominal rated IVT. As a measurement device, CPC100/CP TD1, which is frequently preferred especially in field applications, is used. Results indicated that, the dissipation factor changes according to the voltage levels. When voltage level gets closer to nominal value or exceeds it, it is seen that tan delta value increases rapidly. Moreover, it is found that the rising frequency has a negative effect on the dielectric loss of the material as a result of the measurements at different frequency values between 50 Hz - 400 Hz.

Analysis of harmonics influences on load switching transients in simple power system

This paper presents the transient analysis of a simple power system. Measurements are taken from a simple system that takes place at Turkish National Power System. Matlab Simpower Toolbox is used for the analysis. Dynamic analysis of the system studied for switching operations. Effects of load acception and reduction are studied as switching operations. Constant impedance load model is used for the simulations. At the case study, added loads have different harmonic components for analyzing effects of harmonics to the system. Harmonic components of the load current are modeled by using current injection method.