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Open Access Article
1 - Drift-Steps-Recovery Diodes Based on Pulse Power Circuits and Their Applications
Seyed Mohammad Hassan Hosseini Roya FealiIn this paper, nanosecond pulse power generators and their applications are reviewed. Generally, in pulse generating circuits, the Drift-Steps-Recovery diodes (DSRDs) play an important role as the opening switches. The simulation of a pulse generating circuit using (DSR MoreIn this paper, nanosecond pulse power generators and their applications are reviewed. Generally, in pulse generating circuits, the Drift-Steps-Recovery diodes (DSRDs) play an important role as the opening switches. The simulation of a pulse generating circuit using (DSRDs) is done by using MATLAB software. A generating circuit of unipolar and then bipolar pulses are simulated and discussed. Whereas in all simulations we focus on a pulse generator circuit because of its important application. Manuscript profile -
Open Access Article
2 - Effect of Impulse Voltage on Partial Discharge of Oil and Paper - Oil Insulators Containing Air Cavity
Seyed Mohammad Hassan Hosseini Roya ShmsaliIn power systems, usually by lightning strikes or switching operation, impulse voltage is produced. This paper reviews the effect of high impulse voltage on the PD parameters. In recent years, numerous studies on PD in the insulation, under the impulse has been done. De MoreIn power systems, usually by lightning strikes or switching operation, impulse voltage is produced. This paper reviews the effect of high impulse voltage on the PD parameters. In recent years, numerous studies on PD in the insulation, under the impulse has been done. Despite the use of power equipment and tools, switching impulse is created in the system. So, studies on PD activity with the initiation and end voltage PD in insulators have been investigated. However, the combination of PD characteristics with AC and impulse has not been studied in many studies so far. Unlike previous studies, in this paper, along with the impulse voltage, the AC voltage effects are also considered. On the other hand, dielectric characteristics show the quality of insulation in terms of the soundness or deterioration of equipment over time. The deterioration and aging of equipment can be due to electrical stresses such as alternating current PDs or transient stresses or due to environmental pressures and temperature or mechanical pressures. At this point, the effect of the PD alternating current (AC) on paper combination insulation oil dielectric frequency response equipment is investigated. In this review, a brief history of the performance of insulation against partial electrical discharge is addressed, and the finite element method software (Maxwell) is used to simulate partial electrical discharge for objects that are particularly sharp. Manuscript profile -
Open Access Article
3 - Homogenizing Electric Field of Lightning in L.P.S. XLPE Descending Conductor
Ali Amirjalali Seyed Mohammad Hassan HosseiniIn this paper, behavior of MV cross-linked polyethylene insulation and homogenization of its electric field against the current flow, resulting from lightning stroke to arrest, is studied. In addition, it is shown that using two conductors with different structures fiel MoreIn this paper, behavior of MV cross-linked polyethylene insulation and homogenization of its electric field against the current flow, resulting from lightning stroke to arrest, is studied. In addition, it is shown that using two conductors with different structures field distribution can be homogenized and smoothed in the cable. A theoretical model is proposed for field distribution in the cable and the proposed cable. There is only a radial field (along x) inside a coaxial cable which its external conductor is grounded and varies with distance. That is, Schwager coefficient inside the coaxial cable is a function of this radius, and purpose of this study is to increase insulation breakdown voltage. For instance, if Schwager coefficient reaches 1, no insulation is required, and cable has a maximum breakdown voltage between middle conductor and external conductor. Therefore, by increasing Schwager coefficient, less insulation can be used. By reaching a Schwager coefficient of 58%, field inside the cable becomes homogenized and uniform; insulation can be used for the remained 42%. Now, if this insulation is made of refractory material, cable would provide high insulation strength. Among other advantages of refractory material, high melting point can be mentioned as a result of which they become pasty under critical and boundary conditions. One of the best insulations is XLPE or polyethylene with cross connections between its layers (cross-linked). In this study, critical and boundary condition for coaxial cable are applying lightning stroke of 1.2/50µsec. That is, wave front is 1.2ms and half wave front is 50µs. This current induces a voltage in devices including descending conductor between the aerial terminal of the arrester and ground connection of the arrester which might be several million volts. After obtaining field equations in the studied cable, characteristics of waveforms and creation of these waveforms are described in Simulink. Manuscript profile -
Open Access Article
4 - Partial discharge detection by using combined VHF and AE sensors in XLPE power cables
Ahmad Moradi Seyed Mohammad Hassan HosseiniThe purpose of this article is to troubleshoot and detection a partial discharge in cross-linked polyethylene (XLPE) cable by combining two very-high-frequency (VHF) and acoustic emission (AE) sensors, which is a novel approach to troubleshooting. The small size of thes MoreThe purpose of this article is to troubleshoot and detection a partial discharge in cross-linked polyethylene (XLPE) cable by combining two very-high-frequency (VHF) and acoustic emission (AE) sensors, which is a novel approach to troubleshooting. The small size of these signals is the main problem in partial discharge (PD) measurements, which might cause the signal mix completely with noise and make troubleshooting difficult. Hence, attention has been paid to high bandwidth to eliminate disturbing noise. In this paper, Rogowski's coil is designed as a kind of VHF sensor for troubleshooting purposes. Then, it simulates and examines the characteristics of the partial discharge in the power cables that have been occurred due to the existence of a cavity. In the end, in order to prove the efficiency of the intended method, the actual partial discharge test was performed using the VHF and AE sensors. The combination of two VHF and AE sensors is capable of eliminating electrical interference and electromagnetic noise in the test site, as well as identifying different types of discharge, and providing a model for troubleshooting partial discharges in online and offline tests. In addition, due to the simple design and installation of the sensor in the equipment and have not to need to cut off equipment from the network, this method is economically very cost effective. Manuscript profile -
Open Access Article
5 - A Method for Measuring Transient Switching Overvoltage Case study: Electricity network of Imam Khomeini Airport City
Mojtaba Rabiei Seyed Mohammad Hassan HosseiniTransient voltage increase in electricity networks is of great importance due to security of devices and insulation considerations. One of the factors which results in transient voltage increase is connection switching. This overvoltage cannot be measured and recorded v MoreTransient voltage increase in electricity networks is of great importance due to security of devices and insulation considerations. One of the factors which results in transient voltage increase is connection switching. This overvoltage cannot be measured and recorded via usual measurement devices. In this study, possibility of using power quality analyzer for recording and measuring transient overvoltages is studied. To this end, switching in a 20KV electricity network in Imam Khomeini airport city is simulated using EMTP-RV. Then, real switching is performed and overvoltage is measured by power analyzer. Then, these two methods are compared. Manuscript profile -
Open Access Article
6 - New Modeling of Metal Oxide Surge Arresters
SeyedMohammad Hassan Hosseini Yoones GharadaghiThis paper describes simplified modeling of metal oxide surge arrester (MOSA) to operate analysis. This model is a new model proposed (P-K Model) to verify the accuracy in order to compare with IEEE and Pinceti Model. The simulations are performed with the Alternative T MoreThis paper describes simplified modeling of metal oxide surge arrester (MOSA) to operate analysis. This model is a new model proposed (P-K Model) to verify the accuracy in order to compare with IEEE and Pinceti Model. The simulations are performed with the Alternative Transients Program version of Electromagnetic Transient Program (ATP-EMTP). In the present paper, the MOSA models were verified for several medium voltages which consist of 18 kV and 21 kV, which 18 kV arrester was used in 22 kV system of Provincial Electricity Authority (PEA) and 21 kV arrester was used in 24 kV system of Metropolitan Electricity Authority (MEA) in Thailand. The P-K model was evaluate from different manufacturing, it is based on the General Electric (GE), Siemens and Ohio Brass as well as IEEE and Pinceti Model. The tests are performed by applying a fast front current surge with front time of up to 0.5μs and the standard impulse current surge (8/20μs). The results were compared between three models in order to calculate the error operation of the MOSA in the ATP-EMTP Program. The relative error of arrester models show that the P-K model can be used to simulate and calculate in ATP-EMTP program as well as IEEE and Pinceti model. In the case of fast front current surge, the P-K model has a maximum error of 5.39% (Ohio Brass, 10 kA, 21 kV) and has a minimum error of 0.24% (GE, 10 kA, 18 kV). Also, the standard impulse current surge, P-K model has a maximum error of 2% (Ohio Brass, 10 kA, 18 kV) and has a minimum error of 0.32% (Siemens, 10 kA, 21 kV) in the voltage response. Manuscript profile
List of Articles S. M. hassan Hosseini
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