Abstract: Energy transmission pipelines are one of the most vital parts of each country which several strict laws have been conducted to enhance the safety of these lines and their vicinity. One of these laws is the safety distance around high pressure gas pipelines. Safety distance refers to the minimum distance from the pipeline where people and equipment do not confront with serious damages. In the present study, safety distance around high pressure gas transmission pipelines were determined by using numerical methods. For this purpose, gas leakages from cracked pipeline and created jet fires were simulated as continuous ignition, three dimensional, unsteady and turbulent cases. Numerical simulations were based on finite volume method and turbulence of flow was considered using k-ω SST model. Also, the combustion of natural gas and air mixture was applied using the eddy dissipation method. The results show that, due to the high pressure difference between pipeline and environment, flow chocks in the cracked area and velocity of the exhausted gas reaches to sound speed. Also, analysis of the incident radiation results shows that safety distances around 42 inches high pressure natural gas pipeline based on 5 and 15 kW/m2 criteria are 205 and 272 meters, respectively.
Abstract: Single phase transmission lines are used to transfer data or energy between two users. Transient conditions such as switching operations and short circuit faults cause the generation of the fluctuation on the waveform to be transmitted. Spatial voltage distribution on the single phase transmission line may change owing to the position and duration of the short circuit fault in the system. In this paper, the state space representation of the single phase transmission line for short circuit fault and for various types of terminations is given. Since the transmission line is modeled in time domain using distributed parametric elements, the mathematical representation of the event is given in state space (time domain) differential equation form. It also makes easy to solve the problem because of the time and space dependent characteristics of the voltage variations on the distributed parametrically modeled transmission line.
Abstract: Voltage level must be raised in order to deliver the
produced energy to the consumption zones with less loss and less
cost. Power transformers used to raise or lower voltage are important
parts of the energy transmission system. Power transformers used in
switchgear and power generation plants stay in human's intensive
habitat zones as a result of expanding cities. Accordingly, noise
levels produced by power transformers have begun more and more
important and they have established itself as one of the research field.
In this research, the noise cause on transformers has been
investigated, it's causes has been examined and noise measurement
techniques have been introduced. Examples of transformer noise test
results are submitted and precautions to be taken were discussed for
the purpose of decreasing of the noise which will occurred by
transformers.
Abstract: In this study, electric field distribution analyses for
three pylon models are carried out by a Finite Element Method
(FEM) based software. Analyses are performed in both stationary and
time domains to observe instantaneous values along with the
effective ones. Considering the results of the study, different line
geometries is considerably affecting the magnitude and distribution
of electric field although the line voltages are the same. Furthermore,
it is observed that maximum values of instantaneous electric field
obtained in time domain analysis are quite higher than the effective
ones in stationary mode. In consequence, electric field distribution
analyses should be individually made for each different line model
and the limit exposure values or distances to residential buildings
should be defined according to the results obtained.
Abstract: Energy efficiency is the key requirement in wireless sensor network as sensors are small, cheap and are deployed in very large number in a large geographical area, so there is no question of replacing the batteries of the sensors once deployed. Different ways can be used for efficient energy transmission including Multi-Hop algorithms, collaborative communication, cooperativecommunication, Beam- forming, routing algorithm, phase, frequency and time synchronization. The paper reviews the need for time synchronization and proposed a BFS based synchronization algorithm to achieve energy efficiency. The efficiency of our protocol has been tested and verified by simulation