Desert Pollution Research Articles

The Method of the Equivalent Deposit of Deposited Salt (DESD) to Determine the Contamination of the Insulation of Electric Lines in Areas of Manabita Region

The present work is related to the quantitative determination of the environmental contamination that affects the insulators in the subtransmission electrical networks existing between the cities of Montecristi and Manta. This area is the one with the largest industrial settlement, in addition to the proximity to the sea and other road development activities that contribute to contaminating the insulators of the 69, 138 and 230 kV lines causing interruptions in the supply of electricity to various sectors of the city of Manta. That is, the types of pollution known as industrial pollution, marine pollution, desert pollution and other types of pollution that are generated by industries near the sea converge. The results of this research work ended, being able to determine the levels of contamination by means of the Equivalent Deposit of Deposited Salt (DESD) method after 12 months of monitoring of the control insulators. This method consists of obtaining the level of environmental contamination in milligrams of NaCl, capable of forming a solution whose electrical conductivity is equal to that obtained from the solution composed of the contaminant deposited on the insulator and a volume of low conductivity water used. To remove the contaminant on the insulator surface.

Features Characterizing the Surface State of HV Insulator Glass Model under Desert Pollution

This paper deals with the monitoring of the surface state of HV insulator model under discontinuous layer of pollution. Natural desert sand is used to simulate the pollution influence in Algerian Sahara regions. Experimental tests are carried out on a glass plane model of 1512L cap-pin insulator largely used in the said regions. Leakage current LC signal is recorded for different positions and widths of the polluted-band. First, the obtained results are discussed to describe the behavior of the insulator model. For each configuration, time-frequency decomposition is established using Discrete Wavelet Transform (DWT) for information extraction corresponding to the flashover process. Decomposition results indicate that the detail D3 is highly correlated with the measured LC signal. Recurrence Plot (RP) technique and Recurrence Quantification Analysis (RQA) are applied to quantify the temporal patterning in LC signal, giving information on the position and width of the polluted-band on the insulating surface. It was found that RQA indicators increase with the polluted-band width according to the position of this polluted-band. Based on the plan model, the findings demonstrate the capability of RQA indicators for the glass insulator monitoring, providing information on the width and position of the polluted-band on its surface.

A Study on Obstacle-surmounting Performance of Sand Milling Vehicles

According to the changing characteristics of the geological environment of Gobi desert pollution abatement area, this paper introduces a kind of milling vehicle of 3point supporting type. The general equilibrium equations under the simultaneously surmounting obstacle by front wheels were derived using a simplified obstacle surmounting mechanical mode. As in a complex environment, the key terrain obstacle parameters are uncertain and the traction force to surmount the obstacle is also uncertain. This paper uses fuzzy sets method for terrain angle and the traction force needed by the vehicle to surmount the obstacle was calculated. By establishing a wheel-road model and using multi-dynamics software, the simulations showed that the theoretical results were reliable.

Flashover process and leakage current characteristics of insulator model under desert pollution

The present work aims to investigate the effect of the desert pollution on an insulating plan model behavior. We focused on the effect of the sand quantity in term of non-soluble deposit density (NSDD) and the width of polluted layer on the flashover process. For this purpose, we use the magnitude and frequency analysis of the leakage current (LC) as indicator of the insulator behavior with regard to both of the pollution level and the electrical discharges activity on the insulator surface, particularly for this kind of Algerian desert pollution, not studied so far. Indeed, most of the research works in this domain were rather interested in marine and industrial types of pollution. Careful analysis of recorded videos, filmed by digital camera, allows us to examine visually the development and the evolution of arcs, until total flashover, according to the applied voltage. The odd harmonics and the fundamental component have been investigated to characterize the insulator surface state. Furthermore, a wavelet transform technique has been adopted to study the frequency-time characteristics and to calculate the standard deviation (STD) of different harmonic components of LC. In the uniform case, the STD of low frequency details, D9, D10 and D11, respectively the ninth, the tenth and the eleventh details extracted from LC, represent a good indicator of the pollution level. In the non-uniform case of pollution, the STD of detail D11, and the STD of high_frequency details show a good correlation with polluted layer width and the activity of the electric discharges.

Experimental techniques to simulate naturally polluted high voltage transmission line insulators

This paper represents experimental techniques to simulate the naturally polluted high voltage insulators, under conditions that simulate the desert environment. Usually, the IEC fog method is used for testing the polluted insulators of high voltage transmission lines, but it does not simulate them under the desert pollution environments. For that reason, in this paper two other suggested techniques are added to the IEC one. The first one is to explain the performance of the polluted insulators under the dew and the second one is to explain their performance under the simultaneous fog and dew. The results of these three tests are compared with each other under different surface polluted layer conductivities. The aim of this paper is to record the leakage current and the warning voltage under different simulation weather conditions that to monitor the insulator strings before the occurrence of the flashover that of course is useful for the efficient maintenance. Also, in this paper, an attempt to simulate the flashover of the insulator in the field condition (actual outdoor condition) is presented. Where, the surface of the insulator is polluted naturally over a relatively long period, while it is permanently under high voltage.

Laboratory simulation of naturally polluted high‐voltage transmission line insulators

This study represents experimental techniques for testing the high-voltage polluted insulators under conditions simulating the natural environment. International Electrotechnical Commission (IEC) fog method is used for testing the insulators of type π-ϕ-E4.5, but it does not simulate the desert pollution environments. For that reason, other two suggested techniques are added to explain the performance of the polluted insulators under dew and under simultaneous fog and dew, respectively. The leakage current bursts are recorded in each test type. Also the effect of the wetting method of the insulators under testing on the flashover voltage is investigated. The results of the three types of tests are compared with each other, under different surface layer conductivities. It is concluded that the analysis of leakage current bursts can be used to monitor the severity of pollution on the electrical network.

Risk assessment of desert pollution on composite high voltage insulators

Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber) insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator’s leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing – and thus justifying – the use of this type of insulators in Sinai and similar critical areas.

Influence of desert pollution on the lightning impulse breakdown voltages of rod to plane air gaps

A discussion is presented of the influence of desert contamination on the breakdown voltage characteristics of rod-plane air gaps when subjected to standard lightning impulse voltages of positive and negative polarities. Experimental simulation of desert air pollution was carried out in a chamber where particle parameters could be controlled independently. The gaps studied were from 5 cm up to 2 m with applied voltages, there is a considerable influence on the breakdown behavior. For such cases, the breakdown voltages for dust contaminated gaps can be lower as well as higher than the corresponding values for clean air gaps, depending upon the gap length and the cathode radius. Detailed results and analysis are provided.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>