Study And Simulation Of Power Quality Improvement In Distribution Network In The Case Of Metehara Sugar Factory

Abstract

Nowadays, Ethiopia has been building a competitive sugar industry which is operated by the supervision of sugar corporation. Those industries need a considerable amount of electric power for their progressive consumption. Metehara Sugar Factory is one of the figurative sugar industries in the country. In this factory the electric power is generated from industrial power stations of noncondensing steam. In non-condensing steam power plants, a continuous supply of fresh feed of water is required. The steam power plant produces steam for industrial purpose besides of producing electric power that achieved by raising the steam in the boilers, expanding it through the turbine and coupling the turbine to the generators which convert mechanical energy to electrical energy. Most of the loads in the industry are nonlinear loads which affect seriously the quality of the power. Therefore, study is needed to identify the level of power quality problems in the company to be able to develop an appropriate mitigation technique. The aim of this study is to evaluate the power quality problem in the factory and to assess the use of D-STATCOM device to reduce the level of the problem. To prove the power quality, appropriate measurement has been taken by using the power quality analyzing device namely HIOKI-3196 and the measurement data is analyzed by using PQA HiVIEW PRO 9624-50 software, as a result of flexible PC analysis the following specified problem is identified. The measurements of the line to neutral current indicate the harmonic distortion level of 26.20%, 22.58% and 42.95% with major 5th and 7th order harmonics for each phases. In addition to that, the total current harmonics distortion (THDI) is 54.07%. Even though, an SVC has been installed on the distribution substation, the above problem and the low power factor of 0.54 was recorded. Modeling and simulation of the DSTATCOM of 10 MVA with phase shifting transformer has been done using DigSilent software version 15.1, accordingly the total harmonics distortion level is reduced to 5.4% and the power factor is improved to 0.95 with an increase of voltage to 225V from the previous value of 200V.