Power Research

Rajashekar P. Mandi ¹, Janak J. Patel ², Hitesh R. Jariwala ², Ankur Vashi ³

Affiliations
1 Energy Effi ciency & Renewable Energy Div, Central Power Research Institute, Banglore 560 080, IN
2 Department of Electrical Engineering, Ichhanath, SVNIT, Surat - 395 007, IN
3 Student, Department of Electrical Engineering, Ichhanath, SVNIT, Surat - 395 007, IN

Abstract

An arc of an electric arc furnace as a virtual short circuit is purely resistive load but the reactor connected in series with primary of furnace transformer to smoothen the arc makes the total combination as an inductive load, with its fluctuating active and reactive power requirements, it leads to power quality issues such as poor power factor, harmonic generation, etc. This paper presents measurement and analysis of harmonics generated by alternate current electric arc furnace (AC EAF) and laddle furnace (LF) loads and also defines terms like harmonics, total harmonic distortion etc. Harmonic Filter Banks (HFB) of static Var compensator (SVC) are tuned to particular order of frequency to provide least resistance path to that order of harmonics for elimination. This paper also describes design criteria for harmonic filter banks of 100 Hz, 150 Hz and 200 Hz and presents the SVC as a solution for control of harmonics. The final results are compared with allowable limits set by international standards.

Keywords

Alternate current electric arc furnace (AC EAF), Laddle furnace (LF), Harmonics, Total harmonic distortion, Harmonic fi lter banks (HFB) and Static Var compensators (SVC)

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Rajashekar P. Mandi ¹, Janak J. Patel ², Hitesh R. Jariwala ², Ankur Vashi ²

Affiliations
1 Energy Effi ciency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560 080, IN
2 Department of Electrical Engineering, SVNIT, Surat - 395 007, Gujarat, IN

Abstract

An electric arc is purely resistive load, but the series connected reactor to smoothen the arc makes the combination inductive load creating power quality issues like harmonic generation, poor power factor, voltage flickers etc. An electric arc furnace is heart of integrated steel plant used for smelting of steel with help of electric arc. Temperatures insider the furnace can reach up to 1800° centigrade and capacity wise electric arc furnaces are available from 1–300 tonnes. The charged material is directly exposed to the electric arc and results into hot liquid steel. The charged material can be steel scrap, direct reduced iron and hot metal. The electric arc furnace can be classified as alternate current electric arc furnace (AC EAF) and direct current electric arc furnace (DC EAF) depending upon source of power used at furnace for arcing. The objective of this review is to compare the configuration and harmonics generated by operation of AC EAF and DC EAF. Static Var compensator (SVC) is solution to mitigate the power quality issues generated by the electric arc furnace. This review also compares configurations of the SVCs used for AC EAF and DC EAF.

Keywords

AC EAF, DC EAF, SVC, Harmonic fi lter bank (HFB) and Total demand distortion (TDD)

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Dipak Mehta ¹, Hitesh R. Jariwala ²

Affiliations
1 Manager, Electrical dept, Essar Oil Ltd., Refi nery Site, 39 KM, Jamngar–Okha Highway, Vadinar-361305, Gujarat, IN
2 Associate Prof., Department of Electrical Engineering, SVNIT, Surat, Gujarat, IN

Abstract

This paper presents analysis of power transformer insulation by one fundamental insulation power factor test, also known as Tan Delta. It is a routine test conducted at site to know the healthiness of insulation in transformers. Out of 108 transformers tested for research work, case studies were chosen for analysis purpose. Experimental data shows our experience on the measurement of Tan Delta techniques of earthing systems and dryness of insulation in transformers. Result shows that the Tan Delta testing method is very effi cient method.

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Janak J. Patel ¹, Hitesh R. Jariwala ¹, Ankur Vashi ²

Affiliations
1 Department of Electrical Engineering, SVNIT, Surat, Gujarat, IN
2 Student-Manager, Essar Steel India Ltd., 27th km, Hazira Road, Surat - 394270, Gujarat, IN

Abstract

Non linear and erratic loads like an alternating current electric arc furnace with almost instantaneous fl uctuations with its active and reactive power requirements, leads to power quality issues such as poor power factor, harmonic generation etc. We propose to simulate such unique load and prepare its simulation for active and reactive power requirements. Static var compensator is perfect solution for eliminating the above mentioned threats to power quality. SVC behaves like shunt connected variable impedance, which can either generate or absorbs reactive power [2]. Through this review we also present simulation of SVC with AC EAF and prove that all reactive power required by AC EAF during its operation at various power stages is supplied by the SVC only and net reactive power drawn/ supplied from system is almost zero in line with actual field practice.

Keywords

AC EAF, SVC, TCR, HFB.

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