Static Var Compensator
Static Var Compensator (SVC) parameters definition for electric arc furnace without preliminary energy measurements. Harmonics analysis of SVC with TCR 13Mvar, 6kV and 3rd- and 5th-order harmonic filters in power grid
Overview
Static Var Compensator (SVC) with Thyristor Controlled Reactor (TCR) use for compensation reactive power and filtering harmonics.
Challenge was to develop compensation system without any measurements because electric furnace was in production. And arc electric furnace is complex object for modeling and definition harmonics produced by furnace.
In this study, we develop SVC 6kV for arc electric furnace 15 ton and make harmonics analysis to SVC with harmonics filters in power grid.
Scope of work:
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Calculation parameters of electric grid 6kV and model development
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Development model of arc electric furnace
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Simulation of work the arc electric furnace without a compensation system. Making harmonics analysis
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Determination order of harmonic filters. Calculation power of harmonic filters.
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Calculation power and inductance of Thyristor Controlled Reactor (TCR)
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Development the control system for TCR. Tuning the controller.
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Development model of SVC with harmonic filters and adding it to model with the arc electric furnace.
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Simulation of work the arc electric furnace with the compensation system in varies of modes.
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Making harmonics analysis.
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Making analysis of simulation results
Based on the simulation results, requirements for the parameters of the circuit elements were issued, and a report was submitted.
The initial data were:
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parameters of arc electric furnace
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operating modes of furnace
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power grid parameters
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requirements for the level of harmonics in the grid and reactive power
The criteria for achieving the goal were:
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ensuring the specified requirements for the level of harmonics in the grid and reactive power
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minimization of capital costs for equipment
Calculations showed the need to install SVC with the following parameters:
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TCR 13 MVAR, 6 kV
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3rd-order harmonic filter with a power of 9 MVAR;
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5th-order harmonic filter with a power of 7.2 MVAR.
Proof
Based on the results obtained, SVC was manufactured by one of the Ukrainian enterprises and delivered to the site. By using SVC on site, the following have been achieved:
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reduce the voltage ripple to ±2% (against 15% without SVC)
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compensate the reactive power to a value ±1%
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reduce the total harmonic distortion of voltage (THDu) to 3% (against 7.5% without SVC)
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reduce the magnitude of 3rd and 5 th harmonics more than 10 times
The simulation results were very close to the measurements (active/reactive power, voltage deviations, magnitudes of harmonics, THDu) at the plant.
The model consisted of:
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TCR 13 MVAR, 6 kV
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3 rd -order harmonic filter with a power of 9 MVAR
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5 th -order harmonic filter with a power of 7.2 MVAR
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TCR controller
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Electric grid equivalent
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Arc electric furnace equivalent
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Power, voltage, current measurements (instant, RMS, Mean, THD values)
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