Thyristor excitation systems
High-speed microprocessor-based thyristor excitation systems manufactured by the “O’zelektroapparat-Electroshield” JSC and completed with devices made by the foreign manufacturers leading in this field are designed for power supply to the excitation systems of turbine generators and hydrogenerators by rectified controlled current.
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Static excitation systems for turbine and hydraulic generators with and excitation current of no more than 3600 A |
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Static excitation systems for turbine and hydraulic generators with and excitation current of up to 10000 A |
An initial excitation circuit is provided for in the excitation system which automatically forms a short-time voltage impulse on the rotor winding until electromotive force appears in the generator stator winding enough to maintain steady operation of thyristor converter in the self-excitation circuit.
Thyristor excitation systems perform controlling, troubleshooting, signaling, registering, recording, and oscillographic testing of the system operating parameters, pre-alarm and alarm events, as well as working with the automated process control system of the station’s upper level.
Key parameters and specifications of thyristor self-excitation systems (TSES) and thyristor independent excitation system (TIES):
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Parameter name
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Value
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For TSES
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For TIES
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Rectified rated voltage, V
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up to 500
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up to 700
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Rectified rated current, A
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up to 3200
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up to 6000
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Ratio of field-forcing to the excitation voltage of a turbine or hydraulic generator under rated operating conditions, per unit value
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1.6…2.5…3
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1.6…2…2.5
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Ratio of field-forcing to current, per unit value
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1.6…2.0
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Field-forcing duration, sec
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20…50
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Time of excitation voltage building-up to the maximum value with decreasing the positive(-phase)-sequence voltage in the control point by 5% of the rated voltage, ms
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no more than 25
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Time of de-excitation from the maximum positive to the maximum negative excitation voltage, ms
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no more than 30
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Accuracy of voltage maintenance on the busbars of turbine or hydraulic generator relative to the direct-current characteristic, %
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0.2%
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Cooling of the thyristor rectifier
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-forced air cooling;
-natural air cooling;
-water cooling
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Climatic category, placement category according to GOST/IEC
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UKhL4/NF4
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