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VACON STEP-DOWN STEP-UP SOLUTION

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Heikki Salo

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Heikki Salo

~ M~

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Pump or fan

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How to control medium voltage motor

1. Step down transformer 6/0.4 kV or 6/0.69 kV2. Frequency converter Vacon CXC / NX3. Vacon sinus filter4. Step up transformer 0.4/6 kV or 0.69/6 kV5. 6 kV motor

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Heikki Salo

• Pump motor• 630 kW• 6 kV• 72 A

Water treatment plant

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Heikki Salo

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Heikki Salo

800 kW frequency converter for motor test bay

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Heikki Salo

• Frequency converter for motors- 55...500 kW, 400 V- 250..800 kW, 690 V- 250..800 kW, 6 kV and 10 kV via step up trafo- squared torque applications

• No load net voltage 764 V +10%,-15%- UkNettrafo = 4%, UkStep up = 4%, UkFilter = 2%

• Maximum losses at full load- Vacon: 24 kW (=3%)- Filter : 2.2 kW

• Fundamental wave content of output voltage 95%THD < 10%

• Low net voltage distortions by net harmonics

Main customer requirements

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Heikki Salo

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Heikki Salo

800 kW, 690/400 V, 880 Afrequency converter

Block diagram

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Heikki Salo

Net current, transformer primary side, full load 800 kw

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Heikki Salo

Phase to earth voltage Uu1 before the sinus filter

Phase to earth voltage Uu2 after the filter

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Heikki Salo

Output after the sinus filter at full load,800 kW, 690 V

Output voltage after the filter: 500 V, 2 ms per div

Output current after the filter: 500 A, 2 ms per div

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Output voltage and current at different frequencies

50 Hz 30 Hz

20 Hz 10 Hz

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Heikki Salo

What is the maximum peakvoltage after the filter fromphase to earth

Phase to phase voltage U31and current after the filter

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Is there a phase shift between filter in and output

Phase to earth voltage after the filter

Voltage before and afterthe filter together

==> no phase shift

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Heikki Salo

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Heikki Salo

• Vodokanal of St. Petersburg

Four units with step-down transformers, 630 kW FC and motor 690 V.

• Pskov

Two units of step-down/step-up transformers and 630 kW frequency converters for main feeder pumps at a district heating plant.

• Tatarstan

Pumps for 16 units step-down/up -solution 315 kW up to 900 kW. District heating pumps.

• Yakutia

2 units 1000 kW step-down / step-up for 6 kV pump motors.

References • BelarusPower plant pump, 630 kW, 6 kV with step-down / up transformers.

• LithuaniaDistrict heating plants one unit for 630 kW, 6 kV motor; a step-down / step-up transformer and frequency converter and same solution for 315 kW, 6 kV motor.

• PolandPower plant 800 and 1100 kW main feeding pumps 6 kV Step down / step up –solution.

• EstoniaTarto district heating plant 500 kW 6 kV motorStep down / step up solution with existing oil-immersed transformers.

Both 12-pulse and 6-pulse applications are used in the

above mentioned cases

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Heikki Salo

THANK YOU