Infeed: Summation current too high

What does 206210 mean?

This fault occurs when the smoothed total of the phase currents (i1 + i2 + i3) exceeds 4% of the maximum power unit current (r0209). Primary causes include a ground fault in the DC link leading to high summation current, unperformed zero point calibration of current measurement, or a defective current measurement in the power unit. A high DC component in line currents can severely damage the power unit, line reactor, or line filter if left unaddressed, posing a risk of component failure.

• Ground fault in the DC link bus (e.g., between DC+ and PE, or DC- and PE), causing leakage current and current imbalance.
• Capacitor bank failure or degradation in the DC link, leading to excessive ripple and increased instantaneous current demand.
• Severe imbalance in the three-phase AC supply voltage (e.g., one phase dropping below 380V), causing higher currents on the remaining phases.
• Defective current sensor or measurement circuit in the infeed unit, reporting an erroneously high summation current (e.g., r0067, r0068, r0069 readings).
• Malfunctioning pre-charging circuit, causing excessive inrush current during power-up that exceeds transient limits.

Click steps to track your progress.

1. 1

   Disconnect the AC supply and measure insulation resistance between DC+, DC-, and PE terminals of the infeed unit using a megohmmeter (should be >1 MΩ).

2. 2

   Visually inspect the DC link capacitors for bulging, leakage, or signs of overheating; measure capacitance if a suitable LCR meter is available.

3. 3

   Measure the three-phase AC input voltages (L1-L2, L2-L3, L3-L1) at the infeed terminals (e.g., X1) to detect voltage imbalance.

4. 4

   Monitor the individual phase currents (r0067, r0068, r0069) in the drive diagnostics to identify any significant deviation or offset.

5. 5

   Check the pre-charging resistors and bypass contactor operation during the power-up sequence by monitoring contactor auxiliary contacts (e.g., K1 auxiliary 13/14).