ABB RER620 Technical Manual

Also see for RER620: Installation manual Manual Applications manual Product guide Communication protocol manual

Contents

ABB RER620 Technical Manual Manual pdf 192 page image

Section 4 1MAC309294-MB FProtection functions186 RER620Technical Manual4.1.8.5 ApplicationTransformer protections require high stability to avoid tripping during magnetizing inrushconditions. A typical example of an inrush detector application is doubling the pickupvalue of an overcurrent protection during inrush detection.The inrush detection function can be used to selectively block overcurrent andground-fault function stages when the ratio of second harmonic component over thefundamental component exceeds the set value.Other applications of this function include the detection of inrush in lines connected to atransformer.Figure 84: Inrush current in transformerIt is recommended to use the second harmonic and the waveform basedinrush blocking from the transformer differential protection function 87Tif available.