Transformer-energizing inrush current: Difference between revisions
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At the moment of energizing a transformer, high values of transient current (which includes a significant DC component) occur, and must be taken into account when considering protection schemes (see {{FigRef|N31}}). | At the moment of energizing a transformer, high values of transient current (which includes a significant DC component) occur, and must be taken into account when considering protection schemes (see {{FigRef|N31}}). | ||
{{FigImage|DB422663_EN|svg|N31|Transformer-energizing inrush current}} | |||
The magnitude of the current peak depends on: | The magnitude of the current peak depends on: | ||
*The value of voltage at the instant of energization | *The value of voltage at the instant of energization | ||
*The magnitude and polarity of the residual flux existing in the core of the transformer | *The magnitude and polarity of the residual flux existing in the core of the transformer | ||
*Characteristics of the load connected to the transformer | *Characteristics of the load connected to the transformer | ||
The first current peak can reach a value equal to 10 to 15 times the full-load r.m.s. current, but for small transformers ( | The first current peak can reach a value equal to 10 to 15 times the full-load r.m.s. current, but for small transformers (< 50 kVA) may reach values of 20 to 25 times the nominal full-load current. This transient current decreases rapidly, with a time constant θ of the order of several ms to severals tens of ms. | ||
[[ru:Ток намагничивания трансформатора при включении]] | [[ru:Ток намагничивания трансформатора при включении]] | ||
[[zh:变压器励磁涌流]] | [[zh:变压器励磁涌流]] | ||
Revision as of 01:23, 9 December 2016
At the moment of energizing a transformer, high values of transient current (which includes a significant DC component) occur, and must be taken into account when considering protection schemes (see Fig. N31).
Fig. N31 – Transformer-energizing inrush current
The magnitude of the current peak depends on:
- The value of voltage at the instant of energization
- The magnitude and polarity of the residual flux existing in the core of the transformer
- Characteristics of the load connected to the transformer
The first current peak can reach a value equal to 10 to 15 times the full-load r.m.s. current, but for small transformers (< 50 kVA) may reach values of 20 to 25 times the nominal full-load current. This transient current decreases rapidly, with a time constant θ of the order of several ms to severals tens of ms.
ru:Ток намагничивания трансформатора при включении zh:变压器励磁涌流
