Sungrow SG125HV-30, Руководство пользователя

Страница: 47 / 105

User Manual 5 Electrical Connection
37

The transformer should be capable of withstanding a certain level of
harmonic current. The maximum total harmonic current is 5% of the
fundamental current at nominal power output.

The transformer should be capable of withstanding a certain level of DC
current injection 0.5% of the fundamental current at nominal power.

The transformer should be capable of withstanding a certain degree of
phase imbalance 5% of the current at nominal power.

The protection degree of the transformer should be taken into account to
coordinate with the inverters.

For thermal rating, the load curve of the transformer and the ambient
conditions at the respective installation site should be taken into account.

The applicable country-specific standards should be taken into account.

The short-circuit apparent power of the transformer at grid-tied point should
be no less than 10 times of its rated power

If the Anti-PID function is to be enabled,
1) Neutral line grounding is strictly prohibited at the LV side of transformer.
2)The transformer's secondary windings shall be able to handle Vrms=842V
phase to ground voltage, which must also be considered when selecting the
cables and devices connected with the LV side of the transformer, including the
SPDs, any meters, etc.
3) The maximum continuous working voltage and action voltage of the low-
voltage side lightning protection device of the grid-connected transformer must
meet the requirements. The "3+1" method is recommended as shown in Fig. 5-
2, where the maximum continuous working voltage of M1-M3 are 500V, M4 is
more than 750V.