User Manual
32
At an ambient temperature of 25
℃
, transformers should withstand 110% of total
load rating.
Short Circuit Impedance Z(%) of the transformer should be 6%(the impedance
allows 10% error margins.).
For thermal rating, the load curve of the transformer and the ambient conditions
at the respective installation site must be taken into account.
The inverter apparent power is not permitted to exceed the transformer power.
The maximum nominal AC current of all connected inverters must be taken into
account. If the number of the grid-connected inverters exceeds 40, please
contact Sungrow to confirm the technical solution.
The transformer must be protected from overloading and short circuiting.
The transformer is an important part of grid-connected PV generation system.
The fault carrying capacity of the transformer should be taken into account at all
times. The fault types include: system short-circuit, grounding fault, voltage drop,
and etc...
Ambient temperature, relative humidity, altitude, air quality, and the relevant
indexes should be taken into account at all times.
The country (region)-specific power grid frequency should be taken into account
at all times.
The country (region)-specific standards and directives should be taken into
account at all times.
6.2.2 Grid Connection
An AC terminal block inside the connection cabinet is used for the five-wire grid
connection (L1, L2, L3, N,PE) of the inverter. And feed-in power is always three-phase
via the AC terminal.
If the AC side has anti-PID function, the voltage of the grid-connection side
transformer or the AC output of the low-voltage switch cabinet to the
ground may be increased. The following requirements therefore need to be
met.
If the low-voltage winding is Wye, the neutral point cannot be grounded;
The max. effective voltage of the inverter AC output to the ground: 850V;
peak value: 1000V. The max. continuous work voltage and the action
voltage of the SPD selected for the transformer low-voltage side and the
