Ingecon SUN 125 TL U 208 Outdoor, Installation Manual, Page: 36 / 88

ABB2000IKI01
36
Installation manual Ingeteam
5.3. Requirements for transformers and insulation monitor
5.3.1. Grid connection transformer (units without a transformer)
This section lists the technical features of the grid connection transformer which converts the medium or high supply
voltage to the operating voltage of the INGECON SUN Power U unit.
1. The transformer’s power must be greater than the sum of the power ratings of the connected inverters. Take
into account the environmental conditions of the site.
2. INGECON SUN Power U inverters connected to the inverter’s low voltage winding must be synchronized.
3. MPPTs connected via INGECON SUN Power U to the same transformer must have the same voltage settings.
4. The Ucc short circuit voltage of the transformer must be equal or less than 6%.
5. We recommend inserting a grounded metal screen between the high voltage winding and low voltage winding.
6. The low voltage winding must withstand pulsating voltage components with dU/dt of 500 V/uS voltage.
7. Because of inverter operation, the voltage between a phase and ground can reach 3/2 of the open circuit
voltage of the PV array.
8. We recommend using the Dy11 connection.
9. The neutral of the low voltage winding
must not be grounded
.
10. The connection to the medium voltage network will be the nominal connection point.
11. We advise using transformers equipped with five-point voltage regulators, with the possibility of selecting
the following options:
5% 2.5% 0% -2.5% -5%
No electronic equipment may be connected to the power grid. All auxiliary loads must be isolated from the power grid
through a transformer with galvanic isolation.
5.3.2. Auxiliary transformer
The auxiliary transformer transforms the voltage from the power part of the unit to its control and consumption part.
P S
P
S
Ingecon
®
Sun Power U
220 ~ 240 Vac
60 Hz
Auxiliary
protection