Private house owner is planning PV system roof top installation. System dimensioning should fulfill following SENER regulations:
Question:
Private house owner is planning PV system roof top installation. System dimensioning should fulfill following SENER regulations:
- Grid voltage should not change more than 4 % at connection point
- Nominal power of the inverter should be less than Sk/25, where Sk is the short circuit apparent power at PCC (Point of common coupling).
- Maximum fuse for the inverter is 3x20A, since main fuse at the switchboard is 3x25A, and selectivity must be kept (PV inverter fuse must be smaller than main board fuse).
The low voltage grid, to which the house is connected, is supplied by a 20/0.4 kV 100 kVA transformer, which has relative short circuit impedance 4% ( can be assumed fully inductive). The length of the low voltage cable between the house and transformer is 1 km. The cable type is AMCMK 4x50/160, which has resistance per phase is 0.77 ohm/km and inductance per phase is 0.27 mH/km. The short circuit impedance at medium voltage side is so small, that it can be neglected.
Select maximum inverter power, which fulfills all the mentioned requirements (voltage drop, short circuit power, fuse selectivity) this is all given information.
(Answer with an accuracy of at least three significant digits.)
The maximum inverter power by short circuit power:
Answer kW
The maximum inverter power by max. 20 A fuse:
Answer kW
The most limiting factor for inverter nominal power is: select one
voltage drop or
short circuit power or
fuse selectivity
Inverter maximum power is:
Answer kW
International Marketing And Export Management
ISBN: 9781292016924
8th Edition
Authors: Gerald Albaum , Alexander Josiassen , Edwin Duerr