SMA SUNNY CENTRAL CP XT Series - Passive Islanding Detection; Behavior in Case of Increasing Temperatures

10 Function Description
SMA Solar Technology AG
User ManualSCCPXT-E7-BA-en-5886
10.2.2.4 Passive Islanding Detection
The inverter is equipped with passive islanding detection. This function can be activated if required. The islanding
detection function detects the formation of stand-alone grids and disconnects the inverter from the utility grid.
Islanding can occur when at the time of utility grid failure, the load in the shut-down sub-grid is roughly equivalent to
the current feed-in power of the PV power plant.
Unlike active islanding detection, with passive islanding detection the utility grid is not actively influenced, but simply
passively monitored. This involves monitoring the speed of the frequency change.
If the power frequency changes by a certain amount in a certain time, a stand-alone grid is detected and the inverter
disconnects from the utility grid. The magnitude of the frequency change and the time in which this change must take
place can be configured via parameters on the grid monitoring relay.
10.2.2.5 Behavior in Case of Increasing Temperatures
Sunny Central 500CP XT/630CP XT/720CP XT/760CP XT/800CP XT/850CP XT/900CP XT
At temperatures up to 25°C, the inverter works at 110% nominal power. At temperatures between 25°C and 50°C,
the AC power supplied by the inverter decreases to 100% of the nominal power indirectly proportional to the
increasing temperature. From 50°C upwards, the AC power of the inverter decreases significantly, only reaching half
of the nominal power at 55°C. For example, the inverter with a nominal power of 900kVA will still supply 450kVA at
55°C.
At ambient temperatures of 60°C, the inverter will only supply 10% of its nominal power. The inverter switches off at
62°C.
Figure 17: Reduction of AC power with increasing temperature
25°C 40°C 50°C 55°C 60°C 62°C
SunnyCentral500CPXT 550kVA 520kVA 500kVA 250kVA 50kVA 0kVA
SunnyCentral630CPXT 700kVA 658kVA 630kVA 315kVA 63kVA 0kVA
SunnyCentral720CPXT 792kVA 749kVA 720kVA 360kVA 72kVA 0kVA
SunnyCentral760CPXT 836kVA 790kVA 760kVA 380kVA 76kVA 0kVA
SunnyCentral800CPXT 880kVA 832kVA 800kVA 400kVA 80kVA 0kVA