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election of differential protection downstream of the inverter
All ABB string inverters marketed in Europe are equipped with a device
for protection against ground faults in accordance with the safety
standard IEC 62109-2, please refer to sections 4.8.2 and 4.8.3 of the
Standard (equivalent to Standard DIN V VDE V 0126-1:2006, section
4.7). In particular, ABB inverters are equipped with a redundancy on the
reading of the ground leakage current sensitive to all components of
both direct and alternating current. Measurement of the ground leakage
current is carried out at the same time and independently by 2 different
processors: it is sufficient for one of the two to detect an anomaly to trip
the protection, with consequent disconnection from the grid and stopping
of the conversion process.
There is an absolute threshold of 1.0 A for PVS-100-TL or 1.2 A for PVS-
120-TL and of total leakage current AC+DC with protection tripping time
at a max. of 300 msec.
Furthermore, there are another three tripping levels with thresholds
respectively at 30 mA, 60 mA and 150 mA to cover the "rapid" changes
in fault current induced by accidental contact with leaking live parts. The
max. tripping times are progressively shortened as the speed of change
in the fault current increases and, starting from the 300 msec/max for
the 30 mA change, they are shortened respectively to 150 msec and 40
msec for 60 mA and 150 mA changes.
For protection of the AC line, on the basis of the information above with
regard to the differential protection integrated in ABB inverters, it is not
necessary to install a type B ground fault switch.
In case of installation of a residual current protection device must meet
the following characteristics:
Type
Sensibility
In accordance with article 712.413.1.1.1.2 of Section 712 of IEC Standard 64-8/7, we hereby
declare that, because of their construction, ABB inverters do not inject ground fault direct
currents.
The use of an AC type circuit breaker with differential thermal magnetic protection with tripping
current of 1.0 A for PVS-100-TL or 1.2 A for PVS-120-TL is advisable so as to prevent false
tripping, due to the normal capacitive leakage current of photovoltaic modules.
In the case of systems which consist of several inverters connected to a single switch with
differential protection it is recommended that a device is installed which allows the adjustment
of the tripping value and the tripping time.
PVS-100-TL
A / AC
1.0 A
- 70 -
5 - Installation
PVS-120-TL
1.2 A
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