SB21
Building > Photovoltaic systems >
Safe disconnection of the PV plant
How can PV strings/generators be
safely disconnected during maintenance
and inspection or in the event of fire?
Requirement
The DIN VDE 0100-712 standard stipulates safe disconnection of individual PV strings
or generators from the inverter in the event of a fault in photovoltaic plants. DC safety
disconnectors with the relevant switching capacity for DC currents enable safe
disconnection of all poles under load.
If the DC safety disconnector is integrated into the inverter, its actuation shuts
down the entire plant and no current is produced. The full generator voltage (up to
1,000 V DC) is still active on the DC line between the PV modules and the inverter.
There is therefore a high risk to emergency service personnel in the event of a fire.
For this reason, the shutdown equipment should be installed as close to the PV
modules as possible.
As a DIN rail device, the DC safety disconnector 5TE2 515-1 can be integrated into
existing string boxes or generator boxes. It enables selective shutdown of individual
PV strings/generators. The remainder of the plant thus continues to generate current.
Safe
photovoltaic plant
www.siemens.com/ee-applications
Our answer:
DC safety disconnector for photovoltaic plant
to 1,000 V DC, 63 A
Photovoltaic generators
Light
Structure of a PV plant with remote
control DC safety disconnector for
safe isolation of individual
PV strings
DC safety disconnector
Inverter
Miniature circuit breaker
Residual current
circuit breaker
In hazardous situations, the DC
safety disconnector between the
inverter and PV modules can be remotely tripped with the undervoltage
release. It can also be de-activated
again with a remote actuator.
AC overvoltage
protection
Infeed
meter
SHU
Measuring equipment
SHU
Highlights
System integration
• Selective distributed disconnection of the PV strings/generators
• Compact mounting rail device for applications up to 1 000 V DC
Service-friendly
• Can also be switched remotely with additional components
Reliability
• Increased safety in the event of fire thanks to disconnection of the DC line
between the PV modules and the inverter
Product description DC safety disconnector
Product
Description of functions
DC safety disconnector
For disconnection of the solar module during maintenance and inspection
and in emergency situations. The DC safety disconnector should be positioned as closely as possible to the solar generator. Can also be switched
remotely using optional accessories.
Order no. 5TE2 515-1
Additional components for DC safety disconnector
Product
Description of functions
Undervoltage release
The undervoltage release ensures tripping of the DC safety
disconnector in the event of a voltage interruption. The voltage
interruption can be achieved by an emergency-off push button
(NC contact) or by shutting down of the grid connection by the
fire-fighting services in the event of fire.
Order no. 5ST3 043
Remote operating
mechanism
Order no. 5ST3 050
Auxiliary switch
Order no. 5ST3 010
Handle locking device
Order no. 5ST3 801
The remote actuator is used for switching on the DC
disconnector again remotely, but manual switching on-site is
also possible. It can be mechanically disabled and locked to
safeguard service personnel during maintenance work.
The auxiliary switch switches low currents and voltages and is
thus used to drive programmable controllers (PLCs) or the
binary inputs of bus systems. It can be used to scan the
switching state of the DC disconnector or other components.
The handle locking device safeguards the DC switch
disconnector against undesired mechanical on/off switching.
It can be sealed and secured with a padlock.
Other accessories for string boxes
Product
Description of functions
Casing
Can be used as a string box or generator connection box for
interconnecting and holding the DC protection components.
Insulated distribution
system
Order no. 8HP
DC overvoltage
protection
Order no. 5SD7 483
Terminal blocks
Type 2 surge arresters protect the photovoltaic generator and
the input side of the inverter against overvoltages. A device
failure can be signaled remotely. Version available for plants
requiring increased freedom from leakage current.
8WH1 screw-type terminals are characterized by their compact
design, optimal handling and rated insulation voltage up to 1,000 V.
Order no. 8WH1
PV fuse
Size 10 mm x 38 mm
Cylindrical fuse case
Order no. 3NW7 0..-
The PV fuse (string fuse) also handles protection of the PV
modules and connecting cables. It has a DC rated voltage and
operating class gPV. It is characterized by its extremely compact
design (1 modular width) and an attractive price position.
Cylindrical fuse links
Order no. 3NW6 0..-4
Further information
For details on individual products:
www.siemens.com/lowvoltage/photovoltaic
Technical Support:
www.siemens.com/lowvoltage/technical-support
For technical assistance regarding use of products:
www.siemens.com/automation/support-request
Siemens AG
Industry Sector
P.O. Box 48 48
90026 NUREMBERG
GERMANY
www.siemens.com/ee-applications
Subject to change without prior notice 10/11
Order No. E20001-A1490-M102-X-7600
Printed in Germany
© Siemens AG 2011
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which in actual case of use do not always apply as described
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