EP2878057A2

EP2878057A2 - Device for the safe switching of a photovoltaic system

Info

Publication number: EP2878057A2
Application number: EP13742388.5A
Authority: EP
Inventors: Markus WIERSCH; Hubert Harrer; Waldemar Weber
Original assignee: Ellenberger and Poensgen GmbH
Current assignee: Ellenberger and Poensgen GmbH
Priority date: 2012-07-26
Filing date: 2013-07-11
Publication date: 2015-06-03
Also published as: US20150179363A1; CN104428968A; DE202012007257U1; WO2014015947A3; CA2878115A1; KR20150039767A; CN104428968B; KR101663195B1; WO2014015947A2

Abstract

The invention relates to a device (1) for the safe switching of a photovoltaic system (2), having a circuit breaker (10) with input connections (E_{1, 2}) and with output connections (A1, 2), the circuit breaker (9) being designed as a switching module with a module housing (20), with a switch contact (15, 16) arranged inside the housing for isolating at least one current (17, 18) between one of the input connections (E1, 2) and one of the output connections (A1, 2), a modular current sensor (10) for mounting the module housing (20) of the circuit breaker (9) being provided.

Description

description

Device for safely switching a photovoltaic system

The invention relates to a device for safely switching a photovoltaic system (PV system) with a circuit breaker with input terminals for connection to a number of interconnected photovoltaic modules (PV modules) and with output terminals for connecting an inverter.

From DE 10 2011 008 140 A1 a method and a device for safe switching of a photovoltaic system in the case of a DC side occurring arc are known. The known device comprises an inverter, the DC side, an arc sensor is connected upstream, which is connected to a controller for power management. In the case of a sensed arc detected by the control, an adjustment of the power management, the controller in a classification as a serial arc DC isolation by means of a serial converter upstream of the switch and a parallel arc classification on the DC side of the converter by means of this parallel switched short-circuit switch causes.

From DE 10 2009 022 508 A1 discloses a switchgear for a photovoltaic system is known in which in the guided at two terminals leads a switching mechanism for opening contact points and a bypass are provided which is disposed between the two terminals and in front of the switching mechanism and even has a switching mechanism for closing contact points. The switching mechanisms are coupled to one another such that upon actuation of the switchgear initially the contact points of the switching mechanism in the two leads are opened and then closed with a time delay, the contact points of the switching mechanism in the bypass. The known switchgear is used in particular in the case of the use of the fire department to the fact that the photovoltaic system is switched off and energized to at Use of extinguishing agents to prevent injury as a result of electric shocks or electric arcs.

From EP 2 315 328 A2 it is known to provide a protective device in each of a number of strings with series-connected photovoltaic modules of a photovoltaic system both in the positive current path and in the negative current path, which has an overcurrent protection (over current protector). , an arc fault protector, a reverse current protector and / or a ground fault protector.

WO 2005/098458 A1 discloses a current sensor for detecting, in particular, steep-edged current changes, which has a ferromagnetic coupling element and a sensor winding surrounding it with a number of secondary windings and a field winding leading to the current. The known current sensor is used to detect current changes occurring as a result of electric arcs.

From DE 10 2007 013 712 A1 it is known to evaluate fast current changes as a result of electric arcs, using a current sensor from a sensor winding and an excitation winding wound therewith around a common coupling element to produce the time-differentiated sensor signal with a sensor-dependent frequency bandwidth. An evaluation signal generated from the sensor signal is compared with a threshold value, wherein a normalized signal is generated whose pulse duration is extended to a predetermined time value.

From DE 20 2009 004 198 U1 a separation device for DC interruption between a photovoltaic generator and an inverter is known, wherein the separation device comprises a current-carrying mechanical switch and a semiconductor electronics connected in parallel therewith. When a mechanical switch opens as a result of an arc, the arc voltage generated across the switch switches the semiconductor electronics in an electrically conductive manner, which is current-blocking when the mechanical switch is closed. The invention has for its object to provide a particularly suitable device for safe switching of a photovoltaic system.

This object is achieved by the features of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims.

The inventive device comprises a circuit breaker with input terminals for connection to a number of interconnected photovoltaic modules of a photovoltaic system and with output terminals for connecting in particular an inverter. The circuit breaker is designed as a switching module and comprises a module housing with at least one switching contact inside the housing for disconnecting a current path between one of the input terminals and one of the output terminals. Furthermore, a modular current sensor is provided, which is set up for mounting on the module housing of the disconnector. The current sensor can be arranged both in the positive current path and in the negative current path.

The current sensor is preferably provided and configured to detect the current flowing via the current path without contact or galvanically separated. Particularly preferably, the current sensor is a so-called direct-imaging current sensor with a toroidal core and a measuring winding or a Hall sensor. An essential element of the current sensor is the toroidal core. This can be designed in the manner of a Rogowski coil, in particular for detecting the current changes (di / dt), or as a ferromagnetic ring core or as a slotted toroidal core with an air gap for the Hall sensor. The Hall sensor or a measuring winding around the toroidal core or around a part of the toroidal core is used for tapping an induced current or rapid current changes, as generated for example as a result of arcs in the corresponding current path of the circuit breaker. The current sensor has a sensor housing with a passage opening, to which the current sensor or its toroidal core is arranged inside the housing coaxially. In other words, the current sensor or its toroidal core is arranged inside the housing in the region of the passage opening such that it and the opening of the current sensor or its toroidal core are aligned with one another.

This configuration of the current sensor allows its mounting or mounting on the circuit breaker in a simple manner such that a line carrying the current to be detected through the through hole of the sensor housing and the ring core directly, i. without bends and without contact with a circuit board or the like to the corresponding input or output terminal (input and output terminal) of the circuit breaker can be performed.

The current sensor is therefore advantageously designed as a modular module, which is mechanically connected to the module housing of the circuit breaker, that the passage opening of the sensor housing and the ring core and the input and output terminal of the circuit breaker are aligned, so that the current-carrying line in the usual way the corresponding connection of the circuit breaker out there and can be contacted.

Housing internally, d. H. Within the module housing of the circuit breaker or the sensor housing, a device for evaluating the detected current and in particular for the detection of arcing faults is provided. For this purpose, the device is set up in terms of circuitry and / or programming technology to detect, on the basis of the detected current or characteristics resulting from electric arcs, in particular rapid current changes, in the current signal an arc arising in the photovoltaic system and, if necessary, trigger the disconnector.

The tripping of the circuit breaker is suitably effected by means of a switching mechanism arranged in its module housing, preferably also manually operable, which switches to at least one contact point in the corresponding current path of the circuit breaker Disconnector acts and this opens in the event of tripping. The switch lock is expediently connected via a drive to the device for evaluating the detected current. This drive is also suitably used for a remote release of the disconnector.

The modular circuit breaker or its module housing is suitably set up for coupling a remote control module and / or an undervoltage module. While the remote release module or the undervoltage module is set up and provided for lateral mounting on the modular circuit breaker and in this case also designed for top hat rail mounting, the modular current sensor or its sensor housing is provided and set up on a side of the housing parallel to the DIN rail (front or rear side). of the circuit breaker to be mounted. Thus, while the remote trip or undervoltage module is mounted laterally on the disconnect switch, the current sensor is mounted on the front or rear of the disconnect switch.

In a particularly advantageous embodiment of the circuit breaker with attached modular current sensor and the remote release module and the undervoltage module to a so-called fire department switch with integrated arc detection (arc fault detection) are modularly assembled. As a result, assembly times and components are reduced because additional top hat rails, wiring, terminals and the like, as well as an additional wiring of the overvoltage protection or an overvoltage trip and / or the remote release are not required. Rather, the modular design allows in a simple manner an internal coupling of the respective additional modules as well as a direct coupling to the mounted, for example, on a DIN rail or mountable disconnector. Furthermore, the modular structure with respect to the additional modules at least with respect to their housing allows the same parts with the same external shape and only different internal housing structure whose functions, in particular triggering functions are coupled internally with the release mechanism of the circuit breaker or can be coupled. The device is also generally suitable for other DC systems and in this respect also for their safe switching. The device in turn comprises a circuit breaker with input terminals and with output terminals, wherein the circuit breaker has a switching contact for separating at least one current path between one of the input terminals and one of the output terminals, and wherein a current sensor is provided for mounting on the circuit breaker. The preferably directly imaging current sensor has, in particular, a toroidal core for non-contact detection of the current flowing via the current path or via the positive or negative line or of current changes.

Hereinafter, embodiments of the invention will be explained in more detail attachment of a drawing. Show:

1 schematically a device for safely switching a photovoltaic system with a circuit breaker and with a modular current sensor,

2 shows a device according to FIG. 1 in a perspective illustration with a current sensor module mounted on the isolating switch and with a connecting line guided via the latter to the isolating switch and with a remote actuation module mounted on the isolating switch,

3 shows the device according to FIG. 2 in a sectional view,

Fig. 4 shows the device of FIG. 2 in plan view, and

Fig. 5 shows a modular device according to FIG. 4 as a firefighter switch with additionally coupled module for undervoltage release.

Corresponding parts are provided in all figures with the same reference numerals.

1 shows a device 1 for safe switching of a photovoltaic system 2 including inverter 3. The photovoltaic system 2 comprises a number of parallel strings Si to S _n , each with a number of series-connected photovoltaic modules 4. The parallel strings Si to S _n are connected via a common positive line 5 to a first input (input terminal) Ei and via a negative line 6 to a second input (input terminal) E _{2 of} the device 1. On the output side, the device 1 is connected to the inverter 3 via a first output (output terminal) A1 and a second output (output terminal) A2. For this purpose, it is connected on the DC side via a first connecting line 7 to the first output terminal Ai and via a second connecting line 8 to the second output terminal A ₂ .

The device 1 is modular and comprises a disconnecting switch 9, which is also referred to below as a switching module, and a modular current sensor 10. The output connections A1 and A ₂ are assigned to the disconnecting switch 9. The modular current sensor 10 comprises a toroidal core 1 1, through which the connecting line 8 is led to the output terminal A _{2 of} the circuit breaker 9.

In the exemplary embodiment, the current sensor 10 comprises a measuring winding or coil 12 having a number of turns wound around a partial region of the toroidal core 11. The winding 12 is connected to a device 13 for current evaluation and in particular for arc detection (arc fault detection). This device 13 in turn is connected to a drive 14 which is coupled directly or indirectly with switching contacts 15, 16 of the circuit breaker 9. The switching contacts 15 are arranged in a connected to the positive pole (+) of the photovoltaic system 2 or this associated current path 17 between the input terminal Ei of the circuit breaker 9 and its output terminal A1. The further switching contacts 16 are analogously connected to a current path 18 connected to the negative pole (-) of the photovoltaic system 2 between the second input terminal E _{2 of} the disconnecting switch 9 and its second output terminal A ₂ . The circuit breaker 9 is designed as a DC disconnector (DC disconnector) with both the positive current path 17 and the negative current path 18 separating switching contacts 15 and 16 executed.

2 and 3 show the modular device 1 in a perspective view and in a sectional view. Visible, the circuit breaker 1 has a module housing 19 on. On the front side 20 of the modular current sensor 10 is arranged with the sensor housing 21 and - preferably detachably - mounted. The sensor housing 21 has a passage opening 22, which is aligned with the output terminal A _{2 of} the circuit breaker 9. About this passage opening 22 of the modular current sensor 10, the current-carrying connecting line 8 is directly, ie led without bends, turns or other contact points to the output terminal A _{2 of} the circuit breaker 9 and there, for example, clamped or schraubkontaktiert. The sensor housing 21 of the current sensor 10 has a further passage opening 23, which in turn is aligned with the output terminal Ai of the circuit breaker 9.

Within the sensor housing 21 of the toroidal core 11 with the esswicklung 12 is disposed coaxially to the through hole 22 of the modular current sensor 10 and its sensor housing 21. The arrangement of the ring core 11 is such that its enclosed passage opening and the passage opening 22 of the sensor housing 21 with a contact point 24 of a terminal 25 for contacting the live connecting line 8 and thus aligned with the output terminal A ₂ .

As can be seen comparatively clearly in FIG. 3, the connecting end 26 of the connecting line is free of bending, ie guided without bending point directly through the passage opening 22 and the ring core 11 of the current sensor 10 to the contact point 24, 25 and thus to the output terminal A ₂ .

Housing internally, the circuit breaker 1 comprises a switching mechanism 27, which acts on the contact point 16, that is, on the moving contact, which in turn cooperates with a fixed contact associated with a contact bridge 28 to form the contact point 16. The contact bridge 28 is electrically connected via a fail-safe element 29 to a printed circuit board 30. The printed circuit board 30 carries or is electrically connected to the device 13 for current evaluation and Lichtbogende- detection, which in turn is connected via a terminal 31 with the switching mechanism 27 and with this operated actuator 14. The switching mechanism 27 is also connected via an out of the module housing 19 and manually operated Switching or actuating lever 32 for manual actuation of the switching module or disconnector 9 is coupled.

As can also be seen from FIG. 4, which shows a plan view of the device 1 according to FIG. 2, the device 1 is additionally provided with a module 33. For this purpose, this snap-on or latching elements 34 which correspond with corresponding snap-action or latching elements 35 of the module housing 19 of the circuit breaker 9 for producing a releasable latching connection. The module 33 also has on the module side opposite the latching elements 34 latching recesses 35 for coupling a further module 36, as shown in FIG. 5.

The module 33 is a remote release, which is internally coupled to the actuator 14 acting on the switching mechanism 27 of the circuit breaker 1. By means of this remote release module 33 thus a release of the circuit breaker 1, for example, from a central office or the like is possible.

In the further module 36 is an undervoltage release, which is also internally coupled to the drive 14 of the circuit breaker 9. The undervoltage module 36 detects a voltage below a predetermined threshold voltage and causes, if necessary, z. Example by generating a corresponding trigger signal, a separation or opening of the contact points 15, 16 of the circuit breaker. 1

As can be seen in particular from FIG. 5, the or each additional module 33, 36 of the device 1 are mounted laterally on the latter and can be connected to one another in virtually any desired number with different functionalities. In contrast, the current sensor 10 is arranged on the front sides 20 of the circuit breaker 9 or

assembled.

The current sensor 10 can according to FIG. 2 extend over both adjacent output terminals Ai and A ₂ or also according to FIGS. 4 and 5 only in the area of one of the output terminals Ai, A ₂ . In addition, the current sensor 10 at the opposite front or back 20 of the circuit breaker 10 in the region of the input terminals egg, E ₂ or egg and E _{2 be} arranged. In the embodiment according to FIG. 2, the current sensor 10 can also comprise two ring cores 11, ie for each current path 17, 18 a ring core 11.

The current sensor 10 can basically be designed in the manner of a Rogowski coil, as a ferrite ring core with measuring or coil winding 12 or as a direct-imaging current sensor. In this case, the current sensor may be a split ring core with a Hall sensor arranged in the air gap formed in place of the measurement winding 12.

List of numbers Device 32 Switching / operating lever Photovoltaic system 33 Remote control module Inverter 34 Detent element

Photovoltaic module 35 latching element

Plus line 36 Undervoltage module Negative line

Connecting cable A _{1 2} Output connection Connecting cable Ei, 2 Input connection Isolating switch Si ... n string

current sensor

toroidal

Coil / measuring winding

Facility

drive

switching contact

current path

module housing

Front / back

sensor housing

Through opening

contact point

terminal

terminal end

switch lock

Contact bridge

Failsafe element

circuit board

connection

Claims

claims

1. Device (1) for safe switching of a photovoltaic system (2) with a circuit breaker (9) with input terminals (Ei, ₂ ) for connection to a number of interconnected photovoltaic modules (4) and with output terminals (Ai _i2 ), in particular for connection an inverter (3),

characterized,

- That the circuit breaker (9) as a switching module with a module housing (20) and housing inside a switching contact (15, 16) for separating at least one current path (17, 18) between one of the input terminals (Ei, ₂ ) and one of the output terminals (Ai , ₂ ), and

- That a the current over the current path (17, 18) current-sensing modular current sensor (10) for mounting on the module housing (20) is provided.

2. Device (1) according to claim 1,

characterized,

in that the current sensor (10) of the disconnecting switch (9) is provided and set up for non-contact current detection.

3. Device (1) according to claim 1 or 2,

characterized,

in that the current sensor (10) is connected to a device (13) associated therewith or to the circuit breaker (9) for evaluating the detected current, in particular for the detection of arcs.

4. Device (1) according to one of claims 1 to 3,

characterized,

the current sensor (9) comprises a sensor housing (21) with a passage opening (22) and a ring core (11) coaxial with the housing, wherein the passage opening (22) of the sensor housing (19) in the assembled state at the circuit breaker (9) with one of Input terminals (Ei, ₂ ) or one of the output terminals (Ai, ₂ ) are aligned.

5. Device (1) according to claim 4,

characterized,

a connecting line (5 to 8) contacted with the input connection (Ei, ₂ ) or with the output connection (A ₂ ) of the isolating switch (9) encloses the passage opening (22) of the sensor housing (21) and the current sensor (10) or whose ring core (11) passes through.

6. Device (1) according to one of claims 1 to 5,

characterized,

in that the disconnecting switch (9) has a manually actuable switching lock (27).

7. Device (1) according to one of claims 1 to 6,

characterized,

in that the disconnecting switch (9) is provided and arranged for disconnecting both the positive current path (17) and the negative current path (18).

8. Device (1) according to one of claims 1 to 7,

characterized,

in that the disconnecting switch (9) is designed for DIN rail mounting.

9. Device (1) according to one of claims 1 to 8,

characterized, in that the modular current sensor (10) is set up and provided for input-side and / or output-side mounting on the circuit breaker (9).

10. Device (1) according to one of claims 1 to 9,

characterized,

in that the disconnecting switch (9) is set up for coupling a module (33, 36) for remote triggering and / or for undervoltage triggering.

11. Device (1) according to claim 10,

characterized,

in that the module (33, 36) for remote release or for undervoltage release for lateral mounting is set up and provided on the modular disconnecting switch (9).

12. firefighter switch with a device (1) according to any one of claims 1 to 9 and with a module (33, 36) for remote and / or undervoltage release.

13. Device (1) for safe switching of a direct current system (2) with a circuit breaker (10) with input _terminals (Ei _i2 ) and with output _terminals (A _{1 2} ), with a circuit breaker (9) having a switching contact (15, 16) for separating at least one current path (17, 18) between one of the input terminals (Ei _{, 2} ) and one of the output terminals (Ai, ₂ ), and a current sensor (10) provided and arranged for mounting on the circuit breaker (9) ,

14. Device (1) according to claim 13, with a directly imaging current sensor (10), in particular with a toroidal core (11), for non-contact detection of the current flowing through the current path (17, 18) or of current changes.