DE102020100570A1 - MOBILE UNLOCKING DEVICE - Google Patents

Abstract

A mobile disconnection device (2) for a photovoltaic energy generation system (1) can be inserted into a receptacle (6) of the energy generation system (1). The receptacle (6) has two adapter contacts (7), each connected to a direct current line (DC +, DC-) of the power generation system (1), and an adapter earth contact (8) connected to earth potential, with the adapter contacts (7) associated activation contacts (9) and an earth contact (10) assigned to the adapter earth contact (8) can be electrically connected to the assigned adapter contacts (7) and adapter earth contact (8) when the disconnection device (2) is inserted into the receptacle (6). The release device (2) comprises a first switch (15), via which the release contacts (9) can be electrically connected to one another, a second switch (14) via which one of the release contacts (9) can be connected to the grounding contact (10), and an actuating device (11) for changing the first switch (15) and the second switch (14) between a first position in which both switches are open and a second position in which both switches are closed, so that in the second position the direct current lines (DC +, DC-) are short-circuited and connected to earth potential. The disconnection device (2) can be used, for example, in a collecting box or an inverter of a power generation plant.

Description

The invention relates to a mobile disconnection device for a photovoltaic energy generation system. The invention also relates to a collecting box and an inverter with an adapter device for receiving the mobile disconnection device.

In photovoltaic energy generation systems, sunlight is converted into electrical energy and typically fed into an energy distribution network as alternating current. For this purpose, an energy generation system has a large number of solar modules that convert sunlight into direct current power. A series connection can be used to form a string that has a desired output voltage which, in current open-space systems, can assume values of up to 1500 volts. At the same time, a large number of strings can be connected in parallel so that their currents add up and are fed collectively to a DC input of an inverter. In order to connect several strings in parallel, collecting boxes are integrated into the power generation system, which have several DC inputs for connecting a string and a DC output for providing the total currents of the connected strings. For this purpose, collecting boxes often have other elements, for example current or voltage sensors, or disconnectors for the selective separation of strings that are connected to one of the DC inputs of the collecting box. Further disconnectors can also be provided in the inverter. Since the disconnectors must be able to switch a high load current with a high disconnection voltage, at which, for example, arcs occur, such disconnectors are a significant cost factor in power generation plants. Efforts are therefore made to keep the number of switching elements in a power generation system as low as possible.

In order to carry out maintenance work on a power generation system, it is necessary to ensure that no parts that can be touched during maintenance have a dangerous voltage. In principle, the existing isolating switches can be used for this purpose, in which case, however, all solar modules must be disconnected.

If not all solar modules can be separated from the inverter by isolating switches, or in addition to separating the solar modules, an alternative procedure is required. In this case, the direct current lines that connect the solar modules to the inverter are short-circuited and connected to earth potential in a so-called disconnection device. This ensures that the direct current lines do not have any dangerous potential. In this case, however, safety precautions must ensure that the short circuit or the connection to earth potential is not canceled by mistake or by a defect in the short circuit device before the maintenance work has ended.

A voltage reduction within a power generation plant is also required within the framework of standards (for example in the National Electrical Code NEC 2014) when certain operating situations occur. Rapid Shutdown Devices (RSD) are used for this purpose, as described, for example, in the text US 9 742 194 B2 are described.

Such a disconnection device that fulfills the safety requirements is also complex and expensive. For this reason, there is a desire not to have to provide this as an integral part of the energy generation system if standards do not explicitly require their permanent existence.

It is therefore the object of the present invention to provide a disconnection device that enables safe disconnection of an energy generation system, but is not an integral part of an energy generation system, so that it can be brought along by a service technician, briefly installed in the energy generation system, activated and again after the maintenance work has been completed can be deactivated and taken along.

An isolating device according to the invention has the features of independent claim 1. Preferred embodiments are described in the dependent claims. A collecting box according to the invention or an inverter according to the invention has a receptacle for inserting a disconnection device according to the invention.

A mobile disconnection device according to the invention for a photovoltaic energy generation system can be inserted into a receptacle of the energy generation system, the receptacle having two adapter contacts each connected to a direct current line of the energy generation system and an adapter earth contact connected to ground potential. The mobile disconnection device has disconnection contacts assigned to the adapter contacts and a ground contact assigned to the adapter earth contact, which are electrically connected to the assigned adapter contacts and adapter earth contact when the disconnection device is inserted into the receptacle. Furthermore, the release device comprises a first switch, via which the release contacts can be electrically connected to one another, a second switch, via which one of the release contacts can be connected to the grounding contact, and an actuating device for Change of the first switch and the second switch between a first position, in which both switches are open, and a second position, in which both switches are closed, so that in the second position the direct current lines are short-circuited and connected to ground potential. In this switching state, it can be ensured that the direct current lines have a harmless potential, so that maintenance work on the energy generation system can be carried out safely. The ability to use and remove the mobile disconnection device means that the power generation system does not require a permanently installed, costly disconnection device. Instead, the maintenance staff can carry the disconnection device with them and use it on the power generation plant to be serviced.

The mobile release device preferably has a locking device which enables insertion into and removal from the receptacle only in the first position, that is to say when both switches are open. Thus, the short circuit of the direct current lines cannot be caused by inserting the disconnection device in an undesired switch position or canceled by removing the disconnection device in an undesired switch position, which increases the operational reliability of the disconnection device. In addition, a change between the first position and the second position can be blocked if the disconnection device is not properly inserted into the receptacle, i.e. if a reliable electrical connection between the disconnection contacts and the assigned adapter contacts or the ground contact and the assigned adapter ground contact is not guaranteed. Additionally or alternatively, the actuating device can have a mechanical lock against an unauthorized change of position, in the simplest case an eyelet into which a padlock can be hooked.

To further increase the operational safety of the disconnection device, each disconnection contact can comprise two electrically interconnected partial contacts, each of which is assigned two adapter partial contacts that are connected to the same direct current line. Additionally or alternatively, the first switch and / or the second switch can each have two parallel partial switches.

In addition, the disconnection device can have a fault current device which is set up to generate a fault current value from one of the disconnection contacts to the grounding contact for a predetermined period of time at the beginning of a change in the actuation device from the first position to the second position, the period of time being greater than a tripping period of a Residual current protection circuit of the power generation system in the event of a residual current in the amount of the residual current value. The task of the residual current device is to trigger the residual current protection circuit of the energy generation system and thereby achieve a separation of the energy generation system from the network if the energy generation system is still connected to a network at this point in time. If there is an existing network connection, a short-circuit current can otherwise arise between the direct current lines, which would damage the power generation system or the isolating device.

In a preferred embodiment of the disconnection device, the actuating device is set up to close the first switch before the second switch when changing from the first to the second position. This first creates a short circuit between the DC lines, and only then is the DC lines grounded. A period of time between the short-circuiting of the direct-current lines and the grounding of the short-circuited direct-current lines can be predetermined by the design of the actuating device in a known manner.

The actuation device can be, for example, a motorized or a manual actuation device.

The release device advantageously has a visual display. The optical display can display the operating state of the disconnection device, a current flowing through the first switch or a current flowing through the second switch, for example. In this way, it is easy to check whether the energy generation plant is in a safe state for carrying out maintenance work.

Since when the disconnection device is actuated, the components of the disconnection device, in particular the first and second switch, are subject to high stress for a short time, which can lead to wear, the disconnection device can have a counter for recording the number of changes in the actuation device. This counter can be made readable. However, it is also conceivable that the actuating device is set up in such a way that a change from the first position to the second position is blocked when a predetermined count is reached. In this way it can be prevented that a disconnection device is used which has already been exposed to wear and tear which no longer guarantees safe operation. When the specified count is reached, an overhaul or Verification of the activation device can be carried out, which allows the counter to be reset.

In order to make information about the operating state of the disconnection device detectable over a distance that no longer allows the visual display to be read, the disconnection device can furthermore comprise a signal device for generating a signal that is dependent on the position of the actuation device. The signal can be, for example, a radio signal that can be received by a receiving device that the maintenance technician carries with him.

In an advantageous embodiment, a disconnection device according to the invention furthermore has a monitoring device for monitoring a contact quality of the disconnection contacts, the grounding contact, contacts of the first switch and / or contacts of the second switch, the monitoring device in particular having sensors for determining a contact temperature and / or an over has a falling voltage contact. In this case, the signal device can also be set up to generate a signal that is dependent on the contact quality.

In order to reduce short-circuit currents, the disconnection device can furthermore comprise a discharge circuit which is set up for the controlled reduction of a voltage present between the disconnection contacts when the actuating device changes from the first position to the second position before the second position is assumed. A discharge circuit can be implemented, for example, by a brake chopper, that is to say a clocked resistor.

To avoid arcing when the switch is opened, arc extinguishing devices such as those in Scripture DE 102 25 259 A1 disclosed can be used.

In a further aspect of the invention, a collecting box has a receptacle for inserting an activation device described above. However, it is also conceivable to equip an inverter with a receptacle for inserting an isolating device described above.

• 1 eine erste erfindungsgemäße Ausführung einer Freischalteinrichtung und
• 2 eine zweite erfindungsgemäße Ausführung einer Freischalteinrichtung zeigen.

The invention is illustrated below with the aid of figures, of which

• 1 a first inventive embodiment of a disconnection device and
• 2 show a second embodiment of a disconnection device according to the invention.

1 shows a first embodiment of a mobile activation device according to the invention 2 that in a recording 6th a component of a power generation system can be used. The component of the energy generation system has direct current lines DC +, DC- of the energy generation system and can, for example, be a collecting box or an inverter. Inside the recording 6th are two adapter contacts 7th and an adapter ground contact 8th provided, which are arranged such that when the disconnection device is inserted 2 an electrical contact between the adapter contacts 7th and corresponding activation contacts 9 the isolation device 2 , or between the adapter earth contact 8th and a ground contact 10 the isolation device 2 will be produced. The adapter contacts 7th are each connected to different direct current lines DC +, DC-, so that via the isolating device 2 a short circuit between the direct current lines DC +, DC- can be established. The adapter earth contact 8th is connected to earth potential.

Furthermore, the recording 6th Locking receptacles 16 on, in the elements of a locking device 12th the isolation device 2 can intervene to remove the disconnection device 2 from the recording 6th depending on the switching status of the disconnection device 2 to be able to block mechanically. In particular, the disconnection device can be removed 2 only done when the first switch 15th and the second switch 14th are open. The adapter contacts 7th are designed to be safe to touch so that they can be used when the disconnection device is removed 2 can not be touched.

The mobile activation device 2 includes an actuator 11 over which a first switch 15th and a second switch 14th can be operated. Here is the first switch 15th on one side with a first activation contact 9 and on the other side with a second activation contact 9 connected so that through the first switch 15th the direct current lines DC +, DC- can be short-circuited. The second switch 14th is on one side with one of the activation contacts 9 and on the other side with the earth contact 10 connected so that a ground fault of the corresponding direct current line can be generated.

The actuator 11 can be a mechanical device, for example a rotary knob or lever, or a motorized or electromechanical actuating device. The two switches 14th , 15th can be operated together or one after the other. In particular, the first switch 14th after the second switch 15th be operated. The switches 14th , 15th can be mechanical switches, electromechanical switches, semiconductor switches or a combination of the switch types mentioned.

Optionally, the disconnection device 2 a fault current device 13th , for example in the form of a power source. With their help, a desired fault current can be generated between one of the direct current lines and earth potential. Such a generated fault current can occur before the two switches are closed 14th , 15th are generated with the aim of triggering a residual current device of the energy generation system so that the energy generation system disconnects itself from a connected network before short-circuiting the direct current lines DC +, DC-, provided that the network connection exists at this point in time.

One control 17th can control the switching processes within the isolation device 2 control and / or monitor. For this purpose, for example, the timing of the actuation of the fault current device 13th , the actuation of the first and the second switch 14, 15, a detection of temperature, current or voltage values within the disconnection device 2 , a display of the switching status of the disconnection device 2 about elements of an ad 18th and / or data communication via the controller 17th be coordinated. In one embodiment, the controller 17th For example, communicate with an inverter of the power generation system so that the inverter moves the connected solar generators to a voltage-reduced or even voltage-free operating point immediately before the disconnection device changes from the first to the second position, whereby a switching load on the disconnection device can be reduced.

The electrical supply of the control 17th can be done for example from a battery (not shown), which is preferably via the first switch 15th falling voltage can be charged.

To the operational safety of the mobile isolation device according to the invention 2 to increase, the first and / or the second switch can 14th , 15th be designed redundantly as a parallel sub-switch. Redundant adapter contacts can also be used 7th or redundant activation contacts 9 be provided to ensure a reliable permanent short circuit of the direct current lines DC +, DC- by the disconnection device 2 to ensure. Such an implementation is in 2 illustrated.

List of reference symbols

2

Disconnection device

5

DC line

6th

admission

7th

Adapter contact

8th

Adapter earth contact

9

Activation contact

10

Ground contact

11

Actuator

12th

Locking device

13th

Residual current device

14th

counter

15th

counter

16

Locking receptacle

17th

control

18th

display

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 9742194 B2 [0005]
• DE 10225259 A1 [0020]

Claims (21)

Mobile disconnection device (2) for a photovoltaic energy generation system (1) which can be inserted into a receptacle (6) of the energy generation system (1), the receptacle (6) having two each with a direct current line (DC +, DC-) of the energy generation system (1) has connected adapter contacts (7) and an adapter earth contact (8) connected to earth potential, with the adapter contacts (7) assigned activation contacts (9) and an earth contact (10) assigned to the adapter earth contact (8) when the activation device (2) is inserted into the receptacle ( 6) are electrically connected to the associated adapter contacts (7) and adapter earth contact (8), comprising: - A first switch (15), via which the activation contacts (9) can be electrically connected to one another, - A second switch (14), via which one of the activation contacts (9) can be connected to the grounding contact (10), and - An actuating device (11) for changing the first switch (15) and the second switch (14) between a first position in which both switches are open and a second position in which both switches are closed, so that in the second Position the direct current lines (DC +, DC-) are short-circuited with one another and connected to earth potential. Disconnection device (2) Claim 1 , further comprising a locking device (12) which allows insertion into and removal from the receptacle (6) only in the first position. Disconnection device (2) Claim 2 , a change between the first position and the second position is blocked if the release device (2) is not properly inserted into the receptacle (6). Disconnection device (2) according to one of the preceding claims, wherein each disconnection contact (9) comprises two electrically interconnected partial contacts, each of which is assigned two adapter partial contacts which are connected to the same direct current line. Isolation device (2) according to one of the preceding claims, wherein the first switch (14) has two parallel partial switches. Disconnection device (2) according to one of the preceding claims, further comprising a fault current device (13) which is set up to transmit a fault current value from one of the disconnection contacts (9) to the start of a change in the actuating device (11) from the first position to the second position Generate grounding contact (10) for a predetermined period of time, the period of time being greater than a trigger period of a fault current protection circuit of the power generation plant (1) when a fault current is present in the amount of the fault current value. Activation device (2) according to one of the preceding claims, wherein the actuating device (11) is set up to close the first switch (15) before the second switch (14) when changing from the first to the second position. Activation device (2) according to one of the preceding claims, wherein the actuating device (11) is a motorized actuating device. Activation device (2) according to one of the preceding claims, wherein the actuating device (11) is a manual actuating device. Disconnection device (2) according to one of the preceding claims, further comprising an optical display (18) of a current flowing via the first switch. Disconnection device (2) according to one of the preceding claims, further comprising an optical display (18) of a current flowing via the second switch. Disconnection device (2) according to one of the preceding claims, further comprising an optical display (18) for the operating state of the disconnection device (2). Activation device (2) according to one of the preceding claims, further comprising a counter for detecting the number of changes of the actuating device (11). Disconnection device (2) Claim 12 , wherein the actuating device (11) is set up in such a way that a change from the first position to the second position is blocked when a predetermined count is reached. Activation device (2) according to one of the preceding claims, further comprising a signal device for generating a signal dependent on the position of the actuating device. Disconnection device (2) according to one of the preceding claims, further comprising a monitoring device for monitoring a contact quality of the disconnection contacts, the grounding contact, contacts of the first switch and / or contacts of the second switch, the monitoring device in particular sensors for determining a contact temperature and / or a voltage drop across a contact. Disconnection device (2) Claim 15 , as far as referenced Claim 14 , wherein the signal device is further set up to generate a signal that is dependent on the contact quality. Activation device (2) according to one of the preceding claims, wherein the actuating device (11) has a mechanical lock against an unauthorized change of position. Disconnection device (2) according to one of the preceding claims, further comprising a discharge circuit designed to reduce a voltage present between the disconnection contacts (9) when the actuating device (11) changes from the first position to the second position before the second position is assumed. Collection box with a receptacle (6) for inserting a release device (2) according to one of the preceding claims. Inverter with a receptacle (6) for inserting a disconnection device (2) according to one of the Claims 1 to 19th .

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