Self-protecting power transmission unit for supplying a high-power electrical appliance

Description

[0001] The invention relates to an intrinsically safe power transmission subsystem for supplying an electrical device with increased power, suitable for potentially explosive atmospheres. The power transmission subsystem comprises a cable connection and is designed for the intrinsically safe transmission of electrical power via the cable connection from a power source to the electrical device.

[0002] In specific applications, electrical appliances are used in potentially explosive atmospheres, for example, where flammable gases, dusts, or other explosive substances may be present. To prevent the risk of explosion, neither the electrical appliance nor its power supply may act as an ignition source. Therefore, appliances installed or located in potentially explosive atmospheres must be constructed according to specific types of ignition protection.

[0003] The rules for explosion protection defined in relevant national and international standards and guidelines specify various types of ignition protection into which electrical equipment is classified according to the applicable explosion protection requirements. In many cases, the application of the "intrinsic safety" type of ignition protection, abbreviated by the symbol "Ex-i," is advantageous. With this type, voltages, currents, and power are limited to prevent ignition sparks or dangerous heating. The limitations are chosen so that the minimum energy and ignition temperature of an explosive mixture are not reached. Intrinsically safe electrical equipment contains only circuits that meet the requirements for intrinsically safe circuits. Only low-power circuits are suitable for intrinsically safe circuits. Voltages, currents, and power are limited to prevent ignition sparks or dangerous heating.There are two technical versions: "Ex ia" and "Ex ib". "Ex ia" provides particularly high safety, while "Ex ib" provides high safety. The technical specifications are described, for example, in the standard IEC 60079-11.

[0004] Due to limitations regarding voltage, current, and consequently power, supplying measuring sensors via long cables has proven difficult, especially when they require more power than permitted for safety reasons. In the case of the "Ex ia" type of ignition protection, depending on the specific values ​​for current, voltage, cable cross-section, and other device parameters, this often results in a power limit of approximately 2 watts in practice.

[0005] If more power than specified in IEC 60079-11 for a given voltage and current is required to supply an electrical device, the method described in IEC 60079-39 has been available for some time. This method involves detecting a short circuit or open circuit and then interrupting the energy input before an explosion can occur. The method is relatively complex. Due to the necessary electronic current limiting, auxiliary circuits, and decoupling networks, it only achieves the lower level of protection "Ex ib". It is generally not a solution for the higher level of protection "Ex ia".

[0006] Document CN 107 534 290 A describes an intrinsically safe barrier with multiple barrier circuits, each having a cathode node, an output node, and a ground node, wherein Zener diodes are connected in parallel between the cathode node and the ground node, and wherein blocking diodes are connected in series between the cathode node and the output node. Document CN 109 937 459 A describes an intrinsically safe composite cable with a number of device cables, wherein at least one device cable is shielded and at least one other device cable is unshielded. Document CN 209 119 755 U describes an explosion-proof through-wall terminal for a coal mining machine. It features an explosion-proof thread in a cylindrical surface of the explosion-proof housing. Wire feedthrough plates are also provided at both ends of the explosion-proof housing.Document CN 205 194 370 U describes an explosion-proof control cable with various shielding layers.

[0007] There is a need for an intrinsically safe power supply that can provide sufficient power to electrical devices with higher power requirements than can be transmitted intrinsically safely using conventional methods.

[0008] Based on this, the invention aims to increase the transmittable power of an intrinsically safe energy transmission of the type mentioned above.

[0009] The solution according to the invention lies in the features of the independent claims. Advantageous further developments are the subject of the dependent claims.

[0010] In an intrinsically safe power transmission subsystem suitable for an explosion-proof area for supplying an electrical device, comprising a cable connection and designed for the intrinsically safe transmission of electrical power via the cable connection from a power source with several galvanically isolated individual sources to the electrical device, the invention provides that the cable connection is designed as a multi-line cable with several galvanically isolated and individually shielded conductor pairs, each for connection to the individual sources, and that a manifold is provided at the electrical device-side end of the multi-line cable, which is designed in an explosion-proof, ignition-protected enclosure and has separate connections for each of the galvanically isolated conductor pairs as well as a combiner circuit, wherein the connections are provided with decoupling devices in the manifold.which prevent a feedback effect on the connected conductor pairs, and wherein the combiner circuit is configured to combine the electrical power transmitted by the galvanically isolated conductor pairs at the terminals into a total power, the total power being output to the electrical device at an output of the collector device.

[0011] The invention is based on the concept of supplying an electrical device with excessive power in an intrinsically safe manner from a suitable energy source by transmitting power via several galvanically isolated and individually shielded conductor pairs. The individual powers transmitted via each conductor pair are combined after the decoupling device to form a total power output for the electrical device. "Excessive" here means that the power is higher than can be transmitted intrinsically safely via a single conductor. The limit is the permissible power specified in IEC 60079-11 for a given voltage and current. While the individual conductor pairs and their power supply from an energy source, particularly a single energy source, are each intrinsically safe in a known manner, they are not sufficiently powerful in this respect.By distributing the power to be transmitted across multiple conductor pairs, an intrinsically safe transmission of virtually any scalable increased power is possible, using standard conductor pairs for intrinsically safe transmission, for example, according to IEC 60079-25. This enables an intrinsically safe power supply for even an electrical device with excessive power requirements with minimal effort. This is particularly true when the individual conductor pairs are connected to several galvanically isolated power sources, where the power sources are current- and / or voltage-limited, and in particular power-limited, according to IEC 60079-11. Thanks to the invention, a cable connection can thus be created that specifically meets the requirements of IEC 60079-25 and still provides an intrinsically safe power supply for an electrical device with excessive power requirements.

[0012] In the context of the invention, a power limitation is understood to mean a limitation of current and voltage. Such a limitation arises from regulatory requirements and necessarily leads to a corresponding limitation of power. However, the invention fundamentally allows for a particularly high total power output while complying with the regulatory requirements. Therefore, according to the invention, a separate power limitation would not arise from safety-related aspects, but rather, for example, from a non-safety-related property or function of the load, in particular the electrical device.

[0013] A particular advantage of the invention is that this higher power transmission is relatively inexpensive and, in particular, does not require complex electronics. This is especially true compared to the method specified in the introduction according to standard IEC 60079-39. The invention offers the further advantage that a higher degree of reliability can be achieved due to the reduced effort, particularly through less complex electronics.

[0014] Furthermore, thanks to the invention, a particularly high level of safety can be achieved, with which even the protection class "Ex ia" can be met, namely when the circuits of the individual conductor pairs are current-limited by passive components, such as resistors.

[0015] Even in the event of faults, such as damage to the conductor connection due to mechanical impact or insulation failure, the energy transmission according to the invention via the multiple galvanically isolated conductor pairs remains intrinsically safe. If, for example, a conductor is damaged by cutting, first one conductor pair is cut, then the next, and so on. In this process, the cutting tool first cuts the shield, then the first conductor of the conductor pair, subsequently the second conductor of the conductor pair, and finally the remainder of the shield. In the worst-case scenario, assuming a conductive cutting edge, the shield is first connected to the first conductor, and subsequently the first conductor is connected to the second conductor of the conductor pair.Since, in an intrinsically safe energy transmission system, the individual conductor pairs generally only transmit a small, non-hazardous power, even a short circuit results in only a non-hazardous current flow. This sequence is then repeated for the other conductor pairs. Crucially, when a conductor is cut, the individual conductor pairs are severed successively, so that only the current from a single source is interrupted at any one time, and never the sum of the currents from multiple individual sources. Because cutting a single source is inherently safe, the successive cutting of the conductor connection according to the invention does not lead to ignition. The case of a cut is therefore safe in all conceivable scenarios due to the shielding used. The situation can be more critical if the conductor is torn.In the worst-case scenario, out of n pairs of conductors, n-1 return conductors are interrupted first, with the sources being galvanically connected, for example, by a common ground on the source side. If all n pairs of conductors are interrupted simultaneously, the current from each would then flow through the single remaining return conductor. If this return conductor is subsequently also interrupted, n times the current would be disconnected, which could then lead to an ignition spark. This can be avoided by galvanically isolating the individual sources, thus ensuring safety. Finally, the case of insulation failure must also be considered. In principle, the insulation of a conductor connection can fail for various reasons, such as physical overload, particularly due to pressure, temperature, and / or UV radiation, or decomposition caused by chemical influences.In this case, the shielding ensures that if the insulation is lost, only a short circuit will form between the two conductors of a conductor pair inside the shield braid. The short-circuit current thus remains limited to the intrinsically safe level of the current through a conductor pair. Therefore, a dangerous addition of currents cannot occur.

[0016] "Intrinsically safe" refers to a circuit in which no spark or thermal effect occurring under the test conditions specified in the standard can ignite a potentially explosive atmosphere of a specific, standardized composition. With intrinsically safe ignition protection, the power is always limited so that in the event of a short circuit caused by a spark, only a safe energy release can occur. This is also referred to as "ignition protection" or "ignition-protected." It is a measure of secondary explosion protection, hence the term "explosion-proof."These definitions are technical and can be found in the relevant standards, for example, in the IEC 60079 family of standards, particularly in parts -11, -14, and -25. "Non-susceptible to interference" is a technical term used in the relevant standards for intrinsic safety to evaluate components and component groups. For example, Zener diodes for voltage limiting and other semiconductor devices are generally considered susceptible to interference, whereas film or wire resistors for current limiting are considered non-susceptible components under certain normative conditions.

[0017] Advantageously, not only is the energy transmission according to the invention, and in particular its energy source, designed to be intrinsically safe, but the electrical device itself is also explosion-proof according to a standardized type of ignition protection, preferably intrinsically safe according to Ex ia or Ex ib. Particularly preferably, an intrinsically safe chain can be formed for power supply and energy consumption, extending all the way to and including the electrical device.

[0018] It is advantageous for the collector assembly and / or the combiner circuit to be potted and / or housed in a pressure-resistant enclosure. Potting or housing in a pressure-resistant enclosure provides particularly good protection for this critical area where the power flowing through the multiple conductor pairs is concentrated. Due to the potting, explosive gases cannot reach the circuit carrying the full power; otherwise, the pressure-resistant enclosure would act as a protective containment in the event of a fault.

[0019] Preferably, the decoupling devices feature redundant decoupling elements. This redundancy ensures higher operational reliability, as the decoupling function is maintained even if one of the decoupling elements fails. For further simplification, the decoupling elements are preferably designed as passive flow control valves, which allows them to exhibit higher reliability than active components. The flow control valves are connected in a robust series circuit within their respective decoupling devices. This enables failsafe behavior in the event of a failure of one or more of the flow control valves: in the case of an otherwise critical short circuit of the flow control valve, the desired functionality is still achieved in the series connection.

[0020] The combination circuit is advantageously designed to combine the currents transmitted by the conductor pairs, preferably as a parallel circuit. This allows the individual currents transmitted by each conductor pair to be combined into a total current in a circuit that is simple in terms of circuitry and therefore reliable, requiring few components. Alternatively, the combination circuit can also be configured, preferably as a series circuit, such that the individual voltages of each conductor pair are combined to generate a higher total voltage. This allows for a higher supply voltage for the electrical device to be achieved in a simple yet elegant manner.

[0021] It is advantageous to provide current and / or power limiting for the conductor pairs. An intrinsically safe power source will generally already have some form of limitation, be it for current, voltage, and / or power. However, it can still be advantageous, particularly with regard to redundancy or broader applicability, for example, with other, non-limited power sources, for the power transmission unit to have its own current and / or power limiting, especially in and / or at the beginning of the line connection, in the collector assembly, and / or on the power source side of the line connection. A particularly simple and effective way to implement current limiting is by means of a resistor.For a simple implementation of power limitation, even based on a non-safety-related property or function of the load, a resistor can be used in combination with another actuator. A resistor can be placed at the beginning of each wire pair, either as the initial part of the wire pair or as a separate component to ensure the desired limitation is applied across the entire length of the wire pair from the outset. Alternatively, or additionally, the current limiting and / or power limiting, for example, the resistor, can be located in the power distribution unit or integrated into the power source. This allows the wire connection itself to remain free of additional limiting components, simplifying the design.It is advisable to limit the power output of the conductor pairs in a range between 1.5 and 2.5 watts.

[0022] The electrical device is advantageously designed as a field device, particularly as an active sensor, telemetry device, communication device, actuator, and / or controller of a process plant. Furthermore, the electrical device can have its own battery, either to increase reliability or as an additional power supply.

[0023] Preferably, the collector assembly is equipped with a voltage regulator designed to set and / or limit the voltage applied to the terminal of a conductor pair to a predetermined value, wherein the voltage regulator is preferably intrinsically safe, particularly in a shunt topology. This allows a regulated output voltage of the collector assembly to be achieved. This is not only advantageous for supplying electrical devices that require a stabilized supply voltage, but can also be used, for example, for charging batteries for the electrical device. Advantageously, the voltage regulator itself is also intrinsically safe. In particular, in a potted version of the collector assembly, the voltage regulator is also potted. Unlike a conventional linear regulator, the shunt topology enables an intrinsically safe implementation according to "Ex ia" (except for the risk of non-intrinsic safety).Furthermore, the shunt regulator can be used to limit the battery voltage by utilizing the line and internal resistance of the power sources. It is advantageous to position one of the voltage regulator's actuators on the line side before the decoupling device. This offers the benefit that it only "sees" the power from its own source, and not that from any battery that may be installed in the electrical device.

[0024] This is particularly advantageous when the maximum battery voltage of the accumulator needs to be limited using the shunt regulator. For this purpose, a limiter circuit is appropriately provided, which is designed to stop or at least temporarily interrupt the charging of the accumulator when a predefined threshold, such as the maximum battery voltage, is reached.

[0025] Furthermore, to protect the battery, it can be advantageous to provide a release circuit in the electrical device, which is designed to only carry out a charging process of the battery if it has a certain predetermined minimum voltage.

[0026] It is also advantageous that each terminal is assigned its own voltage regulator. This allows the power loss to be distributed among the individual voltage regulators, thus distributing it into n small portions across n voltage regulators connected to n pairs of conductors. Furthermore, mutual interference between the different terminals is avoided. The arrangement of the voltage regulators within the power manifold also has the advantage that its power loss occurs there and not in the potentially more thermally sensitive electrical device.

[0027] Advantageously, the ground wires of the conductor pairs are insulated in the conductor connection and only joined in the collector unit, preferably within the ignition-protected enclosure, or routed through the collector unit to be joined only in the electrical device. They are preferably joined to a non-interference-prone ground potential ("GND"). The interconnection of the individual conductor pairs takes place entirely within the combiner circuit of the collector unit or even within the electrical device being supplied.

[0028] Advantageously, the conductor pairs are arranged in a common sheath. This simplifies routing and protects the cable connection. Furthermore, the cable connection is preferably shielded, with the shield preferably being grounded on one side, particularly on the source side. This one-sided grounding of the shield attenuates interfering electromagnetic interference and prevents potentially hazardous potential transfer via the shield.

[0029] Furthermore, a potential monitor can optionally be provided at the conductor connection. It is expediently designed to monitor the voltages of the individual supply circuits. Additionally, an insulation monitor can optionally be provided, designed to detect a short circuit in and / or between conductor pairs and, upon detection of a short circuit, to limit the current flow through these conductor pairs. With a potential monitor and / or insulation monitor, effective monitoring of the operational safety of the power transmission unit can be achieved.

[0030] The invention further extends to an intrinsically safe power supply system suitable for supplying an electrical device in an explosion-proof area, comprising a power source and a power transmission unit as described above. For further details regarding the power transmission unit, reference is made to the preceding description.

[0031] Regarding the power source, it should be noted that it comprises several individual sources, with each individual source assigned to one of the conductor pairs and galvanically isolated from the other individual sources. The power source and / or its individual sources are preferably current- and / or voltage-limited and expediently have an output resistance for this purpose. This allows the desired limitation of current and voltage to safe values ​​and a corresponding limitation of the transmissible power per individual conductor pair to be achieved in a convenient manner, as required for intrinsic safety. For applications requiring only "Ex ib" protection, redundant electronic current limiting using active components, for example a transistor circuit, is also possible instead of series resistance limiting.

[0032] Regarding the electrical device, it should be noted that the power collection device can optionally be integrated into the electrical device, or vice versa, with the electrical device preferably being a field device, in particular an active sensor, actuator, or controller of a process plant. Especially with an electrical device with high power requirements, it is advantageous to perform the aggregation by means of the power collection device only at the device itself, in order to avoid unnecessarily long transmission paths with already combined currents and / or voltages.

[0033] Preferably, the electrical device includes a battery, preferably with an integrated charge controller for the battery, wherein the charge controller is further preferably designed to be voltage-controlled. The invention can thus be used to charge the battery of the electrical device or to clamp the battery voltage. Preferably, a limiter circuit is also provided, which is designed to terminate charging of the battery when a predefined threshold, in particular a maximum voltage, is reached.

[0034] The invention is described below by way of example with reference to advantageous embodiments. The figures shown are: Fig. 1 a schematic view of an intrinsically safe power supply system; Fig. 2 an equivalent electrical circuit diagram of Fig. 1Fig. 3 a first embodiment with an interconnection of currents; Fig. 4 a second embodiment with an interconnection of voltages; Fig. 5 a shunt regulator for the energy transmission unit; Fig. 6 an energy source with advantageously designed transformers; Fig. 7 an energy transmission unit according to an embodiment variant for supplying various electrical devices.

[0035] A schematic representation of an example of an intrinsically safe energy transmission system 10 according to the present invention is shown in Figure 1 It is shown. It comprises as its main components an intrinsically safe energy transfer subsystem 1 for supplying an electrical device 8 as a load, wherein the required power is fed into the energy transfer subsystem 1 from an energy source 9.

[0036] The energy transmission subsystem 1 comprises a line connection 2 with a multi-line 3, which has several conductor pairs 31-34. Examples are shown in Figure 1 Four pairs of conductors are shown, but there can also be 2, 3, 5, or more pairs. Each pair is provided with its own shielding 35 and arranged in a common enclosure 30. In this embodiment, the shielding 35 is connected to earth potential 36 on one side, namely on the source side, i.e., on the side of the energy source 9.

[0037] The conductor connection 2 has several input terminals 21, 22, 23, 24, the number of which corresponds to the number of conductor pairs 31, 32, 33, 34. A power source 9 with several galvanically isolated individual sources 91, 92, 93, 94 is connected to the input terminals 21, 22, 23, 24, with each terminal 21-24 being assigned one of the power sources 91-94. At the beginning of each of the conductor pairs 31-34, a limiting device 20 is shown, which can be designed as a current or voltage limiter (in the simplest case as a passive resistor). It limits the current and / or voltage in each of the conductor pairs 31-34 to intrinsically safe levels. These levels are determined by the relevant standards and are calculated accordingly by a person skilled in the art. Typically, this results in individual power outputs for each of the conductor pairs 31 - 34 of less than 3 W, mostly in the range of 1.5 to 2.5 W.

[0038] The other end of the multi-core cable 3 is connected to a manifold 4. The manifold 4 has several terminals 41, 42, 43, 44 to which the ends of the conductor pairs 31, 32, 33, 34 are connected. The manifold 4 combines the individual powers transmitted via the individual conductor pairs 31-34 into a total power. Due to the higher currents / voltages involved, the manifold 4 is protected by a pressure-resistant housing 5. Alternatively or additionally, the manifold 5 is enclosed under potting compound 50 (see Figures 3 to 5 The total power thus generated is provided at an output 48 of the collector unit 4, to which the electrical device 8 to be supplied is connected as a load.

[0039] An electrical equivalent circuit diagram is in Figure 2The diagram shows the energy source 9 in the left part of the image, whose output resistance is symbolized by an impedance 99. This impedance 99 limits the maximum current that can be drawn from the source 91 and thus indirectly also the power that can be drawn. This is followed by the line connection 2 with a line resistance 37 arranged in the conductor pair, as well as the line capacitance 37' and line inductance 37". Figure 2 The collector unit 4 is not shown, as it is electrically transparent in this respect. Finally, the electrical device 8 acts as the load.

[0040] A first embodiment is described in Figure 3The circuit is designed such that the currents transmitted in the individual conductor pairs 31-34 are interconnected. For this purpose, the collector unit 4 is equipped with a combiner circuit 47. Terminals 41-44 are connected to this circuit via a decoupling device 45. For redundancy, each of the decoupling devices 45 contains several decoupling elements 46, 46', 46", which in the illustrated embodiment are configured as three diodes connected in series. They act as current valves and direct the current transmitted from the respective conductor pair 31-34 to a combiner circuit 47. In the illustrated embodiment, this circuit is designed to connect the individual currents in parallel and add them together to form a total current.The total current thus generated can be supplied to the load formed by the electrical device 8, which in this embodiment is integrated with the collector device 4 under common potting 50.

[0041] In this embodiment, the current limit 20 is different than in Figure 1 in simplified form, namely as a limiting resistor 39 connected downstream of the individual sources 91 - 94 at the beginning of the line connection 2.

[0042] A second alternative embodiment is described in Figure 4 depicted. It essentially corresponds to the one in Figure 3The embodiment shown is identical, with identical or similar elements bearing the same reference numerals. It differs essentially in that a differently configured combiner circuit 49 is used. This circuit is designed to connect the individual conductor pairs 31-34 in series, thus summing the voltages. The resulting total voltage is then output to the electrical device 8 as a load.

[0043] At the in Figure 5In the illustrated embodiment, a shunt regulator 6 is additionally provided for the power transmission unit. The shunt regulator 6 is shown by way of example at the terminals 44 for the conductor pair 34 – it is also expediently provided for the other terminals. The shunt regulator 6 is also arranged in the potting 50. It is designed to monitor the voltage in the conductor pair 34 and thus ensures a controlled voltage output to the electrical device 8 as the load. In an embodiment not shown, a different standard type of ignition protection, such as encapsulation, is used instead of potting, for example flameproof encapsulation, encapsulation according to the standard type of ignition protection "increased safety", sand encapsulation, oil encapsulation, or pressurized encapsulation.

[0044] The shunt regulator 6 is suitable not only for supplying power to the electrical device 8 itself, but also for charging an integrated accumulator 81 of the electrical device 8. Preferably, it operates in conjunction with a charge controller 61, which is also integrated within the potting compound 50, and a limiter circuit 62, which terminates the charging of the accumulator 81 when a predefined maximum voltage is reached. Optionally, an enable circuit 63 is also provided. This circuit is designed to enable charging only when the accumulator has reached a certain minimum voltage, thus protecting it.

[0045] A particularly safe version of the energy source 9 with transformers 96 is in Figure 6The diagram shows two transformers 96, each with two branches, each branch being connected to one of the conductor pairs 31-34. The transformers 96 each have two separate, galvanically isolated secondary windings, to which a rectifier 97, 97' is connected for conversion to DC voltage. The voltage level is regulated by a voltage regulator 98, 98', which is followed by a current limiting resistor 99, 99'.

[0046] Another variant for collector facility 4 is in Figure 7As shown. In this embodiment, the collector unit 4' does not capture all conductor pairs, but only a portion of them, namely conductor pairs 32-34. The total current, combined by paralleling, is output at several outputs 48, 48', 48" which can be configured differently. For example, a resistive load is connected to outputs 48 and 48', while a DC / DC converter 80 is provided at output 48" to supply an electrical device 8' operating at a different voltage level.

Claims

1. Intrinsically safe energy transmission subsystem (1) which is suitable for an explosion-proof region for supplying an electrical appliance (8), comprises a line connection (2) and is designed for intrinsically safe transmission of electrical power, via the line connection (2), from an energy source (9) having a plurality of galvanically isolated individual sources (91, 92, 93, 94) to the electrical appliance (8), characterized in that the line connection (2) is designed as a multiple line having a plurality of galvanically isolated and individually shielded conductor pairs (31,32, 33, 34) each for connection to the individual sources, and at the electrical appliance end of the multiple line (3), a collector apparatus (4) is provided which is designed to be explosion-proof in an ignition-protected enclosure (5) and has separate terminals (41,42, 43, 44) for the galvanically isolated conductor pairs (31, 32, 33, 34) and a combiner circuit (47, 49), the terminals (41,42, 43, 44) being provided with decoupling devices (45) in the collector apparatus, which prevent a feedback effect on the connected conductor pairs (31,32, 33, 34), and the combiner circuit (47, 49) being designed to combine the electrical power transmitted by the galvanically isolated conductor pairs (31,32, 33, 34) at the terminals (41,42, 43, 44) into a total power, the total power being output at an output (48) of the collector apparatus (4) to the electrical appliance (8).

2. Intrinsically safe energy transmission subsystem (1) according to claim 1, wherein the electrical appliance (8) is explosion-proof according to a standardized type of ignition protection, in particular is intrinsically safe according to Ex ia or Ex ib.

3. Intrinsically safe energy transmission subsystem (1) according to either of the preceding claims, wherein the collector apparatus (4) and / or the combiner circuit (47, 49) are potted and / or arranged in a pressure-resistant housing (5).

4. Intrinsically safe energy transmission subsystem (1) according to any of the preceding claims, wherein the decoupling devices (45) have redundantly designed decoupling elements (46, 46', 46") which in particular are designed as preferably passive current valves, wherein the current valves are preferably connected in their relevant decoupling device (45) in a series circuit which is not prone to faults.

5. Intrinsically safe energy transmission subsystem (1) according to any of claims 1 to 4, wherein the combiner circuit (47, 49) is designed to combine the currents transmitted by the conductor pairs (31, 32, 33, 34), preferably as a parallel circuit, or wherein the combiner circuit (47, 49) is designed to combine the voltages transmitted by the conductor pairs (31, 32, 33, 34), preferably as a series circuit.

6. Intrinsically safe energy transmission subsystem (1) according to any of the preceding claims, wherein current limiting for the conductor pairs (31, 32, 33, 34) is provided, preferably by means of a resistor, in particular in and / or at the beginning of the line connection (2), in the collector apparatus (4) and / or on the energy source side of the line connection (2).

7. Intrinsically safe energy transmission subsystem (1) according to any of the preceding claims, wherein the collector apparatus (4) is provided with a voltage regulator (98, 98') which is designed to set and / or limit the voltage applied to the terminal of a conductor pair (31, 32, 33, 34) to a predetermined value, wherein the voltage regulator (98, 98') is preferably intrinsically safe, in particular designed in a shunt topology.

8. Intrinsically safe energy transmission subsystem (1) according to claim 7, wherein each terminal has its own voltage regulator (98, 98') associated with it.

9. Intrinsically safe energy transmission subsystem (1) according to any of the preceding claims, wherein ground lines of the conductor pairs (31, 32, 33, 34) are insulated in the conductor connection and are only combined in the collector apparatus (4), preferably within an ignition-protected enclosure, or are passed through the collector apparatus (4) to be combined only in the electrical appliance (8).

10. Intrinsically safe energy transmission subsystem (1) according to any of the preceding claims, wherein the conductor pairs (31, 32, 33, 34) are arranged in a common sheath, and / or wherein the line connection (2) is provided with a shield (35), wherein the shield (35) is preferably grounded on one side, in particular on the source side.

11. Intrinsically safe energy supply system (10), comprising an energy source (9) and an energy transmission subsystem (1) which is suitable for supplying an electrical appliance (8) in an explosion-proof region, wherein the energy transmission subsystem (1) according to any of claims 1 to 10 is intrinsically safe.

12. Intrinsically safe energy supply system (10) according to claim 11, wherein the energy source (9) has a plurality of galvanically isolated individual sources (91, 92, 93, 94), wherein each individual source (91, 92, 93, 94) is associated with one of the conductor pairs (31, 32, 33, 34), wherein the energy source (9) and / or the individual sources (91, 92, 93, 94) have an output resistor (99), in particular are current and / or voltage limited.

13. Intrinsically safe energy supply system (10) according to any of claims 11 to 12, wherein the collector apparatus (4) is integrated into the electrical appliance (8), wherein the electrical appliance (8) is preferably a field device, in particular an active sensor, an actuator or a controller of a process engineering plant.

14. Intrinsically safe energy supply system (10) according to any of claims 11 to 13, wherein the electrical appliance (8) has a battery (81), preferably having an integrated charge regulator (61) for the battery, wherein the charge regulator is further preferably designed to be voltage driven.

15. Intrinsically safe energy supply system (10) according to claim 14, wherein a limiter circuit (62) is provided which is designed to terminate charging of the accumulator (81) when a predefined threshold, in particular a maximum voltage, is reached.