Electrical energy supply system with emergency power function for an electrical building network

Abstract

Electrical energy supply system (4) with emergency power function for an electrical building network (3), the energy supply system (4) comprising: a building connection point (9) for the multi-pole electrical connection of the energy supply system (4) to the building network (3); an energy source electrically connected to the building connection point (9) and configured to supply electrical energy to the building network (3) via the building connection point (9); an energy management system (12) for at least partially controlling the energy supply system (4); a circuit breaker (11) having a first switching state in which the energy source is electrically connected via the circuit breaker (11) to a network connection point (5) for connecting the energy supply system (4) to a system-external power supply (2) and having a second switching state different therefrom in which the energy source is electrically isolated from the system-external power supply (2) on all poles by the circuit breaker (11); a sensor system (10) configured to determine, independently of the current switching state of the circuit breaker (11), whether an external electrical power supply for the building network (3) is available on the energy supply system (4); and a switching device (16) configured to establish or break an electrical connection between a neutral conductor (N) of the building network (3) and a protective earth (E) of the building network (3) depending on a control by the energy management system (12); wherein the energy management system (12) is configured to put the circuit breaker (11) into the second switching state and to cause the switching device (16) to establish the electrical connection of the neutral conductor to the protective earth (E), and to activate a backup power operation fed from the energy source for the building network (3) if the sensor system (10) has determined that there is currently no or insufficient system-external electrical power supply for the building network (3) available on the energy supply system (4) according to a defined criterion.

Description

The present invention relates to an electric power supply system with equivalent current function for an electric building network. In particular, the building network can be the electrical network of a single-family or multi-family house or of an operation. The energy supply system can be used in particular in conjunction with a photovoltaic system together with an electrical energy store, in particular a battery system, for supplying the building network with electrical energy. The substitute power function can be used here to supply the building network with electrical energy at least temporarily if the building network is not supplied by an external power supply network, in particular the public power supply network.As a rule, most buildings are supplied with electrical energy by a public power grid which is connected via a grid connection to the building grid formed in the building. To detect the amounts of current supplied, an electricity meter is typically arranged at or in the vicinity of the mains connection point.Although the public power grid typically has a very high availability, so-called power failure can nevertheless occur in individual cases, for example when the power grid or parts of the power grid relevant for the supply of the respective building fail temporarily or are switched off in a targeted manner by lightning strike or on account of maintenance and repair work or in the rare case of a supply shortage.For such cases, the building can have its own backup power supply, which can be supplied in particular by an electrical energy store and / or a separate power generation system. Electrical energy stores, in particular electrochemical batteries, for example lithium-ion batteries, are generally used as energy stores, in particular in conjunction with photovoltaic systems serving for local power generation for the building.It is an object of the present invention to provide an improved electrical energy supply system with a substitute current function for an electrical building network, which is in particular easily installable and / or enables safe operation of the building network in the substitute current operation.To achieve this object, the subject matter is proposed according to the teaching of claim 1. Various embodiments and developments of the solution are the subject matter of the dependent claims.Some of the terms used herein to describe the present solution are explained in greater detail below:The term "replacement current" as used herein is to be understood as meaning electrical current which is or can be provided by the energy supply system if a supply of the building network from the system-external power supply (e.g. public power network) is omitted or is not sufficient to supply all active consumers in the building network. The supply of the building network with replacement current can take place in particular with energy from an energy store of the energy supply system and it can be activated and / or deactivated in particular fully automatically, semi-automatically or manually. The term "replacement power" as used herein includes the related term "emergency power" as a special case, such as when only one selected socket or only one or more selected ones of the existing loads are supplied with power from the power supply system in the event of the system-external power supply being omitted.The term "building network" as used herein is to be understood as an electrical network which is installed at least partially in a building to be supplied therewith and is configured to supply electrical energy to electrical loads belonging to the building or present therein. For this purpose, a building network is typically connected to a system-external power supply for providing the electrical energy to be distributed over the building network. However, it can also itself have one or more energy sources for at least partially providing the required energy. A typical building network comprises all electrical lines which are laid in buildings and serve for supplying power. The consumers closed off therefrom and possibly energy sources (beyond that of the power supply system according to the solution) can also be counted as such.The term "building connection point" as used herein is to be understood as meaning an electrically conductive interface of the energy supply system, by means of which interface it can be electrically connected to a building network in such a way that the energy supply system can feed electrical energy into the building network via this interface for the purpose of supplying said building network. In particular, the interface can have an electrically conductive point or an electrically conductive region, for example a conductor track, a cable or a busbar, of an electrical circuit. A building connection point can thus be punctiform as a single point of the circuit in a geometrical sense defined, but instead can also extend spatially over a finite spatial area. In particular, different electrical lines which are connected to the building connection point can be connected, viewed geometrically, at different points to the conductive region defined as the building connection point. The building connection point is regularly different from the grid connection point at which the building grid is connected or connectable to the public grid, although special cases are conceivable where both points coincide.The term "energy source" as used herein is understood to mean a device, in particular a system or a device, which can deliver energy, in particular electrical energy. An energy source can have, in particular, one or more energy stores, for example electrochemical batteries, and / or one or more energy generators or energy converters, for example photovoltaic installations, wind turbines, water power installations or power generators driven by fuel.The terms "comprises," "includes," "includes," "has," "has," "with," or any other variant thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a method or apparatus comprising or having a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such a method or apparatus.Further, unless expressly stated to the contrary, "or" refers to an inclusive "or" and not an exclusive "or.". For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).The terms "a" or "an" as used herein are defined in the sense of "one / one or more.". The terms "another" and "a further" and any other variant thereof are to be understood in the sense of "at least one further".The term "plurality" as used herein optionally is to be understood as meaning "two or more".The terms "first / r / s", "second / r / s", "third / r / s" and similar terms in the description and in the claims are used to distinguish between similar or otherwise identically named elements and not necessarily to describe a sequential, spatial or chronological order. It is understood that the terms so used are interchangeable under appropriate circumstances and the embodiments of the solution described herein may function in orders other than those described or illustrated herein.The term "configured" or "configured" to fulfil a specific function (and respective modifications thereof), as is optionally used here, is to be understood that a device or component thereof in this respect is already present in a configuration or setting in which it can execute the function or it is at least adjustable, i.e. configurable, in such a way that it can execute the function after corresponding setting. The configuration can be effected, for example, by means of a corresponding setting of parameters of a process sequence or of switches or the like for activating or deactivating functionalities or settings. In particular, the device can have a plurality of predetermined configurations or operating modes, such that the configuration can be effected by means of a selection of one of these configurations or operating modes.One aspect of the solution presented here relates to an electrical energy supply system with a substitute current function for an electrical building network, in particular for a multipolar building network (e.g. three-phase network with three phases, a neutral conductor and a protective earth). The energy supply system has: (i) a building connection point for the multipolar electrical connection of the energy supply system to the building network; (ii) an energy source electrically connected to the building connection point, which is configured to supply electrical energy into the building network via the building connection point; (iii) an energy management system for at least partially controlling the energy supply system; (iv) a circuit breaker having a first switching state in which the energy source is electrically conductively connected via the circuit breaker to a network connection point for connection of the energy supply system to a system-external power supply, and having a second switching state different therefrom in which the energy source is electrically disconnected from the system-external power supply by the circuit breaker; (v) a sensor system configured to determine, independently of the current switching state of the circuit breaker, whether an external electrical power supply for the building network is available at the power supply system; and (vi) a switching device configured to establish or disconnect an electrical connection between a neutral conductor of the building network and a protective earth of the building network as a function of a control by the energy management system.In this case, the energy management system is configured to put the circuit breaker in the second switching state and to cause the switching device to establish the electrical connection of the neutral conductor to the protective earth, and to activate a substitute current mode for the building network fed from the energy source if the sensor system has established that no or no sufficient system-external electrical power supply is currently available for the building network on the energy supply system according to a defined criterion.Such a power supply system is easy to install since it is only necessary to switch (i.e. connect) between a mains connection point for the external electrical power supply and the building mains. In particular, the energy supply system can be connected between the mains connection counter and the building network. The substitute current function is already provided completely by the energy supply system, so that no further components or other preconditions have to be provided in the building network or in addition to the energy supply system for this purpose. The connection of the energy supply system to the building network can be effected in particular directly in the distribution box (house connection box) of the building (e.g. on terminals mounted on a 14 cm top hat rail) and without pre-protection, e.g. directly behind a 35 A or 50 A selective circuit breaker (SLS) switch. For the connection of the energy supply system to the building network, in particular a single polyphase, in particular three-phase, connection line can already suffice (so-called single line connection).The circuit breaker serves to reliably disconnect the building network connected thereto from the external power supply, for example a public power supply network, in standby power operation of the power supply system and thus. The switching device in turn serves to define an electrical ground and thus a new neutral point for the building network on the basis of the electrical connection effected by it between the neutral conductor of the building network and an associated protective earth for the building network. This electrical ground replaces the electrical ground (neutral potential) provided by the system-external power supply in the regulating operation (i.e. not in the substitute current operation). Thus, even in the standby current mode, if the ground of the external power supply is no longer available due to the all-pole disconnection from the external power supply caused by the circuit breaker, a clearly defined electrical ground is available which is defined with respect to the voltages of the phases of the building network. This is relevant in particular with regard to the safety of the building network, since a clearly defined mass may be required in particular for protective functions of the building network, such as for the correct functioning of residual current circuit breakers or fuses.Various exemplary embodiments are described below, which can be combined with one another as desired, in each case, unless this is explicitly excluded or is technically impossible.In some embodiments, the power management system is configured from a logic circuit, a programmable controller, a microprocessor platform with associated software, or any combination of two or more of these implementations.In some embodiments, the energy management system has its own housing within the energy supply system or is designed as its own independent, in particular prefabricated, assembly of the energy supply system. In some other embodiments, the energy management system is housed in a common housing along with other components or assemblies of the power supply system.In some embodiments, the energy source includes a battery storage and / or photovoltaic array. The battery storage can be in particular an accumulator, for example based on galvanic lithium ion cells. A photovoltaic installation assigned to the building and a battery store can also act in particular in combination as an energy source, wherein the photovoltaic installation can be operated as a solar power plant of the building, while the battery store can be used for intermediate storage of energy obtained in particular by the photovoltaic installation. The battery storage can thus be stored as a rule. Dual use serves firstly for temporarily storing the energy supplied by the photovoltaic installation (both in closed-loop and in closed-loop standby power operation) and secondly as an energy source for at least partially supplying closed-loop standby power operation of the building network.In some embodiments, the energy management system has an inverter for converting electrical energy supplied by the battery storage unit and / or the photovoltaic installation, wherein the inverter has the sensor system at least in part. The inverter can thus be used to determine whether and, if appropriate, when an electrical power supply for the building network is omitted, for example by selective switching off, emergency switching off or an external effect, such as, for example, an interruption of the power line or damage caused by a lightning strike in the network. This has the particular advantage that, in addition to the inverter which is already present for many building networks for converting direct current supplied by the photovoltaic system and / or the battery storage unit into alternating current required for the building network, it can be used at the same time as the sensor system mentioned or as a component thereof, so that an additional sensor system can be dispensed with or only has to be additionally provided in parts.In some embodiments, the energy management system is further configured to operate the inverter as a power source in standby power operation independently of a phase and / or frequency of the external power supply. This has the advantage that in the standby current mode no reference frequency and reference phase corresponding to that of the omitted external power supply need be generated and provided in standby fashion. Rather, the inverter as a network former can define the phase and or the frequency for supplying the building network with electrical energy (on the basis of alternating current or three-phase current) even within the scope of the substitute current operation.In some embodiments, when the sensor system has determined that no or no sufficient system-external electrical power supply for the building network is currently available at the power supply system according to a defined criterion, the energy management system is configured to first put the circuit breaker in the second switching state and only subsequently cause the switching device to establish the electrical connection of the neutral conductor to the protective earth in a time-delayed manner. The criterion can be defined in particular with respect to a measure for a voltage, a power and / or a frequency of the external power supply. Examples of these are threshold values for the instantaneous power, voltage and / or frequency, for a power or voltage or frequency averaged over a defined period of time (e.g. in the second range) or for a stability of a power, voltage or frequency of the external power supply. Thus, it is ensured that the disconnection from the external power supply is securely accomplished before the neutral conductor and the ground protection of the building network are electrically connected. Even if the system-external power supply were to be available again, for example temporarily or in a fluctuating manner, it is thus avoided that the energy source is electrically connected to the external power supply if and as long as the connection of neutral conductor and protective ground is effected by switching device and is given subsequently.In some embodiments, the power management system is configured to cause the switching device to establish the electrical connection of the neutral conductor to the ground protection only when it receives a confirmation that the circuit breaker is already placed in its second switching state. This serves for additional protection that the star point activation by interconnecting neutral and ground is carried out only when it is ensured that the energy source is actually electrically decoupled from the external power supply.In some embodiments, the sensor system has a measuring device for measuring an electrical power or energy quantity supplied by the system-external power supply to the energy supply system. The measuring device can be connected in particular directly to the mains connection point in order in this way to be able to measure directly the electrical power fed into the power supply system by the external power supply. In this case, it can be connected in particular directly between the connection point and the circuit breaker. The measuring device can be configured in particular such that it transmits a measurement signal representing the measured power directly to the energy management system.In some embodiments, the energy management system is further configured to, in standby power operation, in the case of a plurality of consumers connected to the building network, selectively define and / or bring about the supply thereof with energy from the energy source according to a defined prioritization. For this purpose, the building connection point can have in particular a plurality of individually switchable contacts to which different consumers or sections of the building network are or can be connected in order to be able to supply them with energy from the energy supply system selectively according to a defined prioritization. The prioritization can be defined in particular by a state of charge of the energy store and / or an, in particular instantaneous, yield of energy generators, such as a photovoltaic system, which may be present in the energy supply system or are connected thereto. The contacts can belong in particular to a defined interface or an electrical bus system, for example according to the EEBUS or KNX industry standards or standards.In some embodiments, the energy management system is configured, when the energy supply system is in the standby power mode, to transfer the power switch from the second switching state into the first switching state and to cause the switching device to disconnect the electrical connection of the neutral conductor to the protective earth and thus to end the standby power mode if the sensor system has determined that a or a sufficient system-external power supply is now ready again for the building network after a previous omission or the occurrence of an insufficient system-external electrical power supply according to the criterion. The energy supply system can thus be returned from a previously assumed standby current operation to the regulating operation again. Overall, it can thus be operated reversibly both in the regulating mode and in the emergency mode in the sense of two different operating modes and can change between the two operating modes depending on the availability of the external power supplies, in particular also repeatedly.In some embodiments, the energy management system is configured to cause disconnection of the electrical connection of the neutral conductor to the ground protection before the circuit breaker is placed in the first switching state after disconnection has taken place. It is thus ensured that the energy supply system is only connected again to the system-external power supply by means of the circuit breaker when the neutral point circuit for the emergency operation is canceled and thus a potentially hazardous coexistence, or coexistence of two different neutral points which is harmful to the building network and its consumers, on the one hand for the regulating operation and on the other hand for the emergency operation is avoided.In some embodiments, the switching device for establishing or disconnecting the connection between the neutral conductor and the protective earth comprises a relay that can be controlled by the energy management system. This on the one hand also makes it possible to switch any large currents by means of the relay when using only a small control current. Simple binary operation is also possible in this way, in which the relay can be switched between a first, electrically conductive switching state and a second, electrically isolating switching state.In some embodiments, the power switch is configured as a normally closed switch so that it is conductive in the absence of driving.This means in particular that the circuit breaker is closed and thus conductive (first switching state) if, for example, the activation or, for example in the case of a configuration by means of a relay, a coil of the switch is defective. The building network is thus also connected to the external power supply in such a fault case and supplied by the latter (if at any rate no standby power operation currently prevails or the power switch is defective in such a way that it is no longer conductive). Acute service cases can thus be avoided, which might otherwise be required in the event of a component failure. In addition, a power switch configured as a normally closed switch, in contrast, does not continuously consume energy to remain in the first switching state. This is relevant in particular against the background that power failures in many power supply networks, for example the public power supply network, are very rare and such networks can therefore have very high availability levels, for example above 99%.In some embodiments, the power supply system includes at least one power generation plant configured to supply electrical power provided thereby at the building connection point. The energy generation plant can be present in particular as a component of the energy source or else in addition thereto and be controlled by the energy management system. It can have, in particular, a power generator, for example operated by fuel, a photovoltaic system or a combined heat and power system.When using such an, in particular additional, energy generation plant, a substitute current operation can also be maintained over a long period of time (e.g. over days), in particular even if a wind- or sun-dependent energy generator implemented by the energy source itself cannot deliver energy or cannot deliver sufficient energy during times of lack of wind or lack of solar energy.In some embodiments, the power supply system includes at least one controllable load configured to draw electrical power at the building connection point. The controllable load can be controlled in particular by the energy management. As controllable loads, heat pumps, charging devices for charging vehicle batteries or other controllable loads such as air conditioners or electric heaters are particularly suitable here. Controllable loads can serve in particular for stabilizing the replacement current operation in the event of excess energy or implement additional building functions, such as additional heating systems or other comfort functions for the building, depending on the situation.Further advantages, features and possible applications of the present solution are evident from the following detailed description in conjunction with the figures. The following shows: FIG. 1 is an illustration of a power supply system connected between an external power supply such as a public power grid and a building grid according to a first exemplary embodiment; FIG. 2 is an illustration based on FIG. 1 for explaining signal flows during the transition from the regulating mode to the standby current mode; FIG. 3 is an illustration based on FIG. 1 for explaining signal flows when returning from the standby current mode to the regulating mode; FIG. 4 is an illustration of a power supply system connected between an external power supply, such as a public power grid, and a building grid, according to a second exemplary embodiment; and FIG. 5 shows an illustration of a further exemplary embodiment, which can be used in particular within the scope of the embodiments from FIGS. 1 and 4 and which shows a detailed view of a building connection point having a plurality of contacts which can be switched independently of one another.In the figures, like reference numerals designate like, similar, or corresponding elements. Elements shown in the figures are not necessarily drawn to scale.FIG. 1 shows an illustration of an electric domestic installation 1 with a power supply system 4 connected between an external power supply 2, for example a public power grid, and a building grid 3, according to a first exemplary embodiment.The domestic electrical installation 1 has a mains connection point 5, via which the energy supply system 4 is connected or can be connected to the system-external power supply 2. The mains connection point 5 represents a current interface for connecting the power supply system 4 to the system-external power supply 2 and can have, in particular, connection contacts for a plurality of, in particular three, phases, a neutral conductor N and a protective earth E. This is illustrated in the upper part of FIG. 1 by way of example with a so-called first outer conductor L 1 (first phase), a second outer conductor L 2 (second phase) and a third outer conductor L 3 (third phase) and also a neutral conductor N and a conductor for a protective earth E. Between the mains connection point 5 and the external power supply, viewed from the external power supply, firstly a mains connection fuse 6 and then a mains connection counter 7 can be arranged in the current path.The building network 3 can in particular have a plurality of different consumers 8, each connected via a power network laid in the building, for example household appliances, infotainment systems, kitchen appliances, etc. (cf. FIG. 3 ).The energy supply system 4 has a building connection point 9, via which the energy supply system 4 is electrically connected or connectable to the building network 3. The building connection point 9 thus represents a power interface via which the energy supply system 4 can supply the building network 3 with electrical energy. The interface can have different electrical contacts which are separate from one another, for example in each case one contact for each of a plurality of phases, a further contact for a neutral conductor N and a still further contact for a protective earth E. Furthermore, further electrical contacts can be provided, in particular phase contacts, via which different loads 8 (cf. FIG. 5 ) of the building network 3 can be supplied with electrical energy selectively, i.e. independently of other loads 8. This will be explained in more detail below with reference to FIG. 3.In a current path between the mains connection point 5 and the building connection point 9, the energy supply system 4 has a sensor system 10 and a power switch 11, which are connected in series. The sensor system 10 can have, in particular, a power measuring device. The power switch 11 can be, in particular, a normally-closed switch (i.e. in the non-actuated case). Both the sensor system 10 and the circuit breaker 11 are each connected by signals to an energy management system 12 of the energy supply system 4 (illustrated by dashed arrows), so that they can thus exchange information on the basis of messages or control signals.As shown in FIG. 1, the energy management system 12 may be a component of an energy storage system 13 in the energy supply system 4. The energy storage system 13 can additionally have an electrical energy store 14, in particular an electrochemical battery store, an inverter 15 (inverter) and a switching device 16, for example in the form of a relay ("NPE relay"). The energy store 14, the energy management system 12 and the switching device 16 can in turn be combined to form a battery unit 17 as a subsystem of the energy store system 13 and can have, for example, a common housing or be designed in another way as a subassembly. In addition, the energy supply system 4 can have a photovoltaic installation 18, for example with solar panels, which is configured to supply photovoltaically generated current which can be used for supplying the building network 3 and for temporarily storing electrical energy in the energy store 14. The energy store 14 and optionally the photovoltaic installation 18 overall form an energy source of the energy supply system 4.With reference to FIG. 2, the mode of operation of the energy supply system 4 during the transition from the regulating mode to the standby current mode is now explained:In the regulating operation (normal operation), i.e. when an energy supply is ensured by the system-external power supply 2, the power switch 11 is in a first switching state, in which it is closed and thus conductive ("system-external" means here external with respect to the energy supply system 4). The power measuring device of the sensor system 10 can be used in the control mode as part of a control, in particular power control, of the energy supply system 4 by measuring an electrical power actually drawn from the external power supply and reporting it to the energy management system 12, in particular (for example periodically) repeatedly or continuously.The inverter 15 in the energy storage system 13 is configured to detect any occurrence of a power failure with respect to the system-external power supply 2. If this case occurs, the inverter 15 thus recognizes that the external power supply has dropped or is at least not sufficiently present according to a criterion (power failure recognition a) and requests an all-pole disconnection from the external power supply via a control signal (disconnection request b) transmitted to the energy management. The energy management system 12 is configured to verify this control signal (verification c) and, if verification c is successful, to actuate the circuit breaker 11 (circuit breaker controller d) such that it enters a second switching state in which it interrupts the current path between the grid connection point 5 and the building connection point 9 and thus disconnects the building grid 3 from the external power supply.The circuit breaker 11 is in turn configured to transmit a related feedback e to the energy management system 12 after successful disconnection. The energy management system 12 is configured to actuate the switching device 16 in response to this feedback e (NPE setting f) such that it short-circuits the neutral conductor to the conductor for the protective earth E at the building connection point 9 (symbolized by vertical dashed arrow). This brings about a "star point simulation", which transmits a release signal g directly or indirectly via the energy management system 12 to the inverter 15. On the basis of this enable signal g, the inverter 15 starts the substitute current operation (initiation of substitute current operation h) and supplies the building network 3 with its consumers 8 with electrical energy from the energy source, that is to say from the energy store 14 and / or optionally from the photovoltaic installation 18.With reference to FIG. 3, the mode of operation of the energy supply system 4 during the transition from the standby current mode to the standby current regulating mode is now explained:During the replacement current operation, the sensor system 10 monitors, in particular periodically or continuously, whether and when the system-external power supply 2 is available again (network monitoring i) and a corresponding monitoring result j is transmitted to the energy management system 12. For this purpose, in particular a voltage value and / or frequency value can be measured with respect to a voltage that can be measured at the mains connection point 5. As soon as these values are again within defined limits that are valid enough (criterion fulfilled), the energy management system 12 signals the inverter 15 by an operating change signal k) that it should again change to the regulating operation (initiation of regulating operation I). This is done by terminating the standby power operation and terminating the control signal representing the disconnect request b and with which it requested the network disconnect. Subsequently, the "star point simulation" is deactivated by the energy management system 12 by appropriate actuation of the switching device 16 (NPE reset n), and the power switch 11 is closed again with a time delay (closing request m) so that the consumers 8 in the building networks 3 can be supplied again by the external power supply.FIG. 4 shows an illustration of an electric domestic installation 1 with a power supply system 4 according to a second exemplary embodiment. The energy supply system 4 from FIG. 4 is evident from that of FIG. 1 by way of supplement, but otherwise corresponds thereto, so that only the supplement is discussed below in order to avoid repetitions.A possible addition is that, in addition to the energy source (energy store 14, with or without an additional photovoltaic installation) already present in the energy supply system 4, at least one energy generation installation is present, which is configured to feed in electrical energy provided for it at the building connection point 9. FIG. 4 illustrates, in summary, as a power generation system 19, various examples of such power supply systems being illustrated, which can be present in each case individually or in any desired combination.A first energy generation plant can have a further photovoltaic plant 20, for example one on a secondary building, for example a garage belonging to the building. A second energy generation plant can be an electric generator (current generator 21) which is operated, for example, by means of a fuel (e.g. hydrogen). A third energy generation plant can be or have a combined heat and power plant 22.A further possible addition, which may be present in addition to or instead of the energy generation system 19, consists in that, in addition to the electrical loads already present in the building network 3 of the loads 8 (cf. FIG. 5 ), at least one load is present, which is configured to draw electrical energy at the building connection point 9 with variable power. FIG. 4 illustrates a combined view of the load system 23, various examples of such controllable loads being illustrated, which can be present in each case individually or in any desired combination.A first controllable load can have a heat pump 24, for example for air conditioning the building. A second controllable load may be a charger 25 (e.g. wallbox) for charging vehicle batteries, in particular for electrically driven vehicles. A third controllable load can be or have an air conditioning system 26 or an electric heater, in particular for the building.FIG. 5 shows an illustration of a further exemplary embodiment, which can be used in particular within the scope of the embodiments from FIGS. 1 and 4 and which shows a detailed view of a building connection point 9 having a plurality of contacts 27 which can be switched independently of one another.In the building network 3, various loads 8 are shown here, which can each be connected to the energy supply system 4 by one of the switchable contacts 27. The contacts refer here either only to one or more phases of the power supply provided by the power supply system 4, or even to all poles, including the neutral conductor N and optionally also the protective earth E.The energy management system 12 can be used to prioritize the various loads 8, which can be relevant in particular when not enough electrical power is available in the standby current mode to simultaneously satisfy the requirements of all loads 8 with regard to their respective power reference. The prioritization can be used, in particular, to selectively supply only individual, higher-prioritized consumers 8 with current by means of the switchable contacts 27 according to the prioritization, while other, lower-prioritized consumers 8 are only connected in when sufficient electrical power can be supplied again in order to also supply them. The latter can be the case in particular if the power consumption of other, higher-priority consumers 8 has decreased or dropped or if additional available power is added by additional energy generation, for example by photovoltaics or in the case of FIG. 4 by further energy generators.LIST OF REFERENCE CHARACTERS1 Domestic electrical installation 2 external power supply 3 building network 4 energy supply system 5 network connection point 6 network connection fuse 7 network connection meter 8 loads 9 building connection point 10 sensor system 11 power switch 12 energy management system 13 energy storage system 14 energy store 15 inverter 16 switching device 17 battery unit 18 photovoltaic installation 19 energy generation system 20 further photovoltaic installation 21 current generator 22 combined heat and power system 23 load system 24 heat pump 25 charger 26 air conditioning system 27 switchable contacts E protective earth L 1 first outer conductor L 2 second outer conductor L 3 third outer conductor N neutral conductor a power failure detection b disconnection request c verification d power switch control e feedback f NPE setting g enable signal h initiation replacement current operation i network monitoring j monitoring result k operating alternating signal l initiation Control Operation m Close Request n NPE Reset

Claims

An electrical energy supply system (4) with a substitute current function for an electrical building network (3), wherein the energy supply system (4) comprises: a building connection point (9) for multipolar electrical connection of the energy supply system (4) to the building network (3); an energy source electrically connected to the building connection point (9) and configured to supply electrical energy into the building network (3) via the building connection point (9); an energy management system (12) for at least partially controlling the energy supply system (4); a circuit breaker (11), having a first switching state in which the energy source is electrically conductively connected via the circuit breaker (11) to a grid connection point (5) for connecting the energy supply system (4) to a system-external power supply (2), and having a second switching state which differs therefrom, in which the energy source is electrically disconnected from the system-external power supply (2) with all poles by the circuit breaker (11); a sensor system (10) which is configured to determine, independently of the current switching state of the circuit breaker (11), whether an system-external electrical power supply for the building grid (3) is available at the energy supply system (4); and a switching device (16) configured to establish or disconnect an electrical connection between a neutral conductor (N) of the building network (3) and a protective earth (E) of the building network (3) as a function of a control by the energy management system (12); wherein the energy management system (12) is configured to put the power switch (11) into the second switching state and to cause the switching device (16) to establish the electrical connection of the neutral conductor to the protective earth (E), and to activate a backup current operation for the building network (3) fed from the energy source if the sensor system (10) has established that no or no sufficient system-external electrical power supply is currently available for the building network (3) at the energy supply system (4) according to a defined criterion.The electrical energy supply system (4) according to claim 1, wherein the energy source comprises a battery storage and / or a photovoltaic system (18).Electrical energy supply system (4) according to Claim 2, wherein the energy management system (12) has an inverter (15) for converting electrical energy supplied by the battery storage unit and / or the photovoltaic installation (18), and the inverter (15) has the sensor system (10) at least in part.The electrical power supply system (4) according to claim 3, wherein the power management system (12) is further configured to operate the inverter (15) as a power source in standby power operation independently of a phase and / or frequency of the external power supply.The electrical energy supply system (4) according to any one of the preceding claims, wherein the energy management system (12) is configured, when the sensor system (10) has determined that no or no sufficient system-external electrical power supply is currently available for the building network (3) at the energy supply system (4) according to a defined criterion, to initially put the circuit breaker (11) into the second switching state and only subsequently cause the switching device (16) to establish the electrical connection of the neutral conductor to the protective earth (E) in a time-shifted manner in comparison.The electric power supply system (4) according to claim 4, wherein the power management system (12) is configured to cause the switching device (16) to establish the electrical connection of the neutral conductor to the protective ground (E) only when it receives a confirmation that the circuit breaker (11) is already placed in its second switching state.Electrical energy supply system (4) according to one of the preceding claims, wherein the sensor system (10) has a measuring device for measuring an electrical power or energy quantity supplied to the energy supply system (4) by the system-external power supply (2).The electrical energy supply system (4) according to any one of the preceding claims, wherein the energy management system (12) is further configured to, in the case of a plurality of consumers (8) connected to the building network (3), selectively define and / or effect the supply thereof with energy from the energy source according to a defined prioritization in the case of a plurality of consumers (8) connected to the building network (3).The electrical energy supply system (4) according to any one of the preceding claims, wherein the energy management system (12) is configured, when the energy supply system (4) is in the standby current mode, to put the power switch (11) from the second switching state into the first switching state and to cause the switching device (16) to disconnect the electrical connection of the neutral conductor to the protective earth (E) and thus to end the standby current mode if the sensor system (10) has determined that after a previous omission or the occurrence of an electrical power supply which is not sufficient system-external according to the criterion for the building network (3) now a or a sufficient system-external power supply (2) is again available.The electrical power supply system (4) according to claim 9, wherein the power management system (12) is configured to cause the electrical connection of the neutral conductor to be disconnected from the protective earth (E) before the power switch (11) is placed in the first switching state after disconnection has taken place.Electrical energy supply system (4) according to one of the preceding claims, wherein the switching device (16) has a relay which can be controlled by the energy management system (12) for establishing or disconnecting the connection between the neutral conductor (N) and the protective earth (E).Electrical energy supply system (4) according to one of the preceding claims, characterized in that the power switch (11) is designed as a normally closed switch, so that it is conductive in the absence of activation.The electrical energy supply system (4) according to any one of the preceding claims, further comprising, in addition to the energy source, at least one energy generation plant configured to feed electrical energy provided by it at the building connection point (9).The electrical power supply system (4) according to any one of the preceding claims, further comprising at least one controllable load configured to draw electrical power at the building connection point (9).

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