Energy supply method for local energy supply network

Abstract

An energy supply method for an energy supply network (1) connectable to a superior energy supply network (4), at least one of the participants (6a) comprising an energy supply device (9) having an inverter (10a, 10b), the method comprising: i) disconnecting the energy supply network (1) from the superior energy supply network (4); ii) disconnecting all participants (6a, 6b) from the energy supply network (1); iii) determining a master inverter (10a) and a slave inverter (10b); iv) connecting the participant (6a) having the energy supply device (9) to the energy supply network (1); v) outputting the alternating voltage (U) via the master inverter (10a) and the slave inverter (10b), wherein the frequency (f), the voltage amplitude (A) and the phase angle (phi) are defined by the master inverter (10a); vi) determining the total available energy (Eges) and / or the total available power (Pges) in the energy supply network (1); vii) connecting the participants (6b) without the energy supply device (9) to the local energy supply network (1) after step v) as a function of the total energy (Eges), the total power (Pges), the expected power consumption (PE) and / or the expected energy demand (EE); viii) isolates the participants (6a, 6b) from the energy supply network (1) as needed in order to ensure network stability.

Description

Technical Field

[0001] The invention relates to a method of supplying energy to a local energy supply network, in particular after a power outage. Background Art

[0002] The increasing amount of electrical energy from renewable sources fed into the energy supply network poses a major challenge to grid operators and energy suppliers, since the input power and the amount of energy available from these energy sources (especially wind and solar power systems) often fluctuate over time. In order to compensate for these fluctuations, optional storage devices must be provided in order to store excess energy at one moment and release it again at another moment when required. Since the energy feed-in is mostly decentralized and the fed-in electrical energy also fluctuates, this impairs the stability of the grid and increases the probability of blackouts.

[0003] More and more households have renewable energy sources, such as photovoltaic systems or smaller wind or hydroelectric generators, and corresponding energy storage systems for storing (excess) electrical energy. In the event of a power outage, these households can be self-sufficient using the stored electrical energy. On the other hand, households without energy storage devices remain without energy supply during a power outage. It would therefore be desirable if electricity could be supplied to households without energy storage devices in the event of a power outage.

[0004] Methods for at least partially restoring the energy supply after a power outage are already known from the prior art. In order to prevent the established energy supply from collapsing (again), the power consumption and the required energy must not be greater than the available power or available energy. In the article "Investigation of BlackStarting and Islanding Capabilities of a Battery Energy Storage System Supplying a Microgrid Consisting of Wind Turbines, Impedance-and Motor-Loads" by Jürgen Marchgraber and Wolfgang Gawlik (Energy, 13 (19), 5170, published on October 5, 2020), a method is described in which the connection and disconnection of participants or electrical appliances are based on voltage and frequency. For example, if the frequency drops, the electrical appliance is disconnected from the energy supply network by deactivating the electrical switch. A drop in frequency indicates that the energy currently consumed or the required power is greater than the available energy or power.

[0005] A method is known from US Pat. No. 424,933 B2, which switches on or off electrical appliances of a participant depending on the available energy. However, it does not provide any information on the power supply to other participants or households.

[0006] US2022 / 0200336 Al discloses a system and method for supplying energy to a microgrid in an isolated state. If a fault occurs, the microgrid is disconnected from the upper network and then the power supply to the participants is regulated by the energy management system. In addition, the participants are connected to the microgrid via an inverter, which can feed electrical energy into the microgrid. A master inverter is designated to feed power to the microgrid. Summary of the invention

[0007] In view of the above, the object of the present invention is to alleviate or completely avoid the disadvantages of the prior art. Preferably, the object of the present invention is to provide a method by which participants in a local energy supply network without their own energy supply devices can also be supplied with electrical energy after a power outage.

[0008] This object is achieved by the method of claim 1. Preferred embodiments are described in the dependent claims.

[0009] According to the invention, a method for energy supply for a local energy supply network is provided, in particular after a power outage. The local energy supply network can be connected to a higher-level energy supply network via a connection point and connects a plurality of participants (in particular households) to each other. At least one of the participants includes an energy supply device having an inverter for feeding into the local energy supply network. The method comprises the following steps:

[0010] i) disconnecting the local energy supply network from the higher-level energy supply network by means of an electrical switch at the connection point;

[0011] ii) disconnecting all participants from the local energy supply network using an additional switch located at each participant;

[0012] iii) if there are several participants with energy supply devices, a master inverter and at least one slave inverter are determined among the participants with energy supply devices; otherwise, the inverter of the only participant with energy supply device is determined as the master inverter;

[0013] iv) connecting those participants including the energy supply device to the local energy supply network via corresponding further switches, so that the master inverter and, if any, at least one slave inverter can feed into the local energy supply network;

[0014] v) outputting an AC voltage through a main inverter and (if any) at least one slave inverter, wherein the frequency, voltage amplitude and phase angle of the AC voltage are determined by the main inverter;

[0015] vi) determining the total energy and / or total electrical power available from at least one energy supply device in the local energy supply network;

[0016] vii) connecting at least one participant without an energy supply device to the local energy supply network after step v), at least based on the total available energy, the total available electrical power, the expected power consumption of at least one participant without an energy supply device and / or the expected energy demand of at least one participant without an energy supply device.

[0017] viii) disconnecting participants (especially those without energy supply equipment) from the local energy supply network as required, thereby maintaining the network stability of the local energy supply network.

[0018] By the method of the present invention, in the case of a power outage in the energy supply network, especially in the case of a power outage in the upper energy supply network, electric energy can also be provided for participants who do not have their own energy storage devices. In the method of the present invention, participants are connected at least according to the total available energy, the total available electric power, the expected power consumption of the participants and / or the expected energy demand of the participants. The total energy and the available electric power refer to the total available energy of the participants connected to the local energy supply network and the total available electric power of the participants connected to the local energy supply network, respectively. Participants who have a negative impact on network stability due to excessive expected energy demand or excessive expected power consumption will not be connected to the local energy supply network, thereby avoiding the collapse of the energy supply again. Therefore, compared with the prior art, the connection and disconnection of participants to the local energy supply network is not based on the voltage curve and the frequency of the voltage. If the actual energy demand or power consumption demand of a certain participant is too high and thus brings too much load to the local energy supply network, the participant will be disconnected from the local energy supply network or will not be connected at all. For example, the local energy supply network can be a low-voltage network, or a part of a low-voltage network. In normal operation, the low voltage network is usually operated at a mains voltage of 400V phase-to-phase voltage (rms value). The low voltage network can be connected to the upper energy supply network (e.g., medium voltage network) through a connection point (e.g., transformer). The connection point can be formed by a transformer or include a transformer. The medium voltage network usually includes a voltage of at least 1000V outer conductor voltage (rms value). The geographical extension range of the local energy supply network may include, for example, at least 100 meters, at least 500 meters, at least 1 kilometer, at least 3 kilometers, or at least 5 kilometers. For example, the geographical range between the connection point and the participant can be at least 100 meters, at least 500 meters, at least 1 kilometer, at least 3 kilometers, or at least 5 kilometers. Several participants can be connected to the local energy supply network. Participants can be organizationally independent units. For example, a single participant can be formed by a family or a separate building. Each participant can include his own power connection point, particularly a building connection, to be connected to the local energy supply network. At least one of the participants has an energy supply device, which may also include an energy generating device, such as a photovoltaic system, a wind power system, a hydroelectric system, or other devices for generating electrical energy. It is advantageous if the energy supply device includes an electrical energy storage device (e.g., a household storage device) for storing electrical energy. This enables excess energy to be stored and released later. The energy supply device according to the present invention also includes an inverter that can convert a DC voltage into an AC voltage. In addition to other designs, the inverter is also designed to feed into a local energy supply network. The method according to the present invention provides the following steps, particularly in the event of a power outage in the upper energy supply network:

[0019] In step i), the local energy supply network is disconnected from the upper energy supply network using one or more electrical switches. The one or more switches may include a switching element for each phase conductor of the local energy supply network. The one or more electrical switches may be arranged at or near the connection point, for example, in a transformer building. For example, the one or more electrical switches may be formed by an isolator or a load-breaking switch. In step ii), all participants are disconnected from the local energy supply network by other switches located at the participants. The other switches may all be integrated in a smart meter or may all be controlled by a smart meter. For example, the other switches may form a building connection of the participant. In step iii), if there are several participants with energy supply devices, a master inverter and at least one slave inverter are determined among the participants with energy supply devices; otherwise, the inverter of the only participant with energy supply devices is determined as the master inverter. Preferably, the inverter belonging to the following energy supply device is determined as the master inverter, that is, the energy supply device with the most available stored energy and / or the largest available electrical power. Step iii) can also be performed before steps i) and ii) or during steps i) and ii). In particular, step iii) can have been performed during the normal operation of the local energy supply network, so that the master inverter has been determined at the time of the power outage. In step iv), those participants including the energy supply device are connected to the local energy supply network through corresponding additional switches, so that the master inverter and (if any) at least one slave inverter can feed power into the local energy supply network. It can be provided that only participants with high relevance are connected. Participants with low relevance can be disconnected from the energy supply network or remain disconnected from the energy supply network. For example, step iv) can also be performed simultaneously with step v). Participants can be connected to the energy supply device one by one. In step v), an AC voltage is output by the main inverter and (if any) at least one slave inverter, wherein the frequency, voltage amplitude and phase angle of the AC voltage are specified by the main inverter. As mentioned above, participants with energy supply devices and therefore inverters can be connected one by one. The master inverter can specify a voltage amplitude, in particular an amplitude, frequency and phase angle of an AC voltage, for at least one slave inverter and feed it into a local energy supply network. At least one slave inverter adopts the specifications of the master inverter and feeds the AC voltage according to the voltage amplitude, frequency and phase angle specified by the master inverter. Therefore, the master inverter can also be referred to as a leading inverter. In one embodiment, the inverters can communicate with each other via a wireless or wired communication connection. For example, the communication connection between the inverters can be established via an outer conductor (power line communication) of the local energy supply network, or via a wireless or wired communication channel independent of the local energy supply network.In an alternative embodiment, the at least one slave inverter can measure the AC voltage fed by the master inverter and detect the voltage amplitude, frequency and phase angle therefrom, whereby the at least one slave inverter can also output an AC voltage with the detected voltage amplitude, frequency and phase angle. In this case, no separate data line is required. If the establishment of energy supply with the previously determined master inverter is unsuccessful, another inverter can be determined as the master inverter when several participants include an energy supply device. By outputting the AC voltage in step v) and connecting in step iv), an island network operated by participants with energy supply devices is established. In step vi), the total energy available from at least one energy supply device in the local energy supply network and / or the total electrical power available by at least one energy supply device is determined. Step vi) can also be performed simultaneously with other steps i)-v), or before other steps i)-v). Step vi) can also be performed before a power outage, so that in the event of a power outage, the total power and / or the total power that can be called is already known. The total available energy and the total available power can be determined by detecting the electrical energy stored in at least one energy supply device (especially the energy storage unit of the energy supply device), detecting the energy currently generated by any energy generating device or the power capacity currently provided, and / or predicting the energy or power generation generated by any energy generating device in the future. The total available power may depend on the feed-in power of the energy supply device (especially the inverter). The energy and power generation generated by any energy generating device in the future may depend on the time of day, season and weather, and may preferably be based on statistical data. Therefore, when predicting the total energy and total power, the time of day, season and weather can be considered. Preferably, after connecting those participants including the energy supply facilities, in step vii), the participants without energy supply facilities are connected to the local energy supply network at least according to the total available energy, the total available electrical power, the expected power consumption of the participants and / or the expected energy demand of the participants. In this way, the local energy supply network or at least one energy supply device can be prevented from being overloaded. The expected power consumption and expected energy demand of the participants are the power consumption and energy demand required after the respective participants are assumed to be connected. For example, the expected power consumption and expected energy demand can be determined using statistical data from the previous period or based on the electrical devices that the participant has connected and activated (such as refrigerators, lighting equipment, heating equipment, etc.). For example, if the average value for the past 7 days is 7kWh, it can be determined that the expected energy demand of the participant in the next 24 hours is also 7kWh. The expected power consumption can be determined by statistically recording the power consumption of the participant.

[0020] For example, the maximum power consumption or average power consumption over the past 24 hours can be used as the expected power consumption. For the short term, the expected power consumption is very important for allocating available energy. For long-term planning, the expected energy demand is mainly relevant. If the expected energy demand or expected power consumption of a certain participant is too high, the participant will not be connected to the local energy supply network. In step viii), the participant is disconnected from the local energy supply network as needed to maintain the network stability of the local energy supply network. For example, the connection of the participant is disconnected based on the actual power consumption and / or actual energy demand of the participant. It can also be stipulated that the participants are classified according to the correlation, and the participants with low correlation are disconnected from the energy supply network, while the participants with high correlation remain connected to the energy supply network. Preferably, before the participant with energy supply equipment is disconnected from the local energy supply network, the participant without his own energy supply equipment is first disconnected from the local energy supply network. In other words, the participant with energy supply equipment is preferably given priority. If the actual energy demand and / or actual power consumption of a certain participant is too high and endangers the stability of the local energy supply network, the participant is disconnected from the local energy supply network by switching the corresponding other switches. In one embodiment of the present invention, if the actual energy demand of a participant is higher than the expected energy demand and / or the actual power consumption is higher than the expected power consumption, it can be provided that predefined electrical equipment (such as kitchen appliances or outdoor lighting) is deactivated, preferably automatically, in particular in a predefined order. Electrical equipment can be deactivated using a smart home application. It can also be provided that participants without their own energy supply equipment are alternately (i.e., not simultaneously) connected to the local energy supply network, preferably in a predetermined order to avoid overloading the local energy supply network. Steps i)-viii) can but do not have to be performed in a specified order. As long as it is technically feasible, these steps can also be performed simultaneously, or at least partially or completely overlapped in time. Once the cause of the power outage is corrected and the local energy supply network can be powered by the upper energy supply network again, it can be planned that the main inverter and any slave inverter stop supplying power to the local energy supply network. Then, the electrical switch on the connection point can be closed again so that the local energy supply network obtains electrical energy from the upper energy supply network again. Other switches can also be opened in advance.

[0021] It is advantageous if, in step vii), the expected power consumption of the participant without energy supply equipment is determined in each case by the power consumption quota assigned to the participant, and the expected energy demand of the participant without energy supply equipment is determined in each case by the energy demand quota assigned to the participant. In one embodiment of the invention, the energy demand quota and / or the power consumption quota can be set manually by the user. In another embodiment, the allocated energy demand quota and / or the allocated power consumption quota can be set by the application based on the energy and power consumption quota of the participant in the past. Therefore, the power consumption quota and the energy demand quota can be determined by statistical methods. The total available electrical energy and the total available electrical power can also be divided evenly or into the allocated energy demand quota or power consumption quota taking into account the connected load. In one embodiment of the invention, it can be provided that the participant with energy supply equipment also receives the allocated energy demand quota and the allocated power consumption quota. In one embodiment, all participants whose energy demand exceeds the energy demand quota and / or whose power consumption exceeds the power consumption quota can receive a request to reduce energy demand and / or reduce power consumption.

[0022] In order to avoid energy supply collapse, participants without energy supply equipment and whose actual energy demand / power consumption is higher than the corresponding energy demand quota / corresponding power consumption quota can be disconnected from the local energy supply network in step viii). Measuring devices (especially smart meters) can be used to measure the actual energy demand and actual power consumption of participants. This ensures supply security and does not limit the available energy or available electrical power of other participants.

[0023] In one embodiment of the present invention, it can be provided that the electric devices of the participants in the local energy supply network are classified according to the correlation, and the electric devices that reach the specific correlation category are preferably automatically deactivated. In this way, the energy demand in the local energy supply network can be kept low to prevent exceeding the allocated energy demand quota and power consumption quota. In one embodiment of the present invention, it can also be provided that, according to the available total energy and / or the total power that can be called, the electric devices assigned to the specific correlation category are preferably automatically deactivated. If the available total energy and / or the total power that can be called are low, the electric devices of the lower correlation category are deactivated. If the available total energy is large or the total power that can be called is high, the electric devices of the lower correlation category can also be activated. The correlation categories are preferably arranged in ascending order of correlation. In an exemplary embodiment, electric devices such as refrigerators, heating systems and telecommunications devices can be classified into the highest correlation category. Electric devices such as dishwashers, game consoles and swimming pool water circulation pumps can be classified into lower correlation categories. In one embodiment of the present invention, according to the allocated energy demand quota and / or the allocated power consumption quota of the participant, the electric devices can be activated or deactivated according to the level of the correlation category. For example, if the allocated energy demand quota and / or the allocated power consumption quota are low, only the electrical equipment of the highest relevance category can be activated. If the allocated energy demand quota and / or the allocated power consumption quota are high enough, then the electrical equipment of the lower relevance category can also be activated. For example, if the participant includes an emergency circuit and a normal operation circuit, the relevance category can be defined. In the event of a power outage, the emergency circuit will power important electrical equipment, which defines a high relevance category. Other electrical equipment that is not powered by the emergency circuit belongs to a lower relevance category. By switching to the emergency circuit, the electrical equipment in the lower relevance category is deactivated, and only the electrical equipment in the high relevance category is powered. However, the participant can also have a smart home device connected to the electrical equipment, which can activate or deactivate them according to the relevance category of the electrical equipment. In another embodiment, the inverter can also activate or deactivate them according to the relevance category of the connected electrical equipment. In an alternative embodiment, if a certain participant cannot distinguish and activate or deactivate the electrical equipment of the lower relevance category, the participant can be disconnected from the local energy supply network.

[0024] The connection point can be formed by a transformer or include a transformer which connects the local energy supply network to a higher-level energy supply network.

[0025] The local energy supply network may be formed by a low-voltage network, and the superordinate energy supply network may be formed by a medium-voltage network.

[0026] Preferably, each of the other switches is controlled by a smart meter or each is integrated in a smart meter. A smart meter is a device, in particular an electricity meter, which can receive and transmit data and is integrated in a communication network for remote transmission. Another term for a smart meter is a smart counter.

[0027] If there are several participants with energy supply devices, it is advantageous to determine as master the inverter assigned to the energy supply device which contains the most currently available energy and / or the highest available electrical power among the energy supply devices of all participants at a certain time. The time is preferably determined in step iii).

[0028] For exchanging data, it is advantageous if there is a communication connection between the master inverter, the switch and the further switches, preferably a power line communication, in particular a power line communication in accordance with the HomePlug AV specification, the IEEE 1901-2010 standard or the G.hn standard. It is also advantageous if at least one slave inverter can also communicate with the master inverter via a communication connection. As an alternative to power line communication, for example WLAN or LoRa WAN can also be used.

[0029] In a preferred embodiment, the energy supply device comprises an electrical energy storage device, preferably an energy generation device, in particular a photovoltaic system or a wind turbine. The energy generation device can be fed directly into the local energy supply network or fed into the local energy supply network via the energy storage device using an inverter. A hydroelectric generator can also be provided as an energy generation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is described in more detail below with reference to the accompanying drawings. However, the present invention is not intended to be limited to the accompanying drawings. The accompanying drawings show:

[0031] Figure 1 It is a schematic diagram of the local energy supply network;

[0032] Figure 2 is a flow chart; and

[0033] Figure 3 Here is another flow chart. DETAILED DESCRIPTION

[0034] Figure 1A local energy supply network 1 in the form of a low voltage network 2 is shown, which is connected to a higher level energy supply network 4 in the form of a medium voltage network 5 via a connection point 3. The low voltage network 2 is designed as a TN system (French: Terre Neutre), electrically connecting several participants 6a, 6b to each other. Each participant 6a, 6b includes its own building 7. In the figure shown, each participant represents a separate household. The connection point 3 includes a transformer 8 in a transformer substation 8a, which converts the higher voltage (phase-to-phase voltage of more than 1000V) of the medium voltage network 5 into a lower voltage (phase-to-phase voltage of 400V) of the low voltage network 2. Among the participants 6a, 6b, there are participants 6a with their own energy supply equipment 9, and participants 6b without their own energy supply equipment. The energy supply equipment 9 includes at least one inverter 10a, 10b in each case for feeding into the local energy supply network 1, and preferably also includes an energy storage device 11 and / or an energy generation device 12. The energy generation device 12 can include, for example, a photovoltaic system 13, a wind power generation system or a hydroelectric power generation system (not shown). The local energy supply network 1 is connected to the upper-level energy supply network 4 via at least one switch 14, and can be disconnected from the upper-level energy supply network 4 using the switch 14. The switch 14 may include a separate switching element for each phase conductor. The switch 14 may be arranged in the transformer 8 or on the transformer 8. Each participant 6a, 6b is connected to the local energy supply network 1 via another switch 15. The other switch 15 may also include a switching element for each outer conductor. The other switches may each be integrated into a smart meter 16 or controlled by a smart meter 16. The participants 6a, 6b can be connected to the local energy supply network 1 via another switch 15, or disconnected from the local energy supply network 1. Each participant 6a, 6b includes at least one electrical device 17, which is Figure 1 In the figure, the circuit diagram of the lamp is shown. However, the electric equipment 17 may also be, for example, a refrigerator, or electronic equipment such as a television set and a radio.

[0035] The inverters 10a, 10b, the switch 14 and the further switches 15 can communicate with each other via a wireless or wired communication connection 50. In particular, a power line communication 51 can be provided. The inverters 10a, 10b, the switch 14 and the further switches 15 can communicate with each other via an outer conductor of the local energy supply network 1 and exchange data or instructions.

[0036] In normal operation, a participant 6a whose energy supply device 9 includes an energy generating device 12 can feed excess energy into the local energy supply network 1 via inverters 10a, 10b. In this state, one of the inverters 10a, 10b can be set as the master inverter 10a (see step iii) below). The other inverters 10a, 10b represent slave inverters 10b. A participant 6b without an energy supply device 9 obtains electrical energy from the local energy supply network 1. With the help of the smart meter 16, the actual energy demand E and the actual power consumption P of each participant 6a, 6b can be statistically recorded and stored over time. By statistically detecting the energy demand E and power consumption P of the participants 6a, 6b, the expected energy demand E of each participant 6a, 6b can be estimated. e and expected power consumption P E Make statistical predictions.

[0037] In the event of a power outage 18, for example, in the event of a power outage in the upper energy supply network 4, the participants 6a, 6b can no longer obtain electrical energy from the upper energy supply network 4. However, in order to ensure the energy supply in the local energy supply network, the present invention provides a method for supplying energy, which in a preferred embodiment comprises the following steps (see also Figure 2 ). These steps can be performed in a prescribed order, but this is not necessary. Some steps can also be performed at least partially overlapping, or completely overlapping.

[0038] First, perform normal operation 19 (see Figure 2 ), wherein energy is supplied to the participants 6a, 6b from the higher-level energy supply network 4. The actual energy demand E and the actual power consumption P of the participants 6a, 6b can be measured using smart meters 16. During normal operation 19, the master inverter 10a can already be determined (see the description of step iii) below), as indicated in the first block by the label iii). In the event of a power outage 18, all inverters 10a, 10b can be automatically deactivated.

[0039] In step i), the switch 14 can disconnect the electrical connection between the local energy supply network 1 and the higher-level energy supply network 4. This disconnection can be done automatically if a power outage 18 occurs. However, the switch 14 can also be switched manually, for example during maintenance work, in order to disconnect the local energy supply network 1 from the higher-level energy supply network 4.

[0040] In step ii), all participants 6 a , 6 b are disconnected from the local energy supply network 1 via further switches 15 .

[0041] In step iii) (as described above in connection with normal operation), the master inverter 10a is determined. The remaining inverters 10b represent slave inverters 10b. As described above, the master inverter 10a can already be determined during normal operation 19 of the local energy supply network (i.e. before a power outage 18 occurs). The inverters 10a, 10b can be manually selected as the master inverter 10a. Preferably, the inverter 10a, 10b belonging to the following energy supply device 9 is determined as the master inverter 10a, which energy supply device 9 has the highest available energy E a and / or the maximum available electrical power P a In the embodiment shown, the maximum available energy E a and / or the maximum available electrical power P a The energy supply device 9 is a device having an energy storage device 11, the energy storage device 11 stores electrical energy E s If the grid configuration cannot be realized using the determined master inverter 10 a , a new master inverter 10 a will be determined, as shown by line 21 .

[0042] In step iv), those participants 6 a including the energy supply device 9 are connected to the local energy supply network 1 via corresponding further switches 15 , so that the master inverter 10 a and the slave inverter 10 b can feed into the local energy supply network 1 .

[0043] In step v), an AC voltage U is outputted by the master inverter 10a and the slave inverter 10b, the frequency f, the voltage amplitude A and the phase angle φ of which are given by the master inverter 10a. The frequency f, the voltage amplitude A and the phase angle φ can be transmitted to the slave inverter 10b via a communication connection 50 (in particular, a power line communication 51). The slave inverter 10b outputs an AC voltage U, whose frequency f, voltage amplitude A and phase angle φ correspond to the specifications of the master inverter 10a. The slave inverters 10b can be switched on one by one to check whether they are supplied with an AC voltage containing a specified frequency f, a specified voltage amplitude A and a specified phase angle φ. In this way, an island network is established, which can supply power to participants 6a, 6b independently of the upper-level energy supply network 4, including those participants who do not have their own energy supply equipment 9.

[0044] In step vi), the total electrical energy E that can be provided by the energy supply equipment 9 in the local energy supply network 1 is determined. ges And the total electrical power P ges For example, this step can also be performed simultaneously with steps i) to v), or already during normal operation 19. Total available energy E ges And the total available power P ges The determination can be performed by detecting the electrical energy E stored in the energy storage device 10 of the energy supply device 9. s, detect the energy or power generation currently generated by any energy generating device 12, and / or predict the energy or power generation that any energy generating device 12 will generate in the future.

[0045] In step vii), according to the total available energy E ges , Total available electrical power P ges 、Expected power consumption P of participant 6b E and / or the expected energy requirement E of participant 6b e , connects the participant 6b without energy supply device 9 to the local energy supply network 1. The expected power consumption P of the participant 6b E and expected energy demand E e It is assumed that each participant 6b needs power consumption and energy demand after connecting. For example, the expected power consumption P can be determined by applying statistical data from the past period or based on the connected and activated electrical devices 17 (such as refrigerators, lighting devices, heating devices, etc.) of the participant 6b. E and expected energy demand E e .

[0046] In the energy supply network 1, only as much energy as is available can be consumed. The total actual power consumption P of all participants 6a, 6b must not exceed the total available power P ges In order to comply with these requirements, the expected power consumption P of the participant 6b without the energy supply device 9 is E In each case the power consumption quota K assigned to the participant 6b p The expected energy demand of the participant 6b without the energy supply device 9 is determined in each case by the energy demand quota K assigned to the participant 6b. E It is also possible to allocate a power consumption quota K to the participant 6a that has its own power supply device 9 p and energy demand quota K E .

[0047] If the actual energy demand E or the actual power consumption P of the participant 6b without energy supply device 9 exceeds the correspondingly allocated energy demand quota K E Or the corresponding allocated power consumption quota K p , the participant 6b can be asked to reduce its actual energy demand E or actual power consumption P. If the participant 6b does not comply, it can be provided that in step viii) the participant 6b without its own energy supply device 9 is disconnected from the local energy supply network 1. It can also be provided that the participant 6a with the energy supply device 9 is given priority. If the participant 6a with the energy supply device 9 exceeds its energy demand quota K E Or power consumption quota K p , it can also be provided that the participant 6 b without its own energy supply device 9 is disconnected from the local energy supply network 1 to avoid endangering the network stability.

[0048] Figure 3 Shows in more detail Figure 2 In normal operation 19, the master inverter 10a is determined and the actual power consumption P and the actual energy demand E of the participants 6a, 6b are statistically detected. The energy E contained in the energy storage device 11 is also detected. s and power generation (block 101).

[0049] A power outage 18 occurs in block 102. All inverters 10a, 10b are deactivated in block 103. The source of the fault is determined in block 104. If this is not in the local energy supply network 1, the process continues.

[0050] In block 105 , the switch 14 at the connection point 3 and the other switches 15 at the participants 6 a , 6 b are opened.

[0051] In block 106, the other switch 15 assigned to the participant 6a is closed, and the participant 6a is assigned the main inverter 10a. The main inverter 10a then feeds an AC voltage U with a frequency f, a voltage amplitude A and a phase angle φ into the local energy supply network 1 and starts island operation. If the network configuration fails, a new main inverter 10a is determined (block 107). If this also fails, the process is terminated (block 108). In block 109, the other switches 14 of the other participants 6a with the inverter 10a are connected to the local energy supply network 1. The participant 6b that does not have its own energy supply device 9 is also connected in block 109, preferably after the participant 6a with the energy supply device 8 is connected. Based on the energy demand quota K assigned to the participant 6b E and power consumption quota K p If the actual energy demand E and actual power consumption P of participants 6a, 6b exceed the allocated energy demand quota K E Or the allocated power consumption quota K p , then preferably upon request, the participants 6a, 6b are disconnected from the local energy supply network 1 by opening the corresponding other switches 15 in order to stabilize the grid (block 110). In this case, if the allocated energy demand quota or the allocated power consumption quota of the participant 6a with the energy supply device is exceeded, the participant 6a with the energy supply device 9 can also be given priority by removing the participant 6b without its own energy supply device 9 from the local energy supply network.

[0052] In block 111, the removal of the blackout 18 is reported to the master inverter 10a. In block 112, all inverters 10a, 10b are stopped. In block 113, all other switches 15 are opened. In block 114, the switch 14 is closed. In block 115, the other switches 15 are preferably closed one by one.

Claims

1. A method for supplying energy to a local energy supply network (1), in particular after a power outage (18), wherein: The local energy supply network (1) can be connected to a higher-level energy supply network (4) via a connection point (3) and connects a plurality of participants (6a, 6b), in particular households, wherein at least one of the participants (6a) comprises an energy supply device (9) having an inverter (10a, 10b) for feeding into the local energy supply network (1). The method comprises the following steps: i) disconnecting the local energy supply network (1) from the higher-level energy supply network (4) using an electrical switch (14); ii) disconnecting all participants (6a, 6b) from the local energy supply network (1) by means of further switches (15) located at the participants (6a, 6b); iii) if there are several participants (6a) having energy supply devices (9), a master inverter (10a) and at least one slave inverter (10b) are determined in the participants (6a) having energy supply devices (9); otherwise, the inverter (10a) of the only participant (6a) having energy supply devices (9) is determined as the master inverter (10a); iv) connecting those participants (6a) including the energy supply device (9) to the local energy supply network (1) via corresponding further switches (15) so that the master inverter (10a) and, if applicable, at least one slave inverter (10b) can feed into the local energy supply network (1); v) outputting an AC voltage (U) through a master inverter (10a) and (if any) at least one slave inverter (10b), wherein the frequency (f), voltage amplitude (A) and phase angle (φ) of the AC voltage (U) are predetermined by the master inverter (10a); vi) determining the total available electrical energy (E) in the local energy supply network (1) provided by at least one energy supply device (9); ges ) and / or total electrical power (P ges ); vii) at least based on the total available energy (E ges ), total available electrical power (P ges ), the expected power consumption (P ) of at least one participant (6b) without a power supply device (9) E ) and / or the expected energy demand (E) of at least one participant (6b) without an energy supply device (9) e ), after step v), connecting at least one participant (6b) without an energy supply device (9) to the local energy supply network (1); viii) disconnecting the participants (6a, 6b), in particular the participant (6b) without the energy supply device (9), from the local energy supply network (1) as required, thereby maintaining the network stability of the local energy supply network (1).

2. The method according to claim 1, wherein: In step vii), the expected power consumption (P E ) is in each case determined by the power consumption quota (K P ) determines the expected energy demand (E) of the participant (6b) without the energy supply device (9) e ) is in each case determined by the energy demand quota (K E )Sure.

3. The method according to claim 2, wherein: In step viii), there is no energy supply device (9) and the actual energy demand (E) / actual power consumption (P) is higher than the corresponding energy demand quota (K E ) / corresponding power consumption quota (K P )'s participant (6b) is disconnected from the local energy supply network (1).

4. The method according to any one of claims 1 to 3, wherein: Electrical consumers (17) of participants (6a, 6b) on a local energy supply network (1) are classified according to relevance and electrical consumers (17) reaching a certain relevance category are preferably automatically deactivated.

5. The method according to any one of claims 1 to 4, wherein: The connection point (3) is formed by a transformer (8) or comprises a transformer (8) which connects the local energy supply network (1) to a higher-level energy supply network (4).

6. The method according to any one of claims 1 to 5, wherein: The local energy supply network (1) is a low voltage network (2), and the upper level energy supply network (4) is a medium voltage network (5).

7. The method according to any one of claims 1 to 6, wherein: The other switches (15) are each controlled by a smart meter (16), or are each integrated in a smart meter (15).

8. The method according to any one of claims 1 to 7, wherein: If there are several participants (6a) with energy supply devices (9), the inverter (10a) assigned to the energy supply device (9) which contains the most currently available energy (E) at a certain time among all the energy supply devices (9) of the participant (6a) is determined as the master inverter (10a). a ) and / or provide the highest available electrical power (P a ).

9. The method according to any one of claims 1 to 8, wherein: There is a communication connection (50), preferably a power line communication (51), between the main inverter (10a), the switch (14) and the other switches (15).

10. The method according to any one of claims 1 to 9, wherein: The energy supply device (1) comprises an electrical energy storage device (11), preferably an energy generation device (12), in particular a photovoltaic system (13) or a wind turbine.

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