Method for avoiding a power failure in an electrical grid
Patent Information
- Application Number
- EP2024717201
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-04-04
- Filing Date
- 2024-04-04
- Publication Date
- 2026-02-11
AI Technical Summary
The increasing volatility in electricity generation and consumption due to renewable energy sources and flexible consumer behavior leads to unforeseen power peaks, which can cause network instabilities and potential power failures in electrical sub-networks not designed for these new requirements.
A method that divides electrical consumers into groups with different priorities, calculates a total reduction current amount to avoid overload, determines group target currents, and reduces electricity consumption until target amounts are reached, allowing for dynamic adjustment of power consumption to prevent power failures.
This approach effectively prevents power failures by intelligently managing electricity consumption across different consumer groups, ensuring the electrical network operates within safe limits even during peak demand periods, thereby maintaining network stability.
Smart Images
Figure EP2024059259_10102024_PF_FP_ABST
Abstract
Description
[0001] Method for preventing a power failure in an electrical network
[0002] The invention relates to a method and a device for preventing a power failure in an electrical network, in particular in a sub-network that is connected to a transmission network.
[0003] In an electrical distribution grid, the electrical energy supplied to consumers must always be equal to the electrical energy generated or supplied. An imbalance results in grid instabilities and, in the worst case, can lead to a power supply collapse in at least one subgrid.
[0004] The transmission grid and the connected subgrids are therefore traditionally designed for the maximum possible load that can occur in each of the subgrids. This maximum load is taken into account when planning the grid infrastructure, and the various components, such as cables, are designed accordingly. Overcurrent protection devices are installed to prevent damage to the grid infrastructure if the permissible maximum load is exceeded. As soon as the maximum load for which a subgrid is dimensioned is exceeded, the provided overcurrent protection devices automatically disconnect the affected subgrid from the supply grid, thus preventing damage to the grid infrastructure.
[0005] In scenarios with consumers whose electricity consumption is relatively constant and with relatively continuous electricity generation, the design of the grids and subgrids is relatively simple. However, due to the increasing use of renewable energy sources and the flexible operation of consumers and storage systems, both electricity generation and consumption are becoming significantly more volatile. In concrete terms, solar and wind power plants, for example, only generate sufficient electrical energy when appropriate environmental conditions prevail. Furthermore, the amount of energy generated can fluctuate significantly depending on the time of day. The same applies to consumers, especially electric cars, which represent very large loads on the grid. In addition, both the time and amount of electrical energy consumed by such consumers are difficult to predict, as they depend on the respective user behavior of the users, for example the vehicle owners.With regard to electromobility, conventional subgrids are not designed for these new requirements. The high power peaks caused by volatile generators and consumers can therefore lead to significant disruptions in the operation of electrical grids. In the worst case, the occurrence of unforeseen power peaks can lead to subgrid shutdowns due to the grid infrastructure not being designed for this. Therefore, one object of the invention is to create a method and a device for preventing a power outage in an electrical grid when unforeseen power peaks occur.
[0006] This object is achieved according to the invention by a method having the features specified in patent claim 1.
[0007] The invention accordingly provides a method for avoiding a power failure in at least one electrical sub-network (TN) which is connected to a transmission network (ÜN) for supplying power to electrical consumers, v, of the sub-network (TN), wherein the electrical consumers, v, of the sub-network (TN) are divided into a number, N, of different groups (G1, G2,...Gi...GN) with different priorities (p1,p2, ...pi...pN), comprising the steps:
[0008] Calculating a total required total reduction power quantity, Ired-total, with which the total electrical power quantity, lakt-total, currently consumed by all consumers, v, of the sub-grid (TN) is to be reduced in order to avoid a detected overload in the sub-grid (TN);
[0009] Determining a group target electricity quantity (IsollGi) for each assigned group (Gi) of consumers, v, on the basis of the total required total reduction electricity quantity, Ired-total, and an electricity quantity that can be saved by the respective group (Gi) (DeltaGi = laktGi - IminGi);
[0010] Calculating target currents (Isoll-v) for the electrical consumers, v, of the divided groups (G1, G2,...Gi...GN) of the sub-network (TN) depending on the determined group target current quantity (IsollGi) and
[0011] Reducing the current amount of electricity consumed by the consumers, v, of the respective group (Gi) until the group target current amount (Isoll Gi) determined for the respective group (Gi) is reached.
[0012] In one possible embodiment of the method, the target currents (lsoll-v) of consumers, v, within a classified group (Gi) are derived from the group target current quantity (IsollGi) of the respective group.
[0013] In one possible embodiment of the method, the following steps are carried out to calculate the target currents (lsoll-v) for the electrical consumers, v, of the assigned groups (G1, G2,...Gi...GN) of the sub-network (TN) for each of the assigned groups (Gi) of electrical consumers, v, of the sub-network (TN), starting with the group (GN) of electrical consumers with the lowest priority (pN):
[0014] Calculating the amount of electricity that can be saved by each divided group (Gi) (IsparGi) as the difference between an electrical group electricity quantity, laktGi, of the group (Gi) currently consumed by all consumers, v, of the respective group (Gi) and a minimum group electricity quantity, IminGi of the group (Gi), that is at least required to supply electricity to all consumers of the respective group (Gi); and calculating for each divided group (Gi) a remaining residual electricity quantity based on the total required total reduction electricity quantity by subtracting the calculated saveable electricity quantity of the respective group (Gi) from the residual electricity quantity calculated for the previous group (Gi+1).
[0015] In one possible embodiment of the method, the substeps for calculating the target currents (lsoll-v) of the consumers, v, are repeated until the calculated remaining residual current quantity, Iresti, is less than or equal to zero (Iresti < =0) or until the group (G1) of consumers, v, with the highest priority (G1) is reached.
[0016] In one possible embodiment of the method, after calculating the target currents (Isoll-v) of the consumers v for each of the assigned groups (Gi) of electrical consumers, v, of the sub-network (TN), starting with the group (GN) of electrical consumers with the lowest priority (pN) up to reaching the group (G1) of electrical consumers v with the highest priority (p1), the current amount of electricity consumed by the consumers, v, of the respective group (Gi) is reduced until the group target current amount, Isoll Gi, calculated for the respective group (Gi) is reached.
[0017] In one possible embodiment of the method, an overload that is about to occur within the sub-network (TN) is automatically detected as soon as a currently consumed total amount of electricity, lakt-total, of all consumers, v, of all groups (G1 -GN) of the sub-network (TN) exceeds a predetermined maximum permissible amount of electricity, Imax-TN, of the sub-network (TN).
[0018] In one possible embodiment of the method, the measured currently consumed electrical current quantities, lakt-v, of all consumers, v, of a group (Gi) are summed up to form the group current quantity (I aktGi ) of the group (Gi).
[0019] In one possible embodiment of the method, the currently consumed electrical group current quantities (laktGi) of all divided groups (G1 to GN) of consumers of the sub-grid (TN) are summed to calculate the currently consumed total current quantity, lakt-total, of the sub-grid (TN).
[0020] In one possible embodiment of the method, the required total reduction in electricity, Ired-total, by which the total electricity, lakt-total, currently consumed by all consumers, v, of the sub-grid (TN) is to be reduced to avoid overload in the sub-grid (TN), is calculated as the difference between the total electricity currently consumed, lakt-total, of all consumers, v, of the sub-grid (TN) and the specified maximum permissible electricity, Imax-TN, of the sub-grid (TN). In one possible embodiment of the method, if the calculated remaining electricity, Iresti, is greater than zero (Iresti >0) after reaching the group (G1) of electrical consumers with the highest priority (p1), the following steps (S) are carried out for each of the assigned groups (Gi) of electrical consumers of the sub-grid (TN), starting with the group (GN) of electrical consumers with the lowest priority (pN):
[0021] Marking the respective group (Gi) as a switchable group (Allow to Shut Down), calculating for each consumer, v, of the marked group (Gi) a saveable amount of electricity, Iv, that can be saved by switching off (Shut Down) the respective consumer, v; and
[0022] Reducing the remaining residual power quantity, Iresti, by the amount of power that can be saved by switching off the consumer, v; whereby the above steps are repeated until the calculated remaining residual power quantity, Iresti, is less than or equal to zero (Iresti < =0) or the group (G1) of consumers, v, with the highest priority (G1) is reached.
[0023] In one possible embodiment of the method, following the calculation of the target currents (Isoll-v) of the consumers of the sub-grid (TN) for each group (Gi), the currently consumed electricity quantity, lakt-v, of each consumer, v, within the respective group (Gi) is physically reduced step by step in a round-robin process by a current reduction quantity (Delta-Iminus) until the group target current quantity (IsollGi) determined for the respective group (Gi) is reached. In one possible embodiment of the method, if a group (Gi) of consumers, v, has been marked as a switchable group (Allow to Shut down), the electricity consumption of a consumer, v, within the marked group (Gi) is reduced to zero as soon as the electricity consumption of the consumer, v, falls below a minimum electricity quantity, lmin-v, stored for this consumer, v.
[0024] In a possible embodiment of the method, if after reducing the power consumption of the consumers ,v, of all groups of the sub-network (TN) there is no longer a risk of an overload occurring in the sub-network (TN), the power consumption of the consumers, v, of the sub-network (TN) is increased for each of the divided groups (Gi) of electrical consumers ,v, of the sub-network (TN), starting with the group (G1) of electrical consumers with the highest priority (p1) down to the group (GN) with the lowest priority (pN).
[0025] In this case, a currently consumed amount of electricity, lakt-v, of each consumer, v, within the respective group (Gi) is increased by an electricity increase amount (Delta-Iplus) in one or more increase steps, provided that this does not exceed the permissible maximum amount of electricity, lmax-v, of the respective consumer, v.
[0026] In one possible embodiment of the method, the number, ki, of the increase steps performed to increase the currently consumed amount of electricity, lakt-v, of a consumer, v, within a group (Gi) depends on the priority (pi) of the respective group (Gi) and the number, N, of the assigned groups, G (ki = N-pi). In one possible embodiment of the method, the consumers, v, of the sub-grid (TN) have controllable and / or switchable loads and / or loads that can be connected to charging points of the sub-grid (TN).
[0027] In one possible embodiment of the method, the consumers, v, of the sub-grid (TN) comprise permanently installed loads, in particular heat pumps or inverters, and connectable loads, in particular vehicle batteries that can be connected to charging points of the sub-grid (TN).
[0028] In one possible embodiment of the method, a load is dynamically classified into a group (Gi) upon connection to a charging point of the sub-network (TN) depending on at least one provided classification criterion.
[0029] In one possible embodiment of the method, the amount of current increase and the amount of current reduction depend on the type of consumer, v.
[0030] In a possible embodiment of the method, at least some of the electrical consumers, v, of a sub-network (TN) each share its associated permitted
[0031] amount of power increase and / or its permitted amount of power reduction.
[0032] The invention further provides an electrical sub-network with the features specified in claim 19.
[0033] The invention accordingly provides an electrical sub-network, TN, in particular a charging network, with a plurality of electrical consumers, v, and with a controller for carrying out a method for avoiding a power failure in the sub-network, TN, which is connected to a transmission network (ÜN) for supplying power to electrical consumers, v, of the sub-network (TN), wherein the electrical consumers, v, of the sub-network (TN) are divided into a number, N, of different groups (G1, G2,...Gi...GN) with different priorities (p1,p2, ...pi...pN), with the steps:
[0034] Calculating a total required total reduction power quantity, Ired-total, with which the total electrical power quantity, lakt-total, currently consumed by all consumers, v, of the sub-grid (TN) is to be reduced in order to avoid a detected overload in the sub-grid (TN);
[0035] Determining a group target current quantity (IsollGi ) for each assigned group (Gi) of consumers, v, based on the total required reduction current quantity, Ired-total, and a quantity of electricity that can be saved by the respective group (Gi) (IsparGi); calculating target currents (Isoll-v) for the electrical consumers, v, of the assigned groups (G1, G2,...Gi...GN) of the sub-grid (TN) depending on the determined group target current quantity (IsollGi) and
[0036] Reducing the current amount of electricity consumed by the consumers, v, of the respective group (Gi) until the group target current amount (Isoll Gi) determined for the respective group (Gi) is reached. Possible embodiments of the method according to the invention and the network according to the invention are described in more detail with reference to the figures.
[0037] They show:
[0038] Fig. 1 is a flowchart of a possible embodiment of the method according to the invention;
[0039] Fig. 2 shows an example of a network with two subnetworks to explain the method according to the invention;
[0040] Fig. 3. a flowchart illustrating a possible implementation of steps of the method according to the invention;
[0041] Fig. 4. a flowchart illustrating a possible implementation of further steps of the method according to the invention;
[0042] Fig. 5 to 8 signal diagrams to explain the method according to the invention.
[0043] According to a first aspect, the invention provides a method for preventing a power outage in at least one electrical sub-network (TN). An exemplary embodiment of the method is schematically illustrated as a flowchart in Fig. 1.
[0044] A subgrid (TN) is connected to a transmission grid (TS) to supply power to electrical loads (v) of the subgrid (TN). The subgrid (TN) can, for example, be a residential grid. Furthermore, the subgrid (TN) can also be a grid of an industrial facility. The loads (v) include both DC and AC loads.
[0045] Fig. 2 shows a simple example with two subnetworks TN-A and TN-B, each connected to a supply network via an electricity meter. Each subnetwork TN has a maximum permissible current Imax-TN. In the example shown, the first subnetwork TN-A has a maximum permissible current Imax-TNA = 50 amps, and the second subnetwork TN-B has a maximum permissible current Imax-TNB = 30 amps.
[0046] In the example shown in Fig. 2, the subnetwork TN-A has five consumers v1 A to v5A. The other subnetwork TN-B has eight additional consumers v1 B to v8B in the example shown.
[0047] The electrical consumers, v, of the respective subnetwork TN are initially divided into a number, N, of different groups (G1, G2, ...Gi...GN) with different priorities (p1, p2, ...pi...pN). The number N of divided groups G can vary depending on the application. For example, the first subnetwork TN-A and the second subnetwork TN-B are each divided into three groups with different priorities, as shown in Fig. 2. In subnetwork TN-A, the consumers v1 A, v3A form the group G1 A with the highest priority p1, the consumers v2A,v4A form the group G2A with the highest priority p2 and the consumer vA5 forms the group G3A with the lowest priority p3. In subnetwork TN-B, the consumers v1 B,v2B,v3B form the group G1 B with the highest priority p 1 , the consumer v4B forms the group G2B with the next higher priority p2 and the consumers v5B,v6B,v7B,v8B form the group G3B with the lowest priority p3.
[0048] The groups G can be classified according to a predefined or selectable classification criterion EK. One possible classification criterion EK is the type of consumer v and / or its importance for the operation of a system. Another classification criterion EK is, for example, the operator or user of the respective consumer v. Consumers v or charging points belonging to people in certain departments within a company, for example field staff, are given a higher priority p than consumers v or charging points belonging to other people or users within a company. The person’s expected power consumption can be taken into account. For example, vehicles belonging to field staff generally require more electrical power than vehicles belonging to office staff. The underlying classification criterion EK and thus the group classification of the consumers v can therefore vary over time or dynamically.The allocation criterion EK can also be the electricity price per kWh that a user is willing to pay for charging or supplying electricity to their consumer v. The allocation criterion EK can also be determined by a logical combination of other allocation criteria. Based on the applied allocation criterion EK, a priority p of the consumer v is determined for each consumer v.
[0049] For each assigned group Gi of consumers v, its currently consumed current laktGi is calculated and the minimum permissible current IminGi of the group Gi is determined, as shown in the example in Fig. 2. The currently consumed current lakt G1 of the group G3B with the lowest priority p3 within the sub-network TN-B is, for example, 30 A. The minimum permissible current of this group G1 B is, for example, 24 A. The total current lakt-total consumed within a sub-network TN is the sum of the currently consumed currents of all groups G of consumers v within the sub-network TN.
[0050] In a possible embodiment of the method, an impending overload occurring within the sub-network (TN) is automatically detected in a step SO as soon as a currently consumed total amount of electricity, lakt-total, of all consumers, v, of all groups (G1 -GN) of the sub-network (TN) exceeds a predetermined maximum permissible amount of electricity, Imax-TN, of the sub-network (TN) or a predefined threshold value, lakt-total > Imax-TN.
[0051] The required total reduction in electricity quantity, Ired-total, with which the determined or monitored total electricity quantity, lakt-total, currently consumed by all consumers, v, of the sub-grid (TN) is to be reduced in order to avoid the impending overload in the sub-grid (TN), can be calculated as the difference between the determined total electricity quantity, lakt-total, currently consumed by all consumers, v, of the sub-grid (TN) and a specified maximum permissible electricity quantity, Imax-TN, of the sub-grid (TN): lred-total = lakt-total - Imax-TN
[0052] In the example shown in Fig.2, the total current consumed by all consumers v within the sub-network TN-B is lakt-total-TN-B = 40 Amp (Group G1 B) plus 10 Amp (Group G2B) plus 30 Amp (Group G3B) = 80 Amp
[0053] In the example shown in Fig.2, the maximum permissible current Imax-TN- B is 30 Amp.
[0054] The current surplus Ired-total TN-B to be reduced within the TN-B subgrid is therefore 80 amps (lakt-total-TN-B) minus 30 amps (Imax-TN-B). Ired-total-TN-B = 80 amps - 30 amps = 50 amps
[0055] The currently consumed total electricity quantity lakt-total of a sub-grid TN can be continuously monitored, for example, by periodically measuring the electricity quantity currently consumed by all consumers, v, of the sub-grid TN and subsequently aggregating the measured consumer electricity quantities I of the sub-grid TN to the currently consumed total electricity quantity, lakt-total, of the sub-grid TN. The maximum permissible electricity quantity Imax-TN of a sub-grid TN is predetermined and depends on the connected components, in particular the power lines and overcurrent protection devices connected there.
[0056] The current or instantaneous total electricity quantity lakt-total of all consumers v of the sub-network TN is preferably determined by summing up the measured or reported consumption flows of all consumers, v, of the sub-network TN.
[0057] In one possible implementation, the currently consumed electrical power quantities, lakt-v, of all consumers, v, of a group (Gi), measured by measuring units and reported to the control unit of the sub-network TN, are first added up to form the currently consumed group power quantity (laktGi) of the relevant group (Gi). The currently consumed group power quantities (laktGi) of all divided groups (G1 to GN) of consumers in the sub-network (TN) can then be added up to calculate the currently consumed total power quantity, lakt-total, of the entire sub-network (TN). This currently consumed total power quantity, lakt-total, of the sub-network TN is preferably continuously monitored in step S0 to detect an impending overload in the sub-network TN. The consumers are divided into groups Gi according to a predetermined or selectable division criterion EK in step SGi.To avoid an impending power outage in the affected sub-grid TN, a first step S1 of the method according to the invention initially calculates a total required reduction in electricity, Ired-total. This total required reduction in electricity, Ired-total, is the amount of electricity by which the total electrical electricity, lakt-total, currently consumed by all consumers, v, of the sub-grid (TN) is to be reduced in order to avoid the impending overload in the affected sub-grid (TN) identified in step S0.
[0058] Subsequently, in a step S2 of the method according to the invention, a group target current quantity (IsollGi) is determined for each of the divided groups (Gi) of consumers, v, on the basis of the total required total reduction current quantity, Ired-total, calculated in step S1 and on the basis of a respective current quantity (Ispari) that can be saved by the groups (Gi).
[0059] In step SR1, the first round (RU1) starts, starting with group (GN) with the lowest priority (pN).
[0060] In a further step S3 of the method according to the invention, target currents (Isoll-v) for the different electrical consumers, v, of the various divided groups (G1, G2,...Gi...GN) of the sub-grid (TN) are calculated as a function of the group target current quantity (IsollGi) determined in step S2 for the groups Gi. The target currents (Isoll-v) of consumers, v, within a divided group (Gi) can be derived from the group target current quantity (IsollGi) of the respective group (Gi) determined in step S2.
[0061] In one possible embodiment of the method, in step S3, to calculate the target currents (lsoll-v) for the electrical consumers, v, of the divided groups (G1, G2,...Gi...GN) of the sub-network (TN), the following two sub-steps S3A, S3B are carried out for each of the divided groups (Gi) of electrical consumers, v, of the sub-network (TN), starting with the group (GN) of electrical consumers with the lowest priority (pN).
[0062] In a first sub-step S3A, the amount of electricity (IsaveGi) that can be saved by each assigned group (Gi) of consumers, v, is calculated as the difference between an electrical group electricity amount, laktGi, currently consumed by all consumers, v, of the respective group (Gi) and a minimum group electricity amount, IminGi, of the group (Gi), that is at least required for the electricity supply of all consumers, v, of the respective group (Gi): lsaveGi= laktGi -IminGi
[0063] For example, group G3B with the lowest priority p3 within subnetwork TN-B includes consumers v5B to v8B. These have a minimum group current lminG3B of 24 amps. In contrast, the current consumption of group G3B laktG3B is 30 amps.
[0064] Thus, the amount of electricity that can be saved Ispar G3B of the group G3B of the lowest priority p3 within the subnetwork TN-B is: lsparG3B=laktG3B- lminG3B= 30Amp -24 Amp = 6Amp
[0065] In a second sub-step S3B, a remaining residual electricity quantity Iresti is calculated for each assigned group (Gi) starting from the total required total reduction electricity quantity calculated in step S1 (Ired- total = lrestN + 1), by subtracting the saveable electricity quantity (IsparGi) of the respective group (Gi) calculated in step S3A from the residual electricity quantity (Irest i + 1) calculated for the previous group (Gi + 1).
[0066] Irest i = Irest i + 1 - IsparGi
[0067] In the example shown in Fig. 2, the total required reduction current quantity (lred-total = lirestO) for the sub-network TN-B is 50 Amps. From this, the amount of current that can be saved by the group G3B with the lowest priority p3, lsparG3B = 6 Amps, is deducted to calculate a residual current quantity IrestO.
[0068] The calculated remaining current Iresti is therefore 50 Amp minus 6 Amp equal to 44 Amp.
[0069] Iresti = IrestO (=50Amp)-lpsarG3B (=6 Amp)= 44 Amp
[0070] In a possible embodiment of the method, the sub-step S3A in the first round (RU 1 ) for calculating the target currents (lsoll-v) of the consumers, v, is repeated in a first round (RU 1) until the calculated remaining residual current quantity, Iresti, becomes less than or equal to zero (Iresti < = 0) or until the group (G1) of consumers, v, with the highest priority (G1) has been taken into account.
[0071] In the example shown in Fig. 2, the residual current Irest3 calculated for sub-grid TN-B after taking into account group G1 B with the highest priority p1 is still 24 amps, i.e., the calculated reduction in the consumed current implemented in the first round (RU 1) is not yet sufficient. Therefore, in subsequent steps, it is preferable to check whether the remaining current reduction of 24 amps can be achieved by shedding loads v of sub-grid TN-B in a second round (RU 2).
[0072] In the example shown in Fig.2, the residual current quantity Irest2 calculated for the other sub-network TN-A after taking into account the group G2A with the second highest priority p2 after the first round is already zero Amp, ie the calculated achievable current reduction quantity is already sufficient after the first round (RU 1) and a shedding of consumers v in the sub-network TN-A can be avoided.
[0073] In a step S4 of the method according to the invention, the current quantity currently consumed by the consumers, v, of the respective group (Gi) is reduced until the group target current quantity (Isoll Gi) determined for the respective group (Gi) in step S2 is reached. The reduction in the current quantity in step S4 can initially be carried out computationally, i.e., not yet physically.
[0074] After the calculation of the target currents (Isoll-v) of the consumers v for each of the assigned groups (Gi) of electrical consumers, v, of the sub-network (TN) in the two sub-steps S3A, S3B of step S3, in step S4, starting with the group (GN) of electrical consumers, v, with the lowest priority (pN) up to reaching the group (G1) of electrical consumers, v, with the highest priority (p1), the current amount of electricity laktGi currently consumed by the consumers, v, of the respective group (Gi) is reduced mathematically until the group target current amount, Isoll Gi, calculated for the respective group (Gi) in step S2 is reached.
[0075] In a possible embodiment of the method, if the calculated remaining residual current quantity, Iresti, after taking into account the group (G1) of electrical consumers with the highest priority (p1), is still greater than zero (Iresti >0), for example 24 Amp for sub-network TN-B in Fig.2, for each of the divided groups (Gi) of electrical consumers of the sub-network (TN), starting with the group (GN=G3B)) of electrical consumers v with the lowest priority (pN = p3), in a second round (RU 2), the following further steps (S5, S6, S7) are carried out, wherein step SR2 initiates the start of the second round (RU 2), starting with group (GN) with the lowest priority (pN):
[0076] Mark in step S5 the respective group (Gi) as a switchable group (Allow to Shut Down),
[0077] Calculating in step S6 for each consumer, v, of the marked group (Gi), a saveable amount of electricity, Isparv, that can be saved by switching off (ShutDown) the respective consumer, v; and
[0078] In step S7, the remaining residual current quantity, Iresti, is reduced (computationally) by the amount of electricity that can be saved by switching off the load, v, in each case, lsave-v. For example, by mathematically switching off the loads v5B to v8B of group G3B with the lowest priority p3 within the subnetwork TN-B in round 2, a remaining residual current quantity of zero Amps is achieved, as shown in Fig. 2.
[0079] The above steps S5, S6, S7 of the second round (RU 2) are repeated until the calculated remaining residual current quantity, Iresti, is less than or equal to zero (Iresti < =0) or the group (G1) of consumers, v, with the highest priority (p1) has been considered. Fig. 3 shows a flowchart of a possible implementation of steps S1 to S7 with the two calculation rounds (RU1, RU 2) for calculating the set currents or target currents Isollv for the consumers v of a subnetwork TN. In one possible embodiment of the method, following the calculation of the target currents lsoll-v of the consumers v of the sub-network (TN) in steps S1 to S7, in a further step S8 for each group (Gi) the currently consumed or provided amount of electricity, lakt-v, of each consumer, v, within the respective group (Gi) is gradually reduced in a round-robin process by a current reduction amount (delta iminus) physically or mechanically.actually reduced until the group target current quantity (IsollGi) determined for the group in question (Gi) is reached, as shown in Fig.4.
[0080] Fig. 4 shows a flow diagram of a possible implementation of the physical setting of the consumers v of a sub-network TN in step S8 according to the target currents Isollv of the consumers v of the sub-network TN calculated in the process according to Fig. 3. After the consumers v have been divided into groups Gi in step S8-1, the process starts with the group GN with the lowest priority PN in step S8-2. For this purpose, the consumer current target point group is first initialized in step S8-3 and started with any consumer v in group G in step S8-4. In step S8-5, a new target point ISP-new is calculated for the consumer v. Then, in step S8-6, a check is made as to whether the new target point ISPnew calculated in step S8-5 is lower than the permissible minimum current Ivmin of the consumer v. If this is the case, a further step S8-7 checks whether group G is marked as being switchable or not.If group G is marked as non-disconnectable, the new setpoint ISP-new is set to the minimum current Ivmin in step S8-8 (ISPnew := Ivmin). Conversely, if group G is marked as disconnectable, the new setpoint ISP-new is set to zero in step S8-9 (ISPnew := 0). Subsequently, in step S8-10, the sum of the reduced currents in group G is determined. In step S8-11, the new setpoint ISP-new is sent to the relevant consumer v for physical adjustment.
[0081] In the next step S8-12, a check is made to see whether the reduced current is greater than the current to be reduced (IsollGi). If this is the case, a check is made in step S8-13 to see whether there are any further groups G in the sub-network TN. If there are any further groups, the loop goes back to step S8-4, as shown in Fig.4. However, if there are no further groups G, the process ends. If the check in step S8-12 shows that the reduced current is not greater than the current to be reduced (IsollGi), a check is made in step S8-14 to see whether there are no further consumers v in the group G in question. If there are no further consumers v in the group G, the process goes to step S8-13. However, if there are still further consumers v in the group G, the process goes back to step S8-5 in a loop, as shown in Fig.4. This continues until the current to be reduced for this group G (IsollGi) is reached.
[0082] In a possible embodiment of the method, if a group (Gi) of consumers, v, has been marked in step S5 as a switchable group (Allow to Shutdown), the power consumption Ispneu of a consumer, v, within the marked group (Gi) is reduced to zero (lspneu=0) as soon as the power consumption of the consumer, v, falls below a minimum power quantity, lmin-v, stored for this consumer, v (lspneu <lvmin).
[0083] In a possible embodiment of the method, if after the physical reduction of the power consumption of the consumers ,v, of all groups G of the sub-network (TN) in step S8 there is no longer any risk of an overload occurring in the sub-network (TN), the power consumption of the consumers, v, of the sub-network (TN) is increased again for each of the divided groups (Gi) of electrical consumers ,v, of the sub-network (TN), starting with the group (G1) of electrical consumers v with the highest priority (p 1 ) down to the group (GN) with the lowest priority (pN) in a step S9.
[0084] For this purpose, in step S9, a currently consumed amount of electricity, lakt-v, of each consumer, v, within the respective group (Gi) is increased by a current increase amount (Delta-I plus) in one or more increase steps, provided that this does not exceed a permissible maximum amount of electricity, lmax-v, of the respective consumer, v.
[0085] The number, ki, of increase steps taken to increase the currently consumed amount of electricity, lakt-v, of a consumer, v, within a group (Gi) in step S9 depends on the priority (pi) of the respective group (Gi) and the number, N, of the assigned groups, G: ki= N-pi
[0086] In one possible embodiment of the method, the consumers, v, of the sub-grid (TN) comprise controllable and / or switchable loads. The consumers, v, of the sub-grid (TN) can comprise permanently installed loads, in particular heat pumps or inverters, and connectable loads, in particular vehicle batteries that can be connected to charging points of the sub-grid (TN).
[0087] In one possible embodiment, the subnetwork TN is a charging network with charging points or charging stations for charging electric vehicles that can be connected to it as consumers v. This subnetwork TN can, for example, be provided in a company parking lot for charging employee vehicles. The electric vehicles generally do not have any wireless communication capability with the controller of the subnetwork TN. The electric vehicles normally communicate exclusively with the charging station (wallbox) via a charging cable. This charging station has a wired and / or wireless communication interface with the controller of the subnetwork TN. In an alternative implementation, the electric vehicles each have their own control unit that can communicate directly with the controller of the subnetwork TN via a wireless interface.For example, the control unit of the electric vehicle reports the current state of charge SoC of its vehicle battery directly or indirectly via the charging station to the control of the sub-network TN. One possible classification criterion EK for classifying the consumers or vehicle batteries to be charged is the state of charge SoC. For example, an electric vehicle battery of a high-ranking employee (EK1) of the company is given a high priority p if the state of charge SoC of the electric vehicle battery is below a defined threshold (EK2). The priority p for charging a consumer v can therefore change over time. The group classification of the consumers v can, for example, be periodically renewed. If a consumer v is assigned to a group G with a lower priority p during the charging process, for example, the charging process can be extended.The additional charging time required is communicated to the user of the affected electric vehicle, preferably by the control of the sub-network TN via the wireless interface, for example on a display of the vehicle or on a display of the user's mobile phone.
[0088] In one possible embodiment of the method, a load is dynamically classified into a group (Gi) upon connection to a charging point of the sub-network (TN) depending on at least one provided classification criterion.
[0089] In one possible embodiment of the method, the current increase amount (Delta-Iplus) used in step S9 and the current reduction amount (Delta-Iminus) used in step S8 depend on the type of consumer, v. At least some of the electrical consumers, v, of a subnetwork (TN) can each report or communicate its associated permitted current increase amount (Delta-Iplus) and / or its permitted current reduction amount (Delta-Iminus) to the controller of the subnetwork TN or a server, for example, via a wireless interface.
[0090] The method according to the invention can be executed on a processor of a local controller or a local control unit of a subnetwork TN. Alternatively, the method can also be executed on a cloud server. The method is preferably executed in real time.
[0091] According to a further aspect, the invention provides an electrical sub-network, TN, with a plurality of electrical consumers, v, and with a controller for implementing a method for preventing a power outage in the sub-network TN. The sub-network TN serves to supply power to or charge a plurality of electrical consumers v.
[0092] The TN subnetwork is connected to a transmission network (TS), such as a public electricity grid, at a transfer point. Several TN subnetworks can be connected to a common TS.
[0093] The various electrical consumers, v, of the sub-grid (TN) are divided into a number, N, of different groups (G1, G2, ...Gi...GN) with different priorities (p1, p2, ...pi...pN). The division can be automatic or manual. The local control of the sub-grid TN can have several calculation units:
[0094] A first calculation unit of the control unit is provided for calculating a total required reduction in electricity quantity, Ired-total, with which the total electrical electricity quantity, lakt-total, currently consumed by all consumers, v, of the sub-network (TN) is to be reduced in order to avoid a detected overload in the sub-network (TN). A second calculation unit of the control unit is provided for determining a group target electricity quantity (IsollGi) for each assigned group (Gi) of consumers, v, on the basis of the total required reduction in electricity quantity, Ired-total, and an electricity quantity that can be saved by the respective group (Gi).
[0095] A third calculation unit of the control unit is provided for calculating target currents (Isoll-v) for the electrical consumers, v, of the assigned groups (G1, G2,...Gi...GN) of the sub-network (TN) depending on the determined group target current quantity (IsollGi).
[0096] A fourth calculation unit of the control unit is designed to reduce the current consumption of the consumers, v, of the respective group (Gi). The reduction can be continued mathematically until the group target current (Isoll Gi) determined for the respective group (Gi) is reached.
[0097] The various calculation units are preferably integrated or implemented in a processor of the controller or in a server.
[0098] The method can be implemented as a program or as an application. The grouping of the consumers v of the subnetwork TN can be carried out automatically, semi-automatically, or interactively by a user or operator of the subnetwork TN, for example, using a GUI user interface on a computer in the subnetwork TN. Selectable classification criteria EK can also be displayed to the user. The assigned groups Gi with their consumers v and associated persons or drivers as well as power parameters (e.g., SoC) can also be displayed to the user or operator of the subnetwork TN in real time, for example, schematically as shown in Fig. 2.
[0099] The method according to the invention and the corresponding control device thus intelligently prevent unwanted shutdowns or blackouts of sub-grids TN by actively influencing the power consumption of controllable loads and consumers v of the sub-grid TN. The method makes it possible to regulate the power consumption of consumers v in such a way that there is no overload in a defined sub-grid TN and thus no unwanted shutdowns (blackouts) of a sub-grid TN. The method makes it possible to take into account the properties of the respective consumers / generators v of the sub-grid TN. For example, it can be taken into account that arbitrarily small electrical currents cannot be regulated or that certain consumers v require a minimum current to function properly.Furthermore, the method according to the invention allows the regulation of the consumers v to be prioritized, so that in a typical application, the power consumption of consumers v of certain departments (for example vehicle batteries of a company's office employees) is limited first. The method also takes into account a worst-case scenario, namely the occurrence of a major overload in the sub-network TN. In this case, the method can be used to specifically shed certain loads or consumers v (i.e. switch them off completely), so that although these loads or consumers v are separated from the sub-network TN, the stability of the rest of the network is guaranteed and a total failure of the sub-network TN is prevented. Furthermore, the method also includes the process of reducing the electrical power of the controllable loads or consumers v after the reduction or increase.After the overload has been prevented, the load must be gradually increased again until the previously limited or shed loads are reached.
[0100] The procedure essentially comprises two main functions, namely an increase function and a decrease function.
[0101] In the event of an impending overload of the partial supply network TN detected in step S0, the "reduction" function of the method calculates new target currents Ivsoll for the controllable loads or controllable consumers v in steps S1 - S7 and then, in step S8, also physically reduces the electrical currents of these controllable loads or consumers to these calculated target currents Ivsoll.
[0102] If there is no longer an overload in the subnetwork TN, the "increase" function becomes active and begins to increase the electrical current of the consumers v again in step S9. For this purpose, increase rounds can be calculated for each group Gi, with the group Gi with the highest priority p receiving the most increase rounds. The number ki of increase rounds for a group Gi with a priority pi preferably depends on the cardinality N of the assigned groups G (ki = N-pi). The group GN with the lowest priority pN has exactly one increase round.
[0103] It starts with group G1 with the highest priority p1. The current increase step is, for example, 1 amp. For loads v that have been switched off, this current increase step corresponds to the stored hysteresis current. If the current current laktv of load v plus the increase current does not exceed the permissible maximum current lmax-v of load v, the current of load v is increased by the increase current in this step. This is repeated for all loads v within a group G. The number of increase rounds within a group G is defined by the priority p of the respective group G. The process then continues in the same way with the next group G.
[0104] This boost algorithm ensures that each consumer v, regardless of the priority p, receives at least the hysteresis current or the minimum current, provided the current situation in the grid infrastructure allows it.
[0105] Fig. 5 to 8 show diagrams to explain the functioning of the method according to the invention.
[0106] Fig. 5 shows the currently consumed currents lakt for three different groups G1, G2, and G3 with different priorities p1, p2, and p3. The current current laktG1 of group G1 of consumers v with the highest priority p1 is greater than the current current laktG2 of group G2 of consumers v with the second-highest priority p2, which in turn is greater than the current current la ktG3 of group G3 of consumers v with the lowest priority p3. (laktGI >laktG2>laktG3)
[0107] Fig. 6 shows a simulation of the current power consumption of group G1 of consumers v with the highest priority p1.
[0108] Fig. 7 shows a simulation of the current power consumption of group G2 of consumers v with the second highest priority p2.
[0109] Fig. 8 shows a simulation of the current power consumption of group G1 of consumers v with the lowest priority p3.
[0110] As can be seen in Figures 6 to 8, if necessary, the power consumption of the consumers v of group G1 with the highest priority p1 is reduced or shut down compared to the power consumption of the two remaining groups G2 and G3, which are the last to be shut down. As can be seen in Figure 8, in the example shown, the entire group G3 of consumers v with the lowest priority p3 is shut down at a certain point in time.
[0111] In a possible implementation, the signal diagrams according to Figures 5-8 are displayed to a user via a graphical user interface of a computer of the subnetwork TN or via a graphical user interface of a remote control center connected to it via a data network.
[0112] The computer-implemented method according to the invention is suitable for a wide range of applications. For example, the method can run in the background of a charging network in a company parking lot. Another application, for example, in the field of logistics is the charging of a fleet of electrically powered forklifts or other transport vehicles as loads v. The loads v can also include household appliances in a home network or machines in an automation system. For example, it can also be a mixture of these devices / loads. For example, a manufacturing company can have a heterogeneous composition of these loads or loads v, in particular company cars, logistics fleet, machines, systems, etc.
Claims
Patent claims:
1. A method for preventing a power failure in at least one electrical sub-network (TN) which is connected to a transmission network (ÜN) for supplying power to electrical consumers (v) of the sub-network (TN), wherein the electrical consumers (v) of the sub-network (TN) are divided into a number (N) of different groups (G1, G2,...Gi...GN) with different priorities (p1, p2, ...pi, ..., pN), comprising the steps: Calculating (S1) a total required total reduction current quantity (Ired-total) with which the total electrical current quantity (lakt-total) currently consumed by all consumers (v) of the sub-network (TN) is to be reduced in order to avoid a detected overload in the sub-network (TN); Determining (S2) a group target current quantity (IsollGi) for each assigned group (Gi) of consumers (v) based on the total required reduction current quantity (Ired-total) and the amount of electricity that can be saved by the respective group (Gi) (IsparGi); calculating (S3) target currents (Isoll-v) for the electrical consumers (v) of the assigned groups (G1, G2,...Gi...GN) of the sub-grid (TN) depending on the determined group target current quantity (IsollGi); and Reducing (S4) the current amount of electricity consumed by the consumers (v) of the respective group (Gi) until the group target current amount (Isoll Gi) determined for the respective group (Gi) is reached.
2. Method according to claim 1, wherein the target currents (Isoll-v) of consumers (v) within a divided group (Gi) are derived from the group target current quantity (IsollGi) of the respective group.
3. Method according to claim 2, wherein for calculating (S3) the target currents (lsoll-v) for the electrical consumers (v) of the divided groups (G1, G2,...Gi...GN) of the sub-network (TN) for each of the divided groups (Gi) of electrical consumers (v) of the sub-network (TN), starting with the group (GN) of electrical consumers with the lowest priority (pN), the following steps (S2A, S2B) are carried out: Calculating (S3A) the amount of electricity (IsparGi) that can be saved by each assigned group (Gi) as the difference between an electrical group electricity quantity (laktGi) of the group (Gi) currently consumed by all consumers (v) of the respective group (Gi) and a minimum group electricity quantity (IminGi) of the group (Gi) that is at least required to supply electricity to all consumers of the respective group (Gi); Calculating (S3B) for each assigned group (Gi) based on the total required total electricity reduction quantity (Ired-total) of a remaining residual electricity quantity (Iresti) by subtracting the calculated saveable electricity quantity of the respective group (Gi) from the residual electricity quantity (Irest i+ 1) calculated for the previous group (Gi+ 1).
4. The method according to claim 3, wherein the sub-steps (S3A, S3B) for calculating the target currents (lsoll-v) of the consumers (v) are repeated until the calculated remaining residual current quantity (Iresti) is less than or equal to zero (Iresti < =0) or until the group (G1) of consumers (v) with the highest priority (G1) is reached.
5. Method according to one of the preceding claims 1 to 4, wherein after calculating the target currents (Isoll-v) of the consumers (v) for each of the divided groups (Gi) of electrical consumers (v) of the sub-network (TN), starting with the group (GN) of electrical consumers with the lowest priority (pN) up to reaching the group (G1) of electrical consumers with the highest priority (p1), the current quantity of current (laktGi) currently consumed by the consumers (v) of the respective group (Gi) is reduced mathematically (S4) until the group target current quantity (Isoll Gi) calculated (S2) for the respective group (Gi) is reached.
6. Method according to one of the preceding claims 1 to 5, wherein an overload occurring shortly within the sub-network (TN) is automatically detected (SO) as soon as a currently consumed total amount of electricity (lakt-total) of all consumers (v) of all groups (G1 -GN) of the sub-network (TN) exceeds a predetermined maximum permissible amount of electricity (Imax-TN) of the sub-network (TN).
7. Method according to one of the preceding claims 1 to 6, wherein measured or reported currently consumed electrical power quantities (lakt-v) of all consumers (v) of a classified group (Gi) are summed up to form a currently consumed electrical power quantity (laktGi) of the group (Gi), and wherein the currently consumed electrical power quantities (laktGi) of all classified groups (G1 to GN) of consumers (v) of the sub-network (TN) are summed up to calculate the currently consumed total electrical power quantity (lakt-total) of the sub-network (TN).
8. The method according to claim 7, wherein the required total reduction current quantity (Ired-total) with which the total current quantity (lakt-total) currently consumed by all consumers (v) of the sub-network (TN) is to be reduced in order to avoid overload in the sub-network (TN) is calculated as the difference between the total current quantity (lakt-total) currently consumed by all consumers (v) of the sub-network (TN) and the predetermined maximum permissible current quantity (Imax-TN) of the sub-network (TN).
9. Method according to one of claims 3 or 4, wherein, if the calculated remaining residual current quantity (Iresti) after reaching the group (G1) of electrical consumers with the highest priority (p1), is greater than zero (Iresti >0) for each of the divided groups (Gi) of electrical consumers of the sub-network (TN) starting with the group (GN) of electrical consumers with the lowest priority (pN), the following steps (S) are carried out: Marking (S5) the respective group (Gi) as a switchable group (Allow to Shut Down), and Calculating (S6) for each consumer (v) of the marked group (Gi) a saving amount of electricity (Iv) that can be saved by switching off (shut down) the respective consumer (v); Reducing (S7) the remaining residual electricity quantity (Iresti) mathematically in order to achieve the electricity quantity (Iv) that can be saved by switching off the consumer (v); Repeat the above steps (S5, S6, S7) as long as the calculated remaining residual current quantity (Iresti) is greater than zero (Iresti >0) or until the group (G1) of consumers (v) with the highest priority (G1) has been taken into account.
10. The method according to claim 9, wherein following the calculation of the target currents (Isoll-v) of the consumers (v) of the sub-network (TN) (S1 -S7) for each group (Gi), the currently consumed current quantity (lakt-v) of each consumer (v) within the respective group (Gi) is physically reduced (S8) step by step in a round-robin process by a current reduction quantity (Delta-Iminus) until the group target current quantity (IsollGi) determined (S2) for the respective group (Gi) is reached.
11. Method according to one of the preceding claims 1 to 10, wherein, if a group (Gi) of consumers, v, has been marked as a switchable group (Allow to Shutdown) (S5), the power consumption of a consumer, v, within the marked group (Gi) is reduced to zero if the power consumption of the consumer, v, falls below a minimum power quantity, lmin-v, stored for this consumer, v.
12. Method according to one of the preceding claims 1 to 11, wherein, if after the reduction (S8) of the power consumption of the consumers of all groups (G1 -GN) of the sub-network (TN) there is no longer any risk of an overload occurring in the sub-network (TN), for each of the assigned groups (Gi) of electrical consumers of the sub-network (TN), the power consumption of the consumers (v) is increased (S9), starting with the group (G1) of electrical consumers with the highest priority (p1) down to the group (GN) with the lowest priority (pN), by increasing a currently consumed amount of power (lakt-v) of each consumer (v) within the respective group (Gi) by a current increase amount (Delta-Iplus) in one or more increase steps, as long as this does not exceed a permissible maximum amount of power (lmax-v) of the respective consumer (v).
13. Method according to claim 1, wherein a number (ki) of the increase steps taken to increase the currently consumed amount of electricity (lakt-v) of a consumer (v) within a group (Gi) of the Priority (pi) of the respective group (Gi) and the number (N) of the assigned groups (Gi) depends (ki= N-pi).
14. Method according to one of the preceding claims 1 to 13, wherein the consumers (v) of the sub-network (TN) comprise controllable and / or switchable loads and / or loads connectable to charging points of the sub-network (TN) 15. The method according to claim 14, wherein the consumers (v) of the sub-network (TN) comprise permanently installed loads, in particular heat pumps or inverters, and connectable loads, in particular vehicle batteries of electric vehicles connectable to charging points of the sub-network (TN).
16. The method according to claim 15, wherein a load is dynamically divided into a group (Gi) upon connection to a charging point of the sub-network (TN) depending on at least one provided division criterion.
17. Method according to one of the preceding claims 12 to 16, wherein the current increase amount (Delta-Iplus) and the current reduction amount (Delta-Iminus) depend on a type of consumer (v).
18. The method according to claim 17, wherein at least some of the electrical consumers (v) of a sub-network (TN) each communicate their associated permitted current increase amount (Delta-Iplus) and / or their permitted current reduction amount (Delta-Iminus) to a controller of the sub-network (TN).
19. Electrical sub-network (TN), in particular a charging network, with a plurality of electrical consumers (v) and with a controller for carrying out a method for avoiding a power failure in the sub-network (TN) according to one of the preceding claims 1 to 18.