Method for providing electrical control power for stabilizing an electrical transmission network and / or for providing an energy market product
Patent Information
- Application Number
- EP2024700430
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-13
- Filing Date
- 2024-01-11
- Publication Date
- 2025-11-19
AI Technical Summary
Current methods for stabilizing electrical transmission networks and providing energy market products rely heavily on traditional reserve units like water or gas power plants, which are inefficient in providing inertia reserve, and building batteries are not yet fully utilized for this purpose due to limited implementation of inertia reserve in energy market trading.
A method that aggregates building batteries and slow electrical power units to provide control power, where building batteries with short latency times handle primary control power and slow electrical power units with longer latency times take over to increase power turnover, allowing for the provision of inertia reserve by replacing building batteries in the second group of building networks.
This approach enhances the reliability and efficiency of electrical control power provision by leveraging the quick response of building batteries for primary control power and the slower but significant contributions of slow electrical power units, such as battery-electric vehicles, to stabilize network frequency and support energy market products.
Smart Images
Figure 1.1
Abstract
Description
[0001] Procedure for providing electrical control power for stabilising an electrical transmission system and / or for providing an energy market product
[0002] The invention relates to a method for providing electrical control power for stabilizing an electrical transmission network and / or for providing an energy market product.
[0003] Building batteries are batteries with secondary cells that are installed in the electrical building network of a private household or commercial business and, among other functions, can supply the electrical devices (electrical consumers) present there with electricity as needed. In particular, such electrical power units designed as batteries can be used effectively in conjunction with electrical power units in the form of renewable power generators, such as photovoltaic systems installed in buildings, to support the energy transition. Because they are connected to the public electricity grid of the transmission system operators, they can absorb electrical power from the power grid in a way that benefits the grid as so-called negative control power and, if necessary, supply electrical power to the power grid in an equally beneficial way as so-called positive control power in order to stabilize the transmission grids.Trading on the energy market with the described flexibility capacities is also possible, as is the provision of other energy market products.
[0004] From the perspective of the transmission system operators, so-called reserve units, which were and are also synonymously referred to as technical units, usually have such a high power potential for providing electrical control power that they can output or absorb negative and / or positive control power. Control power within the meaning of the present invention is in particular primary control power, nowadays also referred to in German technical jargon as FCR (Frequency Containment Reserve), or secondary control power, nowadays also referred to in German technical jargon as aFRR (Automated Frequency Restoration Reserve), which can output or absorb in the range of many dozens of MW. Traditionally, this involves, for example, individual hydroelectric or gas-fired power plants for generating electrical energy, whereby these power plants are ramped up or throttled accordingly to provide the desired positive or negative electrical control power.In terms of their latency, upstream control power, in addition to primary control power and secondary control power, there is also control power in the form of the so-called inertia reserve, which compensates for frequency fluctuations from 0 seconds to 30 seconds, usually using the torque of heavy generator turbines. Because building batteries can be controlled to produce sufficiently rapid power output or consumption, it would also be possible to provide the so-called inertia reserve via aggregated building batteries. However, the provision of the inertia reserve is not yet implemented in the general energy market. This market is still limited to the downstream control power types, in particular primary control power and secondary control power. In the future, it is quite likely that the provision of control power in the inertia reserve time regime will also be opened up to energy market trading.In any case, the inertia reserve is included in the concept of providing control power within the scope of this invention.
[0005] In the context of the present invention, the technical term "reserve unit" or, synonymously, "technical unit" is defined much more narrowly than is customary in the art. This means that a reserve unit within the meaning of the invention already exists, for example, in the form of a single building battery or in the form of a single building with an associated building network. In the case of the reserve unit as a single building, this means more precisely that the reserve unit can also be defined as the sum of all electrical energy consumers and / or electrical energy generators whose electrical power flows between this reserve unit and the external transmission grid can be recorded via a common grid connection point with an electrical electricity meter unit. In the context of the present invention, the various electrical energy consumers and electrical energy generators are generically referred to as electrical power units.These consist of a mixture of power input units, power output units and power input / output units, selected from the group comprising:.
[0006] - electrical loads as power consumption units that are technically suitable exclusively for electrical power consumption,
[0007] - electrical storage units as electricity storage units that are technically suitable for both electrical power input and electrical power output and
[0008] - electrical generators as power generation devices that are technically suitable exclusively for electrical power output.
[0009] According to this far-reaching definition, a building network defined by its grid connection point contains at least one, but usually a large number of such previously defined electrical power units.
[0010] The electrical power units of a reserve unit represented by the building network, which are typically present in a large number in a building network, are divided into two groups according to their individual power consumption / output potential in the context of the present invention. If the power consumption / output potential is greater than or equal to two kilowatts, these electrical power units are hereinafter referred to as significant electrical power units.
[0011] In the context of building networks, significant electrical power units include, for example, photovoltaic systems with a correspondingly high electrical output, building battery storage systems with a correspondingly high storage capacity, air conditioning systems and appliances, heat pumps, thermal energy storage systems, charging units for electric vehicles, ovens, and electric water heaters. In commercial building networks, a number of commercial systems and machines with a power consumption of more than two kilowatts also constitute significant electrical power units. Likewise, significant electrical power units can be integrated into the building network in the form of small commercial or private combined heat and power plants with an integrated power generator.
[0012] There is a subgroup of significant electrical power units that, in the context of the present invention, are referred to as so-called dispatchable significant power units. The term dispatchability refers to the controllable possibility of shifting the switch-on or switch-off time of the significant power unit in the building network without significant loss of comfort for one or more users of these power units, and in this way scheduling the power consumption or power output on the time axis. The shift is usually in the range of a few minutes. When a user connects their electric vehicle to the charging point of their building network for charging, it is not a problem for the user if the charging process begins with a delay of many minutes or even hours, given the regularly available downtimes of many hours (overnight in the home garage).The same applies to a heat pump or a thermal energy storage system. Given that complete charging and discharging processes regularly take many hours, such a time delay in the range of minutes or a few hours is manageable for the user without significantly compromising the operating comfort of the building's technology. Therefore, these significant power units are available for a certain timeframe with regard to their electrical performance and are referred to below as available significant power units.
[0013] The situation is different for significant electrical power units, such as air conditioning units and appliances, hot water generators, or household appliances like ovens. Users of these significant electrical power units expect immediate functionality. They cannot and do not want to wait five to ten minutes for the cooled air and / or hot water to arrive or for the household appliance to perform its desired function.
[0014] The boundary between dispatchable and non-dispatchable electrical power units is therefore subjective, depending on specific user habits. However, on average, it is possible to predict with a high degree of probability which significant electrical power units would be classified as dispatchable and which as non-dispatchable from the majority of users' perspective within a time window of up to ten minutes or even several hours.
[0015] If the power consumption / output potential of electrical power units in the building network is less than two kilowatts, these electrical power units are subsequently referred to as small electrical power units. This includes all consumers in building networks, in particular all lighting, all household appliances with power consumption below two kilowatts, such as most vacuum cleaners, water heaters, refrigerators and freezers, washing machines, irons, all types of entertainment electronics, computers, and so on. These small electrical power units are recorded in their accumulated consumption using statistical standard load profile curves.
[0016] It is important to emphasize that the term “building network,” which defines a defined number of electrical power units in the building network via the common grid connection point, does not imply that all electrical power units must be located within a building of any kind. Electrical power units that must be located outdoors anyway, or are usually located there, would be, for example, photovoltaic, hydroelectric, or wind energy systems. Likewise, lighting devices or electrical power units designed as robotic lawnmowers, for example, can be permanently positioned outdoors. Through the common grid connection point, these electrical power units are also assigned to a building network. Likewise, it is conceivable for a reserve unit that the assigned grid connection point and the electrical power units connected via this grid connection point do not have a building at all.The only decisive factor is the common grid connection point, which defines the quantity of electrical power units measured in the connected electrical network. For the sake of simplicity, this electrical network is referred to as a building network because, in the vast majority of cases, the electrical electricity meter unit, which is also required for the grid connection point, is not located outdoors but rather in a building protected from the weather. This building can be so small that, in extreme cases, it only houses the electrical electricity meter unit in the form of a meter connection column, while all electrical power units of this building network, including the meter connection column, are located outdoors.
[0017] In order to use a uniform terminology for the input and output of electrical power by electrical power units within the scope of the present invention, the term "electrical power conversion" is used below. A change in the power conversion of an electrical power unit can therefore mean both a change in the electrical power input and a change in the electrical power output. The term "provision of control power" also includes both the process of inputting electrical power from the transmission grid (negative control power) and the process of outputting electrical power to the transmission grid (positive control power).
[0018] Every grid-beneficial and / or energy market product-relevant change in power consumption occurs within a specific latency period. For the purposes of this patent application, the term "latency period" refers to the period from the provision of an electrical switching command to the stored measurement of the result of the switching command. With regard to all electrical power units, including the aforementioned building energy storage systems in the form of building batteries, such a switching command refers to a change in their respective power consumption within the meaning of the preceding definition of the characteristic "power consumption."
[0019] In the majority of building networks, there is at least one electrical power unit that requires a latency of more than two seconds to significantly change its electrical power consumption. Such electrical power units are referred to below as slow electrical power units. A significant change in power consumption is considered significant within the scope of the present invention if it exceeds 25%.
[0020] To stabilize the grid frequency, the transmission system operators require providers of positive and / or negative control power. Whether for negative and / or positive control power in the form of
[0021] • Frequency Containment Reserve (FCR = primary control power)
[0022] • automated Frequency Restoration Reserve (aFRR = secondary control power), or
[0023] • manual frequency restoration reserve (mFRR=minute reserve).
[0024] EP4000155A1 discloses a method for providing control power. This method is implemented using a plurality of electrical building batteries, each connected to the transmission grid via a grid connection point. These building batteries are each grouped together with other electrical power units in a building grid defined by the grid connection point. All electrical power units connected to the building grid are also considered technical units within the meaning of the present invention and can be referred to as such. Each electrical power unit can absorb electrical power from the building grid and thus, with appropriate control, also from the transmission grid and / or feed it into the transmission grid via the same route, provided that this electrical power unit has this functionality.The building battery, constructed from secondary cells, thus represents such an electrical power unit.
[0025] The method known from EP4000155A1 for providing electrical control power for stabilising an electrical transmission network and / or for providing an energy market product comprises the following steps:
[0026] • Determining a network frequency deviation in the transmission network and / or a request signal for an energy market product,
[0027] • Aggregating a first group of building batteries corresponding to a first group of building networks,
[0028] • Activating a second group of building batteries corresponding to a second group of building networks from the first group of building batteries and
[0029] • Providing the required control power, in particular by means of the group of building batteries to compensate for the determined grid frequency deviation and / or providing the requested energy market product, in particular by means of the group of building batteries.
[0030] The order of the first three procedural steps mentioned is variable.
[0031] It is important that the first step of determining the grid frequency deviation in the transmission grid and / or a demand signal for an energy market product can be performed before, after, during, or between the aforementioned steps of aggregating and activating building batteries. Once the provision of control power has begun, the grid frequency deviation is determined repeatedly to minimize the deviation through the remaining steps and to ensure that the grid frequency is dynamically balanced to minimize fluctuations around the ideal 50.0 Hz.
[0032] In EP4000155A1, in addition to building batteries, other significant electrical power units and the bundling of small electrical power units are used for grid-serving and / or energy market-serving power distribution. Against this background, the invention is based on the objective of further improving the interaction of the various electrical power units for the reliable provision of electrical control power and / or for the provision of an energy market product.
[0033] This object is achieved by a method having the features of claim 1.
[0034] According to the invention, the method is characterized by the step:
[0035] • Deploying a plurality of slow electrical power units within the second group of building networks in such a way that the slow electrical power units replace at least a portion of building batteries from the second group of building batteries in providing the required electrical power by changing their electrical power conversion.
[0036] Building energy storage systems in the form of rechargeable building batteries have comparatively short latencies of less than two seconds when it comes to changes in their power output affecting the electrical transmission grid connected via the grid connection point. They are therefore particularly suitable for providing primary control power (FCR), which must be available to the transmission grid relatively quickly. The short latency therefore enables the aggregated and activated second group of building batteries to provide the required electrical power output first, viewed on the time axis. At the same time, or with a slight delay, slow electrical power units are deployed, which have significantly longer latencies than the building batteries.Depending on its functional design, the use of a slow electrical power unit leads to an increase in electrical power consumption, a decrease in electrical power consumption from the transmission grid, an increase in electrical power output or a decrease in electrical power output to the transmission grid.
[0037] As already mentioned in the introduction to the description, the order of the first three procedural steps (determining the grid frequency deviation, aggregating building batteries, and activating building batteries) can be configured arbitrarily. In particular, according to the current specifications of the transmission system operators, the provision of primary control power must be completed within a maximum of 30 seconds. Therefore, the procedural steps of aggregating and activating building batteries are usually already completed or already underway when a grid frequency deviation is detected. Depending on the algorithms and communication networks used, aggregating and activating also require a time of seconds. The aggregation process and / or the process of activating building batteries can be updated periodically or run continuously.During the aggregation process, the algorithms used preferably perform various optimizations. These can be oriented towards business, sustainability-related, and / or other objectives.
[0038] For the purposes of marketing on the energy market, a control system typically aggregates building batteries suitable for the desired supply of control power and / or an energy market product. This specifically involves identifying this subset of building batteries, referred to as the first group. This first group thus constitutes the suitable building batteries kept on standby for the provision of electrical control power and / or an energy market product.
[0039] The step of activating a second group of building batteries from the first group of building batteries can either include all building batteries of the first group – in which case the first group corresponds exactly in quantity to the second group – or form the second group as a subset of the first group. The process step of activating the second group does not yet mean the provision of electrical power. Rather, process parameters are sent to at least the building batteries of the second group that define when and to what extent these building batteries change their power output in response to a trigger signal to provide control power and / or an energy market product. The process step of provision is only realized with the triggered change in the power output of a triggered electrical power unit.The process parameters used are threshold values of the grid frequency deviation, above or below which the aggregated and activated building batteries and the slow technical power units intervene in the process by changing their power consumption.
[0040] The threshold values transmitted for activation can be applied homogeneously to all building batteries or heterogeneously to different subgroups of the building batteries. Regardless of whether the threshold distribution is homogeneous or heterogeneous, all building batteries are equally activated. However, they differ from one another in their threshold values. The different threshold values influence when the building batteries are triggered to change their electrical power output to provide control power and / or to provide an energy market product.
[0041] The trigger signal can be sent, in particular, by a controller located in the building network, for example the energy flow control system present there, when the grid frequency deviation thresholds set for activating the building batteries or other electrical power units are exceeded or undershot during a local measurement in the building network. In the same scenario, this signal can also be transmitted by a centralized controller. Alternatively, the trigger signal can also be sent directly by a central control instance without performing the threshold comparison. The aggregation step and / or the activation step preferably also includes, in addition to the building batteries, slow electrical power units, provided they are present in the respective building networks of the first group or the second group.This means that the slow technical power units are also aggregated with building batteries in the first group from the outset and are activated in the second group, either completely or as a subset of the first group. However, due to the significantly longer latency times compared to building batteries and higher grid frequency deviation thresholds, the provision of a modified power output will be delayed or occur at a later time once the higher grid frequency deviation thresholds are exceeded.
[0042] Preferably, the grid frequency deviation is determined locally in all or the majority of the aggregated building grids. The local building grid control then triggers its activated building battery and / or its activated low-speed electrical power unit when the grid frequency deviation thresholds specified by the activation are exceeded. Such a delocalized control system exhibits greater resilience against external manipulation attempts in the form of cyberattacks compared to a centralized control system.
[0043] Preferably, the replacement of building batteries when the required electrical power is supplied by slow electrical power units from the same building grid to which the building battery is connected. In this way, from the transmission grid perspective, the replacement of the building battery's power supply by the slow electrical power unit takes place behind the same grid connection point in the same building grid. This makes it easier to control and regulate than if there is a clear spatial separation in the transmission grid between the building battery being replaced and the slow electrical power unit being used.A preferred development of the method consists in the use of slow electrical power units and the replacement of building batteries when the required power is provided by the slow electrical power units used during the provision of the required electrical power, either permanently or periodically. Furthermore, it is advantageous if the aggregation and activation of the building batteries to provide the required electrical power occurs permanently or periodically, and newly activated building batteries also replace activated building batteries already in use when the required electrical power is provided.
[0044] If there is access to a large number of building networks with all their building batteries and the other electrical power units, including the slow ones with a comparatively high latency, then it is advantageous to activate and deploy these electrical power units to provide the required power only for short periods of time (a few minutes) and then replace them. However, this in turn means that after the expiration of a usage time window (a few minutes), a changeover takes place. Consequently, previously activated and deployed electrical power units are fully or partially replaced, and the electrical power units replacing them are deployed so that they can make their contribution to providing the required electrical power. It is expedient if not all activated and deployed electrical power units are replaced by new ones at the same time.Rather, the replacement occurs gradually, so that the overall picture is one of constant coming and going among the activated and deployed electrical power units. Considered in terms of the total number of activated and deployed electrical power units, these are in a permanent replacement process. At the level of the individual electrical power units, the replacement occurs periodically, although the time period used for this does not have to be fixed. It can be adapted in light of the systemic boundary conditions to be met. The method is particularly preferably designed for the use of a large number of slow electrical power units in the form of battery-electric vehicles with EV batteries. Many EV batteries have an energy capacity almost ten times higher than that of building batteries.However, within the meaning of this invention, they are considered slow electrical power units with a comparatively high latency. This is due in particular to the manufacturers of battery-electric vehicles. These often use proprietary control and regulation systems for charging the EV batteries, which can only be used to a limited extent by third parties and are usually not modifiable. In principle, EV batteries represent significant yet slow electrical power units within the meaning of the definitions of this invention given in the introduction to the description. However, their electrical power potential can be used to provide the required electrical power through interaction with the fast building batteries.
[0045] An advantageous further development of the method using battery-electric vehicles is characterized in that in the battery-electric vehicles a charging current is monitored to ensure that it drops in a specific way, which characterizes as an event the achievement of a full charge of the associated EV battery, wherein in response to such a determined event the associated battery-electric vehicle is replaced by other electrical power units if it has contributed to providing the required electrical power up to the determined event, or the associated battery-electric vehicle is marked as not currently available for receiving electrical power.This ensures that a slow electrical power unit contributing to the required electrical power is temporarily replaced by the building battery or other electrical power units in the same building network, or alternatively, by a building battery or other electrical power units located in different building networks. Particularly preferably, the battery-electric vehicles contribute their share of the required electrical power exclusively by consuming electrical power to charge the EV batteries and / or by not consuming power to charge the EV batteries, but not by discharging power from the EV batteries into the transmission grid. Thus, the EV batteries of the battery-electric vehicles are charged exclusively unidirectionally.From the perspective of the transmission grids, they then represent significant electrical power units in the form of comparatively high loads. This eliminates any metrological challenges that would, for example, have to be met to reliably prevent green electricity generated locally in the building, which was previously charged into the EV battery, from now being fed into the transmission grid. Most of the EV batteries currently installed in battery-electric vehicles do not have sufficient cycle stability compared to the expected vehicle service life to allow the EV batteries to be regularly discharged in bidirectional operation, also toward the transmission grid. If the cycle stability is sufficiently greater in the future, the method according to the invention can also be implemented in bidirectional operation of battery-electric vehicles.
[0046] Advantageously, in order to provide the power with unidirectional use of the EV batteries, a working number of battery-electric vehicles to be charged from the transmission grid is determined and formed, whereby this working number defines a maximum possible electrical power consumption from the transmission grid and, in the absence of relevant grid frequency fluctuations and / or lack of requests for an energy market product, an average electrical power consumption of the working number of battery-electric vehicles in the range of 40% to 60% of the maximum possible electrical power consumption is set as the operating point by the working number of battery-electric vehicles.For this purpose, each of the EV batteries belonging to the working number of battery electric vehicles to be charged from the transmission grid is controlled in a state selected from the state group consisting of: - no electrical power consumption from the transmission grid,.
[0047] - maximum possible electrical power consumption from the transmission grid and
[0048] - Electrical power consumption between 0% and 100% of the maximum possible electrical power consumption from the transmission grid. In this way, the operating point for the EV batteries can be set, from which control power to stabilize the transmission grid and / or electrical power for an energy market product can be provided as needed. It is crucial that the operating point can be set in such a way that this charging or non-charging behavior is predictable over a short period (a few minutes) for at least some of the EV batteries. It depends on economic considerations whether, for example, non-charging EV batteries are kept ready for charging, only those that are already charging can be switched off, some or all of the batteries are charged only with a reduced charging current, or a more or less balanced approach between charging and non-charging batteries is chosen. Predictability over at least
[0049] 90 seconds into the future and the control of this state by the method according to the invention. Therefore, the method preferably provides for the predicted maximum possible electrical power consumption of the number of EV batteries in operation to be guaranteed for a period of at least 90 seconds in the future. A grid frequency fluctuation is "relevant" within the meaning of the present invention if, from the perspective of the transmission system operator, it requires the use of control power, preferably primary control power.
[0050] The above statements also apply to the use of EV batteries in bidirectional charging mode. Since energy from the EV batteries can also be fed into the transmission grid during bidirectional charging, the power scope for providing control power is expanded. For the purposes of the present invention, providing control power encompasses both the intake of electrical energy from the transmission grid and the discharge of electrical energy into the transmission grid. However, from the transmission grid's perspective, this discharge can also be achieved by reducing the intake of electrical energy. During bidirectional charging of EV batteries, it would be possible to reduce energy intake to "below zero" by feeding energy into the transmission grid.
[0051] The methods described above are preferably further developed with regard to the use of battery-electric vehicles in such a way that, for accredited battery-electric vehicles, a current state of charge of the respective EV batteries of previously known total charging capacity is determined using the following, temporally upstream analysis steps of a preceding charging process as follows:
[0052] - Saving a date and time of the start of charging of the EV battery;
[0053] - Determining and storing the amount of energy consumed and the charging time required for this and
[0054] - Determining the state of charge of the EV battery at the time charging began by subtracting the previously known total charging capacity from the determined amount of energy consumed, assuming that the charging process was completed without external intervention and that the EV battery is therefore fully charged. This approach is appropriate because many manufacturers of battery-electric vehicles do not provide easy access to data for third parties on parameters such as the vehicle's state of charge (SoC). To be independent of these manufacturers, the evaluation method described above represents a pragmatic approach for retrospectively determining the vehicle's state of charge and thus being able to make largely accurate forecasts for the future.
[0055] In a further development of this statistical evaluation, the method is advantageously characterized in that a statistical analysis of weekday- and time-dependent user behavior of the accredited battery-electric vehicle (BEV) is carried out from a large number of charging processes analyzed in this way in order to determine the state of charge of the EV battery, including an error value, and the probable charging duration based solely on the date and time of commencement of charging. If the statistical analysis has been carried out for a sufficient number of charging processes, user-specific statistics are obtained that allow forecasts for the current state of charge based solely on the time of day and date. This is related to the users' habits. Due to the recurring events in their work and leisure activities, users have regularly recurring mobility needs, which often repeat, for example, on a weekly basis.Even if the periodicity is not a week, but a month or a day, this type of statistical analysis allows for a high probability of matching the current state of charge and the user's charging preferences. Even if the forecast turns out to be incorrect, it is not a dramatic event. This one EV battery is just one among hundreds. If the forecast is correct for a large proportion of EV batteries, then this probability can be used to plan and operate the process. Ultimately, the "fully charged" status of an EV battery is also indicated by a drop in the charging current. This can be used for ad hoc replacement from the reserve pool of a constantly recalculated selection list of building batteries and from building batteries in combination with EV batteries and / or other technical units from the building grid.In addition, the composition of the aggregated and activated building batteries and the slow-battery electrical power units is regularly recalculated and optimized. The use of the building batteries and, in the preferred case, the EV batteries to provide the required electrical power output continues to be preferred only for a period of a few minutes. After that, the building batteries and EV batteries are switched to those that were not previously used but were prioritized on the continuously recalculated selection list. This is intended to prevent a large number of EV batteries from simultaneously and unexpectedly completing their charging process and then having to be replaced. This process stabilizes the necessary process of replacing electrical power units of all kinds.The preceding method with the statistical analysis is further advantageously designed such that the analysis steps of the charging processes and / or the statistical analysis of the charging processes are performed locally in an energy flow control system of the building network, and the resulting results are stored locally. This functionality ensures that the knowledge about the user-specific consumption profiles is localized within the building network. In the event of poor or interrupted data communication with centrally organized control units, the energy flow control systems within the building networks can continue to operate completely or at least partially autonomously for a certain period of time using the user profiles stored there.
[0056] Furthermore, the method is advantageously further developed with regard to statistical analysis so that the results of the statistical analysis of weekday- and time-dependent user behavior, the state of charge of the EV batteries and the probable charging time, are used to determine an operating point for providing the required electrical power using a working number of battery-electric vehicles. The sum of all user-specific statistics determined can be used to forecast the total EV battery power consumption in a future period, along with the associated error. The total EV battery power consumption represents their contribution to the electrical power to be provided, and the associated error determines the necessary reserve, which must therefore be maintained, in order to guarantee the required electrical power despite deviations.
[0057] A further advantageous development of the method is characterized by the fact that the statistically determined parameters such as the state of charge and probable charging time of the EV batteries are replaced in whole or in part by concrete queries of these parameters from users of accredited battery-electric vehicles. The required query is sent to the user via digital end devices. The user can specify at what future point in time the EV battery belonging to the vehicle should have a certain state of charge. Based on the input during the query, the user also consents to the use of the battery-electric vehicle within a defined framework for the method according to the invention.Together with the vehicle's state of charge, which is also queried (alternatively, this state of charge can be estimated from the statistical user-specific analyses), it is possible to determine the earliest and latest charging times for each battery-electric vehicle. An algorithm then distributes the determined charging times more or less evenly for each battery-electric vehicle. The algorithm also plans the operating point formed by the sum of the EV batteries over a specific time interval of, for example, four, eight, or more hours. This corresponds to the currently relevant time periods required by transmission system operators in Germany for the provision of control power. However, shortening these time periods to less than 60 minutes is under discussion. Various incentives, particularly economic ones, are offered to users for the information required to be provided by the user.
[0058] In addition, the mere implementation of operating point planning generates considerable economic benefits, as the evening charging peak feared by the transmission system operator is avoided simply by planning the operating point. This applies even if no control power or energy service is being provided at the time.
[0059] For all the methods described above, it is also preferred that the slow technical units are only used above a defined grid frequency deviation threshold. These can be selected such that their inclusion allows for longer latency periods (e.g., for grid frequency deviations of more than 50 mHz, preferably more than 100 mHz), makes the use of the slow TE rare events, or, through frequent charging in the negative range, directs excess energy from the grid directly into the EV batteries by asymmetrically controlling charging processes. Further features and advantages of the method according to the invention are illustrated in conjunction with the following figures of an exemplary embodiment.
[0060] They show:
[0061] Figure 1 is a schematic representation for the overall explanation of the functional principle of the method according to the invention,
[0062] Figure 2 shows a schematic representation of the use of primary control power to stabilize the grid frequency of a transmission system on a time axis and
[0063] Figure 3 shows an enlarged time section marked III in Figure 2.
[0064] Fig. 1 shows a schematic representation of the components used for the method according to the invention for providing electrical control power for stabilizing an electrical transmission grid N and / or for providing an energy market product. Each of the buildings shown acts as a reserve unit RE1, RE2...REn and comprises a plurality of electrical power units within its respective building grid G, which is connected to the transmission grid N via an associated grid connection point P. The reserve unit RE1 is shown enlarged as an example in Fig. 1 and reveals several electrical power units in its building grid G1. This plurality of electrical power units TE1, TE2...TEm, which are also referred to as technical units, consists on the one hand of the group of significant electrical power units with an electrical power output of more than or equal to two kilowatts each.Secondly, so-called small electrical power units are present in the building network G1 of the reserve unit RE1. These each have an electrical power consumption of less than two kilowatts. Furthermore, the electrical power units TE1, TE2...TEm can be differentiated according to their latency times. For the purposes of the present invention, electrical power units are considered slow if they have a latency time of more than two seconds to realize a significant change in their electrical power consumption. For the definition of latency, power consumption, and a "significant" change in power consumption, please refer to the explanations in the introduction to the description.
[0065] Each of the reserve units RE1, RE2...REn has a significant power unit in the form of a building battery B and an electrical power unit in the form of a PV energy generation system in its building network. These electrical power units are shown separately as components of the respective building network alongside the other electrical power units in the form of the technical units TE1, TE2...TEm. The PV energy generation system preferably generates renewable energy and is usually implemented as a photovoltaic system. However, a wind turbine, a hydropower plant, a biogas plant with a combined heat and power plant, a fuel cell, an emergency power generator, and combinations of these energy generation systems would also be possible.
[0066] Furthermore, in each of the building networks G1, G2...Gn, an energy flow control EFS is set up and designed in such a way that it controls and regulates the energy flows between the energy generation system PV, the technical units TE1, TE2...TEm, the building battery B and the transmission network N in a guideline-compliant and cost-optimized manner for the benefit of a user / owner of the building network N.
[0067] Many of the reserve units RE1, RE2...REn have at least one so-called "slow" significant power unit BEV in their building networks G1, G2...Gn. This has a latency of more than two seconds to realize a significant change in their power consumption. This includes a change in power consumption of more than 25%. Furthermore, the building network G of the reserve unit RE1 is connected to the transmission network N of a transmission network operator via a smart meter SM and an associated smart meter gateway SMGW, which must be certified in accordance with the regulations of the Federal Office for Information Security (BSI) applicable in Germany. As an alternative to connecting the building networks G1, G2...Gn via the smart meter SM and the associated smart meter gateway SMGW, any form of electrical power measurement that supports direct marketing via the transmission network N is also suitable.
[0068] For the further reserve unit RE2, the detailed representation corresponding to the first reserve unit RE1 would show the building network G2 with electrical power units TE1 to TEm, a building battery B, an energy generation system PV and an energy flow control system EFS.
[0069] Another connection, for example via a DSL line, establishes a connection between the reserve group RE1 and the Internet 1. In practice, preferably around 500 to 1000 such reserve units RE1, RE2...REn are in packet-switched data exchange with a control system S via their respective connection to the Internet 1. The control system S forms a data gateway between the Internet 1 and a process network 2 of a transmission system operator. The so-called Customer Premises Equipment CPE is arranged in the process network 2. From the perspective of the process network 2 of the transmission system operator, the large number of clustered reserve units RE1, RE2...REn connected to the control system S acts like a large reserve unit in terms of performance, which is referred to as a reserve group RG. The term virtual technical unit was previously used for such reserve groups RG.This reserve group RG can be operated as a virtual power plant VPP on the process network 2 side, for example, to provide control power for a transmission system operator to stabilize the frequency of the transmission network N and / or an energy market product via the transmission network N. The transition from the domain of the Internet 1 to the domain of the transmission system operator's specially secured process network 2 is achieved through a media break implemented in the hardware of the control system S. This is realized by using a serial interface between the incoming packet-switched data communication and the outgoing packet-switched data communication and is visualized purely schematically by the double arrow.
[0070] The preferred variant of the method described here as an example, based on the scenario shown in Figure 1, which is carried out as method step M1, provides for determining M1 a grid frequency deviation in the transmission grid N and / or a request signal for an energy market product. This determination can be performed either centrally by the control system S and / or delocalized by each reserve unit.
[0071] Further method steps include: aggregation M2 of a first group of building batteries, which corresponds to a first group of building networks, and activation M3 of a second group of building batteries B, which are selected from the first group of building networks. This second group is a subset or the entire set of available reserve units RE1 to REn. Each of these reserve units has a building battery B, which can act as a significant power unit on the transmission network N with a latency of no more than two seconds. The method step of activation M3 thus takes place within this latency. The method step of determining M1 the grid frequency deviation can take place before, between, during and after the method steps of aggregation M2 and activation M3 of the building batteries B.In addition, the aggregation and activation of building batteries is preferably accompanied by the aggregation and activation of slow electric power units BEV.
[0072] The next step in the process, M4, is the provision of the required electrical power by means of the second group of building batteries B to compensate for the determined grid frequency deviation by means of control power and / or to provide the requested energy market product.
[0073] The further method step consists in inserting M5 a plurality of slow electrical power units BEV within the group of building networks in such a way that the slow technical units BEV replace at least a portion of building batteries from the second group of building batteries B in providing the required electrical power by changing their electrical power conversion.
[0074] The fast, significant electrical power units in the form of building batteries B thus initially step in, only to be subsequently fully or partially replaced by the slow electrical power units. In this way, the amount of power turnover change used for control power and / or an energy market product can be significantly increased.
[0075] As a preferred variant of the method, the scenario described below is that the slow electrical power units BEV are each significant electrical power units in the form of battery electric vehicles with EV batteries, which are connected to the respective building networks G1...Gn via charging devices.
[0076] Even if bidirectional charging is fundamentally possible for these EV batteries, i.e. the EV batteries of the battery-electric vehicles BEV feed energy into the transmission grid N, only the unidirectional charging scenario is considered, i.e. the EV batteries only absorb energy from the transmission grid N and therefore do not feed their electrical energy into the transmission grid N at any time.
[0077] Fig. 2 shows a schematic representation of the use of control power in the form of primary control power PFCR to stabilize the grid frequency fc of a transmission grid N on a time axis t. The time axis t is shown horizontally. Vertically, on the right-hand side of the diagram, the primary control power PFCR is plotted between a positive primary control power of +2 MW and a negative primary control power of -2 MW, and on the left-hand side of the diagram, the grid frequency fc is plotted between 49.8 Hz and 50.2 Hz. If the grid frequency is exactly 50.0 Hz, no use of control power is required. However, due to systemic factors, this is not a permanently stable state for the transmission grid N. Rather, a state of dynamic equilibrium must be achieved with the help of primary control power through its use. The solid line shows the oscillating course of the grid frequency around the desired, ideal 50.0 Hz.This frequency curve follows, with a time offset of approximately two seconds, the control power curve shown in dashed lines, which is realized in the grid frequency band between 50.1 Hz and 49.9 Hz exclusively through the use of building batteries B for the provision of primary control power.
[0078] If the grid frequency deviates by more than 0.1 Hz, slow significant power units in the form of EV batteries—battery electric vehicles (BEVs)—are used in addition to the building batteries B to provide the required primary control power. The magnitude of the grid frequency deviation above which slow significant power units are also used to provide primary control power and thus subsequently become grid-beneficial has been selected as 0.1 Hz in this example. However, this threshold can be higher or lower depending on the specific circumstances.
[0079] Figure 3 shows an enlarged time segment, marked III in Figure 2, in which, in addition to the building batteries B, battery-electric vehicles BEVs are also used as slow, significant power units to deploy primary control power in this preferred embodiment. The solid line of the grid frequency falls below 50.0 Hz, and, for example, with a latency of less than two seconds, building batteries B are aggregated and activated to provide positive primary control power PFCR. However, the aggregation and activation of building batteries B can also occur earlier. Only after or during the aggregation and activation does the grid frequency deviation get determined, and the control power is provided in response to this.In Figure 3, the primary control power PFCR provided by the building batteries B alone is not sufficient to increase the grid frequency back towards the desired 50 Hz. As a result, the grid frequency fc continues to fall and falls below 49.9 Hz, so that additional aggregated and activated building batteries (shown in dotted lines) and, in parallel, likewise aggregated and activated, slow significant power units BEV (shown in hatched lines) are used to provide positive control power. However, this does not occur through the EV batteries of the battery-electric vehicles BEV supplying electrical power to the transmission grid N, but rather by, in the present exemplary embodiment, throttling the electrical power consumption of around 50 slow significant power units BEV from the transmission grid N. This ensures that the grid frequency fc rises again.By continuing to use the deployed EV batteries (BEV), the number of activated building batteries (B) can initially be reduced. However, the grid frequency (fc) then drops so sharply that a large number of fast building batteries (B) are deployed in addition to the 50 deployed EV batteries (BEV). At the same time, another 50 activated EV batteries (BEV) are deployed, so that a total of 100 EV batteries (BEV) are deployed. While maintaining the use of the 100 EV batteries (BEV), the number of building batteries (B) deployed can be significantly reduced. The number of deployed EV batteries (BEV) is also reduced from 100 to 50, and if the grid frequency (fc) continues to rise, the 50 still deployed activated EV batteries (BEV) are also deactivated.
[0080] With a corresponding latency offset, slower significant power units in the form of EV batteries (BEV) are deployed in defined situations. If these provide the required negative or positive control power, this allows the number of previously deployed, aggregated, and activated building batteries (B) to be reduced accordingly. List of reference symbols:
[0081] 1 Internet
[0082] 2 Process network
[0083] P Grid connection point
[0084] N transmission network
[0085] PV power generation plant
[0086] EFS energy flow control
[0087] SMGW Smart Meter Gateway
[0088] SM Smartmeter fc Frequency of the transmission network
[0089] PFCR control power, in particular primary control power to stabilize the transmission system
[0090] G Building network
[0091] B Building battery
[0092] TE electrical power unit, technical units
[0093] BEV slow electric power unit, especially battery electric vehicle
[0094] RE reserve unit
[0095] RG Reserve Group
[0096] CPE Customer Premises Equipment
[0097] VPP virtual power plant
[0098] S control system
[0099] M1 Determining the mains frequency deviation
[0100] M2 Aggregation of building batteries
[0101] M3 Activating building batteries
[0102] M4 Provision of control power
[0103] M5 Enabling slow electric power units, especially battery electric vehicles
Claims
Patent claims: 1 . Method for providing electrical control power for stabilizing an electrical transmission network (N) and / or for providing an energy market product, using a plurality of electrical building batteries (B), - which are each connected to the transmission network (N) via a network connection point (P) and - which are each grouped together with other electrical power units (TE1...TEm) in a building network (G1...Gn) defined by the network connection point (P), wherein in a plurality of the building networks (G1...Gn) there is at least one slow electrical power unit (BEV) which requires a latency time of more than two seconds for a significant change in its electrical power consumption, the method comprising the following steps: • Determining (M1) a network frequency deviation in the transmission network (N) and / or a request signal for an energy market product, • Aggregating (M2) a first group of building batteries (B) corresponding to a first group of building networks, • Activating (M3) a second group of building batteries (B), corresponding to a second group of building networks, from the first group of building batteries and • Providing (M4) the required control power using the group of building batteries (B) to compensate for the determined grid frequency deviation and / or providing the requested energy market product, and the process is characterized by the process step: • Using (M5) a plurality of slow electrical power units (BEV) within the second group of building networks in such a way that the slow electrical power units (BEV) replace at least a portion of building batteries from the second group of building batteries (B) in providing the required electrical power by changing their electrical power conversion; • whereby the aggregation and activation of the building batteries (B) to provide the required electrical power takes place permanently or periodically and newly activated building batteries also replace activated building batteries that have already been used to provide power when providing the required electrical power.
2. Method according to claim 1, characterized in that the use of slow electrical power units (BEV) and a detachment of building batteries (B) when providing the required power by the slow electrical power units (BEV) used during the provision of the required electrical power takes place permanently or periodically.
3. Method according to one of the preceding claims, characterized in that a plurality of slow electric power units (BEV) in the form of battery electric vehicles with EV batteries are used.
4. Method according to claim 3, characterized in that in the battery-electric vehicles (BEV), a charging current is monitored to ensure that it drops in a characteristic manner, which characterizes as an event the achievement of a full charge of the associated EV battery, wherein in response to such a determined event the associated battery-electric vehicle (BEV) is replaced by other electrical power units if it has contributed to providing the required electrical power up to the determined event, or the associated battery-electric vehicle (BEV) is marked as not currently available for receiving electrical power.
5. Method according to claim 3 or 4, characterized in that the battery electric vehicles (BEV) contribute their share to providing the required electrical power exclusively by electrical power consumption for charging the EV batteries and / or by non-power consumption for charging the EV batteries, but not by power output from the EV batteries into the transmission grid (N).
6. Method according to one of claims 3 to 5, characterized in that a working number of battery electric vehicles (BEV) to be charged from the transmission network (N) is determined and formed, wherein this working number defines a maximum possible electrical power consumption from the transmission network (N) and in the state of no relevant network frequency fluctuations and / or no request requests for an energy market product, an average electrical power consumption of the working number of battery electric vehicles (BEV) in the range of 40% to 60% of the maximum possible electrical power consumption is set as the working point by the working number of battery electric vehicles (BEV).
7. Method according to claim 6, characterized in that each of the EV batteries belonging to the working number of battery electric vehicles (BEV) to be charged from the transmission network (U) is controlled in a state selected from the group consisting of: - no electrical power consumption from the transmission network (N), - maximum possible electrical power consumption from the transmission network (N) and - electrical power consumption between 0% and 100% of the maximum possible electrical power consumption from the transmission system (N).
8. Method according to claim 6 or 7, characterized in that the predicted maximum possible electrical power consumption of the working number of EV batteries is ensured for a future period of at least 90 seconds.
9. Method according to one of claims 3 to 8, characterized in that for accredited battery electric vehicles (BEV), a current state of charge of the respective EV batteries of previously known total charging capacity is determined with the following, temporally upstream analysis steps of a preceding charging process as follows: - Saving a date and time of the start of charging of the EV battery; - Determining and storing the amount of energy consumed and the charging time required for this and - Determining the state of charge of the EV battery at the time of start of charging by subtracting the previously known total charging capacity less the determined amount of energy absorbed, under the condition that the charging process was completed without external intervention and therefore it is assumed that the EV battery is fully charged.
10. The method according to claim 9, characterized in that a statistical analysis of a weekday- and time-dependent user behavior of the accredited battery-electric vehicle (BEV) is carried out from a plurality of charging processes analyzed in this way in order to determine the state of charge of the EV battery, including an error value, and the probable charging time solely depending on the date and time of the start of charging.
11. Method according to claim 9 or 10, characterized in that the analysis steps of the charging processes and / or the statistical analysis of the charging processes are carried out locally in an energy flow control of the building network (G) and results determined therefrom are stored locally.
12. Method according to claim 11, dependent on claim 9, characterized in that the state of charge of the EV batteries and the probable charging time are used as results of the statistical analysis of the weekday and time-dependent user behavior to determine an operating point for providing the required electrical power by means of a working number of battery-electric vehicles (BEV).
13. Method according to claim 12, characterized in that the statistically determined parameters such as state of charge and probable charging time of the EV batteries are determined in whole or in part by concrete queries of these parameters at users of accredited battery electric vehicles (BEVs).
14. Method according to one of the preceding claims, characterized in that the slow technical units (BEV) are only used above a defined grid frequency deviation threshold.
15. A system for providing electrical control power for stabilizing an electrical transmission grid (N) and / or for providing an energy market product, wherein: the system comprises a plurality of building grids (G1...Gn), each defined by a respective grid connection point (P), and each having an electrical building battery (B) with a latency of no more than two seconds, which is connected to the transmission grid (N) via the grid connection point (P) of the respective building grid and is grouped in the respective building grid together with further electrical power units (TE1...TEm) (G1...Gn); in a plurality of the building grids (G1...Gn) at least one slow electrical power unit (BEV) is present in each case, which requires a latency time of more than two seconds for a significant change in its electrical power consumption; the system is configured to determine a grid frequency deviation in the transmission grid (N) and / or a request signal for an energy market product (M1); and the system further comprises a controller configured to cause the system to carry out the method according to one of the preceding claims.