DE102019220347A1 - Determination of the structure of an energy system that is resilient to the failure of one or more of its components - Google Patents

Abstract

A computer-aided method is proposed for the numerical determination of the structure of an energy system (1) that is resilient to failure of one or more of its components (21, ..., 23), the energy system (1) being described by a target function intended for optimization so that the structure of the energy system (1) is determined by calculating an extremum of the objective function. The method is characterized in that the extremum is calculated under the secondary condition that a critical load PL * (42) continues through one or more contributing components i (21, ..., 23) of the energy system (1) for a call duration TDderart What is covered is that components and / or processes that are dependent on the critical load PL * (42) are not significantly impaired, whereby the time change in the power Pi * of each contributing component (21, ..., 23) within a response time TR of the energy system (1st ) is limited by the nominal power Pnet weighted with the start-up time Tnet, id of the respective component (21, ..., 23). Furthermore, the invention relates to an associated energy management system and an energy system (1).

Description

The invention relates to a method according to the preamble of the patent claim 1 , an energy management system according to the preamble of claim 12 and an energy system according to the preamble of claim 14.

Energy systems typically include several components, in particular energy-related systems, for example energy conversion systems, consumption systems and / or storage systems. Multimodal energy systems are energy systems that generate and / or provide energy in several forms of energy. In particular, a multimodal energy system for an energy consumer, for example a building, an industrial plant or a private plant, provides one or more forms of energy, the provision being made in particular by converting various forms of energy, by transporting various forms of energy and / or through stored forms of energy. In other words, the various forms of energy, for example heat, cold or electrical energy, are coupled by means of the multimodal energy system with regard to their generation, their provision and / or their storage.

A typical industrial multimodal energy system, for example in the food industry, has several energy-related systems (technologies for energy conversion), various storage devices (storage technologies), a connection to a (public) electricity network, a connection to a (public) gas network and / or hydrogen network as well as several electrical and thermal loads.

It is known to design energy systems as efficiently as possible using an energy system design method (energy system analysis), that is, to determine their optimal structure. For this purpose, a mathematical model of the energy system is used, which enables the energy system to be optimized with regard to a target function by means of a numerical optimization method. A plurality of physical parameters (input parameters), for example predictions of load profiles and / or state measurements, for parameterizing the mathematical model or the target function, as well as several secondary conditions, are typically required for this. In other words, energy systems, in particular multimodal energy systems, are designed using data-based optimization methods.

Such a power system design method is for example from the document EP 3561743 A1 known.

An energy system design method thus determines the best possible structure of the energy system, for example with regard to its energetic efficiency. The structure of the energy system is formed in particular by its components, the dimensions and / or capacities of its components, the costs of its components, energy flows, power flows and / or by its energy transfer lines.

For example, a combined heat and power plant (CHP plant) provides electricity, i.e. electrical energy, during peak times. The waste heat from the CHP plant can in turn be at least partially temporarily stored by means of a heat store and used to cover thermal loads. The optimization can be based on measurement data relating to the electrical and thermal loads mentioned.

However, in known methods, measurement data relating to the (external) power grid are not used. This jeopardizes the security of supply of the energy system. So-called backup generators are used to prevent this.

As a result, a certain resilience of the energy system, which is not optimal, can be provided. Typically, energy systems that have a certain resilience, for example to a failure of the external power grid, are overdimensioned.

Here, the term resilience denotes, for example, the ability of the energy system not to fail completely in the event of malfunctions, failures and / or partial failures and / or disruptive events, but rather to maintain critical loads, i.e. to cover them. In this sense, a load is critical if it has to be at least partially, in particular completely, maintained even if a fault, a failure and / or partial failure and / or a disruptive event occurs.

A typical malfunction or a typical failure is a malfunction or a failure of an external power grid connected to the energy system but with respect to this. Failures or malfunctions can therefore be triggered by internal and / or external events in relation to the energy system. In particular, a disruptive event is a power failure, a hacker attack on a control room and / or a technical failure of CHP systems.

A failure of the external power grid is the most common cause of electrical supply interruptions. Long-term interruptions (network interruptions) can be avoided through redundancies and switchovers within the external power grid. Short-term power interruptions (<3 minutes) are typically caused by switchings and correlate with atmospheric events or effects, for example thunderstorms. Thus, in the event of short-term supply interruptions, there are hardly any opportunities for a network operator to intervene. According to EN 50160, up to several hundred short supply interruptions (<3 minutes) per year can therefore be expected.

Electrical supply interruptions can lead to considerable damage, for example through damage to production facilities or through defective products. Newer production plants, especially with regard to the digitization of industrial energy systems or production (Industry 4.0), are particularly vulnerable due to their sensitive control electronics (control unit). The failure of critical processes can also pose a security risk to people.

It is therefore imperative to provide energy systems that are resilient and yet as efficient as possible.

Regarding this is from the document WO 2019/110220 A1 a method for providing the best possible resilience of an energy system is known.

The present invention is based on the object of providing a method for determining the structure of an energy system which leads to an improved resilience of the energy system. Furthermore, an energy system with improved resilience is to be provided.

The object is achieved by a method with the features of independent patent claim 1, by an energy management method with the features of independent patent claim 13 and by an energy system with the features of independent patent claim 15. Advantageous configurations and developments of the invention are specified in the dependent claims.

durch eine oder mehrere beitragende Komponenten i des Energiesystems für eine Abrufdauer T_D derart weiter gedeckt wird, dass von der kritischen Last $P_{\text{L}}^{*}$

abhängige Komponenten und/oder Prozesse im Wesentlichen nicht, insbesondere nicht, beeinträchtigt werden, wobei hierfür die zeitliche Änderung der Leistung $P_i^{*}$

jeder beitragenden Komponente innerhalb einer Antwortzeit T_R des Energiesystems durch die mit der Anlaufzeit T_net,i gewichtete Nennleistung P_net,i der jeweiligen Komponente beschränkt wird.The computer-aided method according to the invention for the numerical determination of the structure of an energy system resilient to a failure of one or more of its components, the energy system being described by a target function provided for optimization, so that the structure of the energy system is determined by calculating an extremum of the target function characterized in that the calculation of the extremum takes place under the secondary condition that a critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

is further covered by one or more contributing components i of the energy system for a call duration T _{D in} such a way that the critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

dependent components and / or processes are essentially not, in particular not, impaired, with the change in performance over time ${\mathrm{P.}}_i^{*}$

of each contributing component within a response time T _{R of} the energy system is limited by the nominal power P _{net, i of} the respective component weighted with the start-up time T _{net, i.}

There can be one or more critical loads.

Services during or after the failure are marked with an asterisk. The services at or before the failure do not have an asterisk.

As described above, a failure is any possible disruption of the operation of the energy system, in particular the at least partial failure of a component of the energy system and / or the at least partial failure of a power grid external to the energy system to which the energy system is connected to exchange electrical energy (reference and / or feed) is connected. If this power grid fails, certain components of the energy system also fail. Other networks, data networks and / or supply networks, for example gas networks and / or hydrogen networks, can alternatively or additionally be provided.

beim oder nach dem Ausfall und/oder die Leistungen P_i beim oder vor dem Ausfall und/oder die Leistungen $P_{\text{L}}^{*}$

beziehungsweise P_L sind grundsätzlich zeitabhängig, das heißt formal gilt $P_i^{*}=P_i^{*}\left(t\right)$

beziehungsweise P_i = P_i(t) und/oder $P_{\text{L}}^{*}=P_{\text{L}}^{*}\left(t\right)$

und/oder P_L = P_L(t). Weiterhin kann die Abrufdauer T_D ebenfalls zeitabhängig sein, das heißt beispielsweise - wie auch die weiteren genannten Größen - vom Zeitpunkt des Ausfalls abhängen. Allerdings wird die Zeitabhängigkeit zum Vereinfachen der Notation vorliegend nicht explizit ausgeschrieben.The component-specific size, such as the services ${\mathrm{P.}}_i^{*}$

during or after the failure and / or the services P _i at or before the failure and / or the services ${\mathrm{P.}}_{\text{L.}}^{*}$

and P _L are basically time-dependent, that is, formally applies ${\mathrm{P.}}_i^{*}={\mathrm{P.}}_i^{*}\left(t\right)$

or P _i = P _i (t) and / or ${\mathrm{P.}}_{\text{L.}}^{*}={\mathrm{P.}}_{\text{L.}}^{*}\left(t\right)$

and / or P _L = P _L (t). Furthermore, the retrieval duration T _{D can} also be time-dependent, that is to say, for example - like the other variables mentioned - it depends on the time of the failure. However, in order to simplify the notation, the time dependency is not explicitly written out here.

By determining the structure of the energy system (design of the energy system), its components, the Dimensioning and / or capacities of its components, the costs of its components, its energy flows, its power flows and / or its energy transfer lines and / or the energetic coupling between its components is determined. Through the optimization, the structure of the energy system and its energy flows or power flows are mapped or modeled holistically so that synergy potentials between the components and / or the various forms of energy can be determined. In particular, the energy-related structure of the energy system is determined.

A load is critical if it must be at least partially, in particular completely, maintained, that is to say must be covered, even when the failure occurs. In this case, the load must be at least partially covered if dependent components and / or processes are significantly impaired by a disturbance in the load. An impairment is significant, for example, if an operation of the component that is dependent on the critical load is no longer possible and / or the process that is dependent on the critical load can no longer be carried out or maintained. In other words, the critical load continues to be covered during the failure in such a way that critical processes associated therewith are not impaired in an impermissible manner.

An optimization within the meaning of the present invention is a method for minimizing or maximizing (calculating an extremum) of an objective function. The minimization or maximization of the objective function is typically extremely complex and can therefore only be done numerically. The objective function characterizes a property or a size of the system, for example the carbon dioxide emissions or the operating costs of an energy system. The objective function is thus a mathematical model of the energy system. The objective function has parameters and variables. The result of the optimization, i.e. in the present case the structure of the energy system, corresponds to the values of the variables of the objective function. The parameters are typically load profiles based on measurement data and parameterize the target function specific to the energy system. Furthermore, the optimization is typically carried out taking into account several secondary conditions, for example energy conservation.

Constraints, constraints or constraints - here collectively referred to as constraints - are conditions, properties and / or relations that the parameters and / or variables of the optimization process must meet. These can be given as an equation and / or inequality and / or explicitly describe a set of permissible values of the parameters and / or permissible values of the variables.

For example, the objective function characterizes the total carbon dioxide emissions of the energy system. The total carbon dioxide emission comprises the individual carbon dioxide emissions of the components of the energy system. Each of the components can provide a specific electrical and / or thermal output for a specific amount of carbon dioxide. Thus, the electrical and / or thermal outputs are the variables of the objective function and the amounts of carbon dioxide per generated electrical and / or thermal output (specific amount of carbon dioxide) are the parameters of the objective function. The optimization minimizes the total carbon dioxide emission (target function). As a result, the energy system can be designed and / or operated as optimally as possible with regard to its carbon dioxide emissions.

jeder zur Deckung der kritischen Last $P_{\text{L}}^{*}$

beitragenden Komponente innerhalb einer Antwortzeit T_R des Energiesystems durch die mit der Anlaufzeit T_net,i gewichtete Nennleistung P_net,i der jeweiligen Komponente (von oben) beschränkt. Dies erfolgt innerhalb beziehungsweise für eine Abrufdauer T_D. Somit weist das Verfahren drei charakteristische Zeitarten beziehungsweise Zeitdauern auf, namentlich die Antwortzeit T_R, die Abrufdauer T_D sowie die einzelnen Anlaufzeiten T_net,i.According to the present invention, the performance ${\mathrm{P.}}_i^{*}$

each to cover the critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

contributing component within a response time T _{R, i} weighted rated power P _net of the power system by the _net with the start-up period T _is restricted _i of the respective component (from above). This takes place within or for a retrieval period T _D. The method thus has three characteristic time types or time durations, namely the response time T _R , the call duration T _D and the individual start-up _{times T net, i} .

The response time T _R is the duration of the change in operation of the energy system that occurs due to the failure. In other words, this is the period of time in which the energy system can react, or reacts, to the failure. It can therefore also be referred to as the response time. Typically, each component of the energy system has a different response time. The response time T _R can be defined as the longest of the response times of the components. In other words, the response time T _{R of} the energy system is determined by the component of the energy system that is slowest in terms of response time. The response time T _{R of} the energy system is thus determined by its components. In particular, CHP systems and / or emergency power systems cannot adjust their operating point at will.

The call duration T _D is the time in which the supply of the critical load must be ensured. In other words must for the time T _{D is} the condition that occurs or from the change in operating points Working points are maintained. Typically, the retrieval duration T _{D is} greater, in particular significantly greater than the response time T _R. The retrieval duration T _D is defined, for example, and can correspond to an average expected downtime. For example, the retrieval duration T _{D is determined} on the basis of local availability statistics of a power grid external to the energy system. If such data are not available and / or are not available, empirical values from comparable locations can be used. The method according to the invention can thus be optimally adapted to the supply quality at the location of the energy system.

The start-up time T _{net, i} is the component-specific period of time in which the respective component increases its output from zero to the nominal output P _{net, i} (from 0 percent to 100 percent). The respective start-up time T _{net, i} is thus determined by the respective associated component.

The change in the power of a component is limited during the call time by the nominal power P _{net, i of} the component (from above) _{weighted with the start-up time T net, i.} For example, the change in the power of the component is less than or equal to P _{net, i} / T _{net, i} (with a linear change in the operating point) for all times within the call duration T _D. The restriction applies to all contributing components, i.e. for all components that contribute to covering the critical load. This ensures that the change in operating status of the respective contributing component is taken into account. In other words, each contributing component needs a certain time to change the operating state, for example to increase its output. However, the performance cannot be increased faster than P _{net, i} / T _{net, i} . This is taken into account by the secondary condition according to the invention. There is thus a transition phase, which _{corresponds to the response time T R} , in which the required stationary power to cover the critical load is not immediately available. In other words, according to the invention, the start-up time or the start-up times of the components is taken into account in the optimization.

A further advantage of the present invention is that, in particular, short-term interruptions in the external power grid are compensated for and the operation of the energy system is therefore not significantly impaired. The present method thus enables critical loads and / or processes and / or systems to be safeguarded at any point in time. In this way, downtime costs can be minimized and, at best, completely avoided.

Another advantage of the present invention is that it enables the energy system to be operated in a manner that is beneficial to the grid. In particular, this enables isolated operation of the energy system, in which decentralized energy-related systems, for example generating systems and / or storage systems, can be operated independently of the power grid or public power grid. As a result, the energy system can provide a flexibility which contributes to the stabilization of the overall network, in particular the power network, or can be used for accelerated network reconstruction.

Furthermore, for many applications and / or integration of the energy system, in particular for integration in a local energy market, the highest possible temporal resolution is required, for example every minute. The method according to the invention correctly maps energy management-relevant bills to a low temporal resolution, for example to 15-minute mean values.

durch eine oder mehrere beitragende Komponenten i des Energiesystems für eine Abrufdauer T_D derart weiter gedeckt wird, dass von der kritischen Last $P_{\text{L}}^{*}$

abhängige Komponenten und/oder Prozesse im Wesentlichen nicht, insbesondere nicht, beeinträchtigt werden, wobei hierfür die zeitliche Änderung der Leistung $P_i^{*}$

jeder beitragenden Komponente innerhalb einer Antwortzeit T_R des Energiesystems durch die mit der Anlaufzeit T_net,i gewichtete Nennleistung P_net,i der jeweiligen Komponente beschränkt wird.The energy management system according to the invention comprises at least one control unit for controlling several components of an energy system, the control of the components being based on a target function provided for optimization, so that control values for controlling the components are determined by calculating an extremum of the target function. The energy management system according to the invention is characterized in that the control unit is designed in such a way that the calculation of the extremum takes place under the secondary condition that a critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

is further covered by one or more contributing components i of the energy system for a call duration T _{D in} such a way that the critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

dependent components and / or processes are essentially not, in particular not, impaired, with the change in performance over time ${\mathrm{P.}}_i^{*}$

of each contributing component within a response time T _{R of} the energy system is limited by the nominal power P _{net, i of} the respective component weighted with the start-up time T _{net, i.}

Similar and equivalent advantages and / or configurations result for the method according to the invention.

The energy management system particularly preferably has a data interface which enables data to be exchanged between the energy management system and a local energy market, a cloud server and / or a decentralized data center.

The energy system according to the invention is characterized in that it comprises an energy management system according to the present invention and / or one of its configuration.

Similar and equivalent advantages and / or configurations result for the method according to the invention and / or for the energy management system according to the invention.

It is preferred here if the call duration T _{D of} the associated energy management system is determined as a function of the location of the energy system.

As a result, a local supply quality, in particular with regard to a power grid to which the energy system is connected, can advantageously be taken into account.

Furthermore, the energy system can comprise spatially distributed partial energy systems. This is the case, for example, with several production sites.

jeder beitragenden Komponente durch P_net,i/T_net,i beschränkt.According to a preferred embodiment of the invention, the change in performance over time ${\mathrm{P.}}_i^{*}$

each contributing component bounded by P _{net, i} / T _{net, i} .

In other words, there is advantageously a linear change in the operating point of the respective component. As an alternative or in addition, there is a non-linear change in the power for at least one of the contributing components. For example, for a non-linear change, the time output of at least one of the contributing components is _{limited by G i} (P _{net, i} / _{Tnet, i} ), where G _{i describes} the non-linear dependence of component i. Alternatively or in addition, G _{i is} independent of the component i, that is, the nonlinear dependence is given for all i by G (P _{net, i} / T _{net, i} ). In the linear case, for example, G (x) = x with x = P _{net, i} / T _{net, i} .

jeder beitragenden Komponente innerhalb der Antwortzeit T_R des Energiesystems (1) durch P_i + P_net,iT_R/T_net,i beschränkt, wobei P_i die Leistung der jeweiligen Komponente i vor oder beim Ausfall bezeichnet.In an advantageous development of the invention, the performance ${\mathrm{P.}}_i^{*}$

of each contributing component within the response time T _{R of} the energy system ( 1 ) limited by P _i + P _{net, i} T _R / T _{net, i} , where P _i denotes the performance of the respective component i before or during failure.

Essentially, P _i + P _{net, i} T _R / T _{net, i is} the integral of the condition that the temporal change in the power of the respective component is limited _{by P net, i} / T _{net, i} within the response time T _{R from above} . The two conditions mentioned are therefore equivalent. In other words, the condition means that only part of the respective nominal power can be provided by the respective component in order to continue to supply the critical load within the response time. Thus, the condition P _i + P _{net, i} T _R / T _{net, i} ≤ P _{net, i} must also always be fulfilled. In other words, the respective performance of the component within the response time is limited from above _{by P i} + P _{net, i} T _R / T _{net, i} and by P _{net, i.}

jeder beitragenden Komponente innerhalb der Antwortzeit T_R durch ihre jeweilige Nennleistung P_net,i (von oben) beschränkt wird.In other words, it is preferred if the performance ${\mathrm{P.}}_i^{*}$

each contributing component is limited within the response time T _R by its respective nominal power P _{net, i} (from above).

According to a preferred embodiment of the invention, non-critical loads are not covered _{during the call duration T D.}

In other words, only critical loads or the critical load are advantageously supplied further. As a result, there is advantageously basically more power available for supplying the critical load or the critical load.

In an advantageous development of the invention, at least one of the contributing components is an energy store, the calculation of the extremum taking place under the further secondary condition that the power P _ES provided by the energy store during the call period T _D satisfies the inequality η _ES P _ES T _D ≤ SOC · Cap _ES met, where η _ES denotes the discharge efficiency of the energy store, SOC the state of charge of the energy store before or after failure and Cap _ES the capacity of the energy store.

In other words, the energy store can only provide part of its nominal output (total output) (for a given point in time). This physical limit is integrated into the optimization by the secondary condition η _ES P _ES T _D SOC · Cap _ES , so that advantageously the optimization or the solution to the optimization (structure of the energy system) takes into account the physical boundary conditions of the energy store. The variables mentioned, in particular the state of charge SOC, can be time-dependent, that is, SOC = SOC (t), for example, so that they can also depend on the time of the failure.

The energy store advantageously provides flexibility within the energy system. Alternatively or in addition, the energy store can reduce peak loads when an energy management system is in place. The energy store is preferably an electrochemical energy store, in particular a battery store. One or more energy stores can be provided.

für alle beitragenden Komponenten i.According to a preferred embodiment of the invention, the calculation of the extremum _{takes place during the retrieval period T D under the secondary condition} ${\sum }_i{\mathrm{P.}}_i^{*}={\mathrm{P.}}_{\text{L.}}^{*}$

for all contributing components i.

This advantageously ensures that the critical load is covered by the contributing components during the failure, that is to say within the retrieval period T _D.

festgelegt, wobei P_L die Leistung der kritischen Last vor oder beim Ausfall bezeichnet, und F die Abhängigkeit der von der kritischen Last P_L abhängigen Komponenten und/oder Prozesse beschreibt.In an advantageous development of the invention, the critical load is carried out during the call period T _D ${\mathrm{P.}}_{\text{L.}}^{*}=\mathrm{F.}\left({\mathrm{P.}}_{\text{L.}}\right)$

defined, where P _L denotes the performance of the critical load before or in the event of failure, and F describes the dependence of the components and / or processes dependent on _{the critical load P L.}

wobei alternativ oder ergänzend nichtlineare Funktionen F vorgesehen sind.In other words, the function F models the condition that components and / or processes dependent on the critical load, that is to say critical processes associated with the critical load, are essentially not impaired, that is to say are not impaired in an impermissible manner. In particular, short-term and unforeseeable load peaks must also be covered. For example, in order to maintain a critical process, a certain percentage α of the critical load present before the failure could additionally be made available by the components of the energy system. In other words, for example ${\mathrm{P.}}_{\text{L.}}^{*}=\mathrm{F.}\left({\mathrm{P.}}_{\text{L.}}\right)=\left(1+\alpha \right){\mathrm{P.}}_{\text{L.}},$

alternatively or additionally, non-linear functions F are provided.

According to an advantageous embodiment of the invention, an energy store, a combined heat and power plant and / or an emergency power system are used as contributing components.

The components mentioned can advantageously be operated dynamically with regard to the provision of power. In particular, the energy store and / or the emergency power system can react essentially immediately to a failure, so that the response time of the energy system is thereby advantageously reduced overall.

In a preferred development of the invention, the respective structure of the energy system is determined _{for a plurality of call periods T D.}

In other words, several structures of the energy system are ascertained or determined for several associated retrieval periods. As a result, the structure of the energy system can advantageously be adapted _{to the call duration T D.} The retrieval duration can depend on the location of the energy system, in particular on the region and / or country in which the energy system is installed or is to be installed. The retrieval duration can therefore be significantly different for different locations or intended locations of the energy system. If the structure is determined as a function of the call duration, the most optimal structure of the energy system can be determined for the location or region. In other words, the location of the energy system is thereby advantageously also taken into account. Particularly preferably, T _{D is determined} for from local availability statistics of a local power network that is superordinate with respect to the energy system, and the structure of the energy system is determined _{for this determined call duration T D.} The energy system is connected to the aforementioned power grid.

According to a preferred embodiment of the invention, the respective value of the objective function and a respective value of a failure function are determined for the several specific structures, the failure function quantifying _{the failure risk of the critical load as a function of the call duration T D} , and a structure being determined from the specific structures which has the smallest value of the sum formed from the objective function and failure function.

The value of the objective function (extremum) characterizes the optimal structure of the energy system. In other words, the value of the objective function, that is, its extreme, is determined as a function of the call duration. The objective function typically characterizes a variable that should be minimized as much as possible, for example the carbon dioxide emissions of the energy system, its primary energy use and / or its costs (operating costs and investment costs). The objective function can, however, be advantageously expanded to determine the best possible structure with regard to a failure and the creation of resilience, since this typically assumes that the energy system is operated without such a failure, that is, from the best possible operation. However, a failure is associated with a certain risk of failure, which is described by the failure function. The failure function is to be added to the original target function, so that a new failure-taking into account target function results depending on the call duration. The optimal structure now results from the minimum of the new objective function mentioned. In other words, the optimal structure is the solution with the lowest value of the sum formed from the objective function, for example the lowest total of the costs (English: Total Expenditure; Totex), and the lowest default risk, for example a financial default risk.

• 1 ein Energiesystem gemäß einer Ausgestaltung der vorliegenden Erfindung;
• 2 ein erstes Diagramm; und
• 3 ein zweites Diagramm.

Further advantages, features and details of the invention emerge from the exemplary embodiments described below and with reference to the drawings. The following are shown schematically:

• 1 a power system according to an embodiment of the present invention;
• 2 a first diagram; and
• 3 a second diagram.

Identical, equivalent or identically acting elements can be provided with the same reference symbols in one of the figures or in the figures.

The 1 shows an energy system 1 according to an embodiment of the present invention. Here, the configuration is described below using an electrical supply system at a node. As an alternative or in addition, further energy-related nodes or networks and / or supply networks, for example with regard to heat, cold and / or chemical substances, for example gas, can be provided.

The energy system 1 comprises several energy-related components 21 , ..., 23, in the present case an energy store 21 , for example a battery storage system, a combined heat and power plant (CHP plant) 22nd , for example a block-type thermal power station and an emergency power system 23 , for example a diesel generator. Furthermore, the energy system includes 1 a control unit 20th .

The energy system 1 is on a regarding the energy system 1 external power grid 3 connected.

Furthermore, the energy system includes 1 a first burden 41 and a second load 42 . Alternatively or in addition, there are also external loads caused by the energy system 1 be supplied, conceivable.

Here is the first load 41 a non-critical load, which means that this is not mandatory in the event of a power grid failure 1 must continue to be covered. The second burden 42 is in contrast to the first load 41 a critical load that occurs in the event of a power grid failure 3 must continue to be covered at least in part. In principle, all loads can be categorized as non-critical load or critical load, whereby a load - depending on the time and / or type of failure - can be a non-critical or a critical load.

The power engineering components 21 , ..., 23 , the control unit 20th as well as the critical load 42 form within the energy system 1 a protected system 2 out. This protected system must be maintained during a power outage 3 Supply yourself with power / energy and certain loads, in this case the critical load 42 , maintained. The first burden 41 however, as a non-critical load, it is not part of the protected system 2 , this means that it will not continue to be supplied in the event of a failure. If the power grid fails 3 , so forms the protected system 2 in this sense an island network.

In the event of a power grid failure 3 must be the critical load for a retrieval period 42 continue to be covered. Here, the retrieval duration of a typical failure duration of the power grid 3 correspond and / or at least as long as the duration of the failure of the power grid 3 be. The power engineering components 21 , ..., 23 in the present exemplary embodiment all contribute to covering the critical load 42 at. They are thus contributing components.

Typically the energy system can 1 not immediately on a failure of the power grid 3 react. The energy system 1 requires a certain response time in order to evaluate the performances of the respective contributing components 21 , ..., 23 set to the required new operating state. For example, the CHP plant must / must 22nd and / or the emergency power system 23 be booted up. The response time of the energy system 1 is then determined, for example, by the longest component-specific response time. According to the present invention, the response time in controlling (the concept of controlling includes the concept of regulating) the power system becomes 1 by the control unit 20th considered. This is done by the fact that the time change in the performance of the respective contributing component 21 , ..., 23 is limited by P _{net, i} / T _{net, i} (in the linear case), where P _net, i denotes the respective nominal power and T _net, i denotes the start-up time of the respective component i. The mentioned restriction is used as a secondary condition in an optimization process, which is used to determine the most optimal structure of the energy system 1 or the optimal operation of the energy system 1 serves, taken into account. During operation, the optimization is carried out by the control unit 20th , for example as part of an energy management system. In this sense, the control unit forms 20th a model-predictive control or this is designed for a model-predictive control.

The 2 shows a first diagram.

On the abscissa 100 In the first diagram, the time after a failure (marked with an asterisk) is plotted in any units. Negative values (crossing point of the abscissa 100 and ordinate 101 ) thus correspond to times before the failure.

On the ordinate 101 The first diagram shows the performance of the respective component in any units. Generation / provision is provided with a positive value and consumption / load with a negative value.

Before the failure, the loads 204 , 205 through the services 202 , 203 covered. The performance 202 is provided by a CHP plant. The performance 203 is provided by a power grid. If the power grid fails (power 203 drops to zero), the critical load must 205 be covered by contributing components of the energy system. In the present embodiment, the critical load 204 after the failure by the CHP plant as well as a power provided by an energy store 201 covered. The non-critical load (power 205 ) is no longer supplied.

The change in the operating state of the contributing components, that is to say in the present case of the energy store and the CHP system, takes place within the response time T _R. The energy storage and the CHP system cannot contribute the ultimately required output within the response time, but only part of their nominal output. According to the present invention, this is taken into account by the secondary conditions which limit the change in the power over time from above. After the response time T _R and within the call duration T _D , the critical load is covered with constant power. This is symbolized by the straight line within the response time in the first diagram.

Is the failure of the power grid 3 remedied, i.e. after the call duration, a comparable adjustment of the operating points can take place, in which case the non-critical load - if still present - is covered again (not shown in the first diagram).

The 3 shows a second diagram, which illustrates an optimal solution, that is, an optimal structure of an energy system, taking into account a failure function.

On the abscissa 100 of the diagram, the call duration T _{D is} plotted in hours. On the ordinate 101 the associated value of the sum of the target function and failure function is plotted.

The diagram is a bar diagram, with the striped bars corresponding to the value of the objective function and the unstriped bars corresponding to the value of the failure function. The sum of the two values thus corresponds to the sum of the bars mentioned.

The existence of an optimal structure with the lowest possible sum of objective function and failure function can be understood based on two extremes of the retrieval duration.

If the call duration has the value zero, there are no additional components or redundancies to create a resilience of the energy system against failure. The value of the objective function is therefore minimal in this regard. However, there is also a high risk of failure, since the energy system has no guarantees whatsoever with regard to failure. The default risk is quantified in this regard by the value of the default function. In other words, the value of the failure function is a maximum for this. As a result, there is typically no minimum of the total (sum of the two bars in the diagram) for this retrieval period.

For a call duration that tends towards infinity, that is, for the longest possible call duration, many additional components must ensure the resilience of the energy system over such a long period of time. For example, the energy system must have a plurality of energy stores, in particular electrochemical stores. As a result, the risk of failure is minimal, but the value of the objective function is maximal. This also does not correspond to a structure of the energy system that is as optimal as possible.

It is therefore necessary to find a compromise between the addition or the provision of components and the risk of failure. In other words, it is advantageous to determine the minimum of the sum of the target function and failure function as a function of the call duration. This minimum corresponds to a structure that is as optimal as possible with a certain call duration and the best possible efficiency. The specified minimum must be arranged between the extremes described above and is indicated in the present case by the arrow 242. The method described can therefore be used to determine the best possible solution, that is to say the best possible structure of the energy system.

Although the invention has been illustrated and described in more detail by the preferred exemplary embodiments, the invention is not restricted by the disclosed examples or other variations can be derived from them by the person skilled in the art without departing from the scope of protection of the invention.

List of reference symbols

1

Energy system

2

critical system

3

power grid

20th

Control unit

21

Energy storage

22nd

Combined heat and power plant

23

Emergency power system

41

not critical load

42

critical load

100

abscissa

101

ordinate

201

Performance energy storage

202

CHP plant power

203

Power grid

204

Performance critical load

205

Performance not critical load

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 3561743 A1 [0005]
• WO 2019/110220 A1 [0015]

Claims (15)

Computer-aided method for the numerical determination of the structure of an energy system (1) that is resilient to the failure of one or more of its components (21, ..., 23), the energy system (1) being described by a target function provided for optimization, so that a Calculating an extreme of the objective function, the structure of the energy system (1) is determined, characterized in that the extreme is calculated under the secondary condition that a critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

(42) is further covered by one or more contributing components i (21, ..., 23) of the energy system (1) for a call duration T _{D in} such a way that the critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

(42) dependent components and / or processes are not significantly impaired, with the change in performance over time ${\mathrm{P.}}_i^{*}$

of each contributing component (21, ..., 23) within a response time T _{R of} the energy system (1) is limited by the nominal power P _{net, i of} the respective component (21, ..., 23) weighted with the start-up time T _{net, i} becomes. Procedure according to Claim 1 , characterized in that the change in performance over time ${\mathrm{P.}}_i^{*}$

of each contributing component (21, ..., 23) is bounded by P _{net, i} / T _{net, i} . Procedure according to Claim 1 or 2 , characterized in that the performance ${\mathrm{P.}}_i^{*}$

of each contributing component (21, ..., 23) within the response time T _{R of} the energy system (1) is _{limited by P i} + P _{net, i} T _R / T _{net, i} , where P _{i is} the power of the respective component (21 , ..., 23) before or during failure. Method according to one of the preceding claims, characterized in that the power ${\mathrm{P.}}_i^{*}$

each contributing component (21, ..., 23) is limited _{within the response time T R} by their respective nominal power P _{net, i.} Method according to one of the preceding claims, characterized in that non-critical loads (41) are not covered _{during the call period T D.} Method according to one of the preceding claims, characterized in that at least one of the contributing components (21, ..., 23) is an energy store (21), and that the calculation of the extremum takes place under the further secondary condition that the energy stored by the energy store ( 21) provided power P _ES during the call duration T _D satisfies the inequality η _ES P _ES T _D ≤ SOC Cap _ES , where η _{ES is} the discharge efficiency of the energy store (21), SOC is the state of charge of the energy store (21) before or during failure and Cap _ES denotes the capacity of the energy store (21). A method according to any of the preceding claims, characterized in that, during the polling period T _D calculating the extremum under the constraint ${\sum }_i{\mathrm{P.}}_i^{*}={\mathrm{P.}}_{\text{L.}}^{*}$

for all contributing components i (21, ..., 23). The method according to any one of the preceding claims, characterized in that the critical load during the call duration T _D by ${\mathrm{P.}}_{\text{L.}}^{*}=\mathrm{F.}\left({\mathrm{P.}}_{\text{L.}}\right)$

is established, where P _L denotes the performance of the critical load (42) before or in the event of failure, and F describes the dependency of the components and / or processes dependent on _{the critical load P L (42).} Method according to one of the preceding claims, characterized in that an energy store (21), a combined heat and power plant (22) and / or an emergency power system (23) are used as the contributing components (21, 22). Method according to one of the preceding claims, characterized in that the respective structure of the energy system (1) is determined _{for several retrieval periods T D.} Procedure according to Claim 10 , characterized in that the respective value of the objective function and a respective value of a failure function are determined for the plurality of specific structures, the failure function quantifying the failure risk of the critical load (42) as a _{function of the call duration T D, and a structure from the specific structures} is determined which has the smallest value of the sum formed from the objective function and failure function. Energy management system, comprising a control unit (20) for controlling a plurality of components (21, ..., 23) of an energy system (1), the control of the components (21, ..., 23) being based on a target function provided for optimization, so that control values for controlling the components (21, ..., 23) are determined by calculating an extremum of the objective function, characterized in that the control unit (20) is designed such that the extremum is calculated under the secondary condition that a critical burden ${\mathrm{P.}}_{\text{L.}}^{*}$

(42) by one or more contributing components i (21, ..., 23) of the energy system (1) for a call duration T _{D in this} way that is covered by the critical load ${\mathrm{P.}}_{\text{L.}}^{*}$

(42) dependent components and / or processes are not significantly impaired, with the change in performance over time ${\mathrm{P.}}_i^{*}$

of each contributing component (21, ..., 23) within a response time T _{R of} the energy system (1) is limited by the nominal power P _{net, i of} the respective component (21, ..., 23) weighted with the start-up time T _{net, i} becomes. Energy management system according to Claim 12 , characterized in that it has a data interface that enables data exchange between the energy management system and a local energy market, a cloud server and / or a decentralized data center. Energy system (1) with several components (21, ..., 23), characterized in that the energy system (1) is an energy management system according to Claim 12 or 13th includes. Energy system (1) according to Claim 14 , characterized in that the call duration T _{D of} the associated energy management system is determined as a function of the location of the energy system (1).

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