Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
  • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
  • H02J3/241—The oscillation concerning frequency
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
  • H02J3/28—Arrangements for balancing of the load in a network by storage of energy

Definitions

• a method for providing control power for stabilizing an AC power network comprising an energy storage
• the present invention relates to a method for providing control power for stabilizing an AC network, comprising an energy store, and a device for carrying out such a method.
• Electricity grids are used to distribute electricity from many energy generators in large areas to many users and to supply households and industry with energy. Energy producers, usually in the form of power plants, provide the required energy. As a rule, power generation is planned and provided based on the forecasted consumption.
• Both the generation and the consumption of energy can lead to unplanned fluctuations. These can arise on the energy producer side, for example, in that a power plant or part of the power grid fails or, for example, in the case of renewable energies such as wind, that the energy production is higher or lower than predicted. Consumers may also experience unexpectedly high or low consumption. For example, the failure of a portion of the grid, which cuts off some consumers from the power supply, can lead to a sudden reduction in power consumption. This generally results in power grid fluctuations due to unplanned variations in power generation and / or consumption. For example, the desired AC frequency in Europe is 50.00 Hz. A reduction in consumption over the plan results in an increase in the frequency of on-board power supplied by the generators, as well as an increase in electricity production over the plan on scheduled consumption.
• secondary control power SRL
• minute reserve power MRL
• SRL minute reserve power
• the required balancing power sources generally need to be operated at part load to accommodate or release additional energy as needed.
• a power plant it would need to be run at partial load to provide additional positive control power when needed.
• a consumer would have to be driven at partial load in order to be able to increase the load when additional negative control power is required.
• hydropump storage systems are also often referred to as the currently most economical technology for storing and removing preferably renewable energies in order to be able to better match the energy supply and demand in terms of time.
• the potential for expanding storage capacity - especially in Norway - is a matter of controversy, as significant capacity in power lines needs to be approved and installed for use. Consequently, the use for the energy management of load management is in competition with the provision of control power.
• DE 10 2008 046 747 A1 also proposes operating an energy store in an island power grid in such a way that the energy store is used to compensate for consumption peaks and consumption minima.
• the disadvantage hereof is that the energy stores do not have the necessary capacity to compensate for a longer disturbance or a plurality of disturbances rectified with respect to the frequency deviation one after the other.
• Accumulators and other energy stores can absorb or release energy very quickly, making them basically suitable for providing PRL.
• a disadvantage is that very large capacities of the batteries must be provided in order to deliver the control power over a longer period or repeatedly.
• very large capacity batteries are also very expensive. Due to the losses during storage and withdrawal of energy takes place at statistically symmetrical deviation of the mains frequencies from the setpoint by the operation sooner or later a discharge of the energy storage, such as a battery. It is therefore necessary to recharge the energy storage more or less regularly targeted. It may be necessary to pay for this charging current separately.
• the process should be as simple and inexpensive as possible.
• the installations with which the procedure can be carried out should be associated with the least possible investment in terms of the provision of control power.
• Another object of the invention is to be seen in that the capacity of the energy storage device should be as low as possible in order to provide the required control power.
• the energy producers and energy consumers should have the most efficient possible energy yield as control power suppliers.
• the inventive method should also be able to provide the necessary control power as needed as quickly as possible.
• the subject of the present invention is accordingly a method for the provision of control power for the stabilization of an alternating current network, comprising an energy store, which can absorb and deliver electrical energy, which is characterized in that the energy storage is used together with a differential power provider to provide the control power, wherein the AC network operates at a default frequency and a frequency band is defined by the default frequency and the control power that is to be provided at a frequency deviation within the frequency band, provided by the energy storage to more than 50%, based on the total control power to be provided.
• the inventive method succeeds in an unpredictable manner, a method for providing control power to stabilize a To provide AC power network, which is free from the disadvantages of conventional methods.
• the method can be carried out in a very simple and cost-effective manner since the storage capacity required for full availability can be provided more cost-effectively or the number of charging and discharging operations required for adjusting the state of charge of the energy store with external energy sources or sinks is reduced can be.
• the energy storage can draw power through the power network through energy trading. This service must be purchased and recalled at a specific time, otherwise the system will malfunction. Actual grid frequency is insignificant for this process as it does not affect the frequency of the grid in the case of a planned, simultaneous feed-in and take-out of a power. Rather, it is important that the feed-in and the removal of this power take place as synchronously as possible.
• the operational life of the memory can be increased, this being an important consideration, in particular for accumulators, which can be surprisingly improved by the present invention.
• the energy generators and / or energy consumers preferably used as differential power suppliers have a very efficient energy yield as control power suppliers. Furthermore, the present invention allows control power to be provided with a high efficiency of the components used.
• the inventors were able to surprisingly determine by a Fourier analysis of the state of charge of energy stores that in addition to state of charge fluctuations with a very short period and those with significantly longer period are available. These lead to fluctuations with much less Number of cycles. Due to the high efficiency, these charge fluctuations can be at least partially compensated by a differential-power driver. With this configuration, the differential power provider can be operated at a higher efficiency, since part of the power can be provided by the energy storage. Furthermore, the Differenz sosbnnger closer, preferably operated at optimum efficiency.
• the inventive method is also suitable to provide the necessary control power very quickly.
• the Differenzertragerbnnger in particular the power generator and / or energy consumers, regardless of the height and direction of the deviation of the grid frequency selectively provide a sufficient amount of positive or negative control power.
• the present method serves to provide control power for stabilizing an AC network.
• the control energy or control power is delivered to the power grid (positive control energy or positive control power) or taken from the mains (negative control energy or negative control power).
• Positive control power can be supplied by energy supply, such as energy input of an energy storage or by connecting a power plant, or by throttling a consumer in the network.
• Negative control power may be supplied to the grid by absorbing energy from an energy store, throttling an energy source, such as a power plant, or by connecting a load to the grid. Further important information on this can be found in the prior art, reference being made in particular to the documents discussed in the introduction. In this context, it should be noted that the terms control power and control power have similar meaning for purposes of this invention.
• control power for a given nominal power is provided by the provider to the network operator.
• the nominal power is to be understood as meaning the power with which the control power source, which is operated by a method according to the invention, is at least prequalified.
• the prequalification performance may be higher than the nominal power provided to the network operator at maximum.
• This nominal power can also be referred to as contracted maximum power, as this power is provided to the grid at maximum.
• the method according to the invention serves to stabilize an AC network.
• AC grids are characterized by a change in the polarity of the electrical current, with positive and negative instantaneous values complementing each other so that the current is zero on average over time. These networks are generally used for the transmission of electrical energy.
• the AC grids are operated at a default frequency currently in Europe, especially in Germany, at 50,000 Hz. In North America, however, the default frequency is 60,000 Hz.
• this default frequency is not fixed, but is slightly varied in order to adapt the so-called network time, which inter alia serves as a clock timer, to the coordinated world time. Consequently, such AC mains operate at a variable default frequency.
• the default frequency is lowered or increased by 10 mHz depending on the deviation of the mains time, so that the default frequency is currently 49.990 Hz, 50.000 Hz or 50.010 Hz. This adjustment is made centrally by the grid operator and taken into account when using secondary control power (SRL) and minute reserve power (MRL).
• SRL secondary control power
• MDL minute reserve power
• the default frequency for example, to adapt to world time, can be easily varied. This can be done for example by an active transmission of the corresponding data by the network operator.
• Control power is currently provided in Europe from a certain maximum deviation of the mains frequency (actual AC frequency) from the default frequency (target AC frequency), with a deviation of +/- 200 mHz, in full. In the area between the dead band and the maximum deviation, only a certain proportion of the maximum available control power in Europe is to be fed into the power grid.
• the type of control power delivery is not critical to the present invention. According to the regulations currently in force in Europe, the amount of the service to be provided is to be increased largely linearly with increasing frequency deviation from the default frequency. Thus, with a deviation of 100 mHz, a control power is usually provided which amounts to 50% of the maximum power. This maximum power is provided at a deviation of 200 mHz and corresponds to the previously defined rated power or contracted maximum power, for which the energy storage is at least prequalified. With a deviation of 50 mHz, accordingly, 25% of the rated power is provided.
• the method can contribute to the stabilization of the network even with a relatively small capacity of the energy store, since a provision of control power can also take place if the network frequency is outside the deadband for a very long period, within which no regulation is necessary.
• an energy store is used to carry out the method, which can absorb and deliver electrical energy.
• the type of energy storage is not essential to the practice of the present invention.
• According to a preferred aspect of the present invention can be used as an energy storage system with an electrochemical element. It can preferably be provided that an energy storage system based on hydrogen, a redox flow element and / or a galvanic element is used as the electrochemical element, preferably an accumulator.
• the batteries include in particular lead-acid batteries, sodium-nickel-chloride accumulators, sodium-sulfur accumulators, nickel-iron accumulators, nickel-cadmium accumulators, nickel-metal hydride accumulators, nickel-hydrogen accumulators, nickel-zinc accumulators, sodium Ion accumulators, potassium ion accumulators and lithium ion accumulators.
• accumulators are preferred, which have a high efficiency and a high operational and calendar life.
• the preferred accumulators accordingly include, in particular, lithium ion accumulators (for example lithium polymer accumulators, lithium titanate accumulators, lithium manganese accumulators, lithium iron phosphate accumulators, lithium iron manganese phosphate Accumulators, lithium-iron-yttrium-phosphate accumulators) and developments thereof, such as lithium-air accumulators, lithium-sulfur accumulators and tin-sulfur lithium-ion accumulators.
• lithium ion accumulators for example lithium polymer accumulators, lithium titanate accumulators, lithium manganese accumulators, lithium iron phosphate accumulators, lithium iron manganese phosphate Accumulators, lithium-iron-yttrium-phosphate accumulators
• developments thereof such as lithium-air accumulators, lithium-sulfur accumulators and tin-sulfur lithium-ion accumulators.
• lithium-ion secondary batteries are particularly suitable for methods according to the invention because of their rapid reaction time, that is, both in terms of the response time and the rate at which the power can be increased or reduced.
• the efficiency is good especially for lithium-ion batteries.
• preferred accumulators exhibit a high power to capacity ratio, this characteristic being known as the C rate.
• energy stores which are not based on electrochemical elements can be used to carry out the present invention.
• an energy storage device which is not based on an electrochemical element, a flywheel, a heat storage, a natural gas generator with gas power plant, a pumped storage power plant, a compressed air storage power plant and / or a superconducting magnetic energy storage is used, or combinations ("pools"). ) of memories or memories with conventional control power sources or of memories with consumers and / or power generators.
• a heat storage device operated as an energy store must be operated together with a device for producing electricity from the stored heat energy.
• energy stores can be used which comprise at least two different energy stores.
• the energy storage can differ, for example, by the efficiency.
• the efficiency of an energy storage device defines the ratio between charge amount and discharge amount. At 100% efficiency, all the charged energy would be available. Since when charging a rechargeable battery part of the charged current can flow in side reactions or is lost by self-discharge, is no longer the entire charged charge available for the discharge. In general, the efficiency decreases both by fast charging and by rapid discharge, since the losses increase in the internal resistance. Similar statements also apply to the other energy storage types set out above.
• the losses include, but are not limited to, thermal losses, such as the internal resistance of an electrochemical element or mechanical friction of an engine, incomplete chemical processes, or self-discharge of an electrochemical element.
• Secondary components which are relevant to the entire storage system and require power in order to enable the storage of electrical energy are to be considered in the efficiency determination.
• these include pumps, compressors or cooling units, as well as the energy that is necessary for the controller and / or for the energy management system.
• the efficiency data In order to compare the efficiency of one battery with that of another energy storage (e.g., in the form of hydrogen), the efficiency data generally refers to energy efficiency, unless otherwise specified.
• n Hw, h Ela
• E E i a represents the extractable energy and E La d represents the energy supplied.
• the rechargeable battery with a rated current of 0.2 C at a temperature of 25 ° is used to determine the efficiency of the rechargeable battery C charged and directly discharged after charging with a related to the nominal capacity of the accumulator current of 0.2 C at 25 ° C. With respect to the rated capacity of the accumulator current of 0.2 C, the accumulator is charged or discharged within 5 hours.
• the nominal capacity can be determined according to the parameters given in DIN 40 729 for different battery types. In many cases the nominal capacity is given for commercial accumulators.
• an energy of at least 4 kWh can be stored in the energy store, preferably of at least 10 kWh, in particular at least 20 kWh, particularly preferably at least 50 kWh, very particularly preferably at least 250 kWh.
• the energy store may have a capacity of at least 5 Ah, preferably at least 10 Ah, particularly preferably at least 50 Ah.
• this memory can advantageously be operated with a voltage of at least 1 V, preferably at least 10 V and particularly preferably at least 100 V.
• the capacity can be adjusted to the rated capacity and the predefined set period. Larger capacities are needed for higher power ratings and longer periods of time.
• the ratio of the storage capacities of the at least two energy storage devices can be adapted to their performance, taking into account the price differences. With very large differences in price and performance, a relatively large difference in capacity will generally make sense.
• Differential power providers in this context are devices that can be different from at least one of the energy storage devices also used and can provide the control power.
• the differential power provider can increase or decrease the power consumption and / or output within 30 s by at least 75%, preferably by at least 80% and particularly preferably by at least 90% of the maximum control power to be provided.
• the present invention can be used as a differential power also an energy storage with a low efficiency, so that the present invention is performed with two energy storage, which differ in efficiency, the energy storage is used with the lower efficiency as a differential power provider.
• the invention can be embodied such that an energy storage system with an electrochemical element and, as a differential power supply, an energy storage system which is not based on an electrochemical element is used as the energy store.
• a differential power provider can be used, which does not represent an energy storage.
• energy producers and / or energy consumers belong to the differential power providers, which do not represent an energy store.
• a power plant is used as the energy generator, preferably a coal-fired power station, a gas-fired power plant or a hydroelectric power plant and / or an industrial plant, for example a plant for producing a substance, in particular an electrolysis plant or a metal plant.
• Plant preferably an aluminum plant or a steel plant.
• those additional differential power providers are preferred, which can also be used in connection with renewable energies, such as electrolysis works or metal works whose production can be reduced to provide positive control power.
• the nominal power of the energy storage can be surprisingly increased without the capacity of the same must be increased.
• the energy storage can be provided by the additional differential power provider even at a high network load in a very short time if needed, without a lengthy energy trading is necessary.
• a relatively high capacity can be delivered at a relatively low capacity of the memory, which can generally be delivered only for a short period of time.
• the additional differential power provider Due to the direct access to the additional differential power provider, the latter can provide or substitute the control power actually to be provided by the energy store after a short time.
• the energy storage contributes to the quality of the control power delivery, as a result, a fast response time is achieved.
• the additional differential power supplier contributes above all to the quantity, since this can deliver control power at a relatively low cost over a design-related, significantly longer time.
• the use of at least one energy generator and / or energy consumer can surprisingly increase the efficiency of this differential power system. Erbringer be increased, so this embodiment is preferred.
• preferred differential power providers do not have their maximum efficiency at a short-term maximum power, but slightly lower.
• one or more differential power providers can be used to carry out the present method, whereby one or more energy producers, one or more energy consumers and combinations of energy producers with energy consumers can be used.
• only one or more energy generators which provide both positive and negative control power can be used as the differential power provider. This embodiment allows easy control and relies on proven techniques.
• only one or more energy consumers that provide both positive and negative control power can be used as the differential power provider.
• This embodiment is also characterized by a simple control and can furthermore be used very well in combination with renewable energies. Furthermore, this can reduce the carbon dioxide emissions.
• as a differential power generator at least one power generator and at least one power consumer may be operated in common, wherein the power that the power consumer draws from the power grid is throttled to provide a positive control power and the power that the power generator supplies to the power grid , is throttled to provide a negative control power.
• This embodiment requires a somewhat more complex control than the first two Embodiments, however, this embodiment is particularly useful with power generators and / or energy consumers, where the maximum efficiency is close to a short-term maximum power.
• the respective device can be operated independently of the power at which the optimum efficiency is given. For example, if the optimum efficiency at a power generator is 100% of the power, this design can provide positive control power, for example, by throttling the power consumer, while operating the power generator at optimum efficiency.
• the energy generator and / or the energy consumer has or have a power of at least 10 kW individually or in the pool, preferably at least 100 kW, more preferably at least 1 MW and most preferably at least 10 MW.
• the ratio of rated power of the energy store to maximum power of the additional differential power provider may preferably be in the range of 1: 10,000 to 100: 1, more preferably in the range of 1: 1000 to 40: 1.
• the rated power of the energy storage refers to the total power, which have all the elements of the energy storage, and energy storage, which do not represent an electrochemical element, are taken into account.
• the devices of a device for carrying out the method according to the invention in particular the energy store and the differential power provider set out above, may be arranged in spatial proximity or placed over a greater distance from one another. It is essential that both devices are controlled jointly by a central control unit, which can be realized in particular by a common management system. In this case, the individual elements of the device can each have a subsystem that performs partial control tasks.
• the AC grid operates at a default frequency, as previously stated.
• a frequency band is defined, wherein the control power to be provided at a frequency deviation within the frequency band to more than 50%, preferably more than 80%, and more preferably more than 90%, based on the overall control power to be provided by the energy storage is provided.
• the differential power amplifier provides the remaining part of the control power, preferably at most 40%, preferably at most 20% and particularly preferably at most 10%, based on the total control power to be provided at a frequency deviation within the frequency band. It should be noted, however, that the Differenziere can be used to adjust the state of charge of the energy storage.
• control power to be provided at a frequency deviation outside the frequency band to more than 50%, preferably more than 80% and more preferably more than 90%, based on the frequency deviation outside the frequency band to be provided by the differential service provider.
• This embodiment is particularly useful for Differenz insgebnnger in which a strong decrease in efficiency is given a provision of control power. This is applicable, for example, if only one energy consumer or one energy generator is used as Differenz insbnnger, so that this system must be operated at a power below the optimum efficiency.
• the energy storage can be spared and optionally regenerated.
• the energy storage provides the remaining part of the control power, preferably at most 40%, preferably at most 20% and more preferably at most 10%, which is to be provided at a frequency deviation outside the frequency band, based on the to be provided for the frequency deviation outside the frequency band control power or the total standard service to be provided.
• the frequency band defined by the default frequency may differ from the frequency range which serves to describe the provision of control power according to the standard specifications.
• deadband is used hereinafter to describe the provision of a control power according to the standard specifications
• frequency band describes a range of frequencies, which serves to determine whether there is a deviation between network frequency and default frequency, which leads to the use of the differential power provider, as described above and below.
• the frequency band defined by the default frequency may correspond to the deadband, alternatively it may be smaller than the deadband, and according to a preferred alternative, the deadband may be smaller than the frequency band.
• a unit with a high measuring accuracy can be used to determine the network frequency, in particular the average network frequency.
• a particularly preferred embodiment of the invention may provide that the frequency deviation is measured with an inaccuracy of a maximum of ⁇ 8 mHz, more preferably of a maximum of ⁇ 4 mHz, most preferably of a maximum of ⁇ 2 mHz, even more preferably of a maximum of ⁇ 1 mHz.
• the bandwidth of the frequency band and / or the position of the frequency band defined by the default frequency may be selected according to the requirements.
• the frequency band may have a fixed width and a fixed position.
• the frequency band can be defined symmetrically around the default frequency.
• the required control can be made relatively simple. Surprising advantages can be achieved in that the bandwidth of the frequency band and / or the position of the frequency band, which is defined by the default frequency, is selected as a function of the state of charge of the energy store.
• the frequency band which is defined by the predefined frequency, has a bandwidth in the range from 20 to 400 mHz, preferably 80 to 300 mHz and particularly preferably 100 to 150 mHz.
• these values represent the maximum values that are set at an optimum state of charge.
• the frequency band can be selected narrower.
• the position of the frequency band which is defined by the default frequency, adapted to the circumstances. A frequency band symmetrically defined around the default frequency can be implemented particularly easily.
• the position of the frequency band can be shifted relative to the default frequency, that the input and output losses described in the introductory part of this document are compensated on average. Accordingly, more negative than positive control power is provided on average by the energy storage, this shift is dependent on the efficiency and / or a possible self-discharge of the energy storage. The optimum values for this can easily be obtained by an optimization. Surprising advantages can furthermore be achieved by making the position of the frequency band dependent on the state of charge of the energy store. At a high state of charge of the energy storage, the frequency band can be shifted so that more positive control power is provided, whereas at a low state of charge of the energy storage increasingly negative balancing power is provided.
• the desired state of charge of the energy store may preferably be in the range from 20 to 80% of the capacity, more preferably in the range from 40 to 60%. Compliance with and / or the return to these state of charge areas can be achieved, for example, by using the mode of operation on which this invention is based and / or via the energy trade, which was explained in more detail above, via the power grid.
• the state of charge corresponds in particular in the case of accumulators as an energy store the state of charge (English: “State-of-Charge", SoC) or the energy content (English: “State-of-Energie", SoE).
• the state of charge via the energy exchange, the estimated during unloading and charging processes by appropriate methods or immediately can be determined.
• the necessary measuring devices are commercially available, the state of charge can be measured continuously or at intervals.
• the desired state of charge of the energy store may depend on forecast data.
• consumption data can be used to determine the optimum state of charge, which depends on the time of day, the day of the week and / or the season.
• the power of the energy store delivered to the power network or the power of the energy store received from the power grid is measured at several times, in particular continuously, and the state of charge of the energy store is calculated continuously at several times, preferably continuously.
• the provision of the control power within the frequency band defined by the predefined frequency takes place predominantly by the energy store, whereas at a network frequency outside the frequency band preferably at least a part of the control power is provided by the differential power carrier.
• the connection of the Differenz soserbringers this can be done in accordance with the inertia of the differential power provider, so that for very short-term deviations, the control power is provided exclusively by the energy storage.
• the control power can also be supplied completely by the Differenz amongserbnnger.
• the transitions can be selected according to the inertia of the differential power supply, so that relatively sluggish systems can be used in a device for carrying out the present invention.
• an excess power caused by the inertia of the differential power supply can be used to regenerate the energy store.
• the specified period depends on the circumstances of the device for carrying out the present method. These conditions include, for example, the inertia of the differential power provider, the performance and the capacity of the energy storage.
• the specified period of time can be, for example, in the range from 1 second to 8 hours, preferably 30 seconds to 1 hour, preferably 1 minute to 30 minutes and more preferably 2 minutes to 15 minutes.
• the specified period of time can also be made variable, this period can be selected, for example, the state of charge of the energy storage. The above values apply in the case of variable periods as the maximum value.
• a permanent frequency deviation outside the frequency band is given if, over the predetermined period of time set out above, the network frequency is at least 60%, preferably at least 80%, preferably at least 90%, especially preferably at least 95% and particularly preferably at least 99% on one side above or below the frequency band lies.
• a permanent frequency deviation outside the frequency band means that the frequency is outside the frequency band over the entire period.
• control power may be provided by the differential power provider after this specified period of time.
• the control power fully provided by the differential service provider.
• the energy storage in combination with the differential power provider provide control power. According to a preferred embodiment, in this case short-term fluctuations can be mitigated by the energy store, while the differential power provider provides a relatively constant control power.
• control power is to be provided by the differential power provider.
• Guiding averaging means that not all data points are used to calculate the mean, but only part of it.
• the moving average is calculated by taking into account the data determined over a period not exceeding three times, preferably not more than twice that of the previously defined period. In particular, it may also only be part of the defined period of time defined above.
• the time period over which the values for determining the average mean value are collected may be in the range from 30 seconds to 2 hours, preferably 1 minute to 1 hour and more preferably 2 minutes to 15 minutes.
• the mean values can be formed in a variety of ways, such as a simple shift, without weighting the data (simple moving average (SMA)).
• a weighted moving average (WMA) in which the younger data is preferably of a higher weight than the older one may be used to determine the variable frequency.
• WMA weighted moving average
• a simple weighting can be done or an exponential smoothing can be performed.
• the number of data points depends on the frequency of the frequency measurement, whereby the average values of the data can be used to reduce the memory space.
• within a period of 1 minute at least 10 data points are formed, which can be used to determine the mean value.
• the differential power provider does not record or emit energy for the provision of control power in the case of a short-term frequency deviation outside a frequency band which is defined by the predefined frequency.
• short-term frequency deviation outside a frequency band defined by the default frequency represents an antonym for a long-term frequency deviation outside a frequency band over a fixed period of time as defined above Frequency deviations, which are present with a high number of oscillations, preferably exclusively provided with the energy storage, while the differential power provider is used to provide control power for frequency deviations, which have a low oscillation number.
• Fourier analyzes may be used, the frequency bands in which the energy store is used preferably being chosen so that the differential control power provider is preferably not more than 10% of the time, more preferably no more than 5% of the time, and most preferably not more than 3% of the time Time, relative to the calendar year, is used.
• This embodiment is particularly suitable in connection with the manner of exploiting tolerances, which, for example, with regard to the amount of control power delivery, the time within which the control power is to be provided, and the frequency tolerances, are able to optimize the state of charge.
• more negative control power can be provided if the state of charge of the energy storage is very low due to a network frequency, which is on average over a longer period below the default frequency.
• tolerances for example the tolerances granted by the differential operator to the grid operator, with regard to the grid frequency, the amount of the regulating power depending on the frequency deviation, the insensitivity h in terms of the frequency change, and the period within which the control power is to be provided, be exploited to adapt the state of charge of the energy storage to the requirements.
• at least 105%, preferably at least 1 10% and particularly preferably at least 1 15% of this control power can be provided instead of the planned negative control power.
• the power to be provided by contract is provided as precisely as possible in this case.
• the energy intake can take place immediately in the case of a low charge state, while the energy is fed in at the latest possible time according to the regulations or with a rise which is as slow as possible according to the regulations.
• the frequency tolerance granted by the network operator can be used by carrying out a measurement with a higher accuracy, whereby the difference thus obtained is specifically used for the given inaccuracy of measurement in order to minimize the power in accordance with the regulations, ie in the given tolerance range to feed in the network or to record as much power as possible from the network.
• a high state of charge can be mirrored procedure. For example, a high energy output when providing a positive control power and a low power consumption when providing a negative control power is possible or realized.
• the tolerance with regard to the amount of the control power provided and the tolerance in determining the frequency deviation, etc., is to be understood by the network operator to be certain deviations between an ideal nominal power due to technical conditions, such as the measurement accuracy in determining the control power supplied or the grid frequency and the actual control power actually delivered.
• the tolerance may be granted by the network operator, but could also comply with a legal requirement.
• the supply of energy in the energy storage may be dependent on the time of day.
• a high stability of the network can be ensured even at a high load at certain times of the day.
• a regeneration of the energy storage the due to the deviation of the mains frequency from the default frequency over a longer period would be useful to be excluded.
• a plurality of energy stores are used in accordance with the present method.
• all or only a part of these energy stores can provide a control power adapted to the state of charge of the energy store, as has been explained above.
• the size of the energy storage within the pool can vary.
• the change from one parameter setting to another not synchronously, but deliberately offset in time to minimize any disturbances in the network or at least tolerable.
• the tolerances used in the various methods vary depending on the time of day, the day of the week or the season. For example, within a period of 5 minutes to 5 minutes after the hour change, tolerances may be more narrowly defined. This is due to the fact that often very rapid frequency changes take place here. It may be in the interest of transmission system operators that there are lower tolerances and thus the control energy supply is more secure in the sense of sharper.
• control power that on average more energy is absorbed from the network than is fed in by the energy store used in the present method. This can be done by providing very much negative control power in accordance with the regulations including the procedure outlined above, whereas according to the regulations including the procedure set out above, preferably only the at least guaranteed power is provided at positive control power.
• an average of at least 0.1% more energy is withdrawn from the network than is supplied, in particular at least 0.2%, preferably at least 0.5%, more preferably at least 1.0%, especially preferably 5%, these values being based on a Average measured over a period of at least 15 minutes, preferably at least 4 hours, more preferably at least 24 hours and especially preferably at least 7 days, and refer to the energy fed.
• the control power provision described above can be used selectively to extract a maximum of energy from the network, the maximum possible negative control power is provided, whereas only a minimum of positive control power is provided.
• the energy thus extracted from the network can be sold via the energy trade described above, preferably at times when the highest possible price is to be achieved.
• forecasts of the price development based on historical data can be used.
• the state of charge at the time of a planned sale of energy may preferably be at least 70%, more preferably at least 80%, and most preferably at least 90% of the storage capacity, the state of charge after sale being preferably at most 80%, in particular at most 70% and most preferably at most 60% of the storage capacity is.
• the supply of control power to the AC grid can be constant, via pulses or via ramps which are characterized by an increase in power supply over a defined period of time.
• An over Pulse (pulses) provided control power allows an improvement in the efficiency of the device and the method for providing control power, as this, the, in particular when using accumulators, necessary power electronics can be operated at a higher efficiency.
• a pulse is to be understood as a time-limited, jerky current, voltage or power curve, whereby these pulses can also be used as a repetitive series of pulses.
• the duty cycle according to DIN IEC 60469-1 can depend on the type of power electronics and the control power to be provided can be selected, wherein this is in the range of greater than zero to 1, preferably in the range of 0.1 to 0.9, particularly preferably in the range of 0.2 to 0.8.
• the power of the energy store is increased over a period of at least 0.5 s, preferably over a period of at least 2 s, particularly preferably over a period of time, depending on the level of the required power change at least 30 s.
• the method of the present invention may preferably be carried out with a device which comprises at least one energy store, at least one differential power provider and a controller for controlling or regulating the power of the energy stores and differential power providers, wherein the differential power providers are connected to a power supply that is provided by the device Energy can be fed into the power grid and removed from the power grid.
• the differential power generator is a controllable power plant with at least two steam turbines operating at a different pressure, with a control valve between the boiler and the high pressure turbine and a valve between the preheater and the medium and low pressure turbine.
• An adjustable block power plant with a block control may include an integrated condensate backup and a turbine control valve.
• the differential power generator is a combined heat and power plant (CHP plant) which has at least one heat storage.
• This combined heat and power plant may preferentially change the power delivered within 30 seconds of the control power requirements.
• CHP plants also utilize thermal energy, resulting in a relatively high overall efficiency of 80 to 90%.
• the systems can be designed and operated either by flow or heat. In current-controlled systems, moreover, the use of heat accumulators is expedient, as this allows the generation of electricity to be regulated independently of the needs of the heat consumer.
• the controller may be connected to a unit for determining the duration and a unit for determining a permanent frequency deviation.
• the device comprises a frequency meter for measuring the mains frequency of the power network and a data memory, wherein in the memory at least one limit value (eg default frequency ⁇ 10 mHz, default frequency ⁇ 200 mHz, etc.) of the network frequency is stored, the controller is designed to compare the mains frequency with the at least one limit value and, depending on the comparison, to control the power of the energy store and optionally the differential power provider, preferably the energy consumer and / or the energy generator.
• this control can also control the power of the at least two energy stores.
• this controller responds to a subsystem, in particular a management system, which the respective power of the at least two energy stores is regulated to the total power requested by the higher-level controller, optionally taking into account the preferred embodiments of the present method set out above.
• a control according to the invention is understood in the present case a simple control.
• each control comprises a control, as in a control, a control in dependence on a difference of an actual value to a desired value takes place.
• the controller is thus designed as a control, in particular with respect to the state of charge.
• the controller is a control system.
• the unit for determining a permanent frequency deviation may be configured as described above. Accordingly, this unit for determining a permanent frequency deviation may comprise, for example, a device for determining an average value. Furthermore, this unit for determining a permanent frequency deviation may comprise a memory in which the magnitude of a frequency deviation is recorded. Here, the absolute deviation can be recorded. In a further embodiment it can be stated whether this frequency deviation exceeds a previously defined size, for example a frequency band defined by the default frequency, or not. The unit for determining the time duration is used, in particular in combination with a unit for determining a permanent frequency deviation, to determine whether the differential power provider is used or not.
• this unit for determining the time duration can have a data memory in which the duration of the frequency deviation that can be determined by the unit for determining a permanent frequency deviation is recorded. Accordingly, a data exchange between the unit for determining the duration and the unit for determining a permanent frequency deviation can take place. In this case, both units can be combined in one device.
• the data is collected at a remote location and evaluated as set forth above, and the appropriate signal is appropriately transmitted to the memory (s) for control power provision.
• this can be done via the known methods of remote data transmission and communication.
• Figure 1 a schematic representation of a device according to the invention for
• Figure 2 a schematic representation of a preferred as
• FIG. 3 shows a flow chart for a method according to the invention.
• FIG. 1 shows a schematic structure of a preferred embodiment of a device 10 for a method according to the invention comprising a controller 1 1, an energy storage 12 and a differential power provider 13.
• the energy storage 12 may generally have a management system which controls the loading or unloading.
• This management system is generally connected to the controller 11.
• this management system can be spatially separated from the controller 1 1 or housed with this in a housing.
• lithium-ion batteries are particularly suitable, and these are quickly and frequently charged and discharged with little harmful effects on the battery, so that lithium-ion batteries according to the invention for all embodiments are particularly suitable and preferred.
• these can be easily accommodated in one or more 40-foot ISO containers.
• lead-acid batteries, redox-flow batteries and energy storage systems based on hydrogen can be used as energy storage.
• the device for carrying out the method according to the invention has at least one differential power generator 13, wherein this differs from the energy store 12.
• energy generators and / or energy consumers can be used as differential power provider 13, with a particularly preferred energy generator being, for example, a block power plant.
• the energy store 12 and the differential power generator 13 are connected to a power grid 16. Furthermore, in the present illustration, the differential power generator 13 is connected to the energy store 12, so that the power which can be provided by the differential power provider 13 can be fed directly into the power grid 16 or used for regeneration of the energy store 12.
• the controller 1 1 is connected to the energy storage 12 and the differential power provider 13.
• the controller 1 1 is connected to a unit for determining the time duration 14 and a unit for determining a permanent frequency deviation 15.
• these units can be accommodated spatially in a housing with the controller.
• the connection between the unit 14 for determining the duration 14 and the unit for determining a permanent frequency deviation 15 with the controller 1 1 allows communication of the determined data, which are processed in the control unit.
• FIG. 2 shows a schematic representation of a block power plant that can preferably be used as a differential power generator.
• the block power plant 20 has a block controller 22, via which the essential components of the block power plant 20 can be controlled.
• the control lines required for this purpose are shown by dashed lines in FIG.
• the block power plant 20 shown here comprises a boiler 24, which is supplied by a fresh air supply 26 and a coal mill 28 with fuel and oxygen, wherein also a gas-fired boiler alternatively can be used.
• the steam generated in the boiler 24 is passed to generate electricity in a high-pressure turbine 30, wherein in this line, a control valve 32 is arranged, via which the steam mass flow can be controlled. Subsequently, the steam is passed into a low pressure turbine 34, whereby two turbines (medium and low pressure turbine) can be switched in succession. The mechanical power is converted via a generator 36 into electricity. A brief increase in the electrical power is achieved by increasing the steam mass flow, which is released via the low-pressure turbine 34. For this purpose, a valve 38 between low-pressure turbine 34 and preheater 40 is fully or partially closed.
• FIG. 3 shows a flow chart for a preferred method according to the invention.
• an energy storage is used.
• step 1 the grid frequency of the power grid is measured.
• decision step 2 it is then checked whether the network frequency lies within or outside the frequency band which was previously determined.
• This frequency band can be identical to a deadband, which is predetermined by the network regulations or by the network operator. Furthermore, this frequency band may be larger or smaller than the deadband determined by the network operators or by the network regulations.
• a control power application is performed by an exclusive use of the energy storage, as shown in step 4.
• the grid frequency is outside the frequency band, it is checked in decision step 3 whether there is a permanent frequency deviation over a specified period of time.
• it can also be checked whether the use of the differential power provider is indicated. This can be given, for example, at a low state of charge of the energy storage. For a short-term deviation the grid frequency and a sufficient state of charge of the energy storage is, as stated above, according to step 4, only the energy storage used.
• the differential power provider will be used to provide control power, as set out in step 5.

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• 2012
  • 2012-12-21 DE DE102012113051.5A patent/DE102012113051A1/de not_active Withdrawn
• 2013
  • 2013-12-09 WO PCT/EP2013/075952 patent/WO2014095457A2/de active Application Filing
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