DE102019124268A1 - Method for external and internal control of a flywheelless storage power plant - Google Patents

Abstract

The invention relates to a method for external and internal control of a flywheelless storage power plant for providing system services which include instantaneous reserve, primary control and secondary control.
It is therefore an object of the invention to eliminate the disadvantages of the prior art and to provide a control system for new flywheel-less storage power plants, with which a new “conventional” storage power plant can take over all the tasks of network control and electrical energy supply in a complete regenerative energy supply.
This object is achieved by the features listed in the claims.

Description

The invention relates to a method for external and internal control of a flywheelless storage power plant for providing system services which include instantaneous reserve, primary control and secondary control.

1. 1 Weiträumige und feinverteilte Energieversorgung benötigt ein Drehstromnetz.
2. 2 Plötzliche Laständerungen müssen instantan durch Momentanreserveleistung gespeist werden.
3. 3 Die Speicher der Momentanreserveleistung müssen im Sekundenbereich durch die Primärregelung entlastet und wieder aufgefüllt werden. Dazu werden Primärregelleistungsspeicher benötigt.
4. 4 Die Primärregelleistung muss im Minutenbereich durch die Sekundärrregelung abgelöst werden. Dabei ist dann auch deren Speicher wieder aufzuladen.
5. 5 Anschließend treten Fahrplanänderungen in Kraft, welche alle Regler wieder „auf null“ stellen.
6. 6 In einer vollregenerativ versorgten Energieversorgung kommt. Noch folgende Aufgabe hinzu: Gewisse Mengen der geernteten Energie müssen für Prognosefehler sowie „Dunkelflauten“ gespeichert werden.

The basic principles of electrical power supply and grid control are universal and must be observed for all types of generation, transmission, distribution and consumption as follows:

1. 1 A three-phase network requires a spacious and finely divided power supply.
2. 2 Sudden load changes must be fed instantaneously by means of instantaneous reserve power.
3. 3 The stores of the instantaneous reserve power must be relieved and replenished in a matter of seconds by the primary control. Primary control power storage is required for this.
4. 4 The primary control power must be replaced by the secondary control in the minute range. In this case, their memory must also be recharged.
5. 5 Then schedule changes come into force, which set all controllers back to "zero".
6. 6 Comes in a fully regenerative energy supply. The following task also needs to be added: Certain amounts of the harvested energy have to be saved for forecast errors and "dark drafts".

• Umwandlung/Anpassung: Die sprungförmige elektrische Leistungsanforderung wird vom Generator bei noch konstanter Drehzahl instantan in eine sprungförmige Erhöhung des Luftspalt-Moments und damit der mechanischen Leistung umgesetzt.
• Speicher: Der Turbosatz bestehend aus Turbine-Generator-Erreger speichert instantan kinetische Energie aus und liefert diese mechanische Leistung. Dadurch sinkt die Drehzahl ab, welche die Größe des Speicherinhaltes kennzeichnet.
• Umwandlung/Anpassung: Der Primärregler greift über ein Turbinenventil auf einen Frischdampfspeicher zu, wodurch im Sekundenbereich der Dampfstrom erhöht wird. Damit steigt das Turbinenmoment an und füllt den Drehzahl-Speicher wieder auf.
• Speicher: Durch den erhöhten Dampfstrom sinkt der Dampfdruck ab, welcher hier die Größe des Speicherinhaltes kennzeichnet.
• Umwandlung/Anpassung: Der Brennstoffregler erhöht die Feuerung um den Druck auszuregeln. Dabei wird mehr Kohlenstoff C mit Sauerstoff O zu CO2 umgewandelt. Im Verdampfer wird mehr Dampf erzeugt. Mit dem erhöhten Dampfstrom wird der Druck-Speicher wieder aufgefüllt.
• Speicher: Der Brennstoffregler greift im Minutenbereich auf die Kohlehalde zu und erhöht den Brennstoff-Massenstrom. Die Kohlemasse der Halde wird weniger, welche hier die Größe des Speicherinhalts kennzeichnet. Hier findet keine Wiederaufladung durch das Kraftwerk selbst statt.

So far, these tasks have been performed by conventional power plants, which are made up of a system chain consisting of differently fast storage units and converters / adapters. This system chain includes (using the example of an abrupt performance request):

• Conversion / adaptation: The step-by-step electrical power requirement is instantly converted by the generator at a constant speed into a step-by-step increase in the air gap torque and thus the mechanical power.
• Storage: The turbo set consisting of a turbine generator exciter instantaneously stores kinetic energy and delivers this mechanical power. As a result, the speed drops, which characterizes the size of the memory content.
• Conversion / adaptation: The primary controller accesses a live steam storage via a turbine valve, which increases the steam flow in the seconds range. This increases the turbine torque and refills the speed memory.
• Storage: Due to the increased steam flow, the steam pressure drops, which indicates the size of the storage content.
• Conversion / adaptation: The fuel regulator increases the combustion to regulate the pressure. More carbon C is converted with oxygen O to CO2. More steam is generated in the evaporator. The pressure accumulator is refilled with the increased steam flow.
• Storage: The fuel regulator accesses the coal stockpile in a matter of minutes and increases the fuel mass flow. The coal mass of the stockpile becomes less, which characterizes the size of the storage content. There is no recharging by the power plant itself.

Due to the increasing availability of renewable energy sources from wind and sun, the conventional power plant has to reduce its output considerably at certain times in order to make room for these producers. To do this, the minimum power must be reduced and the control speed increased. Today, all producers from fossil raw materials have to meet these requirements.

To the above To be able to continue to perform supply and grid control tasks in a fully regenerative world, new “conventional” power plants have already been developed, which not only supply energy in the event of “dark doldrums”, but can also store them in surplus situations. For a transitional period, these new plants must also function in a flywheel-oriented energy supply with conventional power plants. In a purely converter-oriented energy supply, they can then be operated either in a grid-forming manner or in a grid-supporting manner at a constant grid frequency.

In the course of the energy transition, more and more electrical energy is being generated by wind and PV systems, for example. This energy is stored in large chemical stores (storage power plants). These new storage power plants are connected to the three-phase network with converters. So far, attempts have been made to replace the individual tasks of conventional power plants that have been dropped. So batteries were built that can only generate primary control power.

Unlike conventional power plants, the new storage power plants no longer have any inertia due to the system. In contrast, the number of conventional power plants will decrease. So they have to Storage power plants take over all tasks of conventional power plants with flywheels.

A system chain of the new "conventional" power plants includes (using the example of a step-by-step performance requirement):

Conversion / adaptation: The step-by-step electrical power requirement leads to an instantaneous increase in the three-phase current and thus also to an instantaneous increase in the direct current on the direct current side when the line voltage angle is kept constant (line-forming).

Storage: The storage, a super-capacitor, instantly stores electrical energy and delivers this power. As a result, its voltage drops, which characterizes the size of the memory content. This behavior corresponds to the instantaneous reserve of the conventional power plant.

Conversion / adaptation: The regulation of the downstream DC / DC converter should keep the capacitor voltage constant. To do this, it accesses the battery, which increases the battery current in seconds. The capacitor charging current thus rises and fills the voltage storage again. This behavior corresponds to the primary control of the conventional power plant.

Storage: Due to the increased battery current, the battery voltage drops, which indicates the size of the storage content.

Conversion / adaptation: A fuel cell regulator increases the activity of the fuel cell in order to charge the battery and to regulate the battery voltage. More hydrogen 2H2 is converted to H2O with oxygen O2. The DC / DC converter adjusts the voltages. The voltage storage is refilled with the increased battery charging current.

Storage: The fuel cell controller accesses the hydrogen storage in minutes and increases the fuel mass flow. The hydrogen mass of the storage is reduced, which characterizes the size of the storage content. Recharging can take place here.

In order to be able to perform all supply and control tasks in the existing frequency-controlled energy supply system, the storage power plant must be able to react to the grid frequency and its derivation by supplying primary control and instantaneous reserve power

In a power supply with predominantly storage power plants and only a few or no conventional power plants with a flywheel, the "Watt speed control" can be dispensed with and the three-phase network can be operated at a constant frequency of e.g. f0 = 50 Hz. The grid control tasks such as instantaneous reserve and primary control power can then be implemented using the voltage angle at the connection point of the storage power plant.

Presentation of the invention

1. 1 Anschluss des neuen „konventionellen“ Speicherkraftwerks an ein Drehstromnetz, um eine weiträumige und feinverteilte Energieversorgung zu gewährleisten.
2. 2 Plötzliche Laständerungen müssen instantan durch Momentanreserveleistung gespeist werden.
3. 3 Die Speicher der Momentanreserveleistung müssen im Sekundenbereich durch die Primärregelung entlastet und wieder aufgefüllt werden. Dazu werden Primärregelleistungsspeicher benötigt.
4. 4 Die Primärregelleistung muss im Minutenbereich durch die Sekundärregelung abgelöst werden. Dabei ist dann auch deren Speicher wieder aufzufüllen.
5. 5 Anschließend treten Fahrplanänderungen in Kraft.
6. 6 Bei einer voll regenerativ versorgten Energieversorgung müssen definierte Mengen der geernteten Energie für die Prognose von Fehlern sowie für „Dunkelflauten“ gespeichert werden.

It is therefore an object of the invention to eliminate the disadvantages of the prior art and to provide a control system for new flywheel-less storage power plants, with which a new “conventional” storage power plant can take over all the tasks of network control and electrical energy supply in a complete regenerative energy supply. The necessary individual measures, which should be regulated, are:

1. 1 Connection of the new "conventional" storage power plant to a three-phase network to ensure a spacious and finely divided power supply.
2. 2 Sudden load changes must be fed instantaneously by means of instantaneous reserve power.
3. 3 The stores of the instantaneous reserve power must be relieved and replenished in a matter of seconds by the primary control. Primary control power storage is required for this.
4. 4 The primary control power must be replaced by the secondary control in the minute range. In this case, their memory must also be replenished.
5. 5 Changes to the schedule then take effect.
6. 6 In the case of a fully regenerative energy supply, defined amounts of the harvested energy have to be stored for the forecast of errors and for "dark doldrums".

It is the task that the control of the new storage power plant should be frequency-controlled or angle-controlled.

In the following equations, all values except angles are given in related sizes.

This object is achieved by the features listed in the claims.

The object is achieved by means of a method for the external and internal control of a flywheelless storage power plant. The For this purpose, the method has the following method steps, it being conceivable to carry out the method in a sequence other than that described below.

The method for external and internal control of a flywheelless storage power plant for the provision of system services, which include the instantaneous reserve, primary control and secondary control, is divided into an external and an internal control. The external control in turn has active power control (and reactive power control) on a DC / AC converter. The active power control has the following process steps:

1. a. externe Regelung, welche eine Wirkleistungsregelung an einem DC/AC-Umrichter umfasst:
   • - Auswählen eines Regelungsmodus, wobei ein erster Regelungsmodus eine winkelbasierte Regelung (φ_Reg-Modus) ist und ein zweiter Regelmodus eine frequenzbasierte Regelung (f_Reg-Modus) ist, wobei die frequenzbasierte Regelung folgende Verfahrensschritte aufweist:
     1. i. Messen einer momentan abgegeben Wirkleistung p am DC/AC-Umrichter und Vorgabe einer Änderung einer Kraftwerkssollleistung Δp_H2 anhand eines Inhaltes eines Wasserstoffspeichers,
     2. ii. Bilden einer Regelabweichung Δp aus der gemessenen momentan abgegeben Wirkleistung p mit einer Sollwirkleistung, wobei die Sollwirkleistung eine vorgegebene Sekundärleistungsänderung Δp_sec , eine vorgegebene Fahrplanleistung p_FP und die Vorgabe der Änderung der Kraftwerkssollleistung Δp_H2 aufweist und
     3. iii. Errechnen einer synthetischen Netzwinkelgeschwindigkeit Δω₂ aus der Regelabweichung Δp, wobei die synthetische Winkelgeschwindigkeit Δω₂ zu einer integralen Verstellung des Spannungswinkels φ_U2 am DC/AC-Umrichter führt,

Method for the external and internal control of a flywheelless storage power plant for the provision of system services, which include the instantaneous reserve, primary control and secondary control, method comprising the following method steps:

1. a. External control, which includes active power control on a DC / AC converter:
   • - Selection of a control mode, a first control mode being an angle-based control (φ _Reg mode) and a second control mode being a frequency-based control (f _Reg mode), the frequency-based control having the following method steps:
     1. i. Measuring a currently delivered active power p on the DC / AC converter and specification of a change in a power plant target power Δp _H2 based on the content of a hydrogen storage,
     2. ii. Form a rule deviation Δp from the measured active power currently output p with a target active power, the target active power a predetermined change in secondary power Δp _sec , a given schedule service p _FP and the specification of the change in the power plant target output Δp _H2 has and
     3. iii. Calculate a synthetic network angular velocity Δω ₂ from the control deviation Δp , the synthetic angular velocity Δω ₂ for an integral adjustment of the tension angle φ _U2 on the DC / AC converter,

• - Festsetzen einer Regelabweichung Δp=0, wobei der Spannungswinkel φ_U2 am DC/AC-Umrichter konstant bleibt und das Speicherkraftwerk als Spannungsquelle mit konstanter Spannung u₂ und konstanter Frequenz von 50 Hz arbeitet, wobei die winkelbasierte Regelung Sicherungsmechanismen aufweist, welche anhand der gemessenen momentan abgegebenen Leistung p mittels einer Steuerungsseinheit eingeschaltet werden, wobei die Sicherungsmechanismen folgende Varianten umfassen:
  • - Manuelle Einstellung einer Leistung p_man ,
  • - Leistungseinstellung anhand eines vordefinierten Leistungsmaximalwertes p_Max und/oder eines vordefinierten Leistungsminimalwertes p_Min und/oder
  • - Leistungseinstellung anhand einer Vorgabe einer Änderung einer Kraftwerkssollleistung Δp_H2 anhand eines Inhaltes eines Wasserstoffspeichers,

The angle-based control in Slack mode has the following process steps:

• - Setting a control deviation Δp = 0, the tension angle φ _U2 on the DC / AC converter remains constant and the storage power plant as a voltage source with constant voltage u ₂ and a constant frequency of 50 Hz, the angle-based control system having security mechanisms which are based on the measured output power p can be switched on by means of a control unit, the security mechanisms comprising the following variants:
  • - Manual setting of a service p _man ,
  • - Power setting based on a predefined maximum power value p _Max and / or a predefined minimum performance value p _min and or
  • - Power setting based on a specification of a change in a power plant target power Δp _H2 based on the content of a hydrogen storage,

• - Messen einer momentan abgegeben Blindleistung q₂ am DC/AC-Umrichter
• - Vergleichen der momentan abgegebenen Blindleistung q₂ mit einer Sollblindleistung q₀ , wobei eine Differenz gebildet wird mittels welcher und zusammen mit einer vordefinierten Blindleistungsstatik σ_q eine Spannung am Speicherkraftwerk u₂ gebildet wird.

A reactive power control of the external control can have the following method steps according to several embodiments:

• - Measuring a currently given reactive power q ₂ on the DC / AC converter
• - Compare the currently given reactive power q ₂ with a target reactive power q ₀ , whereby a difference is formed by means of which and together with a predefined reactive power statics σ _q a voltage at the storage power plant u ₂ is formed.

• - Ermitteln eines Gleichstroms i_KC , welcher von einem ersten Speicher zum DC/AC-Konverter fließt, aus einer gemessenen Speicherspannung u_C des ersten Speichers und der Wirkleistung p, wobei der Gleichstrom i_KC und ein von einem zweiten Speicher zum ersten Speicher fließende Strom i_CB die Speicherspannung u_C des ersten Speichers integral einstellt.
• - Regeln des Gleichstroms i_CB , welcher vom ersten Speicher zum zweiten Speicher fließt, derart, dass die Speicherspannung u_C des ersten Speichers einen Sollwert der Speicherspannung u_C,soll annimmt
• - Laden des zweiten Speichers mittels eines mit einem ersten Energiewandler erzeugten Gleichstroms i_BF bei Unterschreiten eines ersten Speicherspannungswertes ŭ_B des zweiten Speichers, wobei ein Entladen eines dritten Speichers erfolgt, oder Entladen des zweiten Speichers mittels eines mit einem zweiten Energiewandler erzeugten Stromes i_EB bei Überschreiten eines zweiten Speicherspannungswertes û_B des zweiten Speichers, wobei ein Laden des dritten Speichers erfolgt.

The internal regulation, which provides the required system services from storage, comprises the following procedural steps:

• - Determine a direct current i _KC , which flows from a first memory to the DC / AC converter, from a measured memory voltage u _C of the first memory and the active power p , the direct current i _KC and a current flowing from a second memory to the first memory i _CB the storage voltage u _C of the first memory integrally.
• - rules of direct current i _CB , which flows from the first memory to the second memory, such that the memory voltage u _C a setpoint of the storage voltage of the first storage u _{C, should} assumes
• - Charging the second memory by means of a direct current generated with a first energy converter i _BF when falling below a first storage voltage value ŭ _B of the second store, wherein a third store is discharged, or the second store is discharged by means of a current generated with a second energy converter i _EB when a second storage voltage value û _{B of} the second storage is exceeded, the third storage being loaded.

According to various embodiments, the safety mechanisms are intervened an operating point performance p _AP saved which is the current performance value p saves at the time of the occurrence of an error and which is used for the further procedure in order to ensure a smooth transition from normal operation to minimum / maximum operation.

According to one embodiment, the first memory has a capacitor or the first memory is a capacitor.

According to one embodiment, the second memory has a battery or the second memory is a battery.

According to one embodiment, the third store has a hydrogen store or the third store is a hydrogen store. The use of further or other chemical stores is conceivable, but the use of mechanical and / or thermal stores is also conceivable. This can be a mass of hydrogen m _H be measured at the hydrogen storage, the measured hydrogen mass also m _H as an input variable for the external active power control for the power specification Δp _H2 in frequency control mode f _reg and / or in the angle control mode φ _reg reg is used.

Furthermore, according to one embodiment, the energy converter has a fuel cell or it is a fuel cell, and / or the second energy converter has an electrolyzer or it is an electrolyzer. The use of further and / or other energy converters is conceivable.

According to a further embodiment, a circulating current flows i ₀ between the first energy converter and the second energy converter in order to be able to switch smoothly between the first and the second energy converter.

According to one embodiment, the first storage voltage value is ŭ _B of the second memory as a fixed value to, for example, + 10% of the memory voltage of the second memory u _B set and / or the second storage voltage value û _{B of} the second storage as a fixed value to -10% of the storage voltage of the second storage u _B set. These are examples of these threshold values. Their values are set as constant fixed values. Other threshold values that activate the second and / or the third memory are conceivable.

A conventional power plant can be replaced with the method according to the invention for the external and internal control of a storage power plant for the provision of system services which include the instantaneous reserve, primary control and secondary control. With the help of the process, the new storage power plant does not need any inertial masses and can both absorb and absorb power. It either consumes hydrogen or generates hydrogen. This enables full renewable energy generation, in which these new power plants not only store energy, but can also provide all system services such as instantaneous, primary, secondary control and schedule.

In addition, the power plant can act as a so-called slack power plant in a future angular control of the electrical network, which enables a further stabilization of the electrical energy supply.

With the use of flywheel-free storage power plants with modern and high-performance converter technology, grid control can be operated in a reasonable manner both in frequency- and in angle-controlled networks. In frequency-controlled networks with existing conventional flywheels, these new systems act like normal power plants and can cover all network control tasks such as momentary reserve, primary and secondary control and schedule operation. In addition, they can also store energy from renewable sources, which can make redispatch actions unnecessary. In future, angle-controlled networks without physical flywheel mass, these power plants can work as slack storage power plants, which enables a constant grid frequency to be maintained. However, this requires the precise measurement of the angles and an angle standard. This means that all future applications can be covered, which will enable the safe expansion of a renewable energy supply in the future.

• - externe Regelung, welche eine Wirkleistungsregelung und eine Blindleistungsregelung an einem DC/AC-Umrichter umfasst, wobei die Wirkleistungsregelung folgende Verfahrensschritte aufweist:
  • - Messen einer momentan abgegeben Wirkleistung (p) am DC/AC-Umrichter
  • - Vergleichen der Wirkleistung (p) mit einer Sollwirkleistung (p₀ ), aufweisend einen Primärregelsollwert (p_{p0, prim} )
  • - Bilden einer synthetischen Winkelgeschwindigkeit (Δω₂ ) gemäß $$\Delta {\omega }_2=-\frac{1}{s{T}_M}\cdot \left(p-p_0\right)$$
    
    wobei die synthetische Winkelgeschwindigkeit (Δω₂ ) zu einer integralen Verstellung des Spannungswinkels (ϕ_U2) führt
  • - Bilden eines Primärregelsollwertes (p_{0, prim} ) aus einer vordefinierten Wirkleistungsstatik (σ _p ) und der synthetischen Netzwinkelgeschwindigkeit (Δω₂ ) gemäß $${\text{p}}_{\text{0},\text{prim}}=-\frac{1}{{\mathrm{\sigma }}_{\text{p}}}\mathrm{\Delta }{\mathrm{\omega }}_2$$
    
  und wobei die Blindleistungsregelung folgende Verfahrensschritte aufweist:
  • - Messen einer momentan abgegeben Blindleistung (q₂ ) am DC/AC-Umrichter
  • - Vergleichen der momentan abgegebenen Blindleistung (q₂ ) mit einer Sollblindleistung (q₀ ), wobei eine Differenz gebildet wird mittels welcher, zusammen mit einer vordefinierten Blindleistungsstatik (σ _q ), eine Spannung am Speicherkraftwerk (u₂ ) gebildet wird
  wobei mit der Spannung (u₂ ) der Blindleistungsregelung und dem Spannungswinkel (ϕ _U2) der Wirkleistungsregelung zusammen mit einer vordefinierten Netzspannung (u₁ ) und einer vordefinierten Netzwinkelfrequenz (Δω₁ ) die Wirkleistung (p) geregelt wird
• - interne Regelung: Bereitstellung der Systemdienstleistungen aus Speichern, welche folgende Verfahrensschritte umfasst:
  • - Ermitteln eines Gleichstroms (i_KC ), welcher von einem ersten Speicher zum DC/AC-Konverter fließt, aus einer gemessenen Speicherspannung (u_C ) des ersten Speichers und der Wirkleistung (p), wobei der Gleichstrom (i_KC ) und ein von einem zweiten Speicher zum ersten Speicher fließende Strom (i_CB ) die Speicherspannung (u_C ) des ersten Speichers integral einstellt
  • - Regeln des Gleichstroms (i_CB ), welcher vom ersten Speicher zum zweiten Speicher fließt, derart, dass die Speicherspannung (u_C ) des ersten Speichers einen Sollwert der Speicherspannung (u_{C, soll}) annimmt
  • - Laden des zweiten Speichers mittels eines mit einem ersten Energiewandler erzeugten Gleichstroms (i_BF ) bei Unterschreiten eines ersten Speicherspannungswertes (U_B ) des zweiten Speichers, wobei ein Entladen eines dritten Speichers erfolgt, oder Entladen des zweiten Speichers mittels eines mit einem zweiten Energiewandler erzeugten Stromes (i_EB ) bei Überschreiten eines zweiten Speicherspannungswertes (û_B) des zweiten Speichers, wobei ein Laden des dritten Speichers erfolgt.

A method for the external and internal control of a flywheelless storage power plant for the provision of system services, which include instantaneous reserve, primary control and secondary control, is also disclosed. Process comprising the following process steps:

• - external control, which comprises active power control and reactive power control on a DC / AC converter, the active power control having the following method steps:
  • - Measuring a currently delivered active power ( p ) on the DC / AC converter
  • - comparison of active power ( p ) with a target active power ( p ₀ ), having a primary control setpoint ( p _{p0, prim} )
  • - Form a synthetic angular velocity ( Δω ₂ ) according to $$\Delta {\omega }_{\mathrm{2nd}}=-\frac{1}{s{T}_M}\cdot \left(p-p_0\right)$$
    
    where the synthetic angular velocity ( Δω ₂ ) leads to an integral adjustment of the voltage angle (ϕ _U2 )
  • - formation of a primary control setpoint ( p _{0, prime} ) from a predefined active power statics ( σ _p ) and the synthetic network angular velocity ( Δω ₂ ) according to $${\text{p}}_{\text{0},\text{prim}}=-\frac{1}{{\mathrm{\sigma }}_{\text{p}}}\mathrm{\Delta }{\mathrm{\omega }}_{\mathrm{2nd}}$$
    
  and wherein the reactive power control has the following process steps:
  • - measurement of a currently given reactive power ( q ₂ ) on the DC / AC converter
  • - Compare the currently given reactive power ( q ₂ ) with a target reactive power ( q ₀ ), whereby a difference is formed by means of which, together with a predefined reactive power statics ( σ _q ), a voltage at the storage power plant ( u ₂ ) is formed
  being with the tension ( u ₂ ) of the reactive power control and the voltage angle (ϕ _U2 ) of the active power control together with a predefined mains voltage ( u ₁ ) and a predefined network angular frequency ( Δω ₁ ) the active power ( p ) is regulated
• - Internal regulation: provision of system services from storage, which comprises the following procedural steps:
  • - determining a direct current ( i _KC ), which flows from a first memory to the DC / AC converter, from a measured memory voltage ( u _C ) of the first memory and the active power ( p ), the direct current ( i _KC ) and a current flowing from a second store to the first store ( i _CB ) the storage voltage ( u _C ) of the first memory integrally
  • - DC current rules ( i _CB ), which flows from the first memory to the second memory, such that the memory voltage ( u _C ) Of the first memory a target value of memory voltage (u _{C, soll)} takes
  • Charging of the second memory by means of a direct current generated with a first energy converter ( i _BF ) when falling below a first storage voltage value ( U _B ) of the second store, a third store being discharged, or discharging of the second store by means of a current generated by a second energy converter ( i _EB ) when a second storage voltage value (û _B ) of the second storage is exceeded, whereby the third storage is loaded.

Figure list

• 1 Blockschaltbild der vollständigen Wirkleistungsregelung des Speicherkraftwerkes
• 2 Blockschaltbild zur Blindleistungsregelung
• 3 Darstellung des Kurzzeitverhaltens bei einer erfindungsgemäßen Regelung
• 4 Darstellung des Langzeitverhaltens bei einer erfindungsgemäßen Regelung
• 5 Blockschaltbild der externen p-Regelung für Frequenz- und Winkelregelung des Speicherkraftwerks (a)
• 6 Anlagenschema des Speicherkraftwerks (b)
• 7 Interne Regelung eines ersten Speichers am Beispiel eines Superkondensators (c1)
• 8 Interne Regelung eines zweiten Speichers am Beispiel einer Batterie (c2)
• 9 Interne Regelung eines ersten und zweiten Energiewandlers an den Beispielen eines Elektrolyseurs und einer Brennstoffzelle (c3)

The invention is explained in more detail using exemplary embodiments. Show this

• 1 Block diagram of the complete active power control of the storage power plant
• 2nd Block diagram for reactive power control
• 3rd Representation of the short-term behavior in a control according to the invention
• 4th Representation of the long-term behavior in a control according to the invention
• 5 Block diagram of the external p control for frequency and angle control of the storage power plant ( a )
• 6 System diagram of the storage power plant ( b )
• 7 Internal control of a first memory using the example of a supercapacitor ( c1 )
• 8th Internal control of a second memory using the example of a battery ( c2 )
• 9 Internal control of a first and second energy converter using the examples of an electrolyzer and a fuel cell ( c3 )

• - die Bereitstellung einer Momentanreserve, um plötzliche Laständerungen instant zu speisen,
• - die Bereitstellung einer Primärregelleistung, um einen Momentanreserve-Speicher im Sekundenbereich zu entlasten und wieder aufzufüllen,
• - die Bereitstellung einer Sekundärregelleistung, welche die Primärregelung nach einer bestimmten Zeit im Minutenbereich ablöst und um einen Primärregelungsspeicher wieder aufzufüllen
• - Bereitstellung von Fahrplanänderungen, welche alle Regler wieder auf „Null“ stellen

The method according to the invention for regulating a new storage power plant is divided into an internal and an external regulation of a storage power plant for the provision of system services. System services are

• - the provision of an instantaneous reserve to feed sudden load changes instantly,
• the provision of primary control power to relieve and replenish an instantaneous reserve memory in the range of seconds,
• - The provision of secondary control power, which replaces the primary control after a certain time in the minute range and to replenish a primary control memory
• - Provision of schedule changes that reset all controllers to "zero"

The external control is divided into an active power control and a reactive power control.

In 1 the complete frequency-controlled active power control of the storage power plant is shown, consisting of the external frequency-controlled active power setting and the internal active power supply.

wird bei Veränderung der momentan abgegebenen Leistung p eine Drehzahländerung (Schwungmassen-Drehzahländerung) simuliert. Dies führt dahingehend zu einer integralen Verstellung des Spannungswinkels φ_U2 am DC/AC-Wandler gemäß $$\Delta {\phi }_{u_2}={\Omega }_0{\displaystyle \int \Delta {\omega }_2\cdot dt}$$

und $${\Omega }_0=2\cdot \pi \cdot f_0$$

so dass die Schwankungen möglichst klein gehalten werden und es wieder gilt $$\text{p}-{\text{p}}_{\text{0}}=0$$

The storage power plant, for example a capacitor, is connected to the three-phase network via a DC / AC converter and thereby feeds active power p on. This includes a tension angle φ _U . This angle of tension φ _U forms on the one hand from the tension angle φ _U1 of tension u ₁ of the network center and the other from the angle of tension φ _U2 of tension u ₂ at the storage power plant. The active power p is measured and with a target active power p ₀ compared. How from 1 the target active power is evident p ₀ from the service parts primary control power, secondary control power and timetable. The schedule service is the service planned by the power plant operator. Primary and secondary control power are the power parts that are required to keep the grid stable, the two power parts differing in their time range. The primary control power is the faster power part, which has to compensate for rapid changes in power requirements. While in conventional power plants the flywheel mass of the rotors works like a momentary reserve, in new flywheelless storage power plants these power parts have to be modulated on the power. First of all, the active power currently output p measured and with a target value of the active power p ₀ compared. With the synthetic equation of motion $$\Delta {\omega }_{\mathrm{2nd}}=-\frac{1}{T_M}\cdot \left(p-p_0\right)$$

will change when the current output is changed p a speed change (flywheel speed change) simulated. This leads to an integral adjustment of the tension angle φ _U2 on the DC / AC converter according to $$\Delta {\phi }_{u_{\mathrm{2nd}}}={\mathrm{<figure-callout\; id="0"\; label="\Omega "\; filenames="DE102019124268A1\_0012.png,DE102019124268A1\_0013.png"\; state="\{\{state\}\}">\Omega </figure-callout>}}_0{\displaystyle \int \Delta {\omega }_{\mathrm{2nd}}\cdot dt}$$

and $${\mathrm{<figure-callout\; id="0"\; label="\Omega "\; filenames="DE102019124268A1\_0012.png,DE102019124268A1\_0013.png"\; state="\{\{state\}\}">\Omega </figure-callout>}}_0=\mathrm{2nd}\cdot \pi \cdot {\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102019124268A1\_0012.png,DE102019124268A1\_0013.png"\; state="\{\{state\}\}">f</figure-callout>}}_0$$

so that the fluctuations are kept as small as possible and it applies again $$\text{p}-{\text{<figure-callout id="0" label="p" filenames="DE102019124268A1\_0012.png,DE102019124268A1\_0013.png" state="{{state}}">p</figure-callout>}}_{\text{0}}=0$$

So that with the time constant T _M Instantaneous reserve power is stored out of a memory, for example a capacitor.

moduliert.The determined synthetic network angular velocity also feeds ω ₂ also the primary control. With a specified power plant statics (active power statics), the power section becomes primary control power p _{0, prime} according to $${\mathrm{<figure-callout\; id="0"\; label="p"\; filenames="DE102019124268A1\_0012.png,DE102019124268A1\_0013.png"\; state="\{\{state\}\}">p</figure-callout>}}_{\mathrm{0,}prim}=-\frac{1}{{\sigma }_p}\cdot \Delta {\omega }_{\mathrm{2nd}}$$

modulated.

The angle of tension φ _U1 of tension u ₁ is the specified angle of the mains voltage. The angle follows it φ _U2 regulated according to, the previously described feedback I control acting like a PLL control. The PLL control (English phase-locked loop) is there to influence the phase position and thus the grid frequency via a closed control loop in such a way that the power plant output p the target performance p ₀ follows.

sich die Wirkleistung p ergibt. x ist dabei die bezogene Netzreaktanz.Along with φ _U1 and φ _{reg U2} becomes the angle of tension φ _U formed from which by means of the equation $$p=\frac{u_{\mathrm{2nd}}\cdot u_1}{x}\cdot \text{sin}{\varphi }_u\approx \frac{u_{\mathrm{2nd}}\cdot u_1}{x}\cdot {\varphi }_u$$

the active power p results. x is the related network reactance.

wobei die Blindleistungsregelung folgende Verfahrensschritte aufweist, wie in 2 dargestellt:

• Eine momentan abgegeben Blindleistung q₂ am DC/AC-Umrichter wird gemessen und mit einer Sollblindleistung q₀ verglichen, wobei eine Differenz gebildet wird mittels welcher, zusammen mit einer vordefinierten Blindleistungsstatik σ _q die Spannung am Speicherkraftwerk u₂ gebildet.

The voltage u ₂ follows from the reactive power control, from the equation $$q_{\mathrm{2nd}}=\frac{-{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="DE102019124268A1\_0010.png,DE102019124268A1\_0011.png"\; state="\{\{state\}\}">u</figure-callout>}}_1\cdot u_{\mathrm{2nd}}}{x}\cdot \text{cos}{\phi }_u+\frac{u_{\mathrm{2nd}}{}^{\mathrm{2nd}}}{x}\approx \frac{u_{\mathrm{2nd}}\left(u_{\mathrm{2nd}}-u_1\right)}{x}$$

wherein the reactive power control has the following method steps, as in 2nd shown:

• A currently given reactive power q ₂ at the DC / AC converter is measured and with a target reactive power q ₀ compared, a difference being formed by means of which, together with a predefined reactive power statics σ _q the voltage at the storage power plant u ₂ educated.

With the tension u ₂ the reactive power control and the voltage angle φ _U2 active power control together with a predefined mains voltage u ₁ and a predefined network angular frequency Δω ₁ becomes the active power p regulated

With active power p follows the internal regulation, which includes the provision of system services from storage, for example capacitors, batteries and / or hydrogen storage. For this, the example of 1 from a measured capacitor voltage u _C and the active power p first a direct current i _KC , which flows from a capacitor to the DC / AC converter, the direct current i _KC and a current flowing from a battery to the capacitor i _CB the capacitor voltage u _C integrally.

Furthermore, the direct current i _CB regulated such that the capacitor voltage u _C a setpoint of the capacitor voltage u _{C, should} assumes. The capacitor voltage u _{C, should} can be, for example, 1pu.

The battery is charged and / or discharged using the regulated direct current i _CB , by means of a direct current generated with a fuel cell i _BF , this according to one embodiment when falling below a first battery voltage value ŭ _B takes place, and / or by means of a current generated with an electrolyzer i _EB , which in one embodiment takes place when a second battery voltage value û _B is exceeded. When the battery is discharged using the electricity generated i _EB according to one embodiment, a hydrogen store is charged. With which, depending on the operating case, the hydrogen storage is charged or discharged via the hydrogen mass flow ṁ _H. This can be done, for example, with the control system shown and non-linear transmission elements. Anti-wind-up measures can also be used.

In one embodiment, a circulating current flows _ok between the fuel cell and the electrolyzer in order to be able to switch smoothly between the fuel cell and the electrolyzer.

In 3rd are the curves of active and reactive power in short-term behavior p and q , course of the potentials u _C , u _B , m _H and the courses of the currents i _C , i _B , i _H and i _KC represented over time in a control according to the invention. Again 3rd can be seen, the capacitor initially takes over almost all of the current (instantaneous reserve). Then the battery stores (primary control) and the capacitor current i _C go back. The current of the slow hydrogen storage (secondary control) is not yet active in this time resolution.

In 4th are the in 3rd described courses over a long period of time. In this example, the active power jumps p for 500 seconds after a rapid settling process from 0 to 0.2 pu and then to zero again for up to 1000 seconds. It then jumps to -0.2 pu and then goes back to zero after 1500 seconds. The reactive power always changes by a small amount.

It can also be seen here how the hydrogen storage takes over the entire power generation after approx. 100 seconds and how both the capacitor and the battery return to zero with their currents. The switching times of the active power are clearly recognizable.

It can be seen from the potential curves that the capacitor only ever acts for a very short time with its power supply and supply. This behavior corresponds to the current reserve. The capacitor voltage u _C always takes its initial value again, which enables undisturbed operation of the DC / AC converter. The battery voltage u _B on the other hand, it moves within its limits, which are set to ± 10%, for example. The battery therefore feeds power in and out in the time range of the primary control.

The hydrogen storage becomes active whenever the battery reaches one of its limit values. At the beginning of the period, the storage feeds out and delivers the required power, which is why its hydrogen mass value m _H sinks. In the area 500 to 1000 No power is required for seconds, which is why the memory remains constant. The battery stops near its lower voltage. To 1000 Hydrogen is stored again for a few seconds until the power at 1500 seconds becomes zero again. The hydrogen storage does not quite reach its initial value here because the battery remains charged a little above its starting value.

5 shows a block diagram of an external p-control for frequency and angle control of the storage power plant. The method according to the invention for the external and internal control of a flywheel-free storage power plant for the provision of system services, which include instantaneous reserve, primary control and secondary control, has the following method steps:

An external control, which comprises active power control on a DC / AC converter, also has a reactive power control according to one embodiment, which is not explained here, but is explained further above. The active power control can be angle-based ( φ _Reg ) or frequency-based ( f _reg ) take place, whereby between the angle-based regulation ( φ _Reg ) and frequency-based control ( f _reg ) can be selected.

• - Messen einer momentan abgegeben Wirkleistung p am DC/AC-Umrichter und Vorgabe einer Änderung einer Kraftwerkssollleistung Δp_H2 anhand eines Inhaltes eines Wasserstoffspeichers,
• - Bilden einer Regelabweichung Δp aus der gemessenen momentan abgegeben Wirkleistung p mit einer Sollwirkleistung, wobei die Sollwirkleistung eine vorgegebene Sekundärleistungsänderung Δp_sec, eine vorgegebene Fahrplanleistung p_FP und die Vorgabe der Änderung der Kraftwerkssollleistung Δp_H2 aufweist und
• - Errechnen einer synthetischen Netzwinkelgeschwindigkeit Δω₂ aus der Regelabweichung Δp, wobei die synthetische Winkelgeschwindigkeit ω₂ zu einer integralen Verstellung des Spannungswinkels φ_U2 am DC/AC-Umrichter führt.

The frequency-based control regulates the grid frequency in the grid by increasing the power to be fed in at a low grid frequency or by reducing the power fed in at an increased grid frequency. The frequency-based network control has the following procedural steps:

• - Measuring a currently delivered active power p on the DC / AC converter and specification of a change in a power plant target power Δp _H2 based on the content of a hydrogen storage,
• - Form a rule deviation Δp from the measured active power currently output p with a target active power, the target active power a predetermined secondary power change Δp _sec , a predetermined schedule power p _FP and the specification of the change in the power plant target output Δp _H2 has and
• - Calculate a synthetic network angular velocity Δω ₂ from the control deviation Δp , the synthetic angular velocity ω ₂ for an integral adjustment of the tension angle φ _U2 leads on the DC / AC converter.

To swing the tension angle to be set φ _U2 to prevent, at least damping is applied.

• Festsetzen einer Regelabweichung Δp=0, wobei der Spannungswinkel φ _U2 am DC/AC-Umrichter konstant bleibt und das Speicherkraftwerk als Spannungsquelle mit konstanter Spannung u₂ und konstanter Frequenz von 50 Hz arbeitet. Das bedeutet für netzbildende Umrichter der Slack-Speicherkraftwerke, dass sie ihre Spannungen nach Betrag und Winkel konstant halten können, was einem Slack-Knoten (eingeprägte Spannung) entspricht.

The angle-based control normally works in Slack mode and has the following process steps:

• Establishing a rule deviation Δp = 0, the tension angle φ _U2 on the DC / AC converter remains constant and the storage power plant as a voltage source with constant voltage u ₂ and constant frequency of 50 Hz works. For grid-forming converters of Slack storage power plants, this means that they can keep their voltages constant according to their magnitude and angle, which corresponds to a Slack node (impressed voltage).

To swing the tension angle φ _U2 To prevent the DC / AC converter, the active power controlled system, which is only relevant for frequency control and angular control in the event of a fault, has at least one damping. For example, as in 6 shown by means of a proportional feedback Δp _prim via permanent statics. Additional damping can be integrated for even greater security, such as in 6 shown that a large transient damping by means of a further feedback of the controlled variable Δ p _trans an overshoot of the voltage angle via transient statics φ _U2 prevented even more safely.

1. a. Manuelle Einstellung einer Leistung,
2. b. Leistungseinstellung anhand eines vordefinierten Leistungsmaximalwertes (p_Max ) und/oder eines vordefinierten Leistungsminimalwertes (p_Min ) und/oder
3. c. Leistungseinstellung anhand einer Vorgabe einer Änderung einer Kraftwerkssollleistung anhand eines Inhaltes eines Wasserstoffspeichers.

An angle-based control must be monitored, otherwise the output or power consumed can be too high in slack mode. For these cases, the angle-based control has safety mechanisms which are based on the measured power that is currently being output p be switched on by means of a control unit and / or circuit unit, the security mechanisms comprising the following variants:

1. a. Manual setting of a service,
2. b. Power setting based on a predefined maximum power value ( p _Max ) and / or a predefined minimum performance value ( p _min ) and or
3. c. Power setting based on a specification of a change in a power plant target power based on the content of a hydrogen storage.

5 also shows, by way of example in a switch diagram, how corresponding switches (for example S1 , S2 , S3 , S4 ) can be switched by means of the control unit if, for example, the power is to be entered manually and / or the power has a certain maximum or minimum value of the allowed power ( P _min , p _Max ) exceeds.

6 shows a system diagram of a storage power plant, which is controlled by the inventive method. An active power p (and a reactive power q, not shown here) of a three-phase system serves the external control of the storage power plant as an input variable for the control of the voltage angle φ _U2 , which is set at the storage power plant. The output quantity hydrogen mass m _H The storage power plant also serves the external control as a control variable, around the tension angle φ _U2 based on a filling level of a hydrogen storage device or the like adjust.

The mode of operation of the system diagram shown behaves like that in 1 described mode of action. The representation of the mode of operation of the storage power plant selected here is clearer than that in 1 shown variant, since here a distinction is made in physical units (hardware) and control algorithms. In addition, here is the output variable m _H , as well as the input variable φ _U2 , which follows from the external active power control. The control systems of the three memories are shown in the following figures: 7 ( c1 ) shows an example of an internal control of the first memory, for example a supercapacitor, 8th ( c2 ) shows an example of the internal control of the second memory, for example a battery and 9 ( c3 ) shows an example of the internal control of the first and second energy converters, for example an electrolyser and the fuel cell.

Reference list

a

external p control for frequency and angle control

b

Plant diagram of a storage power plant

c

Control of individual components of the storage power plant

c1

Supercapacitor control

c2

Battery regulation

c3

Regulation fuel cell / electrolyser

f _reg

Control mode frequency control

ϕ _U

Tension angle

ϕ _U1

Tension angle of tension u ₁ at the network center

ϕ _U2

Tension angle of tension u ₂ at the storage power plant

ϕ _Reg

Control mode angle control

u ₁

Network center voltage

u ₂

Voltage at the storage power plant

u _B

Battery voltage

û _B

Battery voltage maximum value

ŭ _B

Battery voltage minimum value

u _c

Capacitor voltage

u _{c, 0}

Setpoint capacitor voltage

i _KC

Direct current from the capacitor to the DC / AC converter

i _CB

DC current from the battery to the capacitor

i _BF

Direct current from the fuel cell to the battery

i _EB

DC current from the battery to the electrolyser

i ₀

Circulating current

i _C

Capacitor current

i _B

Battery power

i _H

Electricity from the fuel cell or hydrogen storage

p

Active power

p ₀

Target active power

p _prim

Primary control setpoint

p _sec

Secondary control setpoint

p _mp

or

p _{0, FP}

Timetable

p _trans

transient performance

p _man

Manual setting of a service

p̌ _man = p _min ,

Minimum allowed output of the storage power plant

p̂ _man = p _max ,

Maximum allowed output of the storage power plant

Δp

Control deviation

Δp _H2

Specification of a change in a power plant target output

Δω _e

Angular velocity of the network frequency

Δω ₁

Angular velocity of the PLL control

Δω ₂

synthetic network angular velocity

T _M

Time constant instantaneous reserve

T _B

Time constant battery

Tc

Time constant capacitor

T _H

Time constant hydrogen storage

T _BF

Time constant control of the fuel cell battery

T _EB

Time constant regulation of battery electrolyser

K _BF

Reinforcement regulation fuel cell battery

K _EB

Reinforcement regulation battery electrolyser

σ _q

Reactive power statics

σ _p

Active power statics

S

Laplace operator

X

Network reactance

Ω ₀

Nominal angular velocity for 50 Hertz

q ₂

Reactive power on the DC / AC converter

q _{2, 0}

Target reactive power at the DC / AC converter

m _H

Hydrogen _mass with limit values m _Hmax (= m̂ _H ) and m _Hmin

ṁ _H

Mass hydrogen flow

1, 2, 3, 4, 5

Transfer points

Claims (9)

Method for the external and internal control of a flywheel-free storage power plant for the provision of system services, which include instantaneous reserve, primary control and secondary control, method comprising the following method steps: - external control, which comprises active power control on a DC / AC converter: selecting a control mode, a Control mode is an angle-based control (φ _Reg mode) and a second control mode is frequency-based control (f _Reg mode), the frequency-based control comprising the following procedural steps: - Measuring a currently delivered active power (p) at the DC / AC converter and Specification of a change in a power plant target power (Δp _H2 ) on the basis of the content of a hydrogen storage, - formation of a control deviation (Δp) from the measured active power (p) currently measured with a target active power, the target active power being a predetermined change in secondary power (Δp _sec ), has a predetermined schedule power (p _FP ) and the specification of the change in the power plant target power (Δp _H2 ) and - calculating a synthetic network angular velocity (Δω ₂ ) from the control deviation (Δp), the synthetic angular velocity (Lω ₂ ) for an integral adjustment of the voltage angle (φ _U2 ) on the DC / AC converter, whereby the angle-based control in Slack mode has the following process steps: - Setting a control deviation Δp = 0, the voltage angle (φ _U2 ) on the DC / AC converter remaining constant and the storage power plant works as a voltage source with constant voltage (u ₂ ) and constant frequency of 50 Hz, the angle-based control having safety mechanisms which are switched on by means of a control unit on the basis of the measured power p currently being output, the safety mechanisms comprising the following variants: manual setting of a power (p _man ), - power setting on hand of a predefined maximum power value (p _max ) and / or a predefined minimum power value (p _min ) and / or - power setting based on a specification of a change in a power plant target power (Δp _H2 ) based on the content of a hydrogen storage, - internal regulation: provision of system services from storage, which comprises the following method steps: determining a direct current (i _KC ) which flows from a first memory to the DC / AC converter, from a measured memory voltage (u _C ) of the first memory and the active power (p), the direct current (i _KC ) and a current C (i _CB ) flowing from a second store to the first store integrally adjusts the store voltage (u _C ) of the first store - regulating the direct current (i _CB ) flowing from the first store to the second store such that the storage voltage (u _C ) of the first storage takes on a target value of the storage voltage (u _{C, should} ) - loading the second iten memory by means of a direct current (i _BF ) generated with a first energy converter when the first memory voltage value (ŭ _B ) falls below the second memory, whereby a third memory is discharged, or discharging the second memory by means of a current generated with a second energy converter (i _EB ) when a second storage voltage value (û _B ) of the second storage is exceeded, the third storage being loaded. Procedure according to Claim 1 , characterized in that an operating point power (p _AP ) is stored / held for intervention by the security _mechanisms . Procedure according to Claim 1 , characterized in that the first memory has a capacitor. Procedure according to Claim 1 or 2nd , characterized in that the second memory has a battery. Method according to one of the preceding claims, characterized in that the third store is the hydrogen store. Method according to one of the preceding claims, characterized in that a hydrogen mass (m _H ) is measured at the hydrogen store, the measured hydrogen mass (m _H ) also being used as an input variable for the external active power control in the frequency control mode (f _Reg ) and / or angle control mode (φ _reg ) is used. Method according to one of the preceding claims, characterized in that the first energy converter has a fuel cell. Method according to one of the preceding claims, characterized in that the second energy converter has an electrolyzer. Method according to one of the preceding claims, characterized in that a circulating current (i ₀ ) flows between the first energy converter and the second energy converter in order to be able to switch smoothly between the first energy converter and the second energy converter.

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