Method for determining the available network power of a power supply network having a power supply connected thereto
Patent Information
- Application Number
- PCT/EP2026/058514
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-27
- Filing Date
- 2026-03-25
- Publication Date
- 2026-10-01
Smart Images
Figure EP2026058514_01102026_PF_FP_ABST
Abstract
Description
[0001] Method for determining the available grid capacity of a power supply network with a connected power supply
[0002] The invention relates to a method for determining the available grid power of a power supply network with a connected power supply, a control for such a power supply for carrying out the method steps, such a power supply with such a control and a battery charging / discharging system with such a power supply and / or control.
[0003] Power supply networks are typically formed by connecting several independent, network-forming generators in parallel.
[0004] Participants involved in network formation have no knowledge of the power available in the power supply network from the other network-forming producers.
[0005] Knowledge of the nominal power potential of the power grid, specifically both active and reactive power, can be very helpful when, for example, an island grid needs to be detected. Currently, the active island grid detection of non-grid-forming systems, such as photovoltaic inverters, typically involves introducing a disturbance or discontinuity in the power feed-in or coupling in another disturbance, and observing the system's reaction. The degree to which the system is affected is then evaluated as a key indicator of islanding.
[0006] A disadvantage is the underlying empirical methodology, which hardly allows for quantitative statements about the existing healthcare system.
[0007] Against this background, the task arises to enable a reliable and less fault-prone method for grid-forming inverters to determine the available grid power of a power supply network.
[0008] To solve the problem, a method according to claim 1 or 3, a control system according to claim 14, a power supply system according to claim 15, and a battery charging and discharging system according to claim 16 are proposed. Embodiments thereof are disclosed in the dependent claims or in the description.
[0009] One aspect is revealed: A method for determining the available active network power of a power supply network that operates at a nominal frequency and for which
[0010] 2023P00399WO a network slope of a frequency-active power characteristic is stored, with a power supply connected to this power supply network.
[0011] The procedure involves the following steps:
[0012] a. in a basic benefit provision step:
[0013] Operating the power supply in this power supply network at a first predetermined active power setpoint, wherein the power supply is designed for a power supply active power rating and is set up to deliver alternating current electrical power to the power supply network according to a setpoint with a power supply slope of a frequency-active power characteristic;
[0014] b. in a variation-power supply step:
[0015] Variation of the power setpoint of the power supply by a predetermined active power difference to a second active power setpoint;
[0016] c. in a network parameter detection step:
[0017] Detection of a frequency change in this power supply network that is temporally related to the variation of the changed active power setpoint; and
[0018] d. in a network performance determination step:
[0019] Determining the available active network power from
[0020] - the power supply's nominal effective power,
[0021] - the power supply slope of the frequency-active power characteristic curve,
[0022] - the network slope of the frequency-active power characteristic,
[0023] - the nominal frequency and
[0024] - the detected frequency change.
[0025] A "power supply" can refer to a single inverter or a system consisting of multiple inverters. For example, 10 or more, particularly 16, inverters can be operated on a single module controller. The inverters can be connected in parallel at their outputs. In such a case, the inverters should be driven synchronously, meaning with both the same frequency and phase.
[0026] Therefore, all participating inverters can be synchronized periodically with a synchronization interval, e.g. every 60 seconds, especially by the module control.
[0027] The synchronization interval can be adjusted by the user.
[0028] 2023P00399WO By “depositing the network slope of a frequency-active power characteristic”, it is meant that such a slope is either known or has been determined or is specified and can be used when executing the network power determination step.
[0029] "Operating or varying at or around a specified active power setpoint" also means that the power supply delivers this active power setpoint at its output and feeds it into the grid. If this is to be achieved in any way other than by specifying an active power setpoint, that is also included.
[0030] The parameters on which the network power determination procedure step is based, i.e., the power supply active nominal power,
[0031] - the power supply slope of the frequency-active power characteristic curve,
[0032] - the network slope of the frequency-active power characteristic curve,
[0033] - the nominal frequency and
[0034] - the detected frequency changes
[0035] These parameters are to be understood as being replaceable by parameters that can be directly traced back to one or more of them. The meaning of the terms "power supply slope of the frequency-active power characteristic" and "network slope of the frequency-active power characteristic," as well as other terms related to the method, power supply, and / or power supply network, are explained in more detail below in connection with the exemplary implementations.
[0036] In one aspect, the network power determination step is carried out according to the following formula:
[0037] PN₂ = DroopkP₂ (fN ΔPset1 DroopkP₁ − 100 ΔfPN₁)
[0038] 100 Δ f DroopkP1
[0039] This includes:
[0040] The available active network power: PN2
[0041] the nominal frequency: fN,
[0042] The network slope of a frequency-active power characteristic: DroopkP2
[0043] the power supply slope of a frequency-active power characteristic: DroopkP₁ the power supply active nominal power PN₁,
[0044] the detected frequency change Af.
[0045] This is a particularly good way to solve the task mentioned above.
[0046] One aspect is revealed: A method for determining the available reactive power of a power supply network operated at a nominal voltage.
[0047] 2023P00399WO is and for which a network slope of a voltage-reactive power characteristic is stored, with a power supply connected to this power supply network.
[0048] The procedure involves the following steps:
[0049] a. in a basic benefit provision step:
[0050] Operating the power supply in this power supply network at a first predetermined reactive power setpoint, wherein the power supply is designed for a power supply reactive power rating and is configured to deliver alternating current electrical power to the power supply network according to a setpoint with a power supply slope of a voltage-reactive power characteristic;
[0051] b. in a variation-power supply step:
[0052] Variation of the power setpoint of the power supply by a predetermined reactive power difference to a second reactive power setpoint;
[0053] c. in a network parameter detection step:
[0054] Detection of a voltage change in this power supply network that is temporally related to the variation of the changed reactive power setpoint; and
[0055] d. in a network performance determination step:
[0056] Determining the available reactive power from
[0057] - the nominal benefit of the power supply,
[0058] - the slope of the voltage-reactive power characteristic curve,
[0059] - the network slope of the voltage-reactive power characteristic curve,
[0060] - the nominal voltage and
[0061] - the change in voltage.
[0062] "Depositing the network slope of a voltage-reactive power characteristic" means that such a slope is either known, determined, or specified and can be used when executing the network power determination step.
[0063] "Operating or varying at or around a specified reactive power setpoint" also means that the power supply delivers this reactive power setpoint at its output and feeds it into the grid. If this is to be achieved in any way other than by specifying a reactive power setpoint, that is also included.
[0064] The parameters on which the network power determination procedure step is based, i.e., the nominal reactive power of the power supply,
[0065] - the slope of the voltage-reactive power characteristic curve,
[0066] - the grid slope of the voltage-reactive power characteristic curve,
[0067] - the nominal voltage and
[0068] 2023P00399WO - the detected frequency change
[0069] Each of these parameters should be understood as being able to be replaced by parameters that can be directly traced back to one or more of these parameters.
[0070] The meaning of the terms "power supply slope of the voltage-reactive power characteristic" and "network slope of the voltage-reactive power characteristic", as well as other terms of the method, the power supply and / or the power supply network are explained in more detail below in connection with the exemplary implementations.
[0071] In one aspect, the network power determination step is carried out according to the following formula:
[0072] DroopkQ2(UN Δ Qset1 DroopkQ1− 100
[0073] QN₂ =
[0074]
[0075] 100 Δ U DroopkQ1
[0076] This includes:
[0077] The available reactive power: QN2
[0078] the nominal voltage: UN,
[0079] The grid slope of a voltage-reactive power characteristic: DroopkQ2
[0080] The slope of a voltage-reactive power characteristic: DroopkQ₁ The nominal reactive power of the power supply: QN₁,
[0081] The detected voltage change: A U.
[0082] This is a particularly good way to solve the task mentioned above.
[0083] In one aspect, the variation-based power supply step is carried out for a predetermined time interval, and then the system returns to the basic power supply step.
[0084] This is a particularly good way to solve the task mentioned above.
[0085] In one aspect, the variation of the power setpoint is increased in the variation power supply step by the active power difference APsetl and / or reactive power difference AQsetl.
[0086] This is a particularly good way to solve the task mentioned above.
[0087] In one aspect, the variation in the power supply step reduces the variation of the power setpoint by the active power difference APsetl and / or reactive power difference AQsetl.
[0088] This is a particularly good way to solve the task mentioned above.
[0089] 2023P00399WOIn one aspect, in the variation-power supply step, the variation of the power setpoint is alternately increased by the power difference APsetl and / or reactive power difference AQsetl and then, in particular immediately afterwards, decreased by the effective power difference APsetl and / or reactive power difference AQsetl.
[0090] This is a particularly good way to solve the task mentioned above.
[0091] In one aspect, the variation-power supply step occurs with a variation frequency.
[0092] This is a particularly good way to solve the task mentioned above.
[0093] In one aspect, the network parameter detection step depends on the variation frequency.
[0094] This is a particularly good way to solve the task mentioned above.
[0095] In one aspect, the network power determination step determines by what factor the available active network power PN2 of the power supply network is greater than the active power supply nominal power PNI and / or the available reactive network power QN2 of the power supply network is greater than the reactive power supply nominal power QN1.
[0096] This is a particularly good way to solve the task mentioned above.
[0097] In one aspect, the network performance determination step determines whether an island grid exists or not.
[0098] For example, a factor of 10 could be specified. This would mean that an island network would be detected if the factor is less than 10, otherwise not.
[0099] In one aspect, this factor can be adjusted and, in particular, selected by the user.
[0100] In one aspect of the development, a control system for a power supply is disclosed, which is designed to feed alternating current electrical power into a power supply network, wherein the control system includes a computer program, or is designed to execute a computer program, wherein the computer program is configured to execute the process steps executable by a computer program according to one of the process steps described herein. The computer program may be stored in non-volatile memory for this purpose.
[0101] 2023P00399WOIn one aspect of the development, a power supply is disclosed which is designed to feed alternating current electrical power into a power supply network and which has a control described herein.
[0102] In one aspect of the development, a battery charging and discharging system is revealed with a power supply as described here, and / or a control system as described here.
[0103] Alternatively or in addition to the advantageous embodiments explained above, the advantageous embodiments and features explained in connection with the device according to the invention can be used in the method.
[0104] Further details and advantages of the development will be explained below with reference to the exemplary embodiments shown in the figures. These show:
[0105] Fig. 1 shows a power supply connected to a power supply network as part of a battery charging and discharging system with control and schematic representation of the control principles.
[0106] Fig. 2 shows a schematic representation of the process steps for determining the available network power.
[0107] Fig. 3 is a schematic diagram illustrating two process steps. Fig. 4 is a schematic representation of an embodiment of a control system. Fig. 1 shows a power supplier 1 connected to a power supply network 2 as part of a battery charging and discharging system 10 with a controller 11 and a schematic representation of the first control parameters 27 for determining the available active network power PN2 and the second control parameters 37 for determining the available reactive network power QN2.
[0108] In order to organize stable operation when several independent, grid-forming generators are connected in parallel to a power supply network, most participants, i.e., grid-forming generators, i.e., power suppliers connected to this power supply network, have so-called statics, also called "droop characteristics", which describe a dependence of the fed-in power on the grid frequency and / or voltage.
[0109] Strictly speaking, the relationship between the slope of the static characteristic curves and the available generator output in the supply network requires that the parameters for the static characteristic curves of all generators forming the network be known, which is generally not the case. However, most generators forming the network have static characteristic curves with slopes ranging from a minimum of 1% to a maximum of 10%. Therefore, it is possible to...
[0110] For example, 2023P00399WO assumes a value of 5% for active power statics that is common in Europe. This allows for at least an approximate determination.
[0111] In an electrical power supply network, also called a power grid, there are several power suppliers and several power consumers, both of which are collectively called "subscribers." Power suppliers are also called "generators" or "voltage sources" because most power suppliers operate with a voltage source characteristic. Power consumers are also called "loads."
[0112] An important parameter in the power supply network is the nominal frequency fN, which is set at 50 Hz in Europe, for example, and at 60 Hz in the USA, for example.
[0113] An important parameter in the power supply network is the nominal voltage UN, which in many European countries is, for example, 230 V. eff, and in other countries, for example, at 120 V e ff, measured from phase to neutral conductor.
[0114] The actual grid frequency f and the actual grid voltage U naturally vary slightly over time t. The variation in the actual grid frequency f can indicate, for example, whether the active power input is greater than, less than, or equal to the active power consumption. If the active power input is greater than the active power consumption, then the actual frequency is usually above the nominal frequency fN. If the active power input is less than the active power consumption, then the actual frequency f is usually below the nominal frequency fN.
[0115] For this reason, grid-stabilizing power suppliers are controlled using a so-called static characteristic, also known as the "droop characteristic" or "f / P droop," which makes the injected active power dependent on the actual grid frequency. The following constants are used for each grid-stabilizing power supplier:
[0116] a) a slope of the frequency / active power characteristic kP with the unit [Hz / W] of the static analysis, b) a percentage slope of the frequency / active power characteristic DroopkP related to the nominal values, given in %, of the static analysis,
[0117] where: DroopkP = 100 * (Δ f / fN) / (Δ P / PN), where a change in frequency and A P This is a change in a performance value. This is shown schematically in Fig. 1 with the reference symbol 27.
[0118] c) a frequency linearization point flin with the unit [Hz] of the frequency / active power characteristic DroopkP of the static analysis. The frequency linearization point flin is usually located at the nominal frequency fN of the power supply network.
[0119] 2023P00399WO The following applies to the relationship between the actual frequency f of the power supply network, the frequency linearization point flin, the slope of the frequency / active power characteristic AP and the active power setpoint Pset as well as the active power actual value Pact:
[0120] f = flin + kP (Pset − Pact)
[0121] (1.1.1)
[0122] ProoffcPJM
[0123] 100 JW (1.1.2)
[0124] Pact-Pset +
[0125]
[0126] (1.1.3)
[0127] A power supply network contains multiple power suppliers and multiple power consumers. The unambiguous allocation of quantities to individual participants is achieved by introducing indices k:
[0128] DroopkP = DroopkP k , kP = kP k ,
[0129] PN = PN k , Pact = Pact k , Pset = Pset k ,
[0130] U = U k , Ulin = Ulin k .
[0131] flin =flin^
[0132]
[0133] Substituting (1.3.1), equations (1.1.1) - (1.1.3) yield the following equations:
[0134] kP k = DroopkP k fN / 100PN k (1.3.2)
[0135] f k = flin k + kP k (Pset k − Pact k ) (1 .3.4)
[0136] p t t , -f k +flin k
[0137] Pact k, = Pset k, H - C rpr -
[0138]
[0139] Kr k (1.3.5)
[0140] If several power suppliers, e.g. as voltage sources, are connected in parallel, a common frequency f emerges for all participants. k =f. The actual power values then adjust themselves depending on the target values, the slopes of the static characteristic curves, and the frequency and voltage of the supply network.
[0141] -f-Pflin k
[0142] Pact k =Pset k P - — - Kt k (1.4.1)
[0143] 2023P00399WO In a steady state, the sum of the active power supplied by all power providers connected to the considered supply network is equal to the total active power of the Pact system, i.e., the sum of all active power drawn by power consumers. This can be described in two further equations as follows:
[0144] ) (1.4.3)
[0145]
[0146] 7 (1.4.5)
[0147] The resulting frequency of the power supply network is therefore:
[0148]
[0149] (1.4.7)
[0150] Starting from the general equations describing the power supply network above, if we now consider a network with only two network-forming power suppliers, i.e., n = 1, 2, the following equations result for the resulting frequency:
[0151]
[0152] The first participant (index 7) can represent a single power supplier, e.g. a single voltage source, e.g. a single inverter, and the second participant (index 2) can represent the sum of all other power suppliers in the power supply network.
[0153] If we now consider two cases A and B, in which the power supply with index 1 makes two different power injections PsetAl, PsetBl, and simultaneously assume that the rest of the power supply network with index 2 remains in a steady state, the following two frequencies fA,fB result:
[0154] 2023P00399WO(1.5.3)
[0155] (1.5.5)
[0156] Now, let us consider
[0157] and
[0158]
[0159] This results in:
[0160]
[0161] (1.5.7)
[0162] Solved for kP2.
[0163]
[0164] (1.5.9)
[0165] This results in an equation whereby, by changing the target values in the service provision with index 1, i.e., by p. setia property of the remaining power supply network can be inferred with the index 2.
[0166] Equation (1.5.9) can be further solved using equation (1.3.2), now with the indices 1 and 2, to give:
[0167]
[0168] (1.5.11)
[0169] Grid-forming generators with static characteristics have static characteristic curves whose slopes (DroopkP) typically range between 1% and 10%. Based on this, a relationship can be established between the slope of the static characteristic curves and the available generator capacity in an existing power supply network.
[0170] 2023P00399WOD Because, the greater the available generating capacity in an existing power supply network, the shallower the slope of the static characteristic curves. Or, the steeper the slope of the static characteristic curve, the lower the generating capacity available in the power supply network.
[0171] As in the last section, we consider a supply network formed by two network-forming voltage sources with corresponding statics.
[0172] This will be illustrated using an example:
[0173] If the following properties are assumed for the benefit provision with index 1:
[0174] DroopkP₁ = 2, PN₁ = 25 kW
[0175] in a power supply network with fN = 50 Hz,
[0176] and then. seti If the power supply network is set to 250 W, then equation (1.5.11) yields, under the further assumption that the remaining power supply network with index 2 has an active power static characteristic curve in the middle of the above-mentioned usual range, i.e. with DroopkP2 = 5:
[0177]
[0178] / (1.6.1) or
[0179]
[0180] Alternatively, for the upper limit of the usual range of a stable remaining power supply network, i.e., with DroopkP₂ = 10:
[0181] 1250
[0182] PN₂ = −125000 + 1250 / Δ_f
[0183] A
[0184] / (1.6.5)
[0185] Based on a measurement resolution of the grid inverter of approximately 3 to 5 mHz, available grid power can be reliably determined at least in the range of less than 5-10 times the nominal power, which is perfectly sufficient, for example, for the application of the method for island grid detection.
[0186] In one aspect, the procedure can be implemented with a network-forming voltage source that has appropriate static properties and the possibility of setpoint specification and frequency / voltage measurement.
[0187] The actual grid voltage U naturally varies slightly over time t. This variation in the actual grid voltage U can indicate, for example, whether the reactive power input is greater than, less than, or equal to the reactive power consumption. If the reactive power input is greater than the reactive power consumption, then the actual voltage U is usually above the nominal voltage UN. If the reactive power input is less than the reactive power consumption, then the actual voltage U is usually below the nominal voltage UN.
[0188] For this reason, grid-stabilizing power suppliers are controlled using a so-called static characteristic, also known as a "droop characteristic" or "U / Q droop," which makes the reactive power supplied dependent on the actual grid voltage. The following constants are used for each grid-stabilizing power supplier:
[0189] a) a slope of the voltage / reactive power characteristic kQ with the unit [V / VAr] of statics,
[0190] b) a percentage slope of the voltage / reactive power characteristic DroopkQ related to the nominal values, given in %, of the static,
[0191] where: DroopkQ = 100 * (AU / UN)I( Q / QN), where Au is a change in voltage and AQ is a change in power. This is shown schematically in Fig. 1 with reference 37.
[0192] c) A voltage linearization point Ulin with the unit [V] of the voltage / reactive power characteristic DroopkQ of the static analysis. The voltage linearization point Ulin is usually located at the nominal voltage UN of the power supply network.
[0193] The following applies to the relationship between the actual voltage U of the power supply network, the voltage linearization point Ulin, the slope of the voltage / reactive power characteristic kQ and the reactive power setpoint Qset as well as the reactive power actual value Qact:
[0194] U = Ulin + kQ (Qset — Qact)
[0195] (1.2.1)
[0196] DroopkQ UN
[0197] ü \Wi QN (1.2.2)
[0198] , — U+ Ulin
[0199] Qact = Qset +
[0200]
[0201] kQ (1.2.3)
[0202] A power supply network contains several power suppliers and several power consumers. The unambiguous allocation of quantities to the individual suppliers and consumers is crucial.
[0203] 2023P00399WO participants are reached through the introduction of indices:
[0204] DroopkQ = DroopkQ_k, kQ = kQ_k
[0205] QN = QN_k, Qact = Qact_k, Qset = Qset_k,
[0206] U = U_k, Ulin = Ulin_k.
[0207]
[0208] Substituting (1.3.1.2), equations (1.2.1) - (1.2.3) yield the following equations:
[0209] (1.3.3)
[0210] U_k = Ulin_k + kQ_k (Qset_k - Qact_k) (1.3.6)
[0211] Qact_k = Qset_k +
[0212]
[0213] k Qt (1.3.7)
[0214] If several power suppliers, e.g., as voltage sources, are connected in parallel, a common voltage U_k = U is established for all participants. The actual power values then adjust themselves depending on the setpoints, the slopes of the static characteristic curves, and the voltage of the supply network.
[0215]
[0216] (1.4.2)
[0217] In steady state, the sum of the reactive power supplied by all power suppliers connected to the considered supply network equals the total reactive power of the Qact system, i.e., the sum of all reactive power consumed by power consumers. This can be described in two further equations as follows:
[0218] (1.4.4)
[0219]
[0220] The resulting voltage of the power supply network is therefore:
[0221] 2023P00399WO
[0222]
[0223] (1.4.8)
[0224] Starting from the general equations describing the power supply network above, if we now consider a network with only two network-forming power suppliers, i.e., n = 1, 2, the following equations result for the resulting voltage:
[0225]
[0226] (1.5.2)
[0227] The first participant (index 7) can represent a single power supplier, e.g. a single voltage source, e.g. a single inverter, and the second participant (index 2) can represent the sum of all other power suppliers in the power supply network.
[0228] If we now consider two cases A and B, in which the power supply with index 1 makes two different power injections QsetAi, QsetBi, and simultaneously assume that the rest of the power supply network with index 2 remains in a steady state, the following two voltages UA, UB arise:
[0229] (1.5.4)
[0230]
[0231] (1.5.6)
[0232] Now, let us consider
[0233] Δ_Qset1 = QsetA₁,- QsetB₁
[0234] and
[0235] Δ_U = UA - UB
[0236] This results in:
[0237] 2023P00399WOA _ ^Qsetl
[0238]
[0239] kQ₂ + kQ₁ (1.5.8)
[0240] Solved for kQ2
[0241] Δ_U kQ₁
[0242] kQ₂ = Δ_U kQ₁ / (Δ_Qset1 kQ₁ − Δ_U)
[0243]
[0244] (1.5.10)
[0245] This results in an equation whereby, by changing the target values in the power supply with index 1, i.e., by Q. Seti a property of the remaining power supply network can be inferred with the index 2.
[0246] Equation (1.5.10) can be solved using equation (1.3.3), now with the
[0247] Indices 1 and 2 are further broken down into:
[0248] QN₂ = DroopkQ₂ (UN Δ_Qset1 DroopkQ₁ − 100 Δ_U QN₁)
[0249] Z / V,
[0250] 100 A^ rooptßj (1.5.12)
[0251] Grid-forming generators with static characteristics have static characteristic curves whose slopes (DroopkQ) typically range between 1% and 10%. Based on this, a relationship can be established between the slope of the static characteristic curves and the available generator capacity in an existing power supply network.
[0252] The greater the available generating capacity in an existing power grid, the shallower the slope of the static characteristic curves. Conversely, the steeper the slope of the static characteristic curve, the lower the generating capacity available in the power grid.
[0253] As in the last section, we consider a supply network formed by two network-forming voltage sources with corresponding statics.
[0254] This will be illustrated using an example:
[0255] If the following properties are assumed for the benefit provision with index 1:
[0256] DroopkQi = 5, QN = 25 kW
[0257] in a power supply network with UN = 230 V,
[0258] and then. Q Seti If the system is set to 250 VAr, then equation (1.5.12) yields, under the further assumption that the remaining power supply network with index 2 has a reactive power static characteristic in the middle of the above-mentioned usual range, i.e. with DroopkQ2 = 5:
[0259] 2023P00399WO
[0260]
[0261] Alternatively, for the upper limit of the usual range of a stable remaining power supply network, i.e., with DroopkQ2 = 10:
[0262] 250 (200 Δ_U − 23)
[0263] QN₂ = −
[0264] (1.6.6)
[0265] Based on a measurement resolution of the grid inverter of approximately 10 to 100 mV, available grid power can be reliably determined at least in the range of less than 5-10 times the nominal power, which is perfectly sufficient, for example, for the application of the method for island grid detection.
[0266] In one aspect, the procedure can be implemented with a network-forming voltage source that has appropriate static properties and the possibility of setpoint specification and frequency / voltage measurement.
[0267] The proposed method enables the grid-forming generator to determine the power available in the connected power supply network from other grid-forming generators. This can be used, for example, for islanding detection.
[0268] Figure 1 also shows an optional filter, specifically designed as a bandpass filter 12. The bandpass filter 12 can be part of the control unit 11.
[0269] The filter, in particular bandpass filter 12, can be arranged outside the control unit 11.
[0270] The filter, in particular bandpass filter 12, can be part of the control system 11. The filter, in particular bandpass filter 12, can be tuned to a variation frequency f1.
[0271] The filter, in particular bandpass filter 12, can be used advantageously if the variation power supply step 102 is carried out with a variation frequency f1.
[0272] The filter, in particular bandpass filter 12, can be used particularly advantageously if the network parameter -detection step 103 depends on the variation frequency f1.
[0273] 2023P00399WOThe filter, in particular bandpass filter 12, can provide the measurement for the mains frequency changes that occur exactly with variation frequency.
[0274] The filter, in particular bandpass filter 12, can therefore filter out the feedback effect on the mains frequency caused by the excitation used from the frequency response and thus allow the differentiation from influences on the mains frequency caused by other means.
[0275] Fig. 2 shows a schematic representation of the process steps for determining the available network power.
[0276] This could be, for example, the available active network power. Then the following applies:
[0277] In a basic power supply step 101, the power supply 1 in this power supply network 2 is operated at a first predetermined active power setpoint PsetAi, wherein the power supply 1 is designed for a power supply active rated power fWi, and is set up to supply alternating current electrical power according to a setpoint with a power supply slope of a frequency-active power characteristic DroopkPj into the power supply network 2.
[0278] In a variation power supply step 102, the power setpoint of the power supply 1 is changed by a predetermined active power difference. seti to a second active power setpoint PsetBj varies.
[0279] Basic service provision step 101 and variation service provision step 102 can be performed periodically with a characteristic repetition frequency. This periodic variation can occur within a specific timeframe or continuously.
[0280] In a network parameter detection step 103, a frequency change in this power supply network 2 is detected, which is temporally related to the variation of the changed active power setpoint PsetBj.
[0281] This allows for the identification of frequency changes in the measured mains frequency that occur exactly at the characteristic repetition frequency.
[0282] In network power determination step 104, the available active network power PN2 is determined from:
[0283] - the power supply active nominal power PN-i,
[0284] - the power supply slope of the frequency-active power characteristic DroopkPj, - the network slope of the frequency-active power characteristic DroopkP2,
[0285] - the nominal frequency fN and
[0286] - the detected frequency change Af.
[0287] 2023P00399WO Alternatively or additionally, Fig. 2 also shows how the available reactive power can be varied. Then the following applies:
[0288] In a basic power supply step 101, the power supply 1 in this power supply network 2 is operated at a first predetermined reactive power setpoint QsetAi, wherein the power supply 1 is designed for a power supply reactive power nominal QN, and is set up to supply AC electrical power according to a setpoint with a power supply slope of a voltage-reactive power characteristic DroopkQ! into the power supply network 2.
[0289] In a variation power supply step 102, the power setpoint of the power supply 1 is changed by a predetermined reactive power difference. Q Seti to a second reactive power setpoint QsetBj varies.
[0290] Basic service provision step 101 and variation service provision step 102 can be executed periodically with a characteristic repetition frequency. This periodic change can occur within a specific timeframe or continuously.
[0291] In a network parameter detection step 103, a voltage change AU in this power supply network 2 is detected, which is related in time to the variation of the changed reactive power setpoint QsetBj.
[0292] This allows for the identification of voltage changes in the measured mains voltage that occur precisely at the characteristic repetition frequency.
[0293] In network power determination step 104, the available reactive network power QN2 is determined from:
[0294] - the nominal power supply blind power QN,
[0295] - the slope of the voltage-reactive power characteristic DroopkQ₁ for the power supply, - the slope of the voltage-reactive power characteristic DroopkQ2 for the network,
[0296] - the nominal voltage UN and
[0297] - the detected voltage change AU.
[0298] Fig. 3 shows a schematic diagram 30 to illustrate the three process steps: basic power supply step 101, variation power supply step 102 and network parameter detection step 103.
[0299] The diagram shows the power 32 on the vertical axis versus time t on the horizontal axis.
[0300] The power can be represented, for example, by an active power setpoint PsetAi or a reactive power setpoint QsetAj.
[0301] 2023P00399WOAs Power Value 33, for example, a first predefined active power setpoint PsetAi or a first predefined reactive power setpoint QsetAj is plotted. This is intended to represent the basic power supply step 101.
[0302] In a variation power supply step 102, the power setpoint of the power supply 1 is, for example, adjusted by a predetermined active power difference. seti to a second active power setpoint PsetBj varies.
[0303] In a network parameter detection step 103, a frequency change Af in this power supply network 2 can then be detected, which is related to the variation of the changed active power setpoint PsetBj.
[0304] Alternatively or additionally, in a variation power supply step 102, the power setpoint of the power supply 1 is adjusted, for example, by a predefined reactive power difference. QSe ti varies to a second reactive power setpoint QsetBj.
[0305] In a network parameter detection step 103, a voltage change AU in this power supply network 2 can then be detected, which is related in time to the variation of the changed reactive power setpoint QsetBj.
[0306] The variation in the variation-power supply step 102 alternates between a positive value 34 and a negative value 35, with a variation period T1 and a variation frequency f1 = 1 / T1. The variation-power supply step 102 is performed for a predetermined time interval t1.
[0307] The periodic excitation can advantageously be carried out continuously, as described above.
[0308] Figure 3 shows two periods only once. This is also possible.
[0309] Fig. 4 shows a schematic representation of an embodiment of a control system 600, which is suitable for executing instructions for carrying out one or more aspects of the methods in one of the devices of the present invention. For example, the control system 600 can be used to implement the control 29 from Fig. 1. The components in Fig. 4 are to be understood as examples and do not limit the scope of use or functionality of hardware, software, firmware, embedded logic components, or a combination of several such components for implementing particular embodiments of the present invention. Some or all of the components shown can be part of the control system 600.
[0310] In this embodiment, the control system 600 includes at least one processor 601, such as a central processing unit (CPU, DSP) or a programmable logic device (PLD, FPGA). The control system 600 can also include a main memory 603 and a data memory 608, both of which are interconnected and linked with each other.
[0311] 2023P00399WO other components communicate via a bus 640. The bus 640 can also connect a display 632, one or more input devices 633, one or more output devices 634, one or more storage devices 635, and various storage media 636 to each other and to one or more devices of the processor 601, the main memory 603, and the data storage 608. All these elements can be connected to the bus 640 directly or via one or more interfaces 622, 623, 624, 625, 626, or adapters.
[0312] The control system 600 can take any suitable physical form, including but not limited to one or more integrated circuits (ICs), printed circuit boards (PCBs), mobile handheld devices, laptop or notebook computers, distributed computing systems, compute grids, or servers. The processor 601 or central processing unit (CPU) may optionally include a cache memory unit 602 for temporarily storing instructions, data, or processor addresses locally. The processor 601 is configured to support the execution of instructions stored on at least one memory medium.
[0313] The memory 603 can have various components, including, but not limited to, a direct-access memory component, e.g., RAM 604, in particular a static RAM ("SRAM"), a dynamic RAM ("DRAM"), etc., a read-only component, e.g., ROM 605, and any combination thereof. The ROM 605 can also function to communicate data and instructions unidirectionally to the processor(s) 601, and the RAM 604 can also function to communicate data and instructions bidirectionally to the processor(s) 601.
[0314] The 608 solid-state memory is bidirectionally connected to the 601 processor(s), optionally via a 607 memory control unit. The 608 solid-state memory provides additional storage capacity. It can be used to store the operating system 609, programs 610, data 611, applications 612, application programs, and the like. Often, but not always, the 608 solid-state memory is a secondary storage medium, such as a hard drive, which is slower than the primary storage, e.g.,...
[0315] Memory 603 is the primary storage medium. Memory 608 can also include, for example, a magnetic, optical, or transistorized storage device, a solid-state storage device (e.g., flash-based systems), or a combination of any of the above. In suitable cases, information storage 608 can be integrated into memory 603 as virtual storage.
[0316] The 640 bus connects a variety of subsystems. The 640 bus can be any of several types of bus structures, such as a memory bus, a memory controller, a peripheral bus, a local bus, and all combinations thereof, using a
[0317] 2023P00399WO A variety of bus architectures. Information and data can also be displayed via a display 632. Examples of a display 632 include, but are not limited to, a liquid crystal display (LCD), an organic liquid crystal display (OLED), a cathode ray tube (CRT), a plasma display, and any combination thereof. The display 632 can be connected to processor(s) 601, memory 603, 608, input devices 633, and other components via the bus 640.
[0318] The bus 640 can connect all the aforementioned components with a network interface 620 to an external network 630. This could be, for example, a LAN, WLAN, etc. It can establish connections to additional storage media, servers, printers, and display devices. It can provide access to telecommunications equipment and the internet. The bus 640 can connect all the aforementioned components with a graphics controller 621 and a graphics interface 622, which can be connected to at least one input device 633.
[0319] The bus 640 can connect all the aforementioned components to an input interface 623, which can be connected to at least one input device 633. An input device can include, for example, a keypad, a keyboard, a mouse, a pen, a touchscreen, etc.
[0320] The bus 640 can connect all the aforementioned components to an output interface 624, which can be connected to at least one output device 634. An output device 634 can have a light indicator, an LED indicator, a display (e.g., LCD, OLED, etc.), or an interface to such a device.
[0321] The bus 640 can connect all the aforementioned components to a memory access interface 625, which is connectable to at least one memory device 635. The bus 640 can connect all the aforementioned components to another memory access interface 626, which is connectable to at least one memory medium 636. A memory device 635 or a memory medium 636 can be, for example, a solid-state, magnetic, or optical memory, and in particular, a non-volatile memory. The memory medium can be disconnected from the control system during operation without data loss.
[0322] The display 632, input device 633, output device 634, storage device 635, and storage medium 636 can each be located outside the control system 600 or integrated within it. They can also be connected to the control system 600 via a connection to the internet or other network interfaces.
[0323] 2023P00399WO
Claims
Claims 1. Method for determining the available active network power PN2) of a power supply network (2) which is operated at a nominal frequency (fN) and for which a network slope of a frequency-active power characteristic {DroopkP^ is defined, with a power supply (1) connected to this power supply network (2), wherein the method comprises the following steps: a. in a basic power supply step (101): Operating the power supply (1) in this power supply network (2) at a first predetermined active power setpoint {PsetA1'), wherein the power supply (1) is designed for a power supply active rated power (ZW1), and is set up to deliver alternating electrical power according to a setpoint with a power supply slope of a frequency-active power characteristic {DroopkP1') into the power supply network (2); b. in a variation-power supply step (102): Variation of the power setpoint of the power supply (1) by a predetermined active power difference.p set i) to a second effective power setpoint {PsetBi) c. in a network parameter detection step (103): Detection of a frequency change ( / ) in this power supply network (2) that is temporally related to the variation of the changed active power setpoint {PsetBi); and d. in a network power determination step (104): Determining the available active network power PN2) from - the power supply effective nominal power (ZW1), - the power supply slope of the frequency-active power characteristic {DroopkP1'), - the network slope of the frequency-active power characteristic {DroopkP^, - the nominal frequency fN) and - the detected frequency change ( / ).
2. The method of claim 1, wherein the network power determination step (104) is performed according to the following formula: 2023P00399WO3. Method for determining the available reactive power (βJV2) of a power supply network (2) operated at a nominal voltage (UN) and for which a network slope of a voltage-reactive power characteristic (DroopkQ2) is defined, with a power supply (1) connected to this power supply network (2), wherein the method comprises the following steps: a. in a basic power supply step (101): Operating the power supply (1) in this power supply network (2) at a first predetermined reactive power setpoint (QsetAi), wherein the power supply (1) is designed for a power supply reactive power rating (ßJVi) and is set up to supply alternating electrical power according to a setpoint with a power supply slope of a voltage-reactive power characteristic (DroopkQj) into the power supply network (2); b. in a variation-power supply step (102): Variation of the power setpoint of the power supply (1) by a predetermined reactive power difference ( . Q ). Set i) to a second reactive power setpoint (QsetBi)', c. in a network parameter detection step (103): Detection of a voltage change (AU) in this power supply network (2) that is temporally related to the variation of the changed reactive power setpoint (QsetBi); and d. in a network power determination step (104): Determining the available reactive power (QN2) from - the benefit supply blind nominal benefit ((Wi), - the power supply slope of the voltage-reactive power characteristic (DroopkQi), - the network slope of the voltage-reactive power characteristic (DroopkQ2), - the nominal voltage (UN) and - the change in voltage (AU).
4. Method according to claim 3, wherein the network power determination step (104) is performed according to the following formula: DroopkQ2( UNN QsetI DroopkQ l - lOO A^ßAQ 2 100 N u DroopkQ x 2023P00399WO5. Method according to one of the preceding claims, wherein the variation power supply step (102) is performed for a predetermined time interval (t1) and then the system returns to the basic power supply step (101).
6. Method according to one of the preceding claims, wherein in the variation-power supply step (102) the variation of the power setpoint by the effective power difference (.p se ti) and / or reactive power difference. Q Set i) is increased.
7. Method according to one of the preceding claims, wherein in the variation-power supply step (102) the variation of the power setpoint by the effective power difference (.p se ti) and / or reactive power difference. Q Set i) is reduced.
8. Method according to one of the preceding claims, wherein in the variation-power supply step (102) the variation of the power setpoint alternately by the power difference. set i) and / or reactive power difference. Q Set i) increased and thereafter, in particular immediately thereafter, by the effective power difference (.p se ti) and / or reactive power difference. Q Set i) is reduced.
9. Method according to one of the preceding claims, wherein the variation power supply step (102) is performed with a variation frequency (f1).
10. Method according to claim 9, wherein the network parameter detection step (103) is dependent on the variation frequency (f1).
11. Method according to claim 10, wherein the network parameter detection step (103) is performed with a bandpass filter (12) tuned to the variation frequency (f1).
12. Method according to one of the preceding claims, wherein in the network power determination step (104) it is determined by what factor (7) the available active network power {PN2') of the power supply network (2) is greater than the active power supply nominal power (P i) and / or the available reactive network power (QN2) of the power supply network (2) is greater than the reactive power supply nominal power (£Wi).
13. Method according to one of the preceding claims, wherein in the network power determination step (104) a decision is determined as to whether an island network exists or not. 2023P00399WO14. Control (11) for a power supply (1) designed to feed alternating current electrical power into a power supply network (2), wherein the control has a computer program, or is designed to execute a computer program, wherein the computer program is set up to execute the process steps executable by a computer program according to one of the preceding claims.
15. Power supply (1) designed to supply alternating current electrical power to a power supply network (2), comprising a control (11) according to claim 14.
16. Battery charging and discharging system (10) with a power supply (1) according to claim 15 and / or a control system (11) according to claim 14. 2023P00399WO