Cooperative reactive power control method and cooperative reactive power control system

Abstract

Provided are a coordinated reactive power control method and a coordinated reactive power control system. The coordinated reactive power control method includes: obtaining a first electrical information value and a corresponding first target reference value of a new energy station grid connection point, and obtaining a second electrical information value and a corresponding second target reference value of a grid connection point of a grid-type energy storage device; obtaining a first voltage deviation value based on the first electrical information value and the first target reference value, and obtaining a second voltage deviation value based on the second electrical information value and the second target reference value; determining a first reactive power target value of the new energy power generation device based on the first voltage deviation value, and determining a voltage instruction reference value of the grid-type energy storage device based on the second voltage deviation value, issuing a voltage instruction corresponding to the voltage instruction reference value to the grid-type energy storage device, and issuing a reactive power instruction corresponding to the first reactive power target value to the new energy power generation device.

Description

Technical Field

[0001] The present application relates to the field of new energy, and more specifically, to a collaborative reactive power control method and a collaborative reactive power control system for new energy stations. Background Art

[0002] Reactive power control systems for new energy stations generally use closed-loop voltage control, with the final steady-state operating point falling within a relatively small deadband voltage deviation range. At this point, the system's reactive output will be within upper and lower limits. Without considering system reactive power losses, the actual reactive output of the reactive source controlled by the station's reactive power control system will be the same as the reactive output measured at the control point. At this point, the reactive output of the grid-connected energy storage device (referred to as energy storage or energy storage) will remain within the current reactive output range. However, this may result in reactive circulating currents due to the higher reactive output of the energy storage device and the lower output of the controlled reactive source at the new energy station.

[0003] This can lead to irrational reactive power distribution, resulting in a fast but inaccurate reactive power control response for energy storage devices. From a system perspective, long-term use of reactive power by energy storage devices is undesirable, as it can affect their active power response. Energy storage devices primarily address sudden or transient voltage changes in the system, enabling rapid regulation, which is desirable. However, maintaining a constant reactive power output reduces the ability to regulate transient reactive power, hindering overall control.

[0004] Under steady-state regulation control, the reactive power source of the new energy station is sufficient to meet the needs of voltage regulation, and other systems are often not required to make unnecessary adjustments to the reactive power within the station, especially when the voltage has reached a certain control target range.

[0005] Therefore, the current control strategy cannot achieve the optimal control effect and may even affect the functional objectives of the overall system (for example, the active power regulation of energy storage equipment is affected by the large reactive output, and when the reactive output is large, the active output will inevitably be affected). It is necessary to comprehensively consider the reactive power control of the station and energy storage equipment. Summary of the Invention

[0006] One of the objectives of the present disclosure is to provide a collaborative reactive power control method for collaborative control of grid-type energy storage equipment and new energy power generation equipment, which can improve control effects.

[0007] One of the purposes of the present disclosure is to provide a collaborative reactive power control method that can compensate for the shortcomings of low reactive power control accuracy of grid-type energy storage equipment and slow transient response speed of new energy power generation equipment and centralized reactive power compensation equipment.

[0008] According to a first aspect of the present disclosure, a collaborative reactive power control method for a new energy station is provided, wherein the new energy station includes new energy power generation equipment and a grid-type energy storage device, and the collaborative reactive power control method includes: obtaining a first electrical information value and a corresponding first target reference value of a grid-connected point of the new energy station, and obtaining a second electrical information value and a corresponding second target reference value of a grid-connected point of the grid-type energy storage device; obtaining a first voltage deviation value based on the first electrical information value and the first target reference value, and obtaining a second voltage deviation value based on the second electrical information value and the second target reference value; determining a first reactive power target value of the new energy power generation device based on the first voltage deviation value, and determining a voltage command reference value of the grid-type energy storage device based on the second voltage deviation value, issuing a voltage command corresponding to the voltage command reference value to the grid-type energy storage device, and issuing a reactive power command corresponding to the first reactive power target value to the new energy power generation device.

[0009] According to a second aspect of the present disclosure, a collaborative reactive power control system for a new energy station is provided. The new energy station includes new energy power generation equipment and grid-type energy storage equipment. The collaborative reactive power control system may include: a station reactive power control system, configured to: obtain a first electrical information value and a corresponding first target reference value of a grid-connected point of the new energy station, determine a first voltage deviation value according to the first electrical information value and the first target reference value, determine a first reactive power target value of the new energy power generation equipment based on the first voltage deviation value, and issue a reactive power instruction corresponding to the first reactive power target value to the new energy power generation equipment; a grid-type energy storage control system, configured to: obtain a second electrical information value and a corresponding second target reference value of a grid-connected point of the grid-type energy storage equipment, obtain a second voltage deviation value according to the second electrical information value and the second target reference value, determine a voltage instruction reference value of the grid-type energy storage equipment based on the second voltage deviation value, and issue a voltage instruction corresponding to the voltage instruction reference value to the grid-type energy storage equipment.

[0010] According to a third aspect of the present disclosure, a new energy station controller is provided, which includes a memory and a processor. The memory stores instructions or programs, and when the instructions or programs are executed by the processor, the processor is prompted to execute the above-mentioned collaborative reactive power control method.

[0011] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is prompted to execute the above-mentioned collaborative reactive power control method.

[0012] According to the embodiment of the present disclosure, the coordinated reactive power control method provides reactive power through energy storage equipment to prevent excessive voltage drops in the grid, and provides reactive power through new energy power generation equipment to provide reactive power support, so that the grid voltage gradually stabilizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram showing the basic configuration of a new energy station including a wind turbine generator set.

[0014] Figure 2 It shows Figure 1 Schematic diagram of how the energy storage device is connected to the external power grid.

[0015] Figure 3 is a flowchart illustrating a coordinated reactive power control method according to a first embodiment of the present disclosure.

[0016] Figure 4 is a flow chart illustrating obtaining a first voltage deviation value according to an embodiment of the present disclosure.

[0017] Figure 5 is a block diagram illustrating a portion of a coordinated reactive power control system according to a first embodiment of the present disclosure.

[0018] Figure 6 is a flowchart illustrating a process of obtaining a second voltage deviation value according to a second embodiment of the present disclosure.

[0019] Figure 7 is a block diagram illustrating a portion of a coordinated reactive power control system according to a second embodiment of the present disclosure.

[0020] Figure 8 is a flow chart illustrating determination of a first reactive power target value according to an embodiment of the present disclosure;

[0021] Figure 9 is a flow chart illustrating determination of a voltage command reference value of a grid-type energy storage device according to an embodiment of the present disclosure.

[0022] Figure 10 is a block diagram illustrating a station reactive power control system according to an embodiment of the present disclosure.

[0023] Figure 11 is a block diagram illustrating a grid-type energy storage control system according to an embodiment of the present disclosure.

[0024] Figure 12 is a block diagram illustrating a coordinated reactive power control system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] The following detailed description is provided to assist in gaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, the order of operations described herein is merely exemplary and is not limited to the order set forth herein. Equivalent substitutions or variations are possible, except for operations that must occur or be performed in a specific order. Furthermore, for the sake of clarity and conciseness, descriptions of matters known in the art may be omitted or simplified.

[0026] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains after understanding the present disclosure. Unless expressly defined otherwise herein, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0027] Unless otherwise specified, the same reference numerals generally refer to the same elements (e.g., components, steps, and methods). Reference numerals described in previous embodiments may be omitted if they appear again in later embodiments. In addition, the technical features described in different or the same embodiments may be combined in any manner, as long as the combined embodiments or technical solutions are complete and can solve the technical problems of the present application or achieve the technical effects described or not described in this disclosure but can be determined based on the above complete technical solutions. The terms used in this disclosure are explained below.

[0028] The present disclosure fully utilizes the grid-building characteristics of the grid-building energy storage equipment, which has good transient support effect and fast control speed, and the high response accuracy of the new energy power generation equipment, to realize the comprehensive reactive power control of the grid-building energy storage equipment and the new energy units at the station end, meet the dispatching steady-state reactive power control target, achieve rapid transient reactive power support and prevent the deterioration of system faults, and improve the stability of system operation.

[0029] Figure 1 It is a schematic diagram showing the basic configuration of a new energy station including a wind turbine generator set.

[0030] like Figure 1 As shown, the new energy station may include new energy power generation equipment and energy storage equipment (for example, grid-type energy storage equipment), and multiple wind turbines A001, A002, A003 and A004, B001, B002, B003, B004, B005, C001, C002, C003, C004, D001, D002 and D003 as new energy power generation equipment can be electrically connected to the low-voltage side bus. In addition, the energy storage equipment and the centralized reactive power compensation equipment E0001 as the reactive controlled source can be electrically connected to the low-voltage side bus, which is located on the low-voltage side of the step-up transformer. The grid connection point of the new energy station can be located on the high-voltage side bus, and the grid connection point can be electrically connected to the external power grid. The number and capacity of wind turbines are not specifically limited.

[0031] In addition, as an example, a new energy station may include a wind farm station, a photovoltaic station, etc., but the present disclosure is not limited thereto. When the new energy station can also be a combination of a wind farm station and a photovoltaic station, the new energy power generation equipment can include a wind turbine generator set, a photovoltaic generator, etc.

[0032] Figure 2 It shows Figure 1 Schematic diagram of how the energy storage device is connected to the external power grid.

[0033] Reference Figure 2 The energy storage device (referred to as the energy storage device) power conversion module and the energy storage boost transformer can be electrically connected to each other. The power conversion module can be electrically connected to the low-voltage side of the boost transformer, and the high-voltage side of the boost transformer can be electrically connected to the external power grid via the station main transformer. The grid connection point of the energy storage device can be located at the output end or output side of the boost transformer, but this is only an example. The grid connection point of the energy storage device may vary depending on the design of the energy storage device.

[0034] The above are merely examples of the structure of the energy storage device and the way the energy storage device is connected to the power grid, and the present disclosure is not limited thereto. As an example, the energy storage device itself may not include a transformer, but may be configured with a transformer externally.

[0035] Figure 3 is a flowchart illustrating a coordinated reactive power control method according to a first embodiment of the present disclosure, Figure 4 is a flow chart illustrating a method of obtaining a first voltage deviation value according to an embodiment of the present disclosure, Figure 5 is a block diagram illustrating a portion of a coordinated reactive power control system according to a first embodiment of the present disclosure.

[0036] Reference Figure 3 According to an embodiment of the present disclosure, the coordinated reactive power control method may include step S310, step S320, step S330 and step S340.

[0037] In step S310, a first electrical information value and a corresponding first target reference value of a new energy station grid connection point are obtained, and a second electrical information value and a corresponding second target reference value of a grid connection point of a grid-connected energy storage device are obtained.

[0038] As an example, electrical information values ​​of the grid connection point of the new energy station can be obtained through various sensors. The electrical information values ​​may include but are not limited to active power measurement values, voltage measurement values, and reactive power measurement values, and these measurement values ​​may all be average values.

[0039] For example, active power measurements can be obtained using instruments specifically designed to measure parameters such as power, such as power analyzers, or calculated using voltage and current measurements using current and voltage sensors. Reactive power measurements can be obtained using a reactive power meter or calculated from active power and apparent power. For example, all of these electrical information values ​​can be obtained from telecontrol equipment.

[0040] That is to say, the step of obtaining electrical information values ​​in the coordinated reactive power control method of the present invention may only be a reading step, and the coordinated reactive power control method of the present invention may directly read these data from the relevant detection module (for example, remote control equipment) without the need to measure these electrical quantities separately.

[0041] In step S320 , a first voltage deviation value is obtained according to the first electrical information value and the first target reference value, and a second voltage deviation value is obtained according to the second electrical information value and the second target reference value.

[0042] As an example, the first electrical information value and the first target reference value may be a voltage measurement value and a voltage command reference value, respectively. means,wfc It can be the average voltage of the grid connection point of the new energy station, the voltage command reference value V ref,wfc It can be the voltage reference command value obtained from the scheduler.

[0043] The first voltage deviation value can be obtained by subtracting the first electrical information value from the first target reference value. However, this is only an example, and the voltage measurement value V means,wfc and a first target reference value are preprocessed, and then a first voltage deviation value is obtained based on the preprocessed data.

[0044] As an example, the voltage measurement value V means,wfc Filtering is performed to remove high-frequency components. Low-pass filtering is performed on the voltage measurement value to improve control accuracy. In addition, the first target reference value can be limited. The limiting operation can prevent overvoltage and help maintain stable operation of the system. The upper and lower limits of the limiting operation (V max,wfc and V min,wfc ) can be 1.1 pu and 0.9 pu respectively. In addition, a dead zone can be set to first determine the effective control deviation value and then limit the effective control deviation value to obtain the first voltage deviation value.

[0045] Reference Figure 4 The step of obtaining the first voltage deviation value according to the first electrical information value and the first target reference value may include step S321 and step S322.

[0046] In step S321, a first effective control deviation value ΔV is calculated based on the first electrical information value, the first target reference value and the preset first dead zone. wfc .

[0047] The first effective control deviation value ΔV wfc It can be calculated by the following formula 1.

[0048]

[0049] In formula (1), VD bpos,wfc Indicates the upper limit of the first dead zone, VD bneg,wfc Indicates the lower limit of the first dead zone. As an example, VD bpos,wfc Can be 0.5kV, VD bneg,wfc It can be 0.3kV.

[0050] In step S322 , a first voltage deviation value is determined based on the first effective control deviation value.

[0051] As an example, the first effective control deviation value may be calculated based on the first electrical information value, the clipped first target reference value, and a preset first dead zone, and the clipped first effective control deviation value may be determined as the first voltage deviation value.

[0052] Limit upper limit V errmax,wfc and the lower limit value V errmin,wfc The value of is not limited to a specific value and can be adjusted as needed. wfc When the first effective control deviation value is between the upper limit value and the lower limit value, the first effective control deviation value is the first voltage deviation value. When the first effective control deviation value is less than the lower limit value, the lower limit value V errmin,wfc is the first voltage deviation value. When the first effective control deviation value is greater than the upper limit value, the upper limit value V errmax,wfc is the first voltage deviation value.

[0053] For details, please refer to Figure 5 , where V ref,wfc V is the voltage reference value sent by the dispatching control system (dispatching AVC system) to the station reactive power control system. max,wfc is the upper limit value of the voltage reference instruction (limit upper limit value), V min,wfc is the lower limit value of the voltage reference instruction (limit lower limit value), V errmax,wfc is the voltage deviation upper limit (limit upper limit), V errmin,wfc VD is the voltage deviation lower limit (limit lower limit), bneg , wfc is the lower limit of the first dead zone, VD bpos,wfc The voltage reference command value after limiting is V ref,wfc and low-pass filtered (low-pass filter T v,wfc The voltage measurement value V is the first-order inertia filter time constant of the voltage measurement value) meas,wfc The difference is made, and then the effective deviation value is determined after considering the preset first dead zone, and then the first voltage deviation value is obtained after limiting.

[0054] It should be noted that the above-mentioned various limiting operations, filtering, and dead zone settings are all exemplary, and at least one of them may be selectively used according to needs, or none of them may be used.

[0055] Figure 6 is a flow chart illustrating obtaining a second voltage deviation value according to a second embodiment of the present disclosure, Figure 7 is a block diagram illustrating a portion of a coordinated reactive power control system according to a second embodiment of the present disclosure.

[0056] Reference Figure 6 The step of obtaining the second voltage deviation value according to the second electrical information value and the second target reference value may include step S323 and step S324.

[0057] In step S323 , a second effective control deviation value is calculated based on the second electrical information value, the second target reference value, and a preset second dead band.

[0058] The second effective control deviation value can be calculated by the following formula (2).

[0059]

[0060] In formula (2), VD bpos,ess Indicates the upper limit of the second dead zone, VD bneg,ess Indicates the lower limit of the second dead zone.

[0061] In step S324 , a second voltage deviation value is determined based on the second effective control deviation value.

[0062] As an example, the second effective control deviation value may be calculated based on the second electrical information value, the clipped second target reference value, and a preset second dead zone, and the clipped second effective control deviation value may be determined as the second voltage deviation value.

[0063] Limit upper limit V errmax,ess and the lower limit value V errmin,ess The value of is not limited to a specific value and can be adjusted as needed. ess When the second effective control deviation value is between the upper limit value and the lower limit value, the second effective control deviation value is the second voltage deviation value. When the second effective control deviation value is less than the lower limit value, the lower limit value V errmin,ess is the second voltage deviation value. When the second effective control deviation value is greater than the upper limit value, the upper limit value V errmax,ess is the second voltage deviation value.

[0064] For details, please refer to Figure 7 , where V ref,essis the voltage reference value received by the grid-type energy storage (i.e., the voltage instruction reference value sent by the station reactive power control system to the grid-type energy storage device), V max,ess is the upper limit value of the voltage reference instruction (limit upper limit value), V min,ess is the lower limit value of the voltage reference instruction (limit lower limit value), V errmax,ess is the voltage deviation upper limit (limit upper limit), V errmin,ess VD is the voltage deviation lower limit (limit lower limit), bneg,ess is the lower limit of the second dead zone, VD bpos,ess The voltage reference command value after limiting is V ref,ess The low-pass filtered voltage measurement value V meas,ess The difference is made, and then the effective deviation value is determined after considering the preset second dead zone, and then the second voltage deviation value is obtained after limiting.

[0065] The above-mentioned limiting, filtering, and dead zone settings are also exemplary and can be used selectively as needed.

[0066] Reference Figure 3 In step S330, a first reactive power target value of the new energy power generation device is determined based on the first voltage deviation value, and a voltage command reference value of the grid-type energy storage device is determined based on the second voltage deviation value.

[0067] As an example, the first reactive power target value of the new energy power generation equipment and the voltage command reference value of the grid-connected energy storage device can be determined by proportional integral (PI) regulation. This is described in detail below.

[0068] Figure 8 is a flowchart illustrating a method for determining a first reactive power target value according to an embodiment of the present disclosure. Figure 9 is a flowchart illustrating a method for determining a voltage command reference value of a grid-type energy storage device according to an embodiment of the present disclosure. Figure 10 is a block diagram showing a station reactive power control system according to an embodiment of the present disclosure, Figure 11 is a block diagram illustrating a grid-type energy storage control system according to an embodiment of the present disclosure.

[0069] Reference Figure 8 The step of determining the first reactive power target value of the new energy power generation equipment based on the first voltage deviation value may include step S331, step S332 and step S333.

[0070] In step S331 , a first reactive deviation value is determined according to a product of a first voltage deviation value and a first voltage deviation conversion coefficient.

[0071] As an example, the first reactive deviation value Q is calculated according to the first voltage deviation value and the first voltage deviation conversion coefficient (or referred to as the voltage deviation droop adjustment coefficient). err,wfc Specifically, the setting of the first voltage deviation conversion coefficient is generally related to the strength and voltage level of the new energy station access system. The first voltage deviation conversion coefficient can be calculated by the following formula (3).

[0072] K v,wfc =V n,wfc / X formula (3)

[0073] Where V n,wfc is the rated voltage value of the control point of the reactive power control system of the station (i.e., the new energy station), and X is the system impedance of the reactive power control system of the station. The system impedance can be calculated based on the relationship between the voltage and reactive power of the system at different times. In other words, there is a universal conversion relationship between the two. The value range of X is generally [1,100], and the recommended value for engineering projects can be 20.

[0074] The calculation method of the first reactive power target value is not limited to this, and may also be calculated based on voltage measurement values ​​and other electrical information.

[0075] In step S332, PI adjustment is performed on the first reactive deviation value to obtain a total reactive target value of the new energy station.

[0076] In step S333 , a first reactive power target value of the new energy power generation equipment is determined based on the total reactive power target value of the new energy station.

[0077] For details, please refer to Figure 10 , according to the first voltage deviation value and the first voltage deviation conversion coefficient K v,wfc The product of determines the first reactive deviation value Q err,wfc Before performing PI adjustment on the first reactive deviation value, the first reactive deviation value is limited. For example, the first reactive deviation value Q err,wfc Limit the amplitude so that its upper and lower limits are Q errmax,wfc and Q errmin,wfc .

[0078] As an example, after the first reactive deviation value is PI-regulated and the total reactive value of the new energy station is obtained, the total reactive value may be clipped to obtain the total reactive target value Q tar,wfc .

[0079] Reference Figure 10 , K p,wfc K is the proportional coefficient of the deviation PI adjustment, i,wfc is the integral coefficient of the deviation PI adjustment, S is the Laplace operator, Q tar,wfcIt is the total reactive power target value of other controlled reactive power sources in the station (including new energy power generation equipment and / or centralized reactive power compensation equipment).

[0080] Reference Figure 10 , Q set,gen1…N is the reactive power command value of each renewable energy power generation equipment, N is the number of renewable energy power generation equipment, Q set,svg1…M is the reactive power command value of each centralized reactive power device, and M is the number of centralized reactive power devices.

[0081] The total reactive power target value is distributed to each renewable energy power generation unit and centralized reactive power equipment according to a predetermined allocation strategy. The reactive power command distribution for renewable energy power generation equipment and centralized reactive power compensation equipment disclosed herein can be achieved through average distribution, proportional distribution, similarity margin distribution, and optimized distribution. This disclosure does not restrict specific distribution methods, nor does it restrict specific control methods for reactive power target device-level control of renewable energy power generation equipment and centralized reactive power compensation equipment. The only requirement is that the reactive power target closed-loop control objective be met.

[0082] In addition, refer to Figure 10 , T v,wfc K is the first-order inertia filter time constant of the voltage measurement value. trans,wfc is the energy storage voltage conversion coefficient (its calculation method will be described later).

[0083] As mentioned above, V ref,ess is the voltage reference value received by the grid-type energy storage (i.e., the voltage command reference value sent by the station reactive power control system to the grid-type energy storage device), the voltage command reference value (i.e., the first target reference value) V ref,wfc The second target reference value V can be obtained from the power grid dispatching system. ref,ess According to the first target reference value and the energy storage voltage conversion coefficient K trans,wfc The product of is calculated.

[0084] Reference Figure 9 According to an embodiment of the present disclosure, the step of determining the voltage command reference value of the grid-type energy storage device may include step S334, step S335 and step S336.

[0085] In step S334, the reactive power target command value Q is determined according to the product of the second voltage deviation value and the second voltage deviation conversion coefficient. ref,ess .

[0086] The reactive power target command value can be converted into the second voltage deviation value and the second voltage deviation conversion coefficient K according to the second voltage deviation value. v,ess The second voltage deviation conversion coefficient K is calculated by multiplying v,essThe setting of is generally related to the strength of the grid-type energy storage device connected to the system, the voltage level and the rated reactive power of the grid-type energy storage. The generally recommended value can be calculated using the following formula 4:

[0087] K v,ess =Q n,ess / V n,ess ·K ess Formula (4)

[0088] Among them, V n,ess is the rated voltage of the grid connection point of the energy storage device, Q n,ess is the rated reactive power value of the energy storage equipment grid connection point, K ess The value range is generally [1,100], and the recommended value for engineering projects is 10.

[0089] In step S335 , a second reactive deviation value is calculated based on the reactive target value and the actual reactive value in the second electrical information value.

[0090] Reference Figure 11 , can be based on the reactive power target command value Q ref,ess The second reactive deviation value can be calculated by comparing the difference between the reactive measurement value Q and the actual reactive value. means,ess Perform low-pass filtering to obtain the actual reactive power value.

[0091] Reference Figure 11 , T v,ess is the first-order inertia filter time constant of the voltage measurement value, T Q,ess is the first-order inertia filter time constant of the reactive measurement value, V max,ess is the upper limit of the voltage reference instruction, V min,ess is the lower limit of the voltage reference instruction, V errmax,ess is the voltage deviation upper limit (limit upper limit), V errmin,ess VD is the voltage deviation lower limit (limit lower limit), bneg,ess is the lower limit of the second dead zone, VD bpos,ess is the upper limit of the second dead zone, K v,ess is the second voltage deviation conversion coefficient, Q ref,ess is the reactive power target command value.

[0092] In step S336, the second reactive deviation value may be PI regulated to obtain a voltage command reference value. Figure 11 , K p,ess K is the proportional coefficient of PI regulation i,ess is the integral coefficient of PI regulation, and S is the Laplace operator.

[0093] As an example, after PI adjustment is performed on the second reactive deviation value and the voltage command value of the grid-type energy storage device is obtained, the voltage command value can be limited to obtain a voltage command reference value, and the second reactive deviation value can be limited before PI adjustment is performed on the second reactive deviation value.

[0094] Reference Figure 11 , Q errmax,ess is the upper limit of reactive power deviation (limit upper limit), Q errmin,ess is the reactive power deviation lower limit (amplitude limit lower limit), ΔE max,ess is the voltage deviation upper limit (limit upper limit), ΔE min,ess The upper and lower limits of the voltage deviation can be determined as needed.

[0095] Reference Figure 3 In step S340, a voltage command corresponding to the voltage command reference value is issued to the grid-connected energy storage device, and a reactive power command corresponding to the first reactive power target value is issued to the new energy power generation device. The reactive power command corresponding to the first reactive power target value of the new energy power generation device can be as described above and will not be repeated here.

[0096] Reference Figure 11 The voltage command corresponding to the voltage command reference value sent to the grid-type energy storage device can be superimposed with the initial value E0 of the virtual internal potential to obtain the virtual internal potential E of the grid-type converter. d , that is, the d-axis voltage reference value, and the power conversion unit is PWM modulated accordingly. The modulation of the power unit is a general control and will not be described here.

[0097] The coordinated reactive power control method according to an embodiment of the present disclosure may further include: determining a second reactive power target value of the centralized reactive power equipment of the new energy station based on the total reactive power target value of the new energy station, issuing a reactive power instruction corresponding to the second reactive power target value to the centralized reactive power equipment, and referring to Figure 10 , reactive power instructions can be sent to M centralized reactive power devices.

[0098] As described above, the first target reference value may be obtained from the grid dispatching system, and the second target reference value may be calculated based on the product of the first target reference value and the energy storage voltage conversion coefficient.

[0099] As an example, the energy storage voltage conversion coefficient is determined based on whether the measurement point of the second electrical information value is the same as the control point of the new energy station. In response to the measurement point of the second electrical information value being the same as the control point of the new energy station, the energy storage voltage conversion coefficient is determined to be 1. In response to the measurement point of the second electrical information value being different from the control point of the new energy station, the energy storage voltage conversion coefficient is calculated based on the transformation ratio of the main transformer of the new energy station and the transformation ratio of the step-up transformer between the grid-type energy storage device and the low-voltage side of the main transformer of the new energy station.

[0100] It is necessary to convert the voltage command reference value sent by the station reactive power control system to the grid-type energy storage device according to the actual project situation, that is, it is necessary to convert the K trans,wfc Perform parameter tuning, the specific tuning includes the following two situations.

[0101] When the measured voltage of the grid-connected energy storage device is the same as that of the station reactive power control system, that is, both come from the station grid connection point, the energy storage voltage conversion coefficient can be determined by the following formula (5):

[0102] K trans,wfc =1 Formula (5)

[0103] When the measured voltage of the grid-type energy storage device is different from that of the station reactive power control system, the measured voltage needs to be converted according to the electrical information between the grid-type energy storage and the actual control point of the new energy station to obtain the actual voltage value of the control point.

[0104] Specifically, if the measured voltage of the grid-type energy storage is the grid connection point voltage of the power conversion module, the transformation ratio of the main transformer of the new energy station is k1, and the transformation ratio of the step-up transformer between the grid-type energy storage device and the low-voltage side system of the station main transformer is k2, and the line voltage drop in addition to the voltage level change is further considered, the following formula (6) can be used for calculation:

[0105] K trans,wfc =1 / k1 / k2+ΔV Formula (6)

[0106] Among them, ΔV is related to the actual system circuit. If the actual electrical distance is short, that is, the line transmission distance excluding the transformer is short, it can be ignored. If the electrical distance is long, the voltage drop compensation can be performed according to the following formula (7):

[0107] ΔV=(P·R+Q·X) / Vn Formula (7)

[0108] In formula (7), P is the active power of the energy storage device, Q is the reactive power of the energy storage device, R is the equivalent resistance of the line (i.e., the equivalent resistance from the energy storage device to the grid connection point), X is the equivalent reactance of the line (the equivalent reactance from the energy storage device to the grid connection point), and Vn is the rated voltage of the line. It should be noted that the above calculation formula is also applicable when there are multi-stage transformers. It is only necessary to consider the voltage deviation of each stage comprehensively.

[0109] Taking into account the coordination of the regulation process, the regulation control dead zone of the grid-type energy storage device can be greater than or equal to the voltage regulation dead zone of the station reactive power control system. The set values ​​of the first dead zone and the second dead zone in the present disclosure can both be positive values, that is:

[0110] VD bpos,ess ≥0, VD bpos,wfc ≥0, VD bneg,ess ≥0, VD bneg,wfc ≥0.

[0111] For increasing the dead zone, the following formula (8) can be satisfied:

[0112] VD bpos,ess >VD bpos,wfc Formula (8)

[0113] For the lower dead zone, the following formula (9) can be satisfied:

[0114] VD bneg,ess >VD bneg,wfc Formula (9)

[0115] That is to say, the upper and lower limit values ​​of the second dead zone preset for the grid-type energy storage device are correspondingly greater than the upper limit value of the first dead zone preset for the new energy power generation device, and the upper and lower limit values ​​of the first dead zone and the second dead zone are both greater than zero.

[0116] To ensure the stability of the overall control effect, the voltage-reactive power conversion coefficient of the grid-type energy storage equipment and the station reactive power control system can satisfy the following relationship 10:

[0117] K v,ess <K v,wfc Formula (10)

[0118] That is, the first voltage deviation conversion coefficient, which is the voltage deviation droop adjustment coefficient of the grid-type energy storage device, is smaller than the second deviation conversion coefficient, which is the voltage deviation droop adjustment coefficient of the new energy power generation device.

[0119] After the reactive power regulation of the system is in place, there are two triggering regulation processes. The first is the issuance of a new command voltage, and the other is the actual system voltage fluctuation (normal fluctuation or transient fluctuation).

[0120] When a voltage command is issued, considering the difference in regulation speed between the station reactive power control system and the grid-type energy storage, the regulation speed of the grid-type energy storage is generally faster than the overall reactive power regulation of the station. Therefore, after receiving the dispatch voltage command, the station reactive power control system directly forwards the command value to the grid-type energy storage device after calculation, and performs voltage adjustment calculations. The specific voltage command calculation and command issuance logic are described in the station reactive power control logic diagram and will not be repeated here.

[0121] The command sent by the station reactive power control system to the grid-type energy storage device is a voltage command. After receiving the command, the grid-type energy storage device can respond to the voltage command quickly. Its speed and role are similar to the primary voltage regulation in the system.

[0122] Furthermore, after calculating the voltage command deviation, the station reactive power control system further performs deviation PI control to obtain the reactive power control target value, and distributes the reactive power control target value among other controlled reactive power sources in the station. Other controlled reactive power sources include grid-based power generation equipment and centralized reactive power compensation equipment. Their control role on other reactive power sources is similar to the secondary voltage regulation of the system.

[0123] Based on the above control, after the voltage command changes, the grid-type energy storage system prioritizes adjusting the reactive power control, and then the station reactive power control system further refines the voltage deviation, ultimately achieving a steady-state control effect within the dead zone of the station reactive power control.

[0124] It should be noted that during the process of adjusting the voltage deviation at the station, since the command values ​​and measurement values ​​of the grid-type energy storage and the station reactive power control system are of the same source or equivalent to the same source after calculation, the reactive output of the grid-type energy storage is continuously adjusted in the direction of gradually decreasing toward zero output according to the overall control strategy. Affected by the set value of the control dead zone, the reactive output target value of the grid-type energy storage will reach the dead zone range before the station reactive power control system and stop control adjustment (coordinated setting effect of the dead zone set value).

[0125] Furthermore, the calculated reactive power target value is zero at this point, resulting in the following advantages for the overall control process: The grid-connected energy storage device prioritizes voltage deviation adjustment, achieving rapid adjustment, equivalent to coarse adjustment. Other reactive power sources at the station continue to adjust the overall reactive power output, gradually reducing the voltage deviation, equivalent to fine-tuning the reactive voltage.

[0126] As the voltage deviation value gradually decreases, the reactive output of the grid-type energy storage gradually decreases, and the instructions of other controlled reactive source equipment in the station are supplemented in the corresponding direction. This is equivalent to a reactive power replacement process, which effectively guarantees the reactive voltage margin of the grid-type energy storage equipment, is beneficial to the transient voltage response and stable operation of the system, and is also beneficial to its response to active frequency.

[0127] When the voltage command remains unchanged and the system fluctuates, the specific effects are as follows: If the actual voltage fluctuation is normal, the reactive power control of the grid-type energy storage is not triggered. Therefore, its actual reactive power target output is still zero, but the reactive power control of the station reactive power control system is triggered and adjusted to adjust the actual system voltage to the dead zone range, completing the regulation. If the actual voltage fluctuation ΔU ≥ VD bpos,ess , ΔU≤VD bpos,wfc ≤VD bneg,ess ≤0. In this case, both the grid-type energy storage and the station reactive power control are triggered. Depending on the dead zone setting value, this may result in large voltage fluctuations or even transient voltage fluctuations. At this point, because the grid-type energy storage device's control speed is faster than the station reactive power control system's adjustment of the reactive output of other reactive sources, the voltage deviation decreases rapidly. The station reactive power control then updates the control command target value to regulate the reactive output of the entire site, gradually adjusting the voltage deviation to within the dead zone. During this process, the reactive output of the grid-type energy storage increases first and then gradually decreases, similar to the overall reactive power replacement process.

[0128] If the actual voltage fluctuation does not exceed the upper and lower limits of the dead zone, the grid-type energy storage and station reactive power control systems will not trigger control.

[0129] In summary, whether under operating conditions with voltage fluctuations or in the control process of command voltage updates, the overall control uses the actual voltage deviation value as the basis for judgment and adjusts the system to achieve optimal adjustment of the overall control. When the voltage fluctuation is large, the grid-type energy storage can quickly adjust the voltage fluctuation based on the optimized droop control. The magnitude of the adjustment is proportional to the voltage deviation, which is beneficial to prevent the deterioration of voltage fluctuations to a certain extent and belongs to rapid preventive control.

[0130] Subsequently, the station's reactive power control system followed up with detailed reactive power regulation, adjusting the voltage to within the deviation target range. During this process, the station's controlled reactive power source equipment gradually replaced the reactive output of the grid-type energy storage, reserving more sufficient reactive power reserves for the system's transient voltage support, which plays a very important role in the system's operational stability.

[0131] Figure 12 is a block diagram illustrating a coordinated reactive power control system according to an embodiment of the present disclosure.

[0132] The coordinated reactive power control system according to an embodiment of the present disclosure includes a station reactive power control system 110 and a grid-type energy storage control system 120 .

[0133] The station reactive power control system 110 can obtain the first electrical information value and the corresponding first target reference value of the new energy station grid connection point, determine the first voltage deviation value based on the first electrical information value and the first target reference value, determine the first reactive power target value of the new energy power generation equipment based on the first voltage deviation value, and issue a reactive power instruction corresponding to the first reactive power target value to the new energy power generation equipment.

[0134] The station reactive power control system 110 can obtain electrical information values ​​from telecontrol equipment and longitudinally encrypted target reference values ​​from the dispatching AVC system. The station reactive power control system 110 can send reactive power commands to grid-connected power generation units (e.g., photovoltaic power generation units and / or wind power generation units). Furthermore, the station reactive power control system 110 can also send reactive power commands to centralized reactive power compensation equipment.

[0135] The grid-type energy storage control system 120 can obtain various electrical information values ​​from the telecontrol equipment and a second target reference value from the station reactive power control system. It can then determine a second voltage deviation value based on the second electrical information value and the second target reference value. Based on the second voltage deviation value, it can determine a voltage command reference value for the grid-type energy storage device and issue a voltage command corresponding to the voltage command reference value to the grid-type energy storage device. The coordinated reactive power control system according to embodiments of the present disclosure can be deployed on a station controller.

[0136] According to an embodiment of the present disclosure, the new energy station controller may include a memory and a processor, wherein the memory stores instructions or programs, and when the instructions or programs are executed by the processor, the processor is prompted to execute the above-mentioned coordinated reactive power control method.

[0137] According to a computer-readable storage medium of an embodiment of the present disclosure, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is prompted to execute the above-mentioned coordinated reactive power control method.

[0138] The instructions stored in the computer-readable storage medium can be executed in an environment deployed in a computer device such as a client, a host, an agent device, a server, etc. It should be noted that the instructions can also be used to perform additional steps in addition to the above steps or perform more specific processing when performing the above steps. The contents of these additional steps and further processing have been described in detail in the referenced embodiment. Figures 1 to 12 It is mentioned in the description of related systems and methods, so it will not be repeated here to avoid repetition.

[0139] It should be noted that the collaborative reactive power control method according to the exemplary embodiment of the present disclosure can completely rely on the operation of computer programs or instructions to realize the corresponding functions, that is, each device corresponds to each step in the functional architecture of the computer program, so that the entire system is called through a special software package (for example, lib library) to realize the corresponding functions.

[0140] On the other hand, when the systems, units or modules shown in the accompanying drawings are implemented in software, firmware, middleware or microcode, the program code or code segments for performing the corresponding operations can be stored in a computer-readable medium such as a storage medium, so that at least one processor or at least one computing device can perform the corresponding operations by reading and running the corresponding program code or code segments. In addition, the computer-readable medium or storage medium can prompt the processor to execute the above-mentioned collaborative reactive power control method when the computer program is executed by the processor.

[0141] For example, according to an exemplary embodiment of the present disclosure, a computer device including a readable medium storing computer program instructions may be provided, wherein the instructions, when executed by at least one computing device, prompt the at least one computing device to perform at least one of the above steps.

[0142] According to the embodiments of the present disclosure, the coordinated reactive power control method and system of grid-connected energy storage and new energy power generation equipment is implemented based on the site-side AVC control system, which receives the voltage control instructions from the dispatcher upward and coordinates the control of the reactive power output of each grid-connected power generation unit, centralized reactive power compensation equipment and grid-connected energy storage equipment downward.

[0143] According to the embodiments of the present disclosure, the droop control of the grid-type energy storage is optimized and improved so that it can coordinate with the station control system. In the station control system, the voltage reference instruction for the grid-type energy storage is corrected, calculated and issued. At the same time, the dead zone setting and the voltage-reactive power conversion coefficient setting in the grid-type energy storage control system and the station reactive power control system are coordinated with each other. The overall control fully utilizes the characteristics of the grid-type energy storage equipment, which has a fast voltage regulation speed, and the new energy power generation equipment and centralized reactive power equipment, which has a high reactive power response accuracy. It makes up for the shortcomings of the traditional grid-type energy storage equipment, which has a low reactive power control accuracy, and the new energy power generation equipment and centralized reactive power compensation equipment, which has a slow transient response speed. The advantages are complementary, and while meeting the grid voltage regulation requirements, the transient voltage response speed of the system and the safe and stable operation capability of the system are greatly improved.

[0144] The coordinated reactive power control method according to the embodiment of the present disclosure can improve the control effect for the coordinated control of grid-type energy storage equipment and new energy power generation equipment.

[0145] The coordinated reactive power control method according to the embodiment of the present disclosure can make up for the shortcomings of low reactive power control accuracy of grid-type energy storage equipment, slow transient response speed of new energy power generation equipment and centralized reactive power compensation equipment, and meet the voltage regulation requirements of the power grid.

Claims

1. A collaborative reactive power control method for a new energy station, characterized in that: The new energy station includes new energy power generation equipment and grid-type energy storage equipment, and the coordinated reactive power control method includes: Obtaining a first electrical information value and a corresponding first target reference value of a new energy station grid connection point, and obtaining a second electrical information value and a corresponding second target reference value of a grid connection point of a grid-connected energy storage device; Obtaining a first voltage deviation value according to the first electrical information value and the first target reference value, and obtaining a second voltage deviation value according to the second electrical information value and the second target reference value; Based on the first voltage deviation value, a first reactive power target value of the new energy power generation device is determined by PI regulation, and based on the second voltage deviation value, a voltage command reference value of the grid-type energy storage device is determined by PI regulation. issuing a voltage instruction corresponding to the voltage instruction reference value to the grid-type energy storage device, and issuing a reactive power instruction corresponding to the first reactive power target value to the new energy power generation device, Among them, the first voltage deviation conversion coefficient serving as the voltage deviation droop adjustment coefficient of the grid-type energy storage device is smaller than the second deviation conversion coefficient serving as the voltage deviation droop adjustment coefficient of the new energy power generation device, the upper and lower limit values ​​of the second dead zone pre-set for the grid-type energy storage device are correspondingly greater than the upper limit value of the first dead zone pre-set for the new energy power generation device, and the upper and lower limit values ​​of the first dead zone and the second dead zone are both greater than zero.

2. The coordinated reactive power control method for a new energy station according to claim 1, characterized in that: The first target reference value is obtained from a power grid dispatching system, and the second target reference value is calculated based on the product of the first target reference value and an energy storage voltage conversion coefficient.

3. The coordinated reactive power control method for a new energy station according to claim 2 is characterized in that: The energy storage voltage conversion coefficient is determined according to whether a measurement point of the second electrical information value is the same as a control point of the new energy station.

4. The coordinated reactive power control method for a new energy station according to claim 2 is characterized in that: In response to a measurement point of the second electrical information value being the same as a control point of the new energy station, determining the energy storage voltage conversion coefficient to be 1; In response to the fact that the measurement point of the second electrical information value is different from the control point of the new energy station, the energy storage voltage conversion coefficient is calculated based on the transformation ratio of the main transformer of the new energy station and the transformation ratio of the step-up transformer between the grid-type energy storage device and the low-voltage side of the main transformer of the new energy station.

5. The coordinated reactive power control method for a new energy station according to claim 1, characterized in that: The step of obtaining a first voltage deviation value according to the first electrical information value and the first target reference value includes: Calculating a first effective control deviation value based on the first electrical information value, the first target reference value, and a preset first dead zone; The first voltage deviation value is determined based on the first effective control deviation value.

6. The coordinated reactive power control method for a new energy station according to claim 5 is characterized in that: The first effective control deviation value is calculated based on the first electrical information value, the first target reference value after clipping, and a preset first dead zone, and the first effective control deviation value after clipping is determined as the first voltage deviation value.

7. The coordinated reactive power control method for a new energy station according to claim 1, characterized in that: The step of determining a first reactive power target value of the new energy power generation equipment based on the first voltage deviation value includes: determining a first reactive deviation value according to a product of the first voltage deviation value and a first voltage deviation conversion coefficient; Performing PI adjustment on the first reactive power deviation value to obtain a total reactive power target value of the new energy station; A first reactive power target value of the new energy power generation equipment is determined based on the total reactive power target value of the new energy station.

8. The coordinated reactive power control method for a new energy station according to claim 7 is characterized in that: After performing PI adjustment on the first reactive deviation value and obtaining the total reactive value of the new energy station, the total reactive value is limited to obtain the total reactive target value, and the first reactive deviation value is limited before performing PI adjustment on the first reactive deviation value.

9. The coordinated reactive power control method for a new energy station according to claim 7, characterized in that: The coordinated reactive power control method further includes: Determining a second reactive power target value of the centralized reactive power equipment of the new energy station based on the total reactive power target value of the new energy station; A reactive power instruction corresponding to the second reactive power target value is issued to the centralized reactive power device.

10. The coordinated reactive power control method for a new energy station according to claim 1, characterized in that: The step of obtaining a second voltage deviation value according to the second electrical information value and the second target reference value includes: calculating a second effective control deviation value based on the second electrical information value, the second target reference value, and a preset second dead band; The second voltage offset value is determined based on the second effective control offset value.

11. The coordinated reactive power control method for a new energy station according to claim 10, characterized in that: The second effective control deviation value is calculated based on the second electrical information value, the second target reference value after clipping, and a preset second dead zone, and the second effective control deviation value after clipping is determined as the second voltage deviation value.

12. The coordinated reactive power control method for a new energy station according to claim 1, characterized in that: The step of determining the voltage command reference value of the grid-type energy storage device based on the second voltage deviation value includes: determining a reactive power target command value according to a product of the second voltage deviation value and a second voltage deviation conversion coefficient; Calculating a second reactive deviation value based on the reactive target value and an actual reactive value in the second electrical information value; PI regulation is performed on the second reactive deviation value to obtain the voltage command reference value.

13. The coordinated reactive power control method for a new energy station according to claim 12, characterized in that: After PI adjustment is performed on the second reactive deviation value and the voltage command value of the grid-type energy storage device is obtained, the voltage command value is limited to obtain the voltage command reference value, and the second reactive deviation value is limited before PI adjustment is performed on the second reactive deviation value.

14. A collaborative reactive power control system for a new energy station, characterized in that: The new energy station includes new energy power generation equipment and grid-type energy storage equipment, and the coordinated reactive power control system includes: A station reactive power control system is configured to: obtain a first electrical information value and a corresponding first target reference value of a new energy station grid connection point, determine a first voltage deviation value based on the first electrical information value and the first target reference value, determine a first reactive power target value of the new energy power generation equipment through PI regulation based on the first voltage deviation value, and issue a reactive power instruction corresponding to the first reactive power target value to the new energy power generation equipment; The grid-type energy storage control system is configured to: obtain a second electrical information value and a corresponding second target reference value of a grid-type energy storage device grid connection point, obtain a second voltage deviation value based on the second electrical information value and the second target reference value, determine a voltage command reference value of the grid-type energy storage device through PI regulation based on the second voltage deviation value, and issue a voltage command corresponding to the voltage command reference value to the grid-type energy storage device. Among them, the first voltage deviation conversion coefficient serving as the voltage deviation droop adjustment coefficient of the grid-type energy storage device is smaller than the second deviation conversion coefficient serving as the voltage deviation droop adjustment coefficient of the new energy power generation device, the upper and lower limit values ​​of the second dead zone pre-set for the grid-type energy storage device are correspondingly greater than the upper limit value of the first dead zone pre-set for the new energy power generation device, and the upper and lower limit values ​​of the first dead zone and the second dead zone are both greater than zero.

15. A new energy station controller, characterized in that: The new energy station controller includes a memory and a processor, wherein the memory stores instructions or programs, and when the instructions or programs are executed by the processor, the processor is prompted to execute the coordinated reactive power control method according to any one of claims 1 to 13.

16. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to execute the coordinated reactive power control method according to any one of claims 1 to 13.

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