CN113054690B - Voltage control method and system based on event triggering and electronic equipment - Google Patents
Voltage control method and system based on event triggering and electronic equipment Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/50—Controlling the sharing of the out-of-phase component
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E10/70—Wind energy
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Abstract
The invention provides a voltage control method, a system and electronic equipment based on event triggering, wherein the method comprises the following steps: acquiring a voltage prediction error of the fan, and judging whether a voltage preset error is larger than a preset error threshold value or not; if the preset voltage error is smaller than a preset error threshold value, triggering primary voltage control, wherein the primary voltage control is to adjust the voltage of the fan based on a drooping reactive power control model; and if the preset voltage error is larger than the preset error threshold, triggering secondary voltage control, wherein the secondary voltage control is to regulate the voltage of the fan based on model prediction control, and the secondary voltage control considers the influence parameters in the primary voltage control. The invention can finely control the voltage of the fan by triggering the events of primary voltage control and secondary voltage control so as to deal with the problem of overvoltage at the fan end and enhance the high-voltage ride through and after-recovery capability of a large-scale wind power plant. A better balance can be achieved between wind farm voltage control performance and communication and computational burden.
Description
Technical Field
The invention relates to the technical field of new energy power generation, in particular to a voltage control method and system based on event triggering and an electronic device.
Background
The inherent intermittency and volatility of wind energy resources presents a significant challenge to the voltage stability of power systems. Since large wind farms are usually located far from the load centre, the short-circuit proportion of the system is low. Weak disturbances of the external grid may cause large fluctuations in the voltage inside the wind farm and even cascading trips of large wind turbines. Furthermore, voltage fluctuations caused by wind speed variations and low X/R ratio of the medium voltage bus during grid voltage surges may lead to more serious consequences. Therefore, it is necessary to develop a fast and practical voltage control strategy for large wind farms to cope with fast voltage fluctuations. In wind farms, disconnecting large loads, energizing subsea cables, charging capacitor banks, or asymmetric faults may cause the grid voltage to surge. Compared with voltage dip, the sudden rise of the grid voltage can cause a higher transient direct current magnetic flux component of the fan, and further more serious consequences are caused. For example, in large-scale tripping faults of fans in north China and northwest wind farms, more than half of the fans trip due to overvoltage problems of bus end nodes after successfully crossing low-voltage interference. To overcome these problems, it is necessary to further study the dynamic analysis of the sudden rise of the wind turbine grid Voltage and the corresponding High-Voltage Ride-Through (HVRT) control strategy.
The different voltage control schemes of wind farms that have been proposed so far can be summarized as centralized strategies, decentralized strategies and distributed strategies. In general, the reactive requirement of a wind farm with a centralized voltage control function is calculated according to the state of a Point of Common Coupling (PCC), and the voltage deviation can be adjusted by a central controller to all the wind turbines in the wind farm. Under decentralized voltage control, such as droop control, local control of voltage and reactive power at the PCC may be achieved by using local measurements without any communication. The distributed voltage control strategy based on optimization can minimize the voltage deviation of the bus at the wind turbine end and maintain the reactive reserve through cooperation with nearby wind turbines. However, most of the wind farm voltage control strategies described above still use a time-triggered approach, in which control is performed in a periodic manner, which may result in a heavy burden on the wind farm controller for computation and communication, and inefficient use of resources. For example, the patent application number is 201910553468.6, and the patent name is 'a fan high voltage ride through control method and device', the invention provides a fan high voltage ride through control method and device, by detecting the voltage of the power grid in real time, when the power grid is confirmed to enter a high voltage state, the reactive power target value of the fan regulation is determined according to the voltage variation of the power grid before and after entering the high voltage state, meanwhile, the reactive power boundary value of the fan is determined according to the rated active power, the rated capacity and the like of the fan, and the fan is subjected to feedforward control according to the determined reactive power target value and boundary value, so that the accurate regulation of the fan is realized, and the fan can resist the voltage fluctuation of the power grid; meanwhile, the quick response of the reactive power can be ensured, the capacity of the converter is fully utilized, a power loop does not need to be switched out, a switching controller is avoided, and the high voltage ride through capability of the fan is improved. The patent application number is 201911173083.3, and the patent name is 'a wind turbine generator high voltage ride through control method'. In the operation process of the wind turbine generator, the converter transmits a series of analog signals to the main controller through the hardware sampling loop, so that information such as power grid voltage is obtained, and whether a fault with high power grid voltage occurs is judged according to the effective value of the power grid voltage. The voltage of the power grid is divided into 5 states according to the voltage condition in the program, and a high-voltage state machine is adopted as state indication according to real-time voltage sampling. Different control strategies are executed according to the power grid voltage state converter, and voltage phasor on the equivalent inductor at the power grid side is controlled, so that voltage born by the direct current side and the power device of the wind turbine generator converter is smaller than the power grid voltage, the wind turbine generator is safe and stable during high voltage ride through, and is not disconnected, and the wind turbine generator is ensured to normally run for power generation.
Therefore, the existing solutions mainly focus on the feasibility and effectiveness of the current control and voltage stability problems of the individual wind turbines, but in practical wind farms the terminal voltages are different due to the electrical distance between the wind turbines and the PCC and reactive injection points. During grid voltage surges, wind turbine side overvoltages can cause trips, thereby threatening the safe operation of large-scale wind farms. Time-triggered voltage control in general may increase computational and communication burdens.
Disclosure of Invention
The embodiment of the invention provides a voltage control method based on event triggering, which can solve the problem of overvoltage at a fan end and enhance the high-voltage ride through and after-event recovery capability of a large-scale wind power plant. The embodiment of the invention provides a voltage Control method based on Event triggering aiming at high voltage ride through and recovery and enhancement after an Event of a large wind power plant, and by utilizing an Event-Triggered Model Predictive Control (EMPC) strategy, through coordinating a primary droop coefficient during normal operation and coordinating secondary voltage Predictive Control based on Model Predictive Control (MPC) during voltage shock rise, a reactive power reference value of a fan can be optimized and adjusted to keep the voltage within a feasible range, and simultaneously, the voltage deviation is quickly reduced. Applying event triggering conditions to the EMPC strategy enables a better balance between wind farm voltage control performance and communication and computational burden.
In a first aspect, an embodiment of the present invention provides an event trigger-based voltage control method for high voltage ride through and post-event recovery of a wind turbine, including the following steps:
acquiring a voltage prediction error of the fan, and judging whether the voltage preset error is larger than a preset error threshold value or not;
if the preset voltage error is smaller than a preset error threshold value, triggering primary voltage control, wherein the primary voltage control is to adjust the voltage of the fan based on a drooping reactive power control model;
and if the preset voltage error is larger than a preset error threshold value, triggering secondary voltage control, wherein the secondary voltage control is used for regulating the voltage of the fan based on model prediction control, and the secondary voltage control considers influence parameters in primary voltage control.
Optionally, the step of obtaining the voltage prediction error of the fan specifically includes:
and calculating the voltage prediction error of the fan according to the voltage of the fan, the voltage sensitivity coefficient of active injection, the voltage sensitivity coefficient of reactive injection, the predicted voltage of the fan, the active power increment of the fan and the reactive power increment of the fan.
Optionally, the step of adjusting the voltage of the wind turbine based on the droop reactive control model specifically includes:
obtaining a droop curve of the fan, wherein the droop curve of the fan comprises voltage and reactive power of the fan;
according to the droop curve of the fan, matching a first reactive power reference value of the fan;
and adjusting the voltage of the fan based on the first reactive power reference value.
Optionally, the step of adjusting the voltage of the wind turbine based on the first reactive power reference value includes:
and sending the first reactive power reference value to a local controller, and regulating the voltage of the fan through the local controller.
Optionally, the method further includes: and the terminal voltage of the fan is adjusted by combining the dynamic characteristics of a net side converter and a machine side converter of the fan.
Optionally, the influencing parameter in the primary voltage control is a primary droop coefficient, and the step of adjusting the voltage of the fan based on the model predictive control specifically includes:
extracting a primary droop coefficient from a droop curve of the fan;
taking into account the influence of the primary droop coefficient to generate a second reactive power reference value in a prediction step of model prediction;
and adjusting the voltage of the fan based on the second reactive power reference value.
Optionally, the second reactive power reference value is updated cyclically with changes in the voltage sensitivity coefficient, the voltage measurement value and the primary droop coefficient.
Optionally, the step of adjusting the voltage of the wind turbine based on the second reactive power reference value specifically includes:
and sending the second reactive power reference value to a wind power plant central controller, and regulating the voltage of the wind turbine through the wind power plant central controller.
In a second aspect, an embodiment of the present invention further provides an event-triggered voltage control system, configured to perform high voltage ride through and post-event recovery of a wind turbine, where the system includes:
the judgment module is used for acquiring a voltage prediction error of the fan and judging whether the voltage preset error is larger than a preset error threshold value or not;
the primary control module is used for triggering primary voltage control if the preset voltage error is smaller than a preset error threshold value, wherein the primary voltage control is used for adjusting the voltage of the fan based on a drooping reactive power control model;
and the secondary control module is used for triggering secondary voltage control if the preset voltage error is greater than a preset error threshold, wherein the secondary voltage control is used for regulating the voltage of the fan based on model prediction control.
In a third aspect, an embodiment of the present invention provides an electronic device, including: the voltage control method comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the computer program to realize the steps of the voltage control method based on event triggering provided by the embodiment of the invention.
In the embodiment of the invention, the voltage prediction error of the fan is obtained, and whether the voltage preset error is greater than a preset error threshold value is judged; if the preset voltage error is smaller than a preset error threshold value, triggering primary voltage control, wherein the primary voltage control is to adjust the voltage of the fan based on a drooping reactive power control model; and if the preset voltage error is larger than a preset error threshold, triggering secondary voltage control, wherein the secondary voltage control is to regulate the voltage of the fan based on model prediction control, and the secondary voltage control considers influence parameters in primary voltage control. The invention can finely control the voltage of the fan by triggering the events of primary voltage control and secondary voltage control so as to deal with the problem of overvoltage at the fan end and enhance the high-voltage ride through and after-recovery capability of a large-scale wind power plant. A better balance can be achieved between wind farm voltage control performance and communication and computational burden.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flowchart of a method for controlling voltage based on event triggering according to an embodiment of the present invention;
FIG. 1a is a schematic diagram of a Q-V droop control curve provided by an embodiment of the present invention;
FIG. 1b is a schematic diagram of a wind turbine model according to an embodiment of the present invention;
FIG. 1c is a schematic diagram of an event-triggered voltage control according to an embodiment of the present invention;
fig. 2 is a block diagram of a voltage control system based on event triggering according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a voltage Control method based on Event triggering aiming at high voltage ride through and post-Event recovery enhancement of a large wind power plant, which has the principle that an Event-Triggered Model Predictive Control (EMPC) strategy is utilized, and a reactive power reference value of a fan can be optimized and adjusted to keep the voltage within a feasible range and quickly reduce the voltage deviation by coordinating a primary droop coefficient during normal operation and coordinating a secondary voltage Predictive Control based on the Model Predictive Control (MPC) during voltage swell. Applying event trigger conditions to the EMPC strategy enables a better balance between wind farm voltage control performance and communication and computational burden. During grid voltage surges, wind turbine side overvoltages can cause trips, thereby threatening the safe operation of large-scale wind farms. Time-triggered voltage control in general may increase computational and communication burdens. In addition, the embodiment of the invention can solve the problem of overvoltage at the wind turbine end and enhance the high voltage ride through and after-event recovery capability of a large-scale wind power plant. Reactive output between all wind turbines within the wind farm may also be coordinated within the event period to maintain the wind turbine terminal voltage within a feasible range while maximizing the reactive current injection of the wind turbines. Furthermore, the reactive power reference value of the wind turbine is optimized by using the EMPC strategy. The prediction period of the EMPC strategy combines the voltage prediction process during an event with droop-based primary voltage control during normal operation. To reduce the communication and computational burden, an event triggering condition is designed to activate the EMPC, and the event can be embedded into the EMPC to coordinate the EMPC and primary voltage control of the wind turbine controller from a time series perspective. It should be noted that the event trigger in the embodiment of the present invention refers to the condition trigger of activating the EMPC in the high voltage ride through.
Referring to fig. 1, fig. 1 is a flowchart of a voltage control method based on event triggering according to an embodiment of the present invention, where the method is used for high voltage ride through and recovery after an event of a wind turbine, as shown in fig. 1, the method includes the following steps:
and S1, acquiring the voltage prediction error of the fan.
In the embodiment of the invention, the fan is a wind driven generator or a wind driven generator set, the voltage prediction error of the fan is the voltage prediction error of the fan during high voltage ride through of the fan, and the high voltage ride through of the fan refers to the capability of the fan not stopping due to short-time overhigh voltage.
Further, the voltage prediction error of the fan can be calculated according to the voltage of the fan, the voltage sensitivity coefficient of active injection, the voltage sensitivity coefficient of reactive injection, the predicted voltage of the fan, the active power increment of the fan and the reactive power increment of the fan. The voltage of the fan comprises an initial voltage of the fan. The active power injection voltage sensitivity coefficient and the reactive power injection voltage sensitivity coefficient of the fan can be obtained by carrying out sensitivity calculation on wind power plant parameters, the voltage of the fan can be obtained by carrying out voltage measurement on the fan, the predicted voltage of the fan can be obtained by predicting through a voltage sensitivity system, the active power increment of the fan can be obtained through the difference of the active power of the fan between two time steps, and the reactive power increment of the fan can be obtained through the difference of the reactive power of the fan between the two time steps.
Specifically, the voltage prediction error of the fan can be represented by the following equation (1):
wherein, the above-mentioned DeltaVj(k) And the voltage prediction error of the fan corresponding to the kth time step.
The above
Is the predicted voltage of fan j corresponding to the kth time step.
V aboveNIs the initial voltage of the fan.
The above
Is the voltage sensitivity coefficient of the active injection of fan j.
The above
Is the voltage sensitivity coefficient of the reactive injection of fan j.
Δ P mentioned aboveW(k) And the active power increment of the fan corresponding to the kth time step.
Δ Q of the aboveW(k) And the reactive power increment of the fan corresponding to the kth time step.
And S2, judging whether the voltage preset error is larger than a preset error threshold value.
In the embodiment of the present invention, the error threshold is preset, and the determination process may be represented by the following equation (2):
wherein, the above ethresIs a preset error thresholdThe value is obtained.
In the embodiment of the present invention, if the preset voltage error is smaller than the preset error threshold, the step proceeds to step S3, and if the preset voltage error is larger than the preset error threshold, the step proceeds to step S4.
Further, in the embodiment of the present invention, the event trigger condition is whether a preset voltage error is greater than a preset error threshold. The purpose of the event triggering rules is to ensure uninterrupted operation of the wind turbine and to provide reactive support to enable voltage recovery of the utility grid. If a conventional MPC-based voltage regulation strategy is used, the optimization range is limited, and information exchange is required at each time step k, which greatly increases communication and calculation burden. The present invention addresses the above-mentioned deficiencies by devising and incorporating an event triggering strategy into the MPC framework. In order to reduce the number of optimization iterations, the MPC optimization is activated only when the terminal voltage deviation of the wind turbine does not meet the requirement.
And S3, triggering primary voltage control.
In the embodiment of the invention, the primary voltage control is used for adjusting the voltage of the fan based on the drooping reactive power control model. The droop curve of the fan can be obtained, and the droop curve of the fan comprises the voltage and the reactive power of the fan; according to the droop curve of the fan, matching a first reactive power reference value of the fan; and adjusting the voltage of the fan based on the first reactive power reference value, wherein the droop curve can be a Q-V droop control curve of the fan. Specifically, during a sudden rise of the grid voltage, the voltage of the wind turbine may be adjusted by using a droop-based reactive power control model, the wind turbine searches for a reactive power reference value (also called reactive reference) by tracking a Q-V droop control curve, the Q-V droop control curve is shown in fig. 1a, fig. 1a is a schematic diagram of a Q-V droop control curve provided by an embodiment of the present invention, in fig. 1a, K is a schematic diagram of KQiRepresenting the droop coefficient (which may also be referred to as the primary droop coefficient),
representing the reactive power reference of the wind turbine (in primary voltage control,
a first reactive power reference value representing a wind turbine), QWminRepresenting the minimum reactive power, Q, of the fanWmaxRepresenting the maximum value of reactive power, V, of the fanWIndicating the measured voltage, V, of the fanNRepresenting the initial voltage of the fan.
Furthermore, the first reactive power reference value is sent to a local controller, and the voltage of the fan is regulated through the local controller. In the embodiment of the invention, the terminal voltage of the wind turbine can be adjusted by combining the dynamic characteristics of the grid-side converter and the machine-side converter of the wind turbine.
Specifically, the control logic corresponding to the Q-V droop control curve can be embedded into the simplified model of the wind turbine by combining the simplified models of the grid-side converter and the machine-side converter of the wind turbine. The primary voltage control may be as shown in fig. 1b, where fig. 1b is a schematic diagram of a fan model according to an embodiment of the present invention, and in fig. 1b, k ispAnd kiIs the PI parameter, T, of the fanigIs the time constant, T, of the inner loop of the machine side converter (wind farm converter)fgIs the reactive filter time constant of the grid-side converter, K is the slope of the Q-V droop control curve, QWWhich represents the reactive power of the wind turbine,
representing a first reactive power reference value representing the fan, s being a differential factor, Vg being the grid voltage, IqIn order to be a reactive current,
is a reactive current reference value.
And S4, triggering secondary voltage control.
In the embodiment of the invention, since the error is caused by the primary control, the secondary voltage control is introduced to adjust the voltage to the reference value. The secondary voltage control adjusts the voltage of the fan based on model predictive control, and the secondary voltage control takes into account an influence parameter in the primary voltage control. The influencing parameter in the primary voltage control may be a primary droop coefficient.
Further, a primary droop coefficient can be extracted from the droop curve of the fan; considering the influence of the primary droop coefficient to generate a second reactive power reference value in a prediction step of model prediction; and adjusting the voltage of the fan based on the second reactive power reference value. The second reactive power reference value is updated circularly along with the change of the voltage sensitivity coefficient, the voltage measurement value and the primary droop coefficient.
Specifically, the first droop coefficient may be a slope of the Q-V droop control curve. In the MPC based voltage control algorithm, the influence of the primary droop coefficient is taken into account to generate the optimal reactive power reference value as the second reactive power reference value in the prediction step. Each fan adjusts the reactive power by following the optimal reactive power reference, and the optimal reference value is updated circularly along with the change of the voltage sensitivity coefficient, the voltage measurement value and the primary droop coefficient. The incremental reactive model with the primary droop coefficient control can be represented by the following equation (3):
wherein, the above
Representing the reactive power increment of fan j, described above
Represents the initial reactive power measurement, V, of fan jWjIndicating the measured voltage, V, of fan jNWhich represents the initial voltage of the fan,
the primary sag factor is indicated.
In order to improve the high voltage ride through capability of the wind power plant and ensure the global optimality of the operation of the wind power plant, the invention provides an optimization algorithm based on MPC combined with a primary droop coefficient. According toEquation (3), the state variable Deltau of the blower j at the kth time stepWi(k) And decision variable alphaiThe relationship therebetween can be expressed by the following equation (4):
Y2iΔuWi(k)＝Mi(k)αi+Fi (4)
wherein:
according to the formula (4), the above state variable Δ uW(k) Can be represented by the following formula (5):
wherein:
in the above-mentioned formula, the first and second groups,
the predicted voltage of the fan during the event can be determined according to the measurement information.
In the MPC-based quadratic voltage optimization problem expression, M should be updated within each prediction range as the voltage changeswt(k) In that respect However, since an accurate voltage measurement value cannot be obtained, the embodiment of the invention predicts the voltage of the fan in the control period by using the sensitivity coefficient
Mwt(k) Can be represented by the following formula (6):
wherein, Δ PW(k) Is the active power increment delta P of the k step in the prediction processWjAn incremental vector of (a), and
m abovewt(k) The initial state space matrix may be pushed back; kwtIs a primary droop coefficient matrix of the fan.
For a wind farm with primary droop control, its MPC-based discrete state space model can be represented by the following equation (7):
the MPC-based quadratic discrete state space model for a wind farm can be rewritten as the following equation (8):
wherein:
to facilitate fast response of the wind turbine during high voltage ride through and post-event recovery, the control objective is to minimize the terminal voltage deviation of the wind turbine, and the control objective function can be expressed as equation (9) and equation (10):
wherein:
in the formula (I), the compound is shown in the specification,
is a voltage sensitivity coefficient matrix related to active power injection of the fan.
Voltage prediction value of external power grid
Available from Phasor Measurement Units (PMUs), which are commonly used to measure transient voltage vectors.
The above control objective function is constrained by:
QWjmin≤QWj≤QWjmax (11)
isq+igq≥γ(VW/VN-1)×IN (12)
wherein
Is the available wind energy. Equation (12) gives the reactive current injection constraints of the wind turbine according to the grid code requirements. Equations (13) and (14) are the active power constraints of the wind turbine and the wind farm. Equations (15) - (117) are the constraints of wind turbine terminal voltage magnitude and time that are in compliance with the grid regulations. The formulated optimization problem can be converted into a standard Quadratic Programming (QP) problem, which a commercial QP solver can effectively solve within milliseconds.
In the embodiment of the invention, a voltage prediction error of a fan is obtained, and whether the voltage preset error is greater than a preset error threshold value is judged; if the preset voltage error is smaller than a preset error threshold value, triggering primary voltage control, wherein the primary voltage control is to adjust the voltage of the fan based on a drooping reactive power control model; and if the preset voltage error is larger than a preset error threshold, triggering secondary voltage control, wherein the secondary voltage control is to regulate the voltage of the fan based on model prediction control, and the secondary voltage control considers influence parameters in primary voltage control. The invention can finely control the voltage of the fan by triggering the events of primary voltage control and secondary voltage control so as to deal with the problem of overvoltage at the fan end and enhance the high-voltage ride through and after-recovery capability of a large-scale wind power plant. A better balance can be achieved between wind farm voltage control performance and communication and computational burden.
Further, the primary voltage control is performed by a local controller of the wind turbine, the secondary voltage control is performed by a central controller of the wind farm, if a conventional MPC-based voltage regulation strategy is used, the optimization range is limited, and information exchange is required at each time step k, which greatly increases communication and calculation burden. Therefore, in the embodiment of the invention, only when the preset voltage error is greater than the preset error threshold, the voltage regulation strategy based on the MPC is activated to reduce the communication and calculation burden of the central controller of the wind farm, and when the preset voltage error is less than the preset error threshold, the local primary voltage control strategy is adopted to realize the rapid voltage regulation performance. Specifically, as shown in fig. 1c, fig. 1c is a schematic diagram of event-triggered voltage control according to an embodiment of the present invention, in fig. 1c, primary voltage control is primary voltage control based on droop, a primary droop coefficient can be obtained through a Q-V droop control curve of a fan, it is determined through the primary droop coefficient that the voltage of the fan is adjusted through the primary voltage control or the voltage of the fan is adjusted through secondary voltage control, specifically, through the primary droop coefficient, whether an event corresponding to the secondary voltage control is triggered is calculated, that is, whether a preset voltage error is greater than a preset error threshold is determined. The secondary voltage control is based on EMPC secondary voltage control, the event trigger communication protocol is that whether a voltage preset error is larger than a preset error threshold value, and a wind power plant central controller calculates a reactive power reference value for adjusting the voltage of a fan through parameters obtained by carrying out sensitivity calculation and voltage measurement on wind power plant parameters.
Fig. 2 shows a structure diagram of a voltage control system based on event triggering according to an embodiment of the present invention, and as shown in fig. 2, the system includes:
the judging module 201 is configured to obtain a voltage prediction error of the fan, and judge whether the voltage preset error is greater than a preset error threshold;
the primary control module 202 is configured to trigger primary voltage control if the preset voltage error is smaller than a preset error threshold, where the primary voltage control is based on a drooping reactive power control model to adjust the voltage of the fan;
and the secondary control module 203 is configured to trigger secondary voltage control if the preset voltage error is greater than a preset error threshold, where the secondary voltage control is based on model predictive control to adjust the voltage of the fan.
Optionally, the determining module 201 is further configured to calculate a voltage prediction error of the fan according to the voltage of the fan, the voltage sensitivity coefficient of active injection of the fan, the voltage sensitivity coefficient of reactive injection, the predicted voltage of the fan, the active power increment of the fan, and the reactive power increment of the fan.
Optionally, the primary control module 202 specifically includes:
the obtaining submodule is used for obtaining a droop curve of the fan, and the droop curve of the fan comprises the voltage and the reactive power of the fan;
the matching submodule is used for matching a first reactive power reference value of the fan according to the droop curve of the fan;
and the first adjusting submodule is used for adjusting the voltage of the fan based on the first reactive power reference value.
Optionally, the first adjusting sub-module is further configured to send the first reactive power reference value to a local controller, and adjust the voltage of the wind turbine through the local controller.
Optionally, the primary control module 202 is further configured to adjust the generator terminal voltage of the wind turbine by combining the dynamic characteristics of the grid-side converter and the machine-side converter of the wind turbine.
Optionally, the influence parameter in the primary voltage control is a primary droop coefficient, and the secondary control module 203 specifically includes:
the extracting submodule is used for extracting a primary droop coefficient from a droop curve of the fan;
a generation submodule for taking into account the influence of the primary droop coefficient to generate a second reactive power reference value in the prediction step of the model prediction;
and the second adjusting submodule is used for adjusting the voltage of the fan based on the second reactive power reference value.
Optionally, the second reactive power reference value is updated cyclically with changes in the voltage sensitivity coefficient, the voltage measurement value and the primary droop coefficient.
Optionally, the second adjusting submodule is further configured to send the second reactive power reference value to a wind farm central controller, and adjust the voltage of the wind turbine through the wind farm central controller.
It should be noted that the voltage control system based on event triggering provided in the embodiment of the present invention may be applied to electronic devices such as computers and servers that perform voltage control based on event triggering. The voltage control system based on event triggering provided by the embodiment of the invention can realize each process realized by the voltage control method based on event triggering in the method embodiment, and can achieve the same beneficial effects. To avoid repetition, further description is omitted here.
An embodiment of the present invention further provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein:
the processor is used for calling the computer program stored in the memory and used for high voltage ride through and recovery after an event of the fan, and the processor executes the following steps:
acquiring a voltage prediction error of the fan, and judging whether the voltage preset error is larger than a preset error threshold value or not;
if the preset voltage error is smaller than a preset error threshold value, triggering primary voltage control, wherein the primary voltage control is to adjust the voltage of the fan based on a drooping reactive power control model;
and if the preset voltage error is larger than a preset error threshold, triggering secondary voltage control, wherein the secondary voltage control is to regulate the voltage of the fan based on model prediction control, and the secondary voltage control considers influence parameters in primary voltage control.
Optionally, the step of obtaining the voltage prediction error of the fan, executed by the processor, specifically includes:
and calculating the voltage prediction error of the fan according to the voltage of the fan, the voltage sensitivity coefficient of active injection, the voltage sensitivity coefficient of reactive injection, the predicted voltage of the fan, the active power increment of the fan and the reactive power increment of the fan.
Optionally, the step of adjusting the voltage of the wind turbine based on the droop reactive control model executed by the processor specifically includes:
obtaining a droop curve of the fan, wherein the droop curve of the fan comprises the voltage and the reactive power of the fan;
according to the droop curve of the fan, matching a first reactive power reference value of the fan;
and adjusting the voltage of the fan based on the first reactive power reference value.
Optionally, the step of adjusting the voltage of the wind turbine based on the first reactive power reference executed by the processor includes:
and sending the first reactive power reference value to a local controller, and regulating the voltage of the fan through the local controller.
Optionally, the method further includes: and the terminal voltage of the fan is adjusted by combining the dynamic characteristics of a net side converter and a machine side converter of the fan.
Optionally, the influencing parameter in the primary voltage control is a primary droop coefficient, and the step of adjusting the voltage of the fan based on the model predictive control executed by the processor specifically includes:
extracting a primary droop coefficient from a droop curve of the fan;
taking into account the influence of the primary droop coefficient to generate a second reactive power reference value in a prediction step of model prediction;
and adjusting the voltage of the fan based on the second reactive power reference value.
Optionally, the second reactive power reference value is updated cyclically with changes in the voltage sensitivity coefficient, the voltage measurement value and the primary droop coefficient.
Optionally, the step of adjusting the voltage of the wind turbine based on the second reactive power reference value, which is executed by the processor, specifically includes:
and sending the second reactive power reference value to a wind power plant central controller, and regulating the voltage of the fan through the wind power plant central controller.
It should be understood by those skilled in the art that the electronic device is a device capable of automatically performing numerical calculation and/or information processing according to a preset or stored instruction, and the hardware includes, but is not limited to, a microprocessor, an Application Specific Integrated Circuit (ASIC), a Programmable gate array (FPGA), a Digital Signal Processor (DSP), an embedded device, and the like. For example: the electronic device is applied to a computer, a server, or the like that can perform voltage control based on event triggering. The electronic device provided by the embodiment of the invention can realize each process realized by the voltage control method based on event triggering in the method embodiments, and can achieve the same beneficial effects, and in order to avoid repetition, the details are not repeated here.
The memory includes at least one type of readable storage medium including flash memory, hard disks, multimedia cards, card-type memory (e.g., SD or DX memory, etc.), Random Access Memory (RAM), Static Random Access Memory (SRAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Programmable Read Only Memory (PROM), magnetic memory, magnetic disks, optical disks, etc. In some embodiments, the memory may be an internal storage unit of the electronic device, such as a hard disk or a memory of the electronic device. In other embodiments, the memory may also be an external storage device of the electronic device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like provided on the electronic device. Of course, the memory may also include both internal and external memory units of the electronic device. In this embodiment, the memory is generally used to store an operating system installed in the electronic device and various types of application software, such as program codes of the voltage control method based on event triggering. In addition, the memory may also be used to temporarily store various types of data that have been output or are to be output.
The processor may be a Central Processing Unit (CPU), controller, microcontroller, microprocessor, or other data Processing chip in some embodiments. The processor is typically used to control the overall operation of the electronic device. In this embodiment, the processor is configured to execute the program code stored in the memory or process data, for example, execute the program code of the voltage control method based on event triggering.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (5)
1. A voltage control method based on event triggering is used for high voltage ride through and recovery after an event of a fan, and is characterized by comprising the following steps:
calculating a voltage prediction error of the fan according to the voltage of the fan, the voltage sensitivity coefficient of active injection, the voltage sensitivity coefficient of reactive injection, the predicted voltage of the fan, the active power increment of the fan and the reactive power increment of the fan, and judging whether the voltage preset error is larger than a preset error threshold value or not;
if the preset voltage error is smaller than a preset error threshold value, triggering primary voltage control, wherein the primary voltage control is to adjust the voltage of the fan based on a drooping reactive power control model;
if the preset voltage error is larger than a preset error threshold, triggering secondary voltage control, wherein the secondary voltage control is to regulate the voltage of the fan based on model prediction control, and the secondary voltage control considers a primary droop coefficient; wherein the content of the first and second substances,
the step of adjusting the voltage of the wind turbine based on the droop reactive control model specifically comprises:
obtaining a droop curve of the fan, wherein the droop curve of the fan comprises the voltage and the reactive power of the fan;
according to the droop curve of the fan, matching a first reactive power reference value of the fan;
sending the first reactive power reference value to a local controller, and regulating the voltage of the fan through the local controller;
the step of adjusting the voltage of the fan based on model predictive control specifically includes:
extracting a primary droop coefficient from a droop curve of the fan;
taking into account the influence of the primary droop coefficient to generate a second reactive power reference value in a prediction step of model prediction;
and sending the second reactive power reference value to a wind power plant central controller, and regulating the voltage of the fan through the wind power plant central controller.
2. The event-trigger based voltage control method of claim 1, wherein the method further comprises: and the terminal voltage of the fan is adjusted by combining the dynamic characteristics of a net side converter and a machine side converter of the fan.
3. The event-trigger based voltage control method of claim 1, wherein the second reactive power reference value is updated cyclically as a function of the voltage sensitivity coefficient, the voltage measurement value, and the primary droop coefficient.
4. An event-triggered voltage control system for high voltage ride through and post event recovery of a wind turbine, the system comprising:
the judgment module is used for calculating a voltage prediction error of the fan according to the voltage of the fan, the voltage sensitivity coefficient of active injection, the voltage sensitivity coefficient of reactive injection, the predicted voltage of the fan, the active power increment of the fan and the reactive power increment of the fan, and judging whether the voltage preset error is larger than a preset error threshold value or not;
the primary control module is used for triggering primary voltage control if the preset voltage error is smaller than a preset error threshold value, wherein the primary voltage control is used for adjusting the voltage of the fan based on a drooping reactive power control model;
the secondary control module is used for triggering secondary voltage control if the preset voltage error is larger than a preset error threshold value, wherein the secondary voltage control is used for adjusting the voltage of the fan based on model prediction control, and the primary droop coefficient is considered in the secondary voltage control; wherein the content of the first and second substances,
the step of the primary control module adjusting the voltage of the wind turbine based on the droop reactive control model specifically comprises:
obtaining a droop curve of the fan, wherein the droop curve of the fan comprises the voltage and the reactive power of the fan; according to the droop curve of the fan, matching a first reactive power reference value of the fan; sending the first reactive power reference value to a local controller, and regulating the voltage of the fan through the local controller;
the step of adjusting the voltage of the fan by the secondary control module based on the model predictive control specifically comprises:
extracting a primary droop coefficient from a droop curve of the fan; taking into account the influence of the primary droop coefficient to generate a second reactive power reference value in a prediction step of model prediction; and sending the second reactive power reference value to a wind power plant central controller, and regulating the voltage of the fan through the wind power plant central controller.
5. An electronic device, comprising: memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps in the event trigger based voltage control method according to any of claims 1 to 3 when executing the computer program.
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Denomination of invention: Event triggered voltage control methods, systems, and electronic devices Effective date of registration: 20231106 Granted publication date: 20220617 Pledgee: China Co. truction Bank Corp Yiyang branch Pledgor: Huaxiang XiangNeng Technology Co.,Ltd. Registration number: Y2023980063452 |