Power distribution network voltage control method based on adaptive event trigger communication mechanism

Abstract

The invention relates to the technical field of power distribution network control, in particular to a power distribution network voltage control method based on an adaptive event trigger communication mechanism, which comprises the following steps: establishing a power distribution network voltage event trigger control architecture based on inverter reactive output; determining a dynamic system equation of power distribution network voltage deviation, inverter reactive power output and external power disturbance; designing an adaptive event triggering communication mechanism according to the dynamic system equation, and determining a dynamic event triggering threshold value; constructing a linear matrix inequality as a stability condition of a dynamic event trigger threshold; and determining an output feedback controller of the power distribution network voltage event trigger control architecture, and constructing a stability condition of the output feedback controller based on an adaptive event trigger communication mechanism. When the voltage deviation of the power distribution network exceeds the preset threshold value, information interaction is triggered, the triggering threshold value is limited in a specific interval, and communication data redundancy and inverter action frequency are reduced while redundant data transmission is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution network control, and in particular to a power distribution network voltage control method based on an adaptive event-triggered communication mechanism. Background Art

[0002] With the widespread application of large-scale integration of wind energy, solar energy, electric vehicles, etc. in distribution networks. Although the hourly voltage regulation actions of on-load tap-changing transformer ratio, shunt capacitor switching, static VAR compensator and energy storage device can be formulated according to the power forecast of the day before through reactive power optimization technology. However, power changes on a shorter time scale are usually difficult to predict, resulting in the risk of voltage exceeding the limit at some nodes of the distribution network.

[0003] Using photovoltaic energy storage inverters as reactive power sources to provide rapid voltage support is one of the effective means to solve the short-term voltage fluctuations in distribution networks. At present, the voltage control (VC) of distribution networks mainly adopts a periodic control scheme, that is, at each sampling moment, the reactive output of the inverters involved in voltage regulation in the distribution network is set according to the node voltage deviation.

[0004] However, the output of distributed units and random load fluctuations pose a severe challenge to the voltage stability of the distribution network. In the existing adaptive event trigger mechanism scheme, there is no upper limit for the trigger threshold, which will cause the trigger threshold and the corresponding trigger difficulty to increase exponentially after the state deviation is effectively damped, causing the distribution network control center to quickly lose the ability to monitor the operating status; and for the actual distribution network, continuous voltage deviation will also bring about problems such as voltage quality degradation. In addition, the existing adaptive event trigger mechanism scheme also does not take into account the nonlinear saturation characteristics of the inverter participating in reactive power output. Summary of the invention

[0005] To solve the above problems, the present invention provides a distribution network voltage control method based on an adaptive event-triggered communication mechanism, which is applied to a distribution network system, wherein the distribution network system includes a control center, an inverter, and a plurality of load nodes, wherein the plurality of load nodes are communicatively connected to the control center, and the method includes:

[0006] Establish a distribution network voltage event trigger control architecture based on inverter reactive output. Specifically, if the voltage deviation of any load node exceeds a preset threshold, the voltage deviation of the load node is uploaded to the control center. The control center issues a control instruction for the inverter reactive output according to the received voltage deviation. The inverter outputs reactive power according to the control instruction to adjust the distribution network voltage.

[0007] According to the distribution network voltage event trigger control architecture, the dynamic system equations of distribution network voltage deviation, inverter reactive output and external power disturbance are determined;

[0008] Design an adaptive event-triggered communication mechanism based on the distribution network voltage event-triggered control architecture and dynamic system equations, and determine the dynamic event trigger threshold;

[0009] Based on the adaptive event-triggered communication mechanism, a linear matrix inequality is constructed as the stability condition of the dynamic event triggering threshold.

[0010] The output feedback controller of the voltage event-triggered control architecture of the distribution network is determined, and the stability condition of the output feedback controller is constructed based on the adaptive event-triggered communication mechanism.

[0011] In a specific implementation of the first aspect, the dynamic system equation for determining the voltage deviation of the distribution network, the reactive output of the inverter and the external power disturbance is:

[0012]

[0013] Among them, A=C=I, I is the unit matrix; B represents the reactive voltage sensitivity matrix of the inverter; D represents the sum of the active-voltage sensitivity matrix and the reactive-voltage sensitivity matrix of all load nodes; x(t) is the state vector of the dynamic system, y(t) is the measured voltage deviation value, u(t) is the control input vector, and w(t) represents the external power disturbance of the load node.

[0014] The adaptive event-triggered communication mechanism is formulated as follows:

[0015]

[0016] e(i k h)=x(i k h)-x(s k h),

[0017] In the formula, X(s k )=x T (s k h)Mx(s k h) is a given constant, ∈>0, σ ∈ is the positive event trigger parameter associated with ∈, M is a positive definite matrix, s k h represents the last sampling time, s k+1 h represents the next sampling time; e(i k h) indicates state error; i k h represents the current sampling time, h is the period.

[0018] The specific method of constructing the linear matrix inequality as the stability condition of the dynamic event trigger threshold is as follows:

[0019] By giving the scalar α, α represents the convergence rate; Represents the upper limit of delay; given the positive definite matrix G, H, J, construct the linear matrix inequality, the formula is:

[0020]

[0021] in,

[0022] Ξ 22 =J -1 ,

[0023]

[0024] Where F represents the augmented matrix; is the specified positive performance parameter; K is the output control gain, and C is the output matrix.

[0025] In a specific implementation of the first aspect, the distribution network voltage control method also constructs a Lyapunov function to derive the stability condition of the dynamic event trigger threshold under the inverter reactive capacity constraint and bounded transmission delay to perform stability judgment.

[0026] The formula for the output feedback controller is:

[0027] K O =Y O X -1 C T (CC T ) -1 ,

[0028] Where X is a positive definite matrix, C is an output matrix, and Y0 is the measured voltage value.

[0029] The stability condition of the output feedback controller is constructed in the following specific method:

[0030] Based on the scalar α, α represents the convergence rate; represents the upper limit of delay; and the positive definite matrix X, By constructing a linear matrix inequality as the stability condition of the output feedback controller, the formula is:

[0031]

[0032]

[0033] On the other hand, a distribution network voltage control system based on an adaptive event-triggered communication mechanism is provided, comprising:

[0034] An initial module is used to establish a distribution network voltage event triggering control architecture based on inverter reactive output. Specifically, if the voltage deviation of any load node exceeds a preset threshold, the voltage deviation of the load node is uploaded to the control center. The control center issues a control instruction for the reactive output of the inverter according to the received voltage deviation. The inverter outputs reactive power according to the control instruction to adjust the distribution network voltage.

[0035] The initial module is also used to trigger the control architecture according to the distribution network voltage event, and determine the dynamic system equations of the distribution network voltage deviation, inverter reactive output and external power disturbance;

[0036] A processing module is used to design an adaptive event trigger communication mechanism according to the distribution network voltage event trigger control architecture and dynamic system equations, and determine the dynamic event trigger threshold;

[0037] A stability processing module, used for constructing a linear matrix inequality as a stability condition of a dynamic event triggering threshold based on an adaptive event triggering communication mechanism;

[0038] The stability processing module is also used to determine the output feedback controller of the distribution network voltage event triggered control architecture, and to construct the stability condition of the output feedback controller based on the adaptive event triggered communication mechanism.

[0039] The third aspect provides a distribution network voltage control device based on an adaptive event-triggered communication mechanism, comprising a processor and a memory, wherein the processor implements the distribution network voltage control method based on the adaptive event-triggered communication mechanism as described above when executing program data stored in the memory.

[0040] A fourth aspect provides a readable storage medium for storing control program data, wherein the control program data, when executed by a processor, implements the distribution network voltage control method based on the adaptive event-triggered communication mechanism as described above.

[0041] Beneficial effects: The present invention is a distribution network voltage control method based on an adaptive event-triggered communication mechanism. Information interaction is triggered only when the voltage deviation of the distribution network exceeds a preset threshold. The trigger threshold is limited to a specific interval. While reducing redundant data transmission, it ensures the monitoring sensitivity of the distribution network control center to the operating status of the load node, reduces communication data redundancy and inverter action frequency.

[0042] By constructing the linear inequality of the dynamic event trigger threshold and the output feedback controller as the stability condition of the input state and output state of the distribution network voltage event triggered control architecture under the adaptive event triggered communication mechanism, the stability of the distribution network system voltage control is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of a distribution network voltage control method based on an adaptive event-triggered communication mechanism;

[0044] Figure 2 The inverter action frequency diagram triggered by constant events;

[0045] Figure 3 The inverter action frequency diagram triggered by adaptive events;

[0046] Figure 4 The voltage deviation recovery diagram is triggered by a constant event;

[0047] Figure 5 Trigger voltage deviation recovery diagram for adaptive events. DETAILED DESCRIPTION

[0048] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0049] See also Figure 1 This embodiment provides a distribution network voltage control method based on an adaptive event-triggered communication mechanism, which is applied to a distribution network system. The distribution network system includes a plurality of load nodes, a control center, and an inverter. The specific implementation steps of the method are as follows:

[0050] Step 1: Establish a distribution network voltage event trigger control architecture based on inverter reactive output. Specifically, if the voltage deviation of any load node exceeds a preset threshold, the voltage deviation of the load node is uploaded to the control center. The control center issues a control instruction for the inverter reactive output according to the received voltage deviation. The inverter outputs reactive power according to the control instruction to adjust the distribution network voltage.

[0051] In the traditional distribution network voltage periodic control architecture, the control center needs to obtain the voltage deviation of all load nodes in the distribution network system through the communication network at each sampling moment, and then participate in voltage adjustment based on the collected voltage deviation of all load nodes, which leads to the problem of communication load overload.

[0052] Based on this, a distribution network voltage event triggering control architecture is established in which only when the voltage deviation of the load node exceeds the preset threshold, the voltage deviation of the current distribution network system is transmitted to the control center, and the control center formulates the control instructions of the inverter's reactive output according to the latest received voltage deviation.

[0053] Step 2: According to the distribution network voltage event trigger control architecture, determine the dynamic system equations of distribution network voltage deviation, inverter reactive output and external power disturbance;

[0054] Given n=1,2,…,N, n represents the load node number of the distribution network, ΔU n (t) represents the nth load node at iT s Voltage deviation at the moment; ΔQ n (t) is the nth load node at iT s The reactive output adjustment value at the moment; iT s To control the cycle;

[0055] Let x(t)=ΔU(t)=[ΔU1(t),ΔU2(t),...,ΔU n (t)] T , u(t)=[ΔQ1(t),ΔQ2(t),...,ΔQ n (t)] T , the dynamic system equations for determining the voltage deviation of the distribution network, the reactive output of the inverter and the external power disturbance are:

[0056]

[0057] Among them, A=C=I, I is the unit matrix; B represents the reactive voltage sensitivity matrix of the inverter; D represents the sum of the active-voltage sensitivity matrix and the reactive-voltage sensitivity matrix of all load nodes; x(t) is the state vector of the dynamic system equation, y(t) is the measured voltage deviation value, u(t) is the control input vector, and w(t) represents the external power disturbance of the load node.

[0058] Step 3: Design an adaptive event trigger communication mechanism based on the distribution network voltage event trigger control architecture and dynamic system equations, and determine the dynamic event trigger threshold;

[0059] The triggering principles of the distribution network voltage periodic control architecture and the distribution network voltage event triggered control architecture are analyzed.

[0060] The distribution network voltage periodic control architecture is triggered regularly with a fixed sampling period h. Under discrete sampling conditions, the sample set sampled in all time periods is

[0061] In the distribution network voltage event trigger control architecture, not all sampled data will be transmitted, that is, assuming that the sample set of some sampled data is successfully transmitted is

[0062] The sample set and The main difference is that not all sampled data will be transmitted to the distribution network voltage event trigger control architecture. This means that all sampled data are transmitted, and the distribution network voltage event trigger control architecture becomes a time period triggered transmission.

[0063] In the distribution network voltage event triggered control architecture, an event trigger signal is generated by a zero-order holder (ZOH), and the event trigger signal generated by the zero-order holder has a transmission delay.

[0064] Based on the transmission delay of the event trigger signal, the equation for determining the voltage deviation sampling signal and the control input vector according to the dynamic system equation is:

[0065]

[0066] Among them, τ sk Indicates transmission delay; B K =BKC, K is the output control gain, and C is the output matrix.

[0067] At the same time, define e(i k h) is the current sampling time vector x(i k h) and the last sampling time vector x(s) k h) The state error between the two is:

[0068] e(i k h)=x(i k h)-x(s k h),

[0069] Among them, i k h represents the current sampling time, h is the period; s k h represents the last sampling time.

[0070] Based on the transmission delay and transmission error, an adaptive event-triggered communication mechanism is designed, and its formula is:

[0071]

[0072] In the formula, X(s k )=x T (s k h)Mx(s k h) is a given constant, coefficient ∈>0, σ ∈ is the positive event trigger parameter associated with ∈, M is a positive definite matrix, s k h represents the last sampling time, s k+1 h represents the next sampling time; e(i k h) represents the state error.

[0073] In the adaptive event-triggered communication mechanism, the characteristic equation of the dynamic event trigger threshold is:

[0074]

[0075] According to the characteristic equation, when ||x(s k h)||=0, by The upper bound of the dynamic event triggering threshold is provided. The dynamic event triggering threshold can be based on the measured value of the sampling instant of the last transmission || x(s k h)||Direct adjustment.

[0076] Step 4: Based on the adaptive event-triggered communication mechanism, a linear matrix inequality is constructed as the stability condition of the dynamic event trigger threshold to ensure the stability of the input state of the distribution network system;

[0077] By giving the scalar α, α represents the convergence rate; represents the upper limit of delay; given positive definite matrices G, H, and J, a linear matrix inequality is constructed, which is:

[0078]

[0079] in,

[0080] Ξ 22 =J -1 ,

[0081]

[0082] Where F represents the augmented matrix; is the specified positive performance parameter.

[0083] Taking into account the inverter reactive power saturation constraint and uncertain transmission delay, the distribution network voltage control method also constructs a Lyapunov function to derive the stability condition of the dynamic event triggering threshold under the inverter reactive capacity constraint and bounded transmission delay, and performs stability judgment.

[0084] The Lyapunov-Krasovskii functional is quoted as follows:

[0085] V(t)=V1(t)+V2(t)+V3(t),

[0086] V1(t)=x T (t)Gx(t),

[0087]

[0088] Taking the derivative of the Lyapunov-Krasovskii function for the dynamic system equations, we obtain:

[0089]

[0090] With the help of linear matrix inequalities:

[0091]

[0092] Based on Lyapunov function, linear matrix inequality and adaptive event-triggered communication mechanism, we get:

[0093]

[0094] Among them, ξ(t)=col{x(t),x(t-τ(t)),e(s k ,N,i),w(t)} and Ξ are given by the linear matrix inequality. According to the Lyapunov function, it is confirmed that the stability condition of the dynamic event triggering threshold satisfies the linear matrix inequality.

[0095] Step 5: Determine the output feedback controller of the distribution network voltage event-triggered control architecture, and build the stability condition of the output feedback controller based on the adaptive event-triggered communication mechanism to ensure the stability of the output state of the distribution network system;

[0096] The formula for the output feedback controller is:

[0097] K O =Y O X -1 C T (CC T ) -1 ,

[0098] Where X is a positive definite matrix, C is an output matrix, and Y0 is the measured voltage value.

[0099] And based on the existence of scalar α, With a positive definite matrix X, By constructing the linear matrix inequality (LMI) as the stability condition of the output feedback controller, the formula is:

[0100]

[0101] The output feedback controller solves the linear matrix inequality to ensure that the output state of the distribution network system can still achieve consistent asymptotic stability under bounded transmission delay and event-triggered transmission strategy. This design can maintain the stable operation of the distribution network system while reducing the communication volume and frequent inverter operations.

[0102] See also Figure 2-Figure 3 , Figure 2 When the medium constant is triggered, the inverter operating frequency fluctuates around a high level; Figure 3The operating frequency of the medium adaptive triggered inverter fluctuates around the medium level, which is reduced by about 41.7%. This shows that the constant trigger control strategy causes frequent inverter operation due to frequent triggering, which increases equipment wear, while the adaptive control effectively reduces the inverter operation frequency and prolongs the service life of the equipment.

[0103] Depend on Figure 4 and Figure 5 It can be seen that the voltage deviation maintains a high amplitude recovery trend under constant event triggering, while the adaptive triggering control reduces the frequent action of the inverter and can restore the voltage more smoothly and reduce voltage fluctuations. Adaptive control can respond more quickly when there is a large deviation, shortening the recovery time.

[0104] In addition, the present application also provides a distribution network voltage control system based on an adaptive event-triggered communication mechanism, including:

[0105] An initial module is used to establish a distribution network voltage event triggering control architecture based on inverter reactive output. Specifically, if the voltage deviation of any load node exceeds a preset threshold, the voltage deviation of the load node is uploaded to the control center. The control center issues a control instruction for the reactive output of the inverter according to the received voltage deviation. The inverter outputs reactive power according to the control instruction to adjust the distribution network voltage.

[0106] The initial module is also used to trigger the control architecture according to the distribution network voltage event, and determine the dynamic system equations of the distribution network voltage deviation, inverter reactive output and external power disturbance;

[0107] A processing module is used to design an adaptive event trigger communication mechanism according to the distribution network voltage event trigger control architecture and dynamic system equations, and determine the dynamic event trigger threshold;

[0108] A stability processing module, used for constructing a linear matrix inequality as a stability condition of a dynamic event triggering threshold based on an adaptive event triggering communication mechanism;

[0109] The stability processing module is also used to determine the output feedback controller of the distribution network voltage event triggered control architecture, and to construct the stability condition of the output feedback controller based on the adaptive event triggered communication mechanism.

[0110] At the same time, a distribution network voltage control device based on an adaptive event-triggered communication mechanism is also provided, comprising a processor and a memory, wherein the processor implements the distribution network voltage control method based on an adaptive event-triggered communication mechanism as described above when executing program data stored in the memory.

[0111] Finally, a readable storage medium is provided for storing control program data, wherein the control program data, when executed by a processor, implements the distribution network voltage control method based on the adaptive event-triggered communication mechanism as described above.

Claims

1. A distribution network voltage control method based on an adaptive event-triggered communication mechanism, applied to a distribution network system, wherein the distribution network system includes a control center, an inverter and a plurality of load nodes, wherein the plurality of load nodes are connected to the control center in communication, characterized in that: include: Establish a distribution network voltage event trigger control architecture based on inverter reactive output. Specifically, if the voltage deviation of any load node exceeds a preset threshold, the voltage deviation of the load node is uploaded to the control center. The control center issues a control instruction for the inverter reactive output according to the received voltage deviation. The inverter outputs reactive power according to the control instruction to adjust the distribution network voltage. According to the distribution network voltage event trigger control architecture, the dynamic system equations of distribution network voltage deviation, inverter reactive output and external power disturbance are determined; Design an adaptive event-triggered communication mechanism based on the distribution network voltage event-triggered control architecture and dynamic system equations, and determine the dynamic event trigger threshold; Based on the adaptive event-triggered communication mechanism, a linear matrix inequality is constructed as the stability condition of the dynamic event triggering threshold. The output feedback controller of the voltage event-triggered control architecture of the distribution network is determined, and the stability condition of the output feedback controller is constructed based on the adaptive event-triggered communication mechanism.

2. The method for controlling voltage in a distribution network based on an adaptive event-triggered communication mechanism according to claim 1, characterized in that: The dynamic system equation for determining the voltage deviation of the distribution network, the reactive output of the inverter and the external power disturbance is: Among them, A=C=I, I is the unit matrix; B represents the reactive voltage sensitivity matrix of the inverter; D represents the sum of the active-voltage sensitivity matrix and the reactive-voltage sensitivity matrix of all load nodes; x(t) is the state vector of the dynamic system, y(t) is the measured voltage deviation value, u(t) is the control input vector, and w(t) represents the external power disturbance of the load node.

3. The method for controlling voltage in a distribution network based on an adaptive event-triggered communication mechanism according to claim 1, characterized in that: The adaptive event-triggered communication mechanism is formulated as follows: e(i k h)=x(i k h)-x(s k h), In the formula, X(s k )=x T (s k h)Mx(s k h) is a given constant, ∈>0, σ ∈ is the positive event trigger parameter associated with ∈, M is a positive definite matrix, s k h represents the last sampling time, s k+1 h represents the next sampling time; e(i k h) indicates state error; i k h represents the current sampling time, h is the period.

4. The method for controlling voltage in a distribution network based on an adaptive event-triggered communication mechanism according to claim 3, characterized in that: The specific method of constructing the linear matrix inequality as the stability condition of the dynamic event trigger threshold is as follows: By giving the scalar α, α represents the convergence rate; Indicates the upper limit of delay; Given positive definite matrices G, H, and J, construct a linear matrix inequality, whose formula is: in, X 22 =J -1 , Where F represents the augmented matrix; ζ is the specified positive performance parameter; K is the output control gain, and C is the output matrix.

5. The method for controlling voltage in a distribution network based on an adaptive event-triggered communication mechanism according to claim 4, characterized in that: The distribution network voltage control method also constructs a Lyapunov function to derive the stability condition of the dynamic event triggering threshold under the inverter reactive capacity constraint and bounded transmission delay, and performs stability judgment.

6. The method for controlling voltage in a distribution network based on an adaptive event-triggered communication mechanism according to claim 1, characterized in that: The formula for the output feedback controller is: K O =Y O X -1 C T (CC T ) -1 , Where X is a positive definite matrix, C is an output matrix, and Y0 is the measured voltage value.

7. The method for controlling voltage in a distribution network based on an adaptive event-triggered communication mechanism according to claim 6, characterized in that: The stability condition of the output feedback controller is constructed in the following specific method: Based on the scalar α, α represents the convergence rate; Indicates the upper limit of delay; With a positive definite matrix X, By constructing a linear matrix inequality as the stability condition of the output feedback controller, the formula is:

8. A distribution network voltage control system based on an adaptive event-triggered communication mechanism, characterized in that: include: An initial module is used to establish a distribution network voltage event triggering control architecture based on inverter reactive output. Specifically, if the voltage deviation of any load node exceeds a preset threshold, the voltage deviation of the load node is uploaded to the control center. The control center issues a control instruction for the reactive output of the inverter according to the received voltage deviation. The inverter outputs reactive power according to the control instruction to adjust the distribution network voltage. The initial module is also used to trigger the control architecture according to the distribution network voltage event, and determine the dynamic system equations of the distribution network voltage deviation, inverter reactive output and external power disturbance; A processing module is used to design an adaptive event trigger communication mechanism according to the distribution network voltage event trigger control architecture and dynamic system equations, and determine the dynamic event trigger threshold; A stability processing module, used for constructing a linear matrix inequality as a stability condition of a dynamic event triggering threshold based on an adaptive event triggering communication mechanism; The stability processing module is also used to determine the output feedback controller of the distribution network voltage event triggered control architecture, and to construct the stability condition of the output feedback controller based on the adaptive event triggered communication mechanism.

9. A distribution network voltage control device based on an adaptive event-triggered communication mechanism, characterized in that: It comprises a processor and a memory, wherein when the processor executes the program data stored in the memory, it implements the distribution network voltage control method based on the adaptive event-triggered communication mechanism as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: Used to store control program data, wherein the control program data, when executed by a processor, implements the distribution network voltage control method based on an adaptive event-triggered communication mechanism as described in any one of claims 1-7.

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