CN114937993A - State Estimation Method Based on Enhanced Filter Algorithm for Remote Terminal Equipment of Power System - Google Patents

Abstract

The invention relates to the field of power system signal processing, and specifically discloses a state estimation method based on an enhanced filter algorithm for a remote terminal device of a power system, comprising the following steps: Step S100: constructing a control feedback closed-loop system based on the enhanced filter; Step S200: Input the signal with noise obtained by the remote terminal device into the control feedback closed-loop system based on the enhanced filter in step S100 for filtering processing; step S300: the signal with noise is filtered and processed to obtain a filtered signal, so that the filtered signal can be obtained according to the filtering process. The signal performs accurate state estimation on the current operating state of the power system.

Description

State Estimation Method Based on Enhanced Filter Algorithm for Remote Terminal Equipment of Power System

technical field

The invention relates to the field of power system signal processing, and specifically discloses a state estimation method based on an enhanced filter algorithm for remote terminal equipment of a power system.

Background technique

Power system state estimation is one of the core functions of the energy management system (EMS) of the power system dispatch center. Its function is to estimate the current operating state of the power system based on various measurement information of the power system. The safe and economical operation of the modern power grid depends on the energy management system (EMS), and the many functions of the energy management system can be divided into two parts: online application for analyzing real-time changes in power grid and offline application for analyzing typical power flow sections. Power system state estimation can be said to be the basis of most advanced software for online applications. If the state estimation result of the power system is inaccurate, it is impossible to obtain accurate results in any subsequent analysis and calculation.

Power system remote terminal equipment (RTU) can be used in the fields of dynamic monitoring, system protection and system analysis and prediction of power system. It is an important equipment to ensure the safe operation of power grid. The results of field test, operation and application research show that: synchrophasor Measurement technology has been applied or has application prospects in power system state estimation and dynamic monitoring, stability prediction and control, model verification, relay protection, fault location, etc., but how to effectively use RTU measurement in state estimation is a must at present. The problem of correcting and solving, especially when a large amount of noise is mixed in the real-time measurement state, how to extract the effective state filtering signal and other extended signals has strong engineering significance.

Therefore, how to enhance the advantages of state estimation filtering in power system remote terminal equipment (RTU) measurement has become an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art, and to provide a state estimation method based on an enhanced filter algorithm for remote terminal equipment of a power system. On the basis of , different sliding mode surfaces are introduced to construct enhanced filter algorithms, thereby enhancing the advantages of state estimation and filtering of power system remote terminal equipment based on enhanced filter state estimation method.

The technical scheme adopted by the present invention to solve the technical problem is:

A state estimation method based on an enhanced filter algorithm for a remote terminal device of a power system, which specifically includes the following steps:

Step S100: constructing a control feedback closed-loop system of a second-order integral series system with disturbance;

Step S200: Input the signal with noise acquired by the remote terminal equipment of the power system into the control feedback closed-loop system constructed in step S100 for filtering processing;

Step S300: Based on the tracking filtered signal obtained by filtering the noisy signal in step S200, state estimation is performed on the operating state of the power system.

Further, the second-order integral series system control feedback closed-loop system with disturbance constructed in step S100 is defined as formula (1):

where x=[x ₁ , x ₂ ] ^T is the state variable, r is a constant, |u|≤r is the constraint condition of the control input u; disturbance is a function of time t, including uncertainty and external disturbance; using d( x, t), and assume that they are globally bounded and Lipschitz continuous.

Further, in step S300, state estimation is performed on the operating state of the power system, and the specific steps include:

Step S301: For any given initial states x ₁ and x ₂ of the system, calculate whether the sliding mode surface can be reached by constructing a Lyapunov function;

Step S302: For any given system initial states x ₁ and x ₂ , calculate whether the origin can be reached within a limited time by constructing a Lyapunov function;

Convergence of the state is evaluated according to the calculation results of steps S301 and S302.

Compared with the prior art, the present invention and its preferred solution obtain the filtered signal after filtering by inputting the signal with noise obtained by the remote terminal equipment into the control feedback closed-loop system based on the second-order series with disturbance. The current power system operating state can be accurately estimated according to the obtained filtered signal; by introducing different sliding mode surfaces to construct an enhanced filter, the state estimation method of the enhanced filter algorithm of the remote terminal equipment (RTU) equipment is effectively enhanced. advantages in filtering.

Description of drawings

1 is a flowchart of an embodiment of the present invention;

FIG. 2 is a schematic diagram of a comparison of state transition processes of different filtering algorithm systems according to an embodiment of the present invention;

3 is a schematic diagram illustrating the comparison of effects of different filter algorithms in sinusoidal signal tracking filtering according to an embodiment of the present invention;

FIG. 4 is a schematic diagram showing the comparison of effects of different filter algorithms in step signal tracking according to an embodiment of the present invention.

Detailed ways

In order to make the features and advantages of this patent more obvious and easy to understand, the following specific examples are given and described in detail as follows:

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

As shown in FIG. 1 , the state estimation method for a remote terminal device of a power system based on an enhanced filter algorithm provided by this embodiment specifically includes the following steps:

Step S100: constructing a control feedback closed-loop system of a second-order integral series system with disturbance;

Step S200: Input the signal with noise obtained by the remote terminal equipment (RTU) of the power system into the control feedback closed-loop system based on the enhanced filter algorithm in step S100 for filtering processing;

Step S300 : a tracking filtered signal is obtained after the signal with noise is filtered, so that an accurate state estimation of the operating state of the power system can be performed according to the obtained tracking filtered signal.

In this embodiment, the signal with noise obtained by the remote terminal equipment is input into the control feedback closed-loop system based on the second-order series with disturbance, so as to obtain the filtered signal after filtering, and then according to the obtained filtered signal Accurate state estimation is carried out for the current operating state of the power system; the enhancement filter is constructed by introducing different sliding mode surfaces, which effectively enhances the advantages of the state estimation method of the enhanced filter algorithm of the remote terminal equipment (RTU) equipment in filtering.

The specific implementation manner of each step will be further described below.

Step S100: constructing a control feedback closed-loop system of a second-order integral series system with disturbance;

The second-order integral series system control feedback closed-loop system with disturbance constructed in step S100 is defined as formula (1):

where x=[x ₁ , x ₂ ] ^T is the state variable, r is a constant, |u|≤r is the constraint condition of the control input u; disturbance is a function of time t, including uncertainty and external disturbance. They are denoted by d(x,t) and are assumed to be globally bounded and Lipschitz continuous.

Step S200: Input the signal with noise obtained by the remote terminal equipment (RTU) of the power system into the control feedback closed-loop system based on the enhanced filter algorithm in step S100 for filtering processing;

Step S300 : a tracking filtered signal is obtained after the signal with noise is filtered, so that an accurate state estimation of the operating state of the power system can be performed according to the obtained tracking filtered signal.

In this embodiment, the convergence evaluation of accurate state estimation for the current power system operating state is calculated by constructing a Lyapunov function to determine whether it can reach the sliding mode surface and whether it can reach the origin within a limited time.

In this embodiment, the Lyapunov function is constructed to evaluate the convergence and convergence time of the state estimation method of the power system remote terminal equipment (RTU) based on the enhanced filter algorithm, and the specific steps of the evaluation include:

Step S301: Assume s=sign(p), and take the Lyapunov function V(x)=|p| Its differential form is:

它的充分条件是：to prove

Its sufficient conditions are:

Then the upper bound of the perturbation is determined accordingly as:

As shown above, estimate a trajectory arriving at the switching curve starting at x ₀ at time t=0; assuming:

where μ(x,t)>0 is a given function; according to this assumption and the differentiation of the Lyapunov function, we can get:

The solution of this differential equation (4) is:

|p|=ce ^{-∫μ(x,t)dt}

where c is a constant, which can be chosen as c=|p ₀ |, then there are:

|p|＜|p ₀ ||e ^-μ(x,t)

If μ ₀ =minμ(x,t), then the convergence time of x ₀ from time t=0 to the switching curve can be estimated when |p|<ε (where ε is a given constant), as follows :

Step S302: Take the Lyapunov function as:

Its corresponding differential is

它的充分条件是：to prove

Its sufficient conditions are:

Then the upper bound of the perturbation is:

Likewise, the convergence time for states on the switching curve to be driven to the origin can be estimated; assuming:

where ν(x,t)>0 is a given function. According to this assumption, there are:

The solution to the differential equation is:

V=αe ^{-∫ν(x,t)dt}

where α is a constant, which can be taken as α=|V ₀ |; therefore:

V＜|V ₀ |e ^-ν(x,t)

If ν ₀ = minμ(x, t), then when calculating V < ε ₁ (where ε ₁ is a given constant), the convergence time for the state on the switching curve to be driven to the origin is:

Among them, when the parameters r and θ are properly adjusted, the method proposed in this embodiment is robust to a class of disturbances. The stability found in approaching modes is a sufficient condition for its use in sliding modes, since the upper bound on the disturbance satisfies:

At time t= ₀ , the trajectory from x0 will converge to the origin in a finite time less than t, given by t= _t1 + _t2 ; by adjusting the gain of the parameter, the total time can be managed so that the origin Robust and stable.

The enhanced filter algorithm of this embodiment based on the above design will be simulated and verified below. The simulation consists of two parts. The first is the comparison between the enhanced filter algorithm (referred to as TOSMC) and the variable structure control strategy based on the super-helix algorithm, which is common in the sliding mode variable structure control algorithm. The state of the mobile system returns to the origin. Second This embodiment compares the capabilities of the TOSMC-based differentiator and the STA-based differentiator in terms of signal tracking and differential extraction. In the simulation process, the sampling step size of the simulation system is h=0.001s, x ₁ (0)=0, x ₂ (0)=2, θ=0.1, r=80, α=8, λ=6.

The results of the simulation experiments are shown in FIGS. 2-4 , which proves that the effect of the solution provided in this embodiment is better than that of the prior art as a comparison.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations of methods, apparatus (apparatus), and computer program products according to embodiments of the invention. It will be understood that each process in the flowchart, and combinations of processes in the flowchart, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce A device that implements the functions specified in one or more of the flow charts.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The device implements the functions specified in one or more of the flowcharts.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that Instructions provide steps for implementing the functions specified in a flow or flows of the flowchart.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications to equivalent changes. Example. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still belong to the protection scope of the technical solutions of the present invention.

This patent is not limited to the above-mentioned best embodiment, anyone can obtain other various forms of state estimation methods based on the enhanced filter algorithm for the remote terminal equipment of the power system under the inspiration of this patent. All equivalent changes and modifications made shall fall within the scope of this patent.

Claims (3)

1. a state estimation method based on an enhanced filter algorithm for remote terminal equipment of a power system, is characterized in that, specifically comprises the following steps: Step S100: constructing a control feedback closed-loop system of a second-order integral series system with disturbance; Step S200: Input the signal with noise acquired by the remote terminal equipment of the power system into the control feedback closed-loop system constructed in step S100 for filtering processing; Step S300: Based on the tracking filtered signal obtained by filtering the noisy signal in step S200, state estimation is performed on the operating state of the power system. 2. the state estimation method based on the enhanced filter algorithm of the power system remote terminal equipment according to claim 1, is characterized in that, the second-order integral series system control feedback closed-loop system with disturbance constructed in step S100 is defined as formula ( 1):

where x=[x ₁ , x ₂ ] ^T is the state variable, r is a constant, |u|≤r is the constraint condition of the control input u; disturbance is a function of time t, including uncertainty and external disturbance; using d( x, t), and assume that they are globally bounded and Lipschitz continuous. 3. The state estimation method based on the enhanced filter algorithm for the remote terminal equipment of the power system according to claim 2, wherein in step S300, the state estimation is performed on the operating state of the power system, and the specific steps include: Step S301: For any given initial states x ₁ and x ₂ of the system, calculate whether the sliding mode surface can be reached by constructing a Lyapunov function; Step S302: For any given system initial states x ₁ and x ₂ , calculate whether the origin can be reached within a limited time by constructing a Lyapunov function; Convergence of the state is evaluated according to the calculation results of steps S301 and S302.

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