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Transient voltage stability monitoring method based on phase correction Lyapunov exponent

A transient voltage stabilization and phase correction technology, applied to electrical components, circuit devices, AC network circuits, etc., can solve problems such as misjudgment of transient voltage stability in AC and DC systems, model parameter changes, long observation time, etc., to achieve Overcoming the initial time window and observation window, strong versatility and practicability, and weakening the effect of inherent measurement errors

Active Publication Date: 2021-03-16
NORTHEAST DIANLI UNIVERSITY +2
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, the construction methods of MLE all rely on the power system model, and are easily affected by the change of model parameters when performing high-dimensional phase space reconstruction, which is not conducive to the online application of the transient stability state discrimination of the actual power system[13][14 ]
In addition, the method of judging the transient stable state based on the final sign characteristics of MLE needs to find the optimal initial time window length, which depends on the fault scenario, which is difficult to determine and requires a long observation time. When the parameter setting is unreasonable or the voltage oscillates, it is easy to cause misjudgment of the transient voltage stability state of the AC and DC system[15][16]
[0006]Therefore, in order to solve the shortcomings of the existing MLE in adaptability to time windows and power grid oscillations, it is urgent to build a more robust and accurate transient On-line Discrimination Method of Voltage Stability

Method used

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  • Transient voltage stability monitoring method based on phase correction Lyapunov exponent
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  • Transient voltage stability monitoring method based on phase correction Lyapunov exponent

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Embodiment 1

[0065] The embodiment of the present invention provides a transient voltage stability monitoring method based on phase correction Lyapunov exponent, such as figure 1 As shown, the method includes the following steps:

[0066] 101: Use the PMU measurement device to measure the time series data V of the transient voltage of key nodes in real time t ={v t,1 ,v t,2 ,...,v t,n}, to prepare for the subsequent calculation of the Lyapunov index, and to monitor in real time whether the power system fails, and if a failure occurs, perform step 102; otherwise, continue to measure the voltage data of key nodes;

[0067] 102: Initialize the time window length, step size control parameter η and the number of average voltage measurement points n av ;

[0068] Wherein, if a failure occurs, the Lyapunov exponent needs to be calculated, and step 102 is an initialization step in the calculation.

[0069] 103: Perform mode analysis on the voltage trajectory in the initial time window, deter...

Embodiment 2

[0075] Combined with the specific calculation formula, the appended figure 2 , image 3 , Figure 4 The scheme in Example 1 is further introduced, see the following description for details:

[0076] 201: The response trajectory of the key node voltage has obvious dynamic characteristics in the transient process, and the change trajectory of the voltage amplitude of the key node after the fault is converted to the v′-Δv plane, where Δv and v′ are voltage time series data respectively The amplitude deviation and amplitude change rate, such as figure 2 shown.

[0077] Use the PMU measurement data to calculate the Δv of the mth measurement data of node i mΔt,i and v' mΔt,i The method looks like this:

[0078]

[0079] In the formula: v mΔt,i and v (m-1)Δt,i are the voltage time series data of node i at time mΔt and (m-1)Δt respectively; Δv mΔt,i and Δv (m-1)Δt,i Respectively, the voltage amplitude deviation of node i at mΔt and (m-1)Δt; v′ mΔt,i is the rate of chan...

Embodiment 3

[0137] The following combined with specific examples, Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 And table 1 carries out feasibility verification to the scheme in embodiment 1 and 2, see the following description for details:

[0138] This example is to verify the accuracy and effectiveness of the proposed transient voltage stability real-time monitoring method through the modified IEEE-39 node power system. The modified IEEE-39 node power system topology is as follows: Figure 5 shown.

[0139] 1) Accuracy analysis of transient voltage stability monitoring indicators

[0140] In order to verify the accuracy of the MLE index proposed in this paper, take a three-phase short-circuit fault on the Bus4 side of the transmission line Bus4-Bus5 as an example. The simulation time is 10s, the sampling interval is 0.01s, and the initial time window length is D=0.3s. The start time is 0.2s. If the fault removal time is 0.44s, the transient...

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Abstract

The invention discloses a transient voltage stability monitoring method based on a phase correction Lyapunov exponent. The method comprises the steps: carrying out mode analysis on an obtained initialtime window voltage track, determining various parameters of a dominant oscillation mode, and calculating the maximum value of a voltage amplitude change rate; adopting step length control parametersand the number of mean voltage measurement points in a mean value method to eliminate the influence of measurement errors of adjacent voltage tracks, and calculating the change rate of adjacent voltage amplitudes; and judging the transient voltage stable state of the power system according to the maximum value of the voltage amplitude change rate and the adjacent voltage amplitude change rate. According to the invention, the defect that an MLE initial time window and an observation window need to be preset in the prior art is overcome, and high universality and practicability are achieved.

Description

technical field [0001] The invention relates to the field of transient voltages, in particular to a transient voltage stability monitoring method based on a phase correction Lyapunov exponent (maximumlyapunov exponent based on phase correction, PCMLE). Background technique [0002] As my country's AC-DC power grid with large-scale new energy is becoming increasingly electronic, the dynamic loads of air conditioners and industrial motors are increasing, making the transient stability problems caused by large disturbances in the load center area more serious, and its safety and stability control problems are gradually increasing. From power angle stability to transient voltage stability [1] , It also puts forward higher requirements for the transient voltage stability monitoring of AC and DC power grids with a high proportion of power electronic equipment. [0003] The existing transient voltage stability monitoring method is gradually changing from "offline training, online e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/00
CPCH02J3/00H02J2203/10H02J2203/20
Inventor 王长江姜涛陈厚合李雪李国庆范维段方维
Owner NORTHEAST DIANLI UNIVERSITY
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