Abstract: The present invention discloses a method and device for formulating a coordinated action strategy of SSTS and DVR for voltage sag mitigation. The influence of voltage sag on a whole industrial process of a sensitive user is analyzed, and the sensitive loads of SSTS and DVR which satisfy a governance need are grouped; a practical governance scenario of installing a plurality of DVR is considered to install a minimum-capacity DVR to realize a target of a minimum interruption probability of the whole industrial process of the user; an optimal coordinated governance solution of SSTS and DVR based on sensitive load grouping is proposed; a classification result is obtained for duration time at a time when a voltage sag event occurs through a decision tree constructed based on historical data.

Abstract: A state estimation method for a multi-stage voltage sag comprises analyzing characteristics of multi-stage voltage sags due to different causes. A method for determining the cause of sudden change time of an amplitude of the multi-stage voltage sag is based on a jump characteristic of the sag amplitude. Calculation methods of a relay protection action matrix and a faulty line set are utilized to preliminarily obtain a faulty line set based on the fault clearing time of a relay protection device and other characteristics to effectively reduce a calculation amount of sag state estimation. Based on a substantive characteristic that different events cause a change of system impedance, a method for inferring a cause of an event in each stage of the multi-stage voltage sag is used to improve the accuracy of the state estimation. The state estimation method reduces the difficulty in applying to the multi-stage voltage sag.

Abstract: A method for constructing a general probability model of a harmonic emission level for an industrial load is provided. The method establishes, based on harmonic data monitored by a power quality monitoring system, a general probability model by combining a parametric estimation method based on a normal distribution function and a lognormal distribution function with a nonparametric estimation method represented by a kernel density estimation method, taking a degree of approximation between the general probability model and an actual probability distribution of each harmonic current as an objective function based on parameters required by the general probability model, and optimizing and solving the parameters of the proposed general probability model by using a multiplier method to determine parameters of the general probability model to finally obtain a general probability model applicable to different industrial loads.

Abstract: The present invention discloses a method and device for formulating a coordinated action strategy of SSTS and DVR for voltage sag mitigation. The influence of voltage sag on a whole industrial process of a sensitive user is analyzed, and the sensitive loads of SSTS and DVR which satisfy a governance need are grouped; a practical governance scenario of installing a plurality of DVR is considered to install a minimum-capacity DVR to realize a target of a minimum interruption probability of the whole industrial process of the user; an optimal coordinated governance solution of SSTS and DVR based on sensitive load grouping is proposed; a classification result is obtained for duration time at a time when a voltage sag event occurs through a decision tree constructed based on historical data.

Abstract: An SVC compensation strategy optimization method, comprising: calculating a weak voltage node in a fault state based on risk measure; calculating the weak voltage node in a normal state based on a static stability margin; and determining an optimal SVC distribution point and calculating the optimal configuration of SVC capacity. The SVC compensation strategy optimization method overcomes the defects in the prior art, such as low reliability, low optimization precision, poor applicability, etc., and has the advantages of high reliability, high optimization precision, and good applicability.