Back to results
US 11,112,438 B2Granted
Nonlinear oscillation detection method based on measurement data, and recording medium and apparatus for performing the same
AssigneeKorea University Research and Business Foundation
InventorsByongjun Lee, Hwanhee Cho
Life of this patent
Estimating the term…
Abstract
Provided is a nonlinear oscillation detection method at an electric power system, and a recording medium and apparatus for performing the method. The nonlinear oscillation detection apparatus at the electric power system detects various kinds of nonlinear oscillation occurring at the electric power system by applying a nonlinear oscillation precognition algorithm based on a nonlinear dynamic theory to the time series information measured at the electric power system.
Claims12
A nonlinear oscillation detection apparatus, comprising:
- a measurement unit configured to obtain time series information by measuring a physical quantity of an electric power system whose nonlinear oscillation is to be detected;
- a change rate calculation unit configured to calculate a change rate of the time series information;
- a plane distance calculation unit configured to:
- depict a trajectory representing a relationship between the time series information and the change rate of the time series information and a point representing a normal state of the electric power system on a two-dimensional coordinate plane, and
- selectively calculate a distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system;
- a regression estimation unit configured to estimate a nonlinear curve by using the plane distance that is the distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system;
- and
- a determination unit configured to determine whether nonlinear oscillation occurs at the electric power system by calculating a largest Lyapunov exponent of the nonlinear curve,
- wherein the plane distance calculation unit is configured to obtain moving averages of the time series information and the change rate of the time series information during one cycle of oscillation represented by the physical quantity of the electric power system respectively as estimated values representing the time series information and the change rate of the time series information when the electric power system is in a normal state.
6 more elements
A nonlinear oscillation detection method of a nonlinear oscillation detection apparatus that is included in an electric power system to detect nonlinear oscillation of equipment of the electric power system, the nonlinear oscillation detection method comprising:
- obtaining time series information by measuring a physical quantity of the electric power system;
- calculating a change rate of the time series information;
- depicting a trajectory representing a relationship between the time series information and the change rate of the time series information and a point representing a normal state of the electric power system on a two-dimensional coordinate plane, and selectively calculating a distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system;
- estimating a nonlinear curve by using a plane distance that is the distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system;
- and
- determining whether nonlinear oscillation occurs at the electric power system by calculating a largest Lyapunov exponent of the nonlinear curve,
- wherein the step of depicting a trajectory representing a relationship between the time series information and the change rate of the time series information and a point representing a normal state of the electric power system on a two-dimensional coordinate plane further includes obtaining moving averages of the time series information and the change rate of the time series information during one cycle of oscillation represented by the physical quantity of the electric power system respectively as estimated values representing time series information and a change rate of the time series information when the electric power system is in a normal state.
4 more elements
A nonlinear oscillation detection method of a nonlinear oscillation detection apparatus that is included in an electric power system to detect nonlinear oscillation of equipment of the electric power system, the nonlinear oscillation detection method comprising:
- obtaining time series information by measuring a physical quantity of the electric power system;
- calculating a change rate of the time series information;
- depicting a trajectory representing a relationship between the time series information and the change rate of the time series information and a point representing a normal state of the electric power system on a two-dimensional coordinate plane, and selectively calculating a distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system;
- estimating a nonlinear curve by using a plane distance that is the distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system;
- and
- determining whether nonlinear oscillation occurs at the electric power system by calculating a largest Lyapunov exponent of the nonlinear curve,
- wherein the step of selectively calculating a distance from each point of the trajectory representing the relationship between the time series information and the change rate of the time series information to the point representing the normal state of the electric power system includes:
- selecting a measurement point according to a slope of the trajectory representing the relationship between the time series information and the change rate of the time series information;
- and
- calculating a distance from the measurement point to the point representing the normal state of the electric power system as the plane distance.
7 more elements
Dependencies are inferred from the claim text.