Systems and methods to detect poorly damped oscillation modes
First Claim
1. A device for detecting poorly damped oscillation modes in an electric power delivery system, the device comprising:
- a communications interface configured to receive a plurality of measurement signals comprising real-time electric power delivery system information;
a frequency transform calculator configured to compute a frequency transform of at least one of the plurality of measurement signals;
an oscillation mode detector configured to determine an oscillation mode of interest based on the frequency transform;
an amplitude calculator configured to;
determine a sliding window size based on a predetermined multiple of a period of the oscillation mode of interest;
determine a step size for the sliding window based on a predetermined multiple of the period of the oscillation mode of interest;
determine a static window size based on a predetermined multiple of the period of the oscillation mode of interest;
calculate amplitudes of the oscillation mode of interest over the sliding window;
and, a damping calculator configured to compute a damping of the oscillation mode of interest based on changes over time in the amplitudes of the oscillation mode of interest in the plurality of measurement signals, wherein the frequency transform calculator is further configured to compute the amplitudes over the sliding window during the static window, and wherein the changes over time in the amplitudes are determined by shifting the sliding window by the step size, and computing updated amplitudes; and
the device configured to take a control action when the poorly damped oscillation modes are detected, wherein the control action comprises one of;
connecting a capacitor bank, disconnecting the capacitor bank, tripping a relay, or tripping a breaker.
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Accused Products
Abstract
A plurality of measurement signals may be evaluated to detect a poorly damped oscillation mode in an electric power delivery system. An oscillation mode of interest may be detected, and the oscillation mode of interest may be analyzed using a frequency transform. A plurality of amplitudes of the oscillation mode of interest in each measurement signal may be determined using a sliding window. The plurality of amplitudes may be used to calculate a damping of the oscillation mode of interest. The damping may be calculated solving a linearized system of equations. The linearized system of equations may be a least square estimate of the damping based on the logarithm of each amplitude. If the damping indicates that the oscillation mode of interest is poorly damped, a control action may be taken.
38 Citations
18 Claims
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1. A device for detecting poorly damped oscillation modes in an electric power delivery system, the device comprising:
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a communications interface configured to receive a plurality of measurement signals comprising real-time electric power delivery system information; a frequency transform calculator configured to compute a frequency transform of at least one of the plurality of measurement signals; an oscillation mode detector configured to determine an oscillation mode of interest based on the frequency transform; an amplitude calculator configured to; determine a sliding window size based on a predetermined multiple of a period of the oscillation mode of interest; determine a step size for the sliding window based on a predetermined multiple of the period of the oscillation mode of interest; determine a static window size based on a predetermined multiple of the period of the oscillation mode of interest; calculate amplitudes of the oscillation mode of interest over the sliding window; and, a damping calculator configured to compute a damping of the oscillation mode of interest based on changes over time in the amplitudes of the oscillation mode of interest in the plurality of measurement signals, wherein the frequency transform calculator is further configured to compute the amplitudes over the sliding window during the static window, and wherein the changes over time in the amplitudes are determined by shifting the sliding window by the step size, and computing updated amplitudes; and the device configured to take a control action when the poorly damped oscillation modes are detected, wherein the control action comprises one of;
connecting a capacitor bank, disconnecting the capacitor bank, tripping a relay, or tripping a breaker. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A non-transitory computer readable storage medium comprising program code configured to cause a processor to perform a method of detecting poorly damped oscillation modes in an electric power delivery system, the method comprising:
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receiving a plurality of measurement signals comprising real-time electric power delivery system information; computing a frequency transform of at least one of the plurality of measurement signals; determining an oscillation mode of interest from the frequency transform; computing a sliding window size based on a predetermined multiple of a period of the oscillation mode of interest; computing a step size for the sliding window based on a predetermined multiple of the period of the oscillation mode of interest; computing a static window size based on a predetermined multiple of the period of the oscillation mode of interest; computing a plurality of amplitudes of the oscillation mode of interest corresponding to a plurality of time points, each amplitude of the plurality of amplitudes computed over a sliding window during the static window, the sliding window being shifted by the step size to compute another amplitude of the plurality of amplitudes; and calculating a damping of the oscillation mode of interest based on the plurality of amplitudes computed for each of the plurality of measurement signals; and taking a control action when the poorly damped oscillation modes are detected, wherein the control action comprises one of;
connecting a capacitor bank, disconnecting the capacitor bank, tripping a relay, or tripping a breaker. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method for detecting poorly damped oscillation modes in an electric power delivery system, the method comprising:
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receiving, at an intelligent electronic device (IED), a plurality of measurement signals comprising real-time electric power delivery system information from a plurality of phasor measurement units; the IED computing a frequency transform from at least one of the plurality of measurement signals; determining an oscillation mode of interest from the frequency transform; determining a sliding window size based on a predetermined multiple of a period of the oscillation mode of interest; determining a step size for the sliding window based on a predetermined multiple of the period of the oscillation mode of interest; determining a static window size based on a predetermined multiple of the period of the oscillation mode of interest; the IED computing changes over time in amplitudes of the oscillation mode of interest in the plurality of measurement signals, each change in amplitude calculated for adjacent sliding windows shifted by the step size during the static window; and the IED calculating a damping of the oscillation mode of interest based on the changes over time in the amplitudes; and the IED taking a control action when the poorly damped oscillation modes are detected, wherein the control action comprises one of;
connecting a capacitor bank, disconnecting the capacitor bank, tripping a relay, or tripping a breaker.
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Specification