Method for small-signal stability assessment of power systems within instability borders using source side and load side perturbations

摘要

A novel method for real-time small-signal stability analysis within the instability borders for power electronic-based components in a power system. The method may be used to monitor a power system in real-time by perturbing the source side of an electronic-based component of the power system of about 0.5 to 1 percent of a nominal current of the power system at the source side, and perturbing the load side of the power electronic-based component by varying the voltage at the load side. Time-domain results of the perturbations may be transferred to frequency-domain results and the stability of the power system may be monitored by obtaining a Nyquist contour and employing unit circuit criterion or Generalized Nyquist Criterion.

主权项

1. A method for real-time analysis of small-signal stability of
a power system, the method comprising:
providing non-transitory computer readable media having computer-executable instructions for performing a method of running a software program on a computing device, the computing device operating under an operating system, the method including issuing instructions from the software program comprising;observing the power system in a real-time operational mode, the power system comprising a source side and a load side from a perspective of the power electronic-base component;perturbing the source side of the power electronic-based component by injecting a current of about 0.5 to about 1 percent of a nominal current of the power system at the source side using shunt current injection and perturbing the load side of the power electronic-based component by varying a voltage of the power system using series voltage injection, wherein perturbing the source side of the power electronic-based component using shunt current injection and perturbing the load side of the power electronic-based component using series voltage injection occurs simultaneously;measuring currents and voltages at the source side and at the load side;determining a phase of the power system using single-phase Phase Lock Loop;transforming the measured source side current and voltage and the measured load side current and voltage to a d-q reference frame using the determined phase of the power system;transferring time-domain source side current and voltage values and time-domain load side current and voltage values to frequency-domain current and voltage values using Fourier transforms;calculating a frequency-domain return-ratio matrix in the d-q reference frame using the frequency-domain source side current and voltage values and the frequency-domain load side current and voltage values;plotting a Nyquist contour of a d-d component of the frequency-domain return-ratio matrix; anddefining a relative stability of the power system and comparing the relative stability to instability borders of the power system to evaluate the small-signal stability of the power system using stability criteria.