Three-phase AC system impedance measurement unit (IMU) using chirp signal injection

Abstract

Impedance defined in synchronous coordinates is a useful tool to predict and evaluate stability of three-phase AC systems. For online impedance measurement in AC systems, the widely used frequency sweep method takes a long time and may not be practical in systems where the operating point cannot be maintained for a long time. A wide bandwidth signal could be used to significantly reduce the measurement time. This paper suggests a chirp signal and describes its advantages over other signals. Experimental results demonstrate the effectiveness of this approach.

Real-time small signal stability analysis of the power electronic-based components in contemporary distribution systems

“…Chirp signals, also known as swept-sine signals, are a common wide-bandwidth signals used to perturb the system for impedance measurement [24]. This paper proposes using chirp signals for perturbation in the impedance measurement, thus simultaneously enabling real-time capability and nonlinearity consideration of the proposed model.…”

Modular scalable medium-voltage impedance measurement unit using 10 kV SiC MOSFET PEBBs

“…Here implemented single-phase injection considerably simplifies the PIU by still maintaining full required functionality and performance [13]. More information about different types of perturbation signals used in this PIU can be found in [14], [15]. The main PIU components and structure will be briefly described in the following subsections.…”

Small Signal Stability of a Balanced Three-Phase AC Microgrid Using Harmonic Linearization: Parametric-Based Analysis

“…[30] SRF Method Limited to only balanced three-phase systems. [20,33] In the SRF method, the balanced three-phase shunt current perturbation is used for impedance estimation [24,[34][35][36] with the automated unit as presented in [36,37]. The impedance can be measured in real time with negligible additional cost [21,22,25,[38][39][40][41][42][43] by this method.…”