Based on years of theoretical research on impedance analysis methods, technical standard development, and engineering application experience, Shanghai KeLiang has developed the QuiKIS impedance scanning and stability analysis software, which has released Version 2.0. QuiKIS supports impedance scanning for power electronic devices, new energy power plants, high-voltage DC converter stations, and power grids, as well as impedance-based stability analysis at the port level in new power systems. It also features user-friendly import/export, data management, graphical editing, general analysis, and scripting functions. The software interface is available in either Simplified Chinese or English.

Software Homepage

n Data Management

Supports importing, exporting, viewing, plotting, renaming, locating files in explorer, clearing, emptying, and editing data files in CSV, MAT, TXT, and KIS formats. Users can view file attributes (e.g., type, status, path) and detect continuity, duration, and sampling frequency of time-domain data.

Data Detection

n Graph Editor

Supports display selection, axis zooming, layout, synchronization or alignment operations, mouse point acquisition, cursor/trace addition, shape insertion, min/max value tracking, and export. Properties such as labels, axis range, color, text, legend, grid, line width, line style, transparency, tick values, and subtick values can be configured, and attribute settings can be saved to styles.

Graphics Settings

n Export Template

By invoking required paper or report templates, users can one-click batch export edited graphics to designated locations in target documents with automated positioning.

Export Template

n Harmonic Analysis

Phase harmonics and sequence harmonics analysis can be conducted, where the phase harmonics reference signal can be the fundamental wave or direct current. Sequence harmonics include positive sequence, negative sequence, and zero sequence harmonics. The harmonic content can include frequencies below the fundamental frequency. Harmonic amplitude graphs, phase graphs, and fundamental frequency graphs can be plotted.

Negative-Sequence Harmonic Analysis

n Power Calculation

Supports DC power, single-phase power, and three-phase power calculations. For single-phase and three-phase power, graphical displays of instantaneous power, active power, reactive power, apparent power, and power factor can be optionally generated. Calculation results support per-unit system normalization.

Three-Phase Power Calculation

n Impedance/Admittance Scanning

Impedance/Admittance scanning allows configuring the Device Under Test (DUT), disturbance phase sequence, disturbance type, response, sampling voltage, current direction, file type, data parameters, and scanning method for targeted measurements; the results can be visualized as Magnitude Bode Plot, Phase Bode Plot, Real Part-Frequency Plot, Imaginary Part-Frequency Plot, or Nyquist Plot, with support for appending result curves to overlay comparative data.

Real Part-Frequency Plot & Imaginary Part-Frequency Plot

Nyquist Plot

n Impedance/Admittance Data Validation

Accuracy is verified by calculating deviation values of the comparative impedance/admittance data against reference impedance/admittance data. Two sets of comparative impedance/admittance data can be simultaneously selected for validation. The validation results display the maximum magnitude deviation and maximum phase deviation, while generating Bode plots (magnitude and phase) for the reference data, comparative data, and deviation data respectively.

Impedance/Admittance Data Validation

n Impedance Stability Analysis

This analysis enables qualitative and quantitative assessment of source/load impedance data stability using either the Nyquist Criterion or Maximum Peak Criterion. Quantitative metrics include stability margin and risk frequencies. The Maximum Peak Criterion allows setting exclusion radii on a per-frequency-band basis and generates Nyquist plots of the source-load impedance ratio.

Maximum Peak Criterion

n Script

It supports script management, editing, running, and debugging, provides basic functions, and supports loading custom functions. It can be used for the calculation and output of impedance/admittance transfer functions and data files. 

Script

n Provides perturbation injection simulation modules and models

n Manages power calculation, impedance scanning, and script execution processes

n Considers positive sequence, negative sequence, and DC components for perturbation phase sequences and responses

n Supports combined plotting of magnitude and phase Bode diagrams for impedance/admittance

n Supports computation of electrical quantities, statistical metrics, and extreme values

n Wind-Solar-Storage-Charging Integration

n Reactive Power Compensation

n High-Voltage Direct Current (HVDC) Transmission

n Solid State Transformer (SST)

n Energy Router

A provincial electric power research institute adopted QuiKIS impedance scanning and stability analysis software to perform impedance scanning on voltage and current data generated after injecting positive-sequence disturbances into a wind turbine's hardware-in-the-loop (HIL) simulation model. This process obtained the positive-sequence impedance of the wind turbine under typical operating conditions. Utilizing the software's Nyquist criterion function, combined with grid impedance and the turbine's positive-sequence impedance, stability analysis was conducted. The results indicated stable grid connection under typical turbine operation, with a phase margin of 7.4°. This analysis provided critical technical support for enhancing wind power integration capacity and mitigating risks of system-wide broadband oscillations.

Impedance Stability Analysis Based on the Nyquist Criterion

Impedance Scanner