Voltage Stability Monitoring Based on the Concept of Coupled Single-Port Circuit

Abstract

This paper reveals that the impedance match (or the Thevenin circuit) based voltage stability monitoring techniques have problems to predict voltage stability limits when applied to multi-load power systems. Power system loads are nonlinear and dynamic. They cannot be simply represented as Thevenin circuit parameters for impedance match analysis. To overcome these difficulties, a new concept called "coupled single-port circuit" is proposed in this paper. The concept decouples a meshed network into individual single generator versus single bus network and, as a result, a modified version of the impedance match theorem can be used. This leads to a real-time voltage stability monitoring scheme without the need to estimate Thevenin parameters. The scheme can estimate voltage stability margin and identify weak areas in a system based on the SCADA and PMU data. Case studies conducted on several test systems have verified the validity of the proposed method.

Voltage stability monitoring using a modified thevenin impedance

“…This correlation can be used for the Impedance Stability Index (ISI) established in [6], It can be noted that according to [5] and [7] the equivalent voltage ETh and the maximum load ability Smax can be estimated, but these values are not necessarily needed as the method proposed in this paper focuses on an evaluation of the ISI. With the condition for the maximum power transfer (1) the loadability limit is given for ISI equals 1.…”

Power systems wide-area voltage stability assessment considering dissimilar load variations and credible contingencies

“…In general, a power system is designed to operate under various conditions; however, it is inevitable that complex power systems will experience difficulties in the operation process some of which lead to the voltage collapse. In the sequel of many major blackouts [2,3], tackling system voltage instability has attracted researchers' attention [4][5][6][7].…”

Gauss-Seidel Method based Voltage Security Analysis of Distribution System

“…In recent years a lot of work has been done in the area of voltage stability. Voltage stability analysis was done by the researchers using nodal analysis [16], modified differential evolution [17], coupled single port circuit [18], circuit theory [19], catastrophe theory [20], chaotic particle swarm optimization algorithm [21], vector regression model [22] etc. Along with the other methods phasor measurement unit based schemes are also been used in power system to monitor voltage stability [23], [24].…”