The uniform fuzzy index of power system security

Abstract

SUMMARYThe paper presents a new approach to assessment of the power system security. Using fuzzy membership functions of power system elements, it continuously quantifies the security state of a power system, as opposed to conventional methods which use off-line screening for the most vulnerable system states. It introduces global fuzzy security index (GFSI) of the power system using system's variables characterized by fuzzy sets of a trapezoidal form. GFSI is calculated by multiplying the security membership grade (SMG) values of the power system's segments that exhibit the lowest SMG values. The power system security levels are traced continually through time using real data of power flow and state estimation calculations as well as measurements of variables inaccessible by the load flow analysis. The GFSI enables the system operator to identify the insecure state and then continuously monitor the distance of the power system's actual state and the insecure one. Application of the algorithm is illustrated using the data of Bosnian power system.

Online Steady-State Security Awareness Using Cellular Computation Networks and Fuzzy Techniques

“…In the 12-bus power system, ideally to classify the power system states "Secure", "Alert", or "Emergency", it requires abundant combinations of input levels. Assume each of the 11 voltage inputs is classified by five levels (corresponding membership functions are NB, NM, Normal, PM, PB); this would mean 5 11 = 48,828,125 voltage level combinations.…”

“…Marannino et al [10] proposed a neuro-fuzzy method for the voltage collapse risk classification. Halilčević et al [11] used fuzzy membership functions of power system elements to estimate the system security level online. Later, Halilčević et al [12] used the deterministic and fuzzy inference method to continuously estimate the security, adequacy, and reliability of power system current operation.…”

Conceptual Analysis of Different Clustering Techniques for Static Security Investigation

“…Therefore, the need for feature extraction and dimensionality reduction technique has arisen. In [6,61,62] different techniques have been used to eliminate the redundancy problem attached with contingency analysis. Forward sequential method, Entropy maximization, fisher discrimination and principal component analysis (PCA) are some of these techniques.…”

Synthetic Risk Assessment of Catastrophic Event in Power System Based on Uncertainty

“…The credibility index measuring the possibility of event. The credibility theory [4] is axiomatic system of fuzzy mathematics based on the measure theory, proposed by the mathematician Professor Liu Baoding. The credibility measure Cr(I∈A) is calculated as:…”

“…But uncertainty has replaced deterministic assessment due to the deterministic assessment is difficult to portray the uncertainty of the event. The risk assessment is typical in the uncertainty assessment, the determining of synthetic severity index classify as: multiplication [4], summation [5][6][7][8][9]. The multiplication is sensitive of the value close to 0, but it's positive of value close to 1.…”