A method for analysing the reliability of a transmission grid

• Published in: Reliability engineering & system safety Vol. 93; no. 2; pp. 277 - 287
• Main Authors: Haarla, Liisa, Pulkkinen, Urho, Koskinen, Mikko, Jyrinsalo, Jussi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2008; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Failure; Importance; Operational research and scientific management; Operational research. Management science; Power system; Protection; Reliability; Reliability theory. Replacement problems; Substation; Transmission; Power system; Importance; Substation; Transmission; Reliability; Protection; Failure; Statistical analysis; Tree(graph); Probabilistic approach; Fault tree; Grid; Rupture; Program analysis; Dynamical system; Failures; Modeling; Transmission line; Electrical network; Risk factor; Minimal cut; Safety; Emergency system; System analysis
• ISSN: 0951-8320; 1879-0836
• DOI: 10.1016/j.ress.2006.10.025

The paper describes a probabilistic method for transmission grid security evaluation. Power system security is the ability of the power system to withstand sudden disturbances such as short circuits. The method presented here uses event and fault trees and combines them with power system dynamic simulations. Event trees model the substation protection and trip operations after line faults. Different event tree end states (fault duration, circuit breaker trips) are simulated with power system dynamic analysis program. The dynamic analysis results (power system post-fault states) are then classified into secure, alert, emergency and system breakdown. The probabilities, minimal cut sets and grid level importance measures (Fussell-Vesely, risk increase and decrease factors) are calculated for the total and partial system breakdown. In this way, the relative importance of the substation devices regarding to the system breakdown can be reached. Also the more and less likely contributing factors to system breakdown are received. With this method, an existing 400 kV transmission grid with its line fault and device failure statistics is analysed.