263 / 2018-09-24 23:41:24

Risk Assessment Model for GIS Operating under Tropical Conditions

Gas Insulated Switchgears,GIS,RIsk,Risk Assessment,Tropical Conditions

In the operational and tactical Asset Management (AM) within the network utilities, the risk assessment has been used in prioritizing action on the critical transmission assets, like the Gas Insulated Switchgear (GIS). In practice, the asset manager in the transmission utility is usually responsible to about hundreds of CB-bays of GIS with the various health status. The risk assessment can help to prioritize mitigating action on GIS.
This paper proposes a risk assessment model for GIS operating under the tropical conditions. The GIS in the tropics become the subject because we observed GIS failure rates over twice the value reported in the 3rd CIGRE Survey of 2007.
A risk is defined as the product of the probability of an event and its consequences. Our model estimates the risk of having a major failure of a bay in GIS.
The Total Failure Probability (TFP) score has been introduced to accumulate the six influencing parameters that are increasing the probability of GIS failure in tropics. These parameters are namely: 1) the condition of GIS based on the Health Index (HI) assessment, 2) the hazard rate, 3) the number of interruptions per year, 4) the maintenance history, 5) the pollutants level, and 6) the surge arrester readiness in a GIS substation.
Meanwhile, the consequences were defined based on the business values of a transmission utility in the case study. The values include the following: 1) Safety, 2) Financial (i.e., the Extra Fuel Cost and the Equipment Cost, 3) System reliability (i.e., the Energy not Served), 4) Customer Satisfaction, 5) Leadership and 6) Environmental impact.
The risk is finally defined based on the TFP and the consequences. The output is a qualitative measure where the risk falls into one of the four categories, namely: Low, Medium, High, and Very High.