Reliability evaluation of grid substations in Bangladesh power system

Determination of the reliability of a substation is important as it helps locate weak points that may be contributing to overall power system unreliability. This paper evaluates reliability of 230 kV grid substations in Bangladesh subject to protection failures. The problem belongs to the dynamic reliability evaluation field. Event tree analysis is used as the main method. Fault tree analysis is used to get the input of the event tree. Reliability of five grid substations are calculated. Ishurdi grid substation is found to have a mean time to failure of only six months, which will affect seriously the design and safety of the proposed nuclear power station at Rooppur sited closely nearby.