Substation reliability evaluation including switching actions with redundant components

Abstract

Abstract-Failure events in substations often result in multiple outages of generators, lines andlor loads in power systems. The simulation of substation originated outages for practical substation configurations is difficult, due to the complex switching actions with disconnect switches and circuit breakers that can take place. A digital computer program has been developed at the Delft University of Technology, which simulates these complex switching actions following substation failures. The simulation algorithms, which deduce the contingencies before and after switching actions with their corresponding reliability indices, are described in detail in the paper. The paper reports on results obtained from analyzing six different busbar schemes with redundant components.

Evaluation of substation bus schemes considering reliability

“…Failure modes of substation components include four types [6][7][8][9], which are passive failure, active failure, breaker stuck when called upon to open and overlapping failure. Each failure mode has different effect upon load points, and this paper employs the minimal cut-sets method [10,11] to determine whether each failure event may constitutes load point failure event, for the above-mentioned 16 types of substation bus schemes.…”

“…When any active failure event occurs, the circuit breaker inside Primary Protected Zone cannot be tripped for some reason, causing tripping in rear protective circuit breaker and enlarging isolation area. The probability of breaker stuck when called upon to open can be expressed as follows [6,8]:…”

Reliability Evaluation of Distribution Structures Considering the Presence of False Trips

“…Among this, failure to respond to actual fault signals could lead to isolation of larger areas from power supply depending on the fault location and grid design. For example, a whole substation outage can have more number of disconnected customers than failures confined to one or more outgoing feeders from the same station [13]. Analysis of recorded fault registers used by power utilities suggests that even faults occurring on these outgoing feeder lines can escalate through false tripping of breakers in other protection zones due to the aforementioned causes.…”

Reliability evaluation of transmission network including effect of protection systems

“…This method is therefore not a suitable approach for large scale systems. In some of other published papers, the effects of protection system failures are concerned only with substations reliability assessment, and their impacts on network reliability indices are not considered [5][6][7]. Attempts have been made to consider the impacts of protection systems on network reliability in References [1,8,9].…”