Transient outage model considering corrective and preventive maintenance

Abstract

Traditional outage model for the power equipment usually focus on the behavior of the equipment under random factors, and the availability of the power equipment in system analysis is usually confined to the steady value. However, this model may be inaccurate in the short term analysis, where the transient process of availability has not ended yet. Furthermore, the power equipment in the short term analysis might be influenced by both random factors and deterministic factors, yet the impact of deterministic factors cannot be completely reflected in the traditional outage model. Based on the above issues, a Markov-based transient outage model is proposed in this paper, which describes the deterioration and repair process of an equipment. Both the corrective maintenance and preventive maintenance are concerned in the model. The preventive maintenance in the model is considered as deterministic event, in which the start time and duration are both scheduled. Meanwhile the corrective maintenance and the unexpected failure are modeled as random events. The transient state probability and availability of equipment under preventive maintenance is derived. The effect of deterministic events on the availability of equipment is analyzed on numerical tests. The proposed model can be used in the short-term reliability assessment and maintenance scheduling in actual systems.

A bidding mechanism for maintenance of generation units considering inter-ISO power exchange

“…The total bid price for a maintenance action that occupies multiple time slots is the sum of the prices of these time slots. (7) The host ISO decides which maintenance actions should be performed by maximizing the total social welfare. The corresponding optimization problem will be explained in Section 3.2.…”

“…In Step (7) of the bidding process, the host ISO will determine which maintenance actions should be performed. The objective of the bidding process is to maximize the total social welfare.…”

“…Constraint (7) ensures that, when 𝛥(𝑖, 𝑘) = 0, 𝑞 H (𝑖, 𝑘), 𝑞(𝑚, 𝑛, 𝑖, 𝑘) and 𝑝 re (𝑚, 𝑖, 𝑘) are all zero (no reserved energy occupied, no supportive energy purchased, and no reduced transmitted power). The bid maintenance actions can only be performed once:…”

“…In addition, the reserved energy should be above a certain level when some of the generation units are undergoing maintenance, so that the risks of large-scale load loss caused by a reserved energy shortage can be avoided. Thus, the maintenance schedules are required to be properly planned [4][5][6][7]. The ISO manages the planning process of the maintenance considering the costs of maintenance actions for the generation units and the power system reliability.…”