Risk and reliability assessment for electrical distribution systems and impacts of regulations with examples from Sweden

Abstract

The introduction of performance based tariff regulations, and higher media and political pressure have increased the need for well-performed asset management in the operation and planning of electrical distribution systems. In this paper quantitative reliability assessment methods are proposed as a tool to meet these new incentives. Electrical distribution systems have compared to other technical systems several special characteristics which are important to take into consideration when introducing reliability analysis methods. Moreover, the paper gives a brief discussion on the effects and the importance of customer participation in improving system reliability by providing additional system operating reserve from the market perspective. Finally, the paper discusses the reliability analysis with the reliability test systems, and stresses the usefulness of generally known test systems for such assessments. The ideas of future work on development of these test systems to address the changing power systems are presented.

Implementation and evaluation of commonly used risk analysis methods applied to a regional power distribution system

“…The probability has five categories based on the estimated time between failures. The consequence has four categories based on the size of installed power and time, which give a risk value (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The risk matrix is illustrated in Figure 1.…”

“…The estimated risk levels for components/subsystems are noted on a worksheet in the condition monitoring of substations. The resulting risk values (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) …”

“…Furthermore, outages 0.05-12 hours are input to quality regulation and outages >12 hours gives mandatory customer compensations and there exist a functional requirement that outages >24 not are allowed by law. Risk management largely hence focus on outages >12 hours [3].…”

Benefits of reliability centred asset management

“…Tariff regulation has the role of providing incentives for cost-efficient operation with acceptable reliability and reasonable tariff levels [1] [7]. The impact from regulation and from other laws (e.g.…”

Learning from experiences of the prior Swedish electrical distribution system regulation — Reference material when developing the future regulatory incentives

“…Some of the theory of the NPAM is presented in [8], and there are several publications studying the model e.g. [9]- [12], but no stringent description of the complete model is available.…”