**A.1 Fixed cost**

The fixed cost (FC) represents the cash flow at any stage of the planning horizon resulting from the costs of installing new generating units during the planning period. It depends on the current financial status of the utility, the type and size of generating units, and the cost of time on money invested during the planning period. The total fixed costs (*FCT*) for unit(s) being installed can be computed as

*Reliability Evaluation of Power Systems DOI: http://dx.doi.org/10.5772/intechopen.85571*

$$FC\_T = \sum\_{t} \sum\_{k} \left( CAP\_k \cdot CC\_k \cdot NU\_k \right)^t \tag{A.1}$$

where

**8.4 Average service availability index (ASAI)**

*Reliability and Maintenance - An Overview of Cases*

This measure can be defined as

ences to its nature subject matter.

generating unit loaded to the system.

accordance with its envisaged 2030 vision.

benchmarks and improvement targets.

**Appendix A. Power system costs**

be manifested in the following sections.

**A.1 Fixed cost**

**164**

**9. Conclusions**

of view.

ASAI is the customer-weighted availability of the system and provides the same information as SAIDI. Higher ASAI values reflect higher levels of system reliability.

This chapter consists of eight sections that can be briefly summarized as follows: Section 1 starts with an introduction that indicates the importance and viable role of reliability evaluation in power system planning with selected relevant refer-

Section 2 discusses the types of equipment outages, particularly the severe ones that may cause the machine(s) to be out of service unexpectedly in critical condi-

Section 3 reviews some basic theories, assumptions, and mathematical expressions for the reliability evaluation such as the well-known "loss of load expectation"

Section 4 exhibits a new computation method for the energy produced by each

Section 5 demonstrates how the reliability indices can be of significant tools in assessing system planners to arrive at the most appropriate reliability levels that can assure both continuous supply as well as maintaining the least operating cost.

Section 6 highlights the main merits and advantages of electrical interconnection among dispersed and isolated power systems from an economic and reliability point

Section 7 shows the application of the frequency and duration (F&D) indices used in reliability evaluation of transmission lines and distribution networks. These indices are implemented in some industrial zones in a fast-developing country in

Section 8 reveals the most widely used customer-based reliability indices by most of the electric companies since the residential sector has just as much importance as the industrial sector. These indices show adequate measures of reliability

There are several costs that are associated with power system planning and can

The fixed cost (FC) represents the cash flow at any stage of the planning horizon

resulting from the costs of installing new generating units during the planning period. It depends on the current financial status of the utility, the type and size of generating units, and the cost of time on money invested during the planning period. The total fixed costs (*FCT*) for unit(s) being installed can be computed as

tions that can compromise the ability of the system to supply the load.

index and with other important complementary reliability indices.

Customer hours service demand ð Þ pu (27)

ASAI <sup>¼</sup> Customer hours service availability

; - ; ; .
