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SAIFI
The System Average Interruption Frequency Index (SAIFI) is commonly used as a reliability index by electric power utilities. This index measures the average number of times that a system customer experiences an outage during the year or during a given time period. SAIFI is normally calculated on either yearly or monthly basis. SAIFI is calculated as: \mbox = \frac where \lambda_i is the failure rate and N_i is the number of customers for location i. In other words, \mbox = \frac Many factors cause power interruptions, including weather, vegetation patterns, and utility practices. Utilities can report interruption duration values with major events (such as snowstorms or hurricanes), without major events, or both. SAIFI is measured in units of interruptions per customer. According to IEEE Standard 1366-1998 the median value for North American utilities is approximately 1.10 interruptions per customer. References Sources * {{DEFAULTSORT:Saifi Electric power Reliabili ...
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Reliability Index
Reliability index is an attempt to quantitatively assess the reliability of a system using a single numerical value. The set of reliability indices varies depending on the field of engineering, multiple different indices may be used to characterize a single system. In the simple case of an object that cannot be used or repaired once it fails, a useful index is the mean time to failure representing an expectation of the object's service lifetime. Another cross-disciplinary index is forced outage rate (FOR), a probability that a particular type of a device is out of order. Reliability indices are extensively used in the modern electricity regulation. Power distribution networks For power distribution networks there exists a "bewildering range of reliability indices" that quantify either the duration or the frequency of the power interruptions, some trying to combine both in a single number, a "nearly impossible task". All indices are computed over a defined period, usually a year ...
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Electric Power
Electric power is the rate of transfer of electrical energy within a electric circuit, circuit. Its SI unit is the watt, the general unit of power (physics), power, defined as one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively. In common parlance, electric power is the production and delivery of electrical energy, an essential public utility in much of the world. Electric power is usually produced by electric generators, but can also be supplied by sources such as Electric battery, electric batteries. It is usually supplied to businesses and homes (as domestic mains electricity) by the electric power industry through an electrical grid. Electric power can be delivered over long distances by electric power transmission, transmission lines and used for applications such as Electric motor, motion, Electric light, light or Electric heat, heat with high ...
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