Wisconsin Administrative Code › Public Service Commission › Chapter PSC 113 - Service Rules For Electrical Utilities › Subchapter VI - Safety and Service Standards › Section PSC 113.0602 - Definitions

Current through June 24, 2024
In ss. PSC 113.0602 to
				  113.0605, the following definitions
				  shall apply:
(1) "Average number of
				customers served" means the number of active metered customer accounts as
				available in a utility's interruption reporting database on the day that an
				interruption occurs.
(2) "Circuit"
				means a set of conductors serving customer loads that are capable of being
				separated from the serving substation automatically by a recloser, fuse,
				sectionalizing equipment, etc.
(3)
				"Component" means a piece of equipment, a line, a section of line, or a group
				of items which is an entity for purposes of reporting, analyzing and predicting
				interruptions.
(4) "Customer" means
				a separately-metered electrical service point for which a separate bill is
				rendered, i.e., each meter represents a customer.
(5) "Customer interruption" means the loss of
				service due to a forced outage for more than five minutes, for one or more
				customers, which is the result of one or more component failures. For example,
				a downed house service is one interruption and a disconnected hot leg of a
				triplex house service, known as a "half-light" condition, is one customer
				interruption. However, failure of a transformer serving four customers is four
				customer interruptions.
(6)
				"Customer interruptions caused by power restoration process" means when
				customers lose power as a result of the process of restoring power (such as
				from switching operations and fault isolation). The duration of these outages
				is included in the customer-minutes of interruption. However, only the
				customers affected by the power restoration outages that were not affected by
				the original outage are added to the number of customer
				interruptions.
(7)
				"Customer-minutes of interruption" means the number of minutes of forced outage
				duration multiplied by the number of customers affected. For instance, a 90
				minute forced outage on a circuit serving ten customers would total 900
				customer-minutes of interruption.
(8) "Electric distribution line" means
				circuits operating at less than 50,000 volts.
(9) "Forced outage" means an outage which
				cannot be deferred.
(10) "Major
				catastrophic events" means train wrecks, plane crashes, or explosions that are
				beyond the utility's control and result in widespread system damages causing
				customer interruptions that affect at least ten percent of the customers in the
				system or in an operating area and/or result in customers being without
				electric service for durations of at least 24 hours.
(11) "Major storm" means a period of severe
				adverse weather resulting in widespread system damage causing customer
				interruptions that affect at least ten percent of the customers on the system
				or in an operating area and/or result in customers being without electric
				service for durations of at least 24 hours.
(12) "Momentary interruption" means an
				interruption of electric service with a duration shorter than the time
				necessary to be classified as a customer interruption.
(13) "Operating area" means a geographical
				sub-division of each electric utility's service territory that functions under
				the direction of a company office and may be used for interruption reporting
				under this part. These areas may also be referred to as regions, divisions, or
				districts.
(14) "Outage" means the
				failure of a power system component that results in one or more customer
				interruptions.
(15) "Outage
				duration" (reported in minutes) means the one minute or greater period from the
				initiation of an interruption to a customer until service has been restored to
				that customer.
(16) "Partial
				circuit outage customer count" means where only part of a circuit experiences
				an outage, the number of customers affected is estimated, unless an actual
				count is available. When power is partially restored, the number of customers
				restored is also estimated. Most utilities use estimates based on the portion
				of the circuit restored.
(17)
				"Planned outages" means those outages which the utility schedules. When
				customer service interruptions are necessary, the utility should notify
				affected customers in advance. These interruptions are sometimes necessary to
				connect new customers or perform maintenance activities safely. They shall not
				be included in the calculation of reliability indices.
Note:
Also see s.
				  PSC
				  113.0502, Planned service interruptions.
(18) "Police actions" means
				request or order of police or fire officials to interrupt service due to an
				emergency.
(19) "Reliability" means
				the degree to which electric service is supplied without
				interruption.
(20) "Reliability
				indexes" include the following performance indices for measuring frequency and
				duration of service interruptions that have been developed by the Edison
				Electric Institute (EEI), the Institute of Electrical and Electronics Engineers
				(IEEE), the Canadian Electric Association (CEA) and the American Public Power
				Association (APPA). They are recognized as standard definitions for the
				electric utility industry and may be applied to entire distribution systems,
				operating areas, sub-operating areas or individual circuits. Customer
				interruptions attributed to major storms, major catastrophic events, or police
				actions, as defined herein, shall be included in the calculation of these
				indices throughout this standard.
(a) System
				Average Interruption Frequency Index (SAIFI). The SAIFI index is the average
				number of interruptions per customer during a year. It is determined by
				dividing the total annual number of customer interruptions by the average
				number of customers served during the year.
SAIFI =
total number of customer
				  interruptions
average number of customers served
(b) System Average Interruption Duration
				Index (SAIDI). The SAIDI index is the average customer-minutes of interruption
				per customer. It is determined by dividing the annual sum of customer-minutes
				of interruption by the average number of customers served during the year.
SAIDI =
sum of customer-minutes of
				  interruption
average number of customers served
(c) Customer Average Interruption Duration
				Index (CAIDI). The CAIDI index is the average customer-minutes of interruption
				per customer interruption. It approximates the average length of time required
				to complete service restoration. It is determined by dividing the annual sum of
				all customer-minutes of interruption durations by the annual number of customer
				interruptions.
CAIDI =
sum of customer-minutes of
				  interruption
total number of customer interruptions