AUTHORITY: Implementing Sections 8-401 and 16-125 and authorized by Sections 10-101 and 16-125 of the Public Utilities Act [220 ILCS 5].
SOURCE: Adopted by emergency rulemaking at 22 Ill. Reg. 11177, effective June 10, 1998, for a maximum of 150 days; adopted at 22 Ill. Reg. 20042, effective November 7, 1998; amended at 24 Ill. Reg. 12914, effective September 1, 2000; amended at 44 Ill. Reg. 4598, effective March 4, 2020; amended at 46 Ill. Reg. 5653, effective March 22, 2022.
SUBPART A: GENERAL
Section 411.10 Purpose
a) The Commission's policies for reliability of facilities and service have been developed from the following basic principles incorporated in the Public Utilities Act.
1) Reliability encompasses more than statistical data, and the simple absence or occurrence of outages alone may not reflect the true system reliability. The risks of future outages, as indicated by the age, condition, design, and performance of transmission and distribution facilities and by a jurisdictional entity's investment in the maintenance, repair, replacement, and upgrade of its facilities and equipment, are no less important than the past occurrence of outages in assessing system reliability.
2) Potential service reliability improvements should be evaluated considering the costs and benefits of the improvements to the jurisdictional entity and to customers.
3) Reliable electric service is essential to the health, safety and welfare of the citizens of the State of Illinois.
b) Accordingly, this Part is adopted for the purposes stated herein and should be interpreted in a manner consistent with the policies stated herein and in a manner that accomplishes the specific objectives set out in this Part. Ends to be served by this Part are listed below.
1) To define clearly the Commission's process of assessing electric service reliability.
2) To assure the reliable delivery of electricity to all customers in this State.
3) To assure the effective implementation of amendments to the Public Utilities Act relating to the reliable provision of transmission and distribution or delivery services in a competitive environment.
4) To adopt, as required by law, rules and regulations for assessing, and assuring, the reliability of the transmission and distribution systems and facilities that are under the Commission's jurisdiction.
5) To establish uniform measurements to assess transmission, distribution and delivery service and to establish reporting requirements that routinely and periodically inform the Commission about the reliability of transmission and distribution systems under its jurisdiction.
6) To allow the Commission to monitor more effectively the reliability of the transmission and distribution systems over which power and energy from all electric suppliers will be transported to consumers in the State.
7) To provide adequate information for the Commission to monitor aspects of reliability in addition to interruptions.
Section 411.20 Definitions
This Section defines terms as they are used in this Part.
"Alternative retail electric supplier" has the same meaning as defined in Section 16-102 of the Public Utilities Act [220 ILCS 5/16-102].
"Controllable interruption" is an interruption caused or exacerbated in scope and duration by the condition of facilities, equipment, or premises owned or operated by a jurisdictional entity, or by the action or inaction of persons under a jurisdictional entity's control and that could have been prevented through the use of generally accepted engineering, construction, or maintenance practices.
"Customer", for the purposes of this Part only, means a retail customer, as that term is defined in Section 16-102 of the Act, or a single entity that is using and has agreed to pay for electric power or energy, or electric transmission or distribution service, from a jurisdictional entity in a wholesale transaction. A single customer can have one or more points of service or meters at a given location. Customer, for the purpose of this Part, shall not include entities that are using electric power or energy unlawfully (e.g., through an illegal tap).
"Distribution circuit" is a circuit owned and/or operated by a jurisdictional entity and designed to operate at a nominal voltage of 15,000 volts or less and to supply one or more distribution transformers.
"Distribution circuit interruption" is an interruption originating at a point that is between the circuit interrupting device at the substation supplying the distribution circuit and the distribution transformer.
"Electric service" means the availability of electric power and energy purchased by the customer at the point of connection between jurisdictional entity equipment and customer equipment, on those terms and conditions provided for in the jurisdictional entity's tariffs, in its terms and conditions of service, or in any contract between a jurisdictional entity and the customer.
"Electric utility" or "Utility" means a public utility, as defined in Section 3-105 and Section 16-102 of the Act, that has a franchise, license, permit or right to furnish or sell electricity to retail customers within a service area.
"Facilities" includes all lines, cables, equipment, plant, computer systems, customer service systems, apparatus, property, and any other items of similar kind that are used to provide or that affects the reliability of transmission, distribution or delivery services.
"Independent system operator" shall have the meanings given in Article XVI of the Act [220 ILCS 5/Art. XVI].
"Interruption" or "Outage", except as used in Sections 411.210 and 411.220, means the failure or operation of a single component, or the simultaneous failure or operation of physically and directly connected components of a jurisdictional entity's transmission or distribution system that results in electric service to one or more of its customers being lost or being provided at less than fifty percent of standard voltage for a period longer than one minute in duration and requiring human intervention by the jurisdictional entity to restore electric service.
Service to a multi-phase point of service is interrupted if service to one or more phases is interrupted.
The Commission does not intend this definition to require a jurisdictional entity to install and operate voltage sensing equipment specifically to identify interruptions involving provision of service at less that fifty percent of standard voltage.
This definition specifically excludes occurrences of the loss of electric service when automatic switches, automatic line reclosing devices, or other automatic jurisdictional entity devices successfully restore electric service.
The term "interruption" or "outage" shall not include the interruptions listed below.
Interruptions intentionally initiated by a jurisdictional entity, pursuant to the provisions of an interruptible service tariff or contract and affecting only those customers taking electric service under such tariff or contract.
Interruptions intentionally initiated by a jurisdictional entity for nonpayment of a bill and according to the provisions of Sections 8-201, 8-202, 8-203, 8-204, 8-205 and/or 8-206 of the Act [220 ILCS 5/8-201, 8-202, 8-203, 8-205, and 8-206] and 83 Ill. Adm. Code 280.
Interruptions intentionally initiated by a jurisdictional entity due to tampering with service equipment.
Interruptions intentionally initiated by a jurisdictional entity due to its being denied access to service equipment located on the affected customer's private property.
Interruptions intentionally initiated by a jurisdictional entity due to hazardous conditions located on the affected customer's private property (such as a fire).
Interruptions intentionally initiated by a jurisdictional entity due to a request by the affected customer.
Interruptions intentionally initiated by a jurisdictional entity due to a request by a law enforcement agency, fire department, other governmental agency responsible for public welfare, or any agency or authority responsible for bulk power system security (e.g., North American Electric Reliability Council, a regional reliability council, or an independent system operator).
Interruptions caused by the failure of a customer's equipment; the operation of a customer's equipment in a manner inconsistent with statute, an approved tariff, rule, regulation, or an agreement between the customer and the jurisdictional entity; or the failure of a customer to take a required action that would have avoided the interruption, such as failing to notify the jurisdictional entity of an increase in load when required to do so by a tariff or contract.
Interruptions caused by the actions or omissions of another jurisdictional entity or other supplier of electricity or electrical services shall not be deemed an "interruption" of the jurisdictional entity providing transmission and distribution services so long as that jurisdictional entity's transmission and distribution facilities serving the customer remained operational.
Scheduled interruptions initiated by a jurisdictional entity for repair, maintenance, or reinforcement shall not be considered an interruption for the purposes of the targets set forth in Section 411.140(b)(4) and calculating reliability indices. For all other purposes under this Part, the term "interruption" shall include scheduled interruptions initiated by a jurisdictional entity for repair, maintenance, or reinforcement. Scheduled interruptions are reportable under Section 411.120(b)(3)(C).
As used in Sections 411.210 and 411.220, "Interruption" has the same meaning as when used in Section 16-125(e) of the Act.
"Interruption duration" means a period of time measured in one-minute increments that starts when a jurisdictional entity is notified or becomes aware of an interruption and ends when a jurisdictional entity restores electric service.
"Jurisdictional entity" means an electric utility or alternative retail electric supplier owning, controlling, or operating transmission and distribution facilities and equipment subject to the Commission's jurisdiction.
"Operating area" is a geographic area defined by the jurisdictional entity that is a distinct area for administration, operation, or data collection with respect to the facilities serving, or the service provided within, the geographic area.
"Power fluctuation" or "Surge," except as used in Sections 411.200, 411.210, and 411.220, means departure of more than one minute in duration in the frequency or voltage of power supplied to the customer's point of service that is caused by the failure or operation of a single component, or simultaneous failure or operation of directly connected components, of a jurisdictional entity's transmission or distribution system, that exceeds the Commission's standards for frequency and voltage (or, where the customer and the jurisdictional entity have agreed on frequency and voltage standards, exceeds the variation allowed thereby), and that causes damage to customer goods. An interruption shall not be deemed a power fluctuation. A power fluctuation or surge shall not include voltage variations or frequency variations caused by:
Unpreventable damage due to weather events or conditions;
Customer tampering;
Unpreventable damage due to civil or international unrest or animals; and
Damage to a jurisdictional entity's equipment or other actions by a party other than the jurisdictional entity, its employees, agents, or contractors.
As used in Section 411.200, the term "Power Fluctuation", and as used in Sections 411.210 and 411.220, the term "Power Surge or other Fluctuation", have the same meanings as when those terms are used in Section 16-125(f) of the Act.
"Reliability indices" are as listed below.
"System Average Interruption Frequency Index (SAIFI)" is the average number of interruptions per customer during the year. It is calculated by dividing the total annual number of customer interruptions by the total number of customers served during the year.
SAIFI |
= |
Total Number of Customer Interruptions |
Total Number of Customers Served |
"Customer Average Interruption Duration Index (CAIDI)" is the average interruption duration for those customers who experience interruptions during the year. It is calculated by dividing the annual sum of all customer interruption durations by the total number of customer interruptions.
CAIDI |
= |
Sum of all Customer Interruption Durations |
Total Number of Customer Interruptions |
"Customer Average Interruption Frequency Index (CAIFI)" is the average number of interruptions for those customers who experience interruptions during the year. It is calculated by dividing the total annual number of customer interruptions by the total number of customers affected by interruptions. In determining the total number of customers affected, each customer is counted only once regardless of the number of customer interruptions that the customer may have experienced during the year.
CAIFI |
= |
Total Number of Customer Interruptions |
Total Number of Customers Affected |
"Unpreventable damage" is damage interruptions or fluctuations that could not be reasonably foreseen and prevented through the use of generally accepted engineering, construction, and maintenance practices. For example, damage shall be deemed unpreventable when it is:
Caused by a customer's failure to follow good engineering practices with respect to its own equipment; or
When engineering, construction, operations, or maintenance practices or actions have been identified and proposed by the jurisdictional entity to prevent the interruption, fluctuation, or damage, but the jurisdictional entity has not been allowed or permitted by a governmental authority or property owner to implement such practices or actions.
"Worst-performing circuits" are those distribution circuits that, for each reliability index, are among the one percent of all circuits in an operating area (or at least one circuit for each reliability index) with the highest achieved values (lowest performance levels) for the reliability index. For the purpose of identifying worst-performing circuits, only distribution circuit interruptions and customers affected by such interruptions shall be considered in calculating the reliability indices.