§ 57.192. Definitions.
The following words and terms, when used in this subchapter, have the following meanings, unless the context clearly indicates otherwise:
Adequacy—The ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers from various electric generation suppliers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements.
Circuit—A conductor or system of conductors through which an electric current is intended to flow.
Conductor—A material, usually in the form of a wire, cable, or bus bar, suitable for carrying an electric current.
Control area—An electric system or systems, bounded by interconnection metering and telemetry, capable of controlling generation to maintain its interchange schedule with other control areas and contributing to frequency regulation of the interconnected systems.
EDC—Electric distribution company—An electric distribution company as defined in 66 Pa.C.S. § 2803 (relating to definitions).
Electric generation supplier or electricity supplier—An electric generation supplier or electricity supplier as defined in 66 Pa.C.S. § 2803.
FERC—Federal Energy Regulatory Commission.
IEEE—Institute of Electrical and Electronic Engineers.
Interruption duration—A period of time measured to the nearest 1-minute increment which starts when an electric distribution company is notified or becomes aware of an interruption, unless an electric distribution company can determine a more precise estimate of the actual starting time of an interruption, and ends when service is restored. Interruptions shall be categorized, based on duration, such as momentary or sustained interruptions, or by similar descriptions, as adopted by the IEEE or similar organization identified by the Commission. This subchapter requires tracking, reporting and evaluation of two categories of interruption duration that will incorporate any changes in the terms used or the definitions of those terms as adopted by the IEEE or Commission order.
Major event—(i) Either of the following:
(A) An interruption of electric service resulting from conditions beyond the control of the EDC which affects at least 10% of the customers in the EDC’s service territory during the course of the event for a duration of 5 minutes each or greater. The event begins when notification of the first interruption is received and ends when service to all customers affected by the event is restored.
(B) An unscheduled interruption of electric service resulting from an action taken by an EDC to maintain the adequacy and security of the electrical system, including emergency load control, emergency switching and energy conservation procedures, as described in § 57.52 (relating to emergency load control and energy conservation by electric utilities), which affects at least one customer.
(ii) The term does not include scheduled outages in the normal course of business or an electric distribution company’s actions to interrupt customers served under interruptible rate tariffs.
Momentary customer interruption—(i) The loss of electric service by one or more customers for the period defined as a momentary customer interruption by the IEEE as it may change from time to time.
(ii) The term does not include interruptions described in subparagraph (ii) of the definition of “major event,” or the authorized termination of service to an individual customer.
NERC—North American Electric Reliability Council—An organization of regional reliability councils established to promote the reliability of the electricity supply for North America.
Performance benchmark—A numerical value that characterizes an EDC’s average historical reliability performance for a specific time period in the past. The benchmark is based on an EDC’s performance for the entire service territory and is a reference point for comparison of future reliability performance. The Commission will, from time to time, establish benchmarks for each reliability index and each EDC. The performance benchmarks are established by Commission Order at Docket No. M-00991220.
Performance standard—A numerical value that establishes a minimum level of EDC reliability allowed by the Commission. The performance standard is a criterion tied to the performance benchmark that applies to reliability performance for the EDC’s entire service territory. The Commission will, from time to time, establish new performance standards for each reliability index for each EDC. The performance standards are established by Commission Order at Docket No. M-00991220.
Regional reliability council—An organization established to augment the reliability of its members’ bulk electric supply systems through coordinated planning and operation of generation and transmission facilities. The following regional reliability councils impact the bulk electric supply systems within this Commonwealth:(i) The East Central Area Reliability Coordination Agreement (ECAR).
(ii) The Mid-Atlantic Area Council (MAAC).
(iii) The Northeast Power Coordinating Council (NPCC).
Reliability—The degree of performance of the elements of an electric system that results in electricity being delivered to customers within accepted standards and in the desired amount, measured by the frequency, duration and magnitude of adverse effects on the electric supply and by considering two basic and functional aspects of the electric system: adequacy and security.
Reliability indices—Service performance indicators which measure the frequency, duration and magnitude of customer interruptions, excluding outages associated with major events.(i) CAIDI—Customer Average Interruption Duration Index—The average interruption duration of sustained interruptions for those customers who experience interruptions during the analysis period. CAIDI represents the average time required to restore service to the average customer per sustained interruption. It is determined by dividing the sum of all sustained customer interruption durations, in minutes, by the total number of interrupted customers. This determination is made by using the following equation:
where:
i = an interruption event
ri = restoration time for each interruption event
and Ni = number of customers who have experienced a sustained interruption during the reporting period
(ii) MAIFI—Momentary Average Interruption Frequency Index—The average frequency of momentary interruptions per customer occurring during the analysis period. It is calculated by dividing the total number of momentary customer interruptions by the total number of customers served. This determination is made by using the following equation:
where:
Mi = number of customers who have experienced a momentary interruption during the reporting period
(iii) SAIDI—System Average Interruption Duration Index—The average duration of sustained customer interruptions per customer occurring during the analysis period. It is the average time customers were without power. It is determined by dividing the sum of all sustained customer interruption durations, in minutes, by the total number of customers served. This determination is made by using the following equation:
where:
NT = total number of customers served for the area being indexed
(iv) SAIFI—System Average Interruption Frequency Index—The average frequency of sustained interruptions per customer occurring during the analysis period. It is calculated by dividing the total number of sustained customer interruptions by the total number of customers served. This determination is made by using the following equation:
Security—The ability of the electric system to withstand sudden disturbance such as electric short circuits or unanticipated loss of system elements.
Sustained customer interruption—The loss of electric service by one or more customers for the period defined as a sustained customer interruption by IEEE as it may change from time to time. This term does not include interruptions described in subparagraph (ii) of the definition of ‘‘major event,’’ or the authorized termination of service to an individual customer.
Authority The provisions of this § 57.192 amended under the Public Utility Code, 66 Pa.C.S. § 501; and the Electric Generation Customer Choice and Competition Act, 66 Pa.C.S. § § 2801—2812.
Source The provisions of this § 57.192 amended September 17, 2004, effective September 18, 2004, 34 Pa.B. 5135. Immediately preceeding text appears at serial pages (246395) to (246396) and (263685) to (263686).
Cross References This section cited in 52 Pa. Code § 57.142 (relating to forecast of energy demand, peak load and number of customers); 52 Pa. Code § 57.143 (relating to existing and planned generating capability); and 52 Pa. Code § 57.147 (relating to scheduled imports and exports).
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