Section 7 in Rajasthan Electricity Regulatory Commission (Distribution Licensees Standards of Performance) Regulations, 2003
7. Reliability of the system.
- (i) Reliability of the distribution system operated by the licensee shall be computed on the basis of number and duration of sustained interruption in a year. In a power delivery system, it may take a few minutes to restore power after transient faults or to reroute power in the network to restore supply to the affected areas where a large number of customers are involved. Such momentary interruptions of up to ten minutes shall not be considered but sustained interruptions of more than ten minutes duration shall be considered for judging the reliability of the system.(ii)Reliability standards of the licensee shall be judged by the following two indices:(a)System average interruption frequency index, which shall be calculated by dividing the total number of sustained interruptions to consumers in a year by the total number of consumers served. An interruption in supply to a consumer shall be considered as one interruption to one consumer. In case of failure of a line or transformer, number of interruptions shall be equal to the number of consumers affected. The index shall be expressed as number of interruption per consumer per year and shall be calculated annually.(b)System average interruption duration index, which shall be calculated by dividing the total minutes of sustained interruption in supply to consumers in a year by the total number of consumers served. The index shall be expressed as number of minutes of interruption per consumer per year and shall be calculated annually.(iii)While calculating the above indices, the following types of interruptions shall not be taken into account:(a)Planned outages.(b)Momentary outages of ten minutes or less.(c)Outages due to failure of upstream power system including generation and transmission network.(d)Outages due to reasons beyond licensees control like fire, earthquake, floods, storms, and riots.(iv)For calculating reliability indices, licensee shall maintain data at each sub-station in the form prescribed in appendix A and draw an abstract every month in appendix 'B' The licensee shall compile monthly data for each Circle to ascertain Circle-wise reliability indices of the system.
