Quality of supply indices are considered to be one of the most important issues for customers, it involves indices for (quality of the voltage supply, electric power distribution reliability, customers quality of services and indices related to the electrical distribution network).

These documents have been sent to the different electrical distribution companies to check, study, and comment whether the data mentioned inside are compatible with its regulation and codes or not.

Quality of supply voltage is considered to be one of the most important issues that electrical distribution companies must consider meanwhile connecting their customers with electric power supply. This Chapter consists of:

“Electric power distribution reliability indices” , the interruptions in electrical distribution networks has been divided into two groups: sustained interruption indices and momentary interruption indices, sustained interruptions indices include SAIFI, SAIDI, CAIDI , … etc, while momentary interruptions indices includes MAIFI, MAIFIE, moreover, two example has been studied to explain different ways to calculate the electric power distribution reliability indices, at the end of the chapter, a survey was made to show the most common and widely used electrical power distribution reliability indices. The data mentioned in this chapter was quoted from the international reference: IEEE Std 1366-1998. This Chapter consists of:

Customer quality of service indices is considered to be one of the most important issues of supply quality, knowing that electric supply differs from different groups of customers. The definitions mentioned hereinafter are quoted from the report “Council of European Energy Regulators CEER (April-2001)" www.autorita.energia.it. This Chapter consists of:

One of the most important issues is to determine the size of the network of each distribution company, to make the proper comparison between these companies. The definitions mentioned hereinafter are quoted from “The Annual Statistical Report 96-97 issued by the Construction &Electric Power Distribution Company”. This Chapter consists of:

"Availability of supply indices" presents a new method or tools for calculating availability of supply indices depending not only on the number of interrupted customer per interruption and total number of served customers, but also on:

1. Number of defected transformer/substation and total number of served transformer/substation
2. Amount of interrupted kVA (capacity) and total connected capacity.

The appendix data are quoted from the Union of The Electricity Industry (EURELECTRIC) documents,www.eurelectric.org

• Reliability Indicators
• Reliability Indicators taking into consideration the number of years in commercial service
• Indicators for Efficiency and Labor Productivity

Ref. ( NERC : North American Electric Reliability Council )

The Transmission Indicators consists of:

• In case where the Number of Delivery points interrupted and the duration of interruption is recorded or estimated
  Ref. ( IEEE - 1996 )
• In case where the Interrupted MVA and the Duration of interruption is recorded or estimated for transformers
  Ref. ( National Power Corporation Philippines-2002)
• In case where the Number of Forced Outages and the Duration of interruption is recorded or estimated for transmission equipment
  Ref. ( National Power Corporation Philippines-2002)
• In case where the Energy sales (MWh) and the Aggregate transformers capacity (MVA) is recorded or estimated for transmission system
  Ref. ( Government Trading Enterprises Performance Indicators Australia, GTEs - 1996 )