Reliability of the power system is generally defined as the overall ability of the system to perform its function. It can also be defined as the ability of the power system to meet its load requirements at any time. Two distinct aspects of system reliability are identifiable: system security and system adequacy. System security involves the ability of the system to respond to disturbances arising internally, whereas system adequacy relates to the existence of sufficient facilities within the system to satisfy the customer-load demand. The function of the power system is to provide electrical energy as economically as possible and with an acceptable degree of reliability and quality. Economics of reliability tries to strike a reasonable balance between cost and quality of service. Such balance varies from one country to another, just as from one category of consumers to another. Most developing countries cannot afford the high costs of ensuring the high reliability of supply, taken for granted in industrialised countries. Gradually, however, quality of supply is improving worldwide.

Chapter Contents:

• 11.1 Introduction
• 11.2 The value of reliability
• 11.3 Reliability in system planning
• 11.3.1 Empirical planning rules
• 11.3.2 Supply design standards
• 11.3.3 Cost-benefit analysis
• 11.4 Detailed financial and economic evaluation
• 11.4.1 System adequacy and economics
• 11.4.2 Assessment and economics of generation adequacy
• 11.4.2.1 Loss-of-load expectation (LOLE) method
• 11.4.2.2 Frequency and duration method with a load model
• 11.4.2.3 Percentage energy loss (PEL) index
• 11.5 Financial and economic evaluation of quality of electrical power
• 11.6 Evaluation of investment in generation
• 11.6.1 Valuing cost of interruptions
• 11.6.2 Incorporating reliability worth in generation planning
• 11.7 Renewables and reliability of supply
• References

Inspec keywords: power system economics; power system security; load management; power system reliability; power supply quality

Other keywords: power supply reliability economics; customer-load demand; electrical energy; system adequacy; load requirements; supply quality; system security; power system reliability

Subjects: Power system management, operation and economics; Reliability; Power system protection; Power supply quality and harmonics