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This paper introduces a stochastic methodology to assess annual performance of distribution network and individual customers with respect to voltage sags, long duration interruptions, equipment trips, and process trips. These values are then used to evaluate financial losses in the entire distribution network. For each of the large number of simulated faults throughout the network, a probability of sag and long duration interruption occurrences is evaluated at each network bus. The methodology then includes for the first time the concept of process immunity time in order to assess as accurately as possible the resulting financial loss due to process interruption. To increase the accuracy of the assessment of financial loss, the methodology also considers the possibility of equipment and process restart, reliability, and type of fault. The methodology is illustrated on a real distribution network and it shows that inclusion of PIT in financial loss assessment results in a reduction of about 25% in estimated financial loss. [ABSTRACT FROM AUTHOR]

This paper investigates the factors that influence the outcome of financial-loss analysis in voltage sag studies. Focusing on industrial processes, this paper considers the effects of voltage sag profile estimation, plant-load profile modelling, and process cycle modelling on the financial risk associated with process failure. Based on voltage sag monitoring records, sag profile is probabilistically modeled for the estimation of future sag characteristic. Variations in financial risk due to varying process activities in different stages of a process (process cycle) and load profile are also investigated. The effects of the individual factors are analyzed through Monte Carlo simulation. The stochastic net present value method is introduced as a financial analysis tool. [ABSTRACT FROM AUTHOR]

The second part of this paper presents a practical implementation and application of the methodology for the stochastic assessment of the annual financial losses due to interruptions and voltage sags discussed in the first part of this paper. The costs of interruptions and voltage sags are determined separately and then combined in order to estimate the total financial losses in the network. The methodology is illustrated on a generic realistic distribution network with all relevant network components modeled appropriately. Finally, different network topologies are compared taking into account total financial losses in the network. It is shown that the inclusion of the financial losses due to voltage sags that may account for up to about 20% of the interruption costs may alter the network topology ranking. [ABSTRACT FROM AUTHOR]

This paper presents a generalized methodology for stochastic/probabilistic assessment of the annual financial losses due to interruptions and voltage sags. The costs of interruptions and voltage sags are treated separately and then combined in order to estimate the total financial losses in the network per annum. The methodology proposed is applicable to both assessment of individual customer losses and assessment of total network losses. It takes into account in a probabilistic manner all the uncertainties associated with the voltage sag calculation, sensitivity of customers' equipment to voltage sags, the interconnection of the equipment within an industrial process, and customer types and the location of the process in the network. [ABSTRACT FROM AUTHOR]