چكيده
Abstract:
Voltage Interruptions and outages are the most frequent monetary events, and their costs on large industrial and commercial customers are considerable. On the other hand, evaluation of these costs is not possible by using the existing test systems due to absence of necessary data for cost calculation. In this thesis, after modification and applying some changes on a standard distribution test system, a new distribution system with residential, commercial, and industrial customers was produced. The test system was employed for simulation purposes using one precise method and some approximate procedures for evaluation of customer interruption costs. The obtained simulation results were discussed, analyzed, and compared to each other in the next step.
Simulation results illustrate that even the precise method for evaluation of customer interruptions costs requires a lot of detailed data from each customers and systems, but its results have a high precision and can be used as a base method to compare approximate methods.
Approximate methods for evaluation of customer interruptions costs are based on using customer sector data rather than individual customer data. In this study, three approximate methods were represented and implemented in the system. In the first approximate method, all customers in a same class related load point were combined and a single load is created. In the second method, all of same class customers of the system, without taking into account to their special load point, are combined and a single load is created for each class. In the third approximate method, all of system customers, regardless of their special class, are considered so that a single load is created. Based on the simulation results, average differences of the first, second, and third method with the base method, at each hour of a specific day, are calculated as almost 1.0%, 2.5%, and 10% respectively. The simulation results confirmed that the second approximate method is the best replacement for the base method, due to its simplicity in surveying and acceptable precision as compared to the first and third methods respectively.
The simulation results also confirm that if number of residential customers are considerable, or if the industrial and commercial customers have a less variety, the results due to applying approximate methods will have a less differences to the base method. Although, the second approximate method has an acceptable precision, its algorithm is very similar to the base one. Therefore, with combination of load and cost models, the second approximate method is modified to simplify the cost allocation procedure on the test system. The results illustrated a 5% difference to the second approximate method and can be replaced with the second method in some applications
