Modeling of simultaneous faults to reliability enhancement and risk assessment in distribution system
Dehghani, Nematollah (2015)
2015
Master's Degree Programme in Electrical Engineering
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2015-10-07
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201509241618
https://urn.fi/URN:NBN:fi:tty-201509241618
Tiivistelmä
The main purpose of an electric power system is to provide electricity from the generation source to the customer point. Security and adequacy are the two most important requirements in power system reliability. As most of the faults that happen in a distribution network are experienced by the customers, improving the security of the distribution side can have a beneficial effect on the entire network. Faults can occur in single or multiple, faults can also occur at the same time in many different places in the network. It is the simultaneous faults that can drastically affect the security of a
network, and directly decrease the reliability. This thesis work studied the modelling of simultaneous faults by using the Monte-Carlo Simulation (MCS) algorithm in a distribution network. This makes it possible to evaluate the effect of the repair time in different situations, and also to model various solutions to enhance the reliability of the network. An actual overhead line feeder in a distribution network from a rural electricity distribution company was chosen for modelling the MC algorithm and to study the reliability procedures based on it. The calculations in the simulation model are based on number of the faults and the availability of maintenance and repair crews in the case of simultaneous faults. The algorithm can also be used for calculating the reliability indices in radial and mesh configurations with radially operated feeders. As the investment is one of the important parts of planning, evaluation of outage cost also applied to find a valuable view of network for future investment. Risk assessment is a second goal of this thesis to study and analyze future planning of network. Probability and consequence are two main functions of risk studies, three classes of major storm described and analyzed to find the effect on the network reliability based on the percentage of customers without electricity and outage time. These are two tools which are using in financial studies to make investment decision and applicable in power systems are Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR). The Final result shows an improvement in reliability indexes of the network which shoes the capability of thesis work to apply in practical aspects.
network, and directly decrease the reliability. This thesis work studied the modelling of simultaneous faults by using the Monte-Carlo Simulation (MCS) algorithm in a distribution network. This makes it possible to evaluate the effect of the repair time in different situations, and also to model various solutions to enhance the reliability of the network. An actual overhead line feeder in a distribution network from a rural electricity distribution company was chosen for modelling the MC algorithm and to study the reliability procedures based on it. The calculations in the simulation model are based on number of the faults and the availability of maintenance and repair crews in the case of simultaneous faults. The algorithm can also be used for calculating the reliability indices in radial and mesh configurations with radially operated feeders. As the investment is one of the important parts of planning, evaluation of outage cost also applied to find a valuable view of network for future investment. Risk assessment is a second goal of this thesis to study and analyze future planning of network. Probability and consequence are two main functions of risk studies, three classes of major storm described and analyzed to find the effect on the network reliability based on the percentage of customers without electricity and outage time. These are two tools which are using in financial studies to make investment decision and applicable in power systems are Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR). The Final result shows an improvement in reliability indexes of the network which shoes the capability of thesis work to apply in practical aspects.