Loading...
| Friend's email | |
| Your name | |
| Your email | |
| enter code | |
This page was sent successfuly
- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 44741 (05)
- University: Sharif University of Technology
- Department: Electrical Engineering
- Advisor(s): Vakilian, Mehdi
- Abstract:
- There is an increasing trend nowadays toward Distributed Generation (DGs). DG poses positive and negative side effects for both utility and customers. Reduction of system expansion costs, decreasing power loss and reliability enhancement are some benefits of DGs. Connecting DGs to the distribution system can lead to some troublesome issues. Anti-islanding protection is one of these issues. Islanding is the situation in which a distribution system becomes electrically isolated from the remainder of the power system, yet continues to be energized by DG connected to it. Traditionally, a distribution system doesn’t have any active power generating source in it and it doesn’t get power in case of a fault in transmission line upstream but with DG, this presumption is no longer valid. Current practice is that almost all utilities require DG to be disconnected from the grid as soon as possible in case of islanding. The main philosophy of detecting an islanding situation is to monitor the DG output parameters and/or system parameters and decide whether or not an islanding situation has occurred from change in these parameters. Islanding detection techniques can be divided into remote and local techniques and local techniques can further be divided into passive, active and hybrid techniques. Remote islanding detection techniques are based on communication between utilities and DGs. Although these techniques may have better reliability than local techniques, they are expensive to implement and hence uneconomical. Passive detection methods are based on the measurement of system parameters at the DG site, like voltage, frequency, etc. Active methodsdirectly interact with the power system operation by introducing perturbations. The idea of an active detection method is that this small perturbation will result in a significant change in system parameters when the DG is islanded, whereas the change will be negligible when the DG is connected to the grid. Hybrid methods employ both the active and passive detection techniques. At first, a review is made over the active and passive islanding detection methods and their performance are compared. Then the different kinds of distributed generators and inverters and their controlling structure are presented. Finally, a hybrid islanding detection method is presented and its effectiveness is examined by the UL1741 standards
- Keywords:
- Hybrid Methods ; Islanding Operation ; Dispersed Generation ; Distribution System ; Microgrid
Digital Object List
-
محتواي کتاب
- view
Bookmark