Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
How about an H - bridge version of the coupled inductor Cuk converter - with re-configurable output stages to get hi volts / lower current or low volts/ higher current...?
dear orsan,
can we talk on email humachauhdry@live.com
i have a opic in mind but need help to execute that project.let me brif u about it..that is improved earth fault detection n its direction determination.
This feature involves detection of high impedance fault when overhead line conductors loose support and fall on poorly conductive surfaces. This type of faults cannot be detected by the existing techniques that are already available to detect even the sensitive earth fault conditions.
Although the high impedance fault draws little fault current, it is really a hazard for safety.
HIZ feature mainly focuses on the detection of ground faults with high impedance at the fault point. Since there is little fault current flows in the circuit in steady state due to the high impedance in the fault path, it is very difficult for conventional over-current relay to detect such kind of fault.
Generally when fault occurs in HV & EHV transmission system, the fault path will be easier to breakdown with large fault current, which mostly leads to the low impedance fault in HV & EHV system. This high impedance fault mostly occurs in the MV distribution system with system voltage below 15 kV. While the MV often serves directly to end user, this implies the distribution system like Overhead lines and cables are often in reach of the public. So unlike the transmission system, personal safety and property security are the major concerns for distribution system protection. Due to the frequency of occurrences and long lasting fault in nature, High impedance fault presents challenges to present techniques, hence is considered a key problem for the distribution protection.
In some situation, HIF is not defined as a Fault for its limited effects on the system, so to trip or not to trip is another problem for outage management of utilities. However, with the downed feeder, contact on the ground is exposed to the public. This may result in death by electrocution, severe electrical burns or fires ignited by arcing and heating of materials. It is rather the responsibility for utilities and protection engineers to clear such fault as immediately as possible. Based on the demands from the utilities and customers, the detection of High Impedance fault has been studied for decades, yet no confirmed solution for this subject has been reached.
As a summary, the major difficulties are:
1. Little fault current.
2. Arcing and randomness.
3. Discrimination from normal system operation.
4. Detection rather than protection
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
