Fundamental / Power System Electrical Books

Fundamental / Power System Electrical Books:

1. Protective Relaying: Principles and Applications by J. Lewis Blackburn and Thomas J. Domin, 3rd Edition, CRC Press

• The method of symmetrical components was discovered by Charles L. Fortescue.
• In Symmetrical components, the sequence quantities i.e. Voltage and Current are LINE to NEUTRAL or LINE TO GROUND (opposed to Power system where L-L Voltages are used).
• Positive sequence is a-b-c, 120 deg counterclockwise; Negative sequence is a-c-b, 120 deg reversed to positive sequence; Zero sequence is always in phase
• Phasors always exist as a set of 3 but never alone.
• Unbalanced 3-Ph quantities are divided into the seque nce component as they are independent components in a balanced system network.
• Electric power systems are balanced or symme trical from the generators to the point
  of single-phase loading, except in an area of a fault.

Wireless Wifi Based Battery Charger for Phones

Wireless Wifi Based Battery Charger for Phones:

Imagine wireless charging of mobile batteries. Its amazing to know that we can harness the energy from the WIFI signals to actually charge our phone batteries. Its simply magic for me as I cannot imagine charging of the batteries on the air ... There are various links available which definetly justifies something like charge on the fly is going to be true ... As per the 3rd link, the Airenergy charger will hit the market this summer for $40, but the battery using the Wi-Fi harvesting technology won't be available until soon afterward.

1. http://www.engadget.com/2010/01/09/airnergy-wifi-power-system-gives-rca-a-reason-to-exist-video/
2. http://www.pocketpc-live.com/top-stories/wifi-battery-charger-believe-it-or-not.html
3. http://www.tomsguide.com/us/RCA-Charger-Battery-Wi-Fi-hotspot,news-5547.html

Links for IEC61850

Links for IEC61850

1. http://www.61850.com/ This link is useful if you want to check the validation of the SCD or ICD or CID files.
2. http://www.tissues.iec61850.com/default.mspx
3. http://en.wikipedia.org/wiki/IEC_61850 This is the general wiki. But has few very good presentation on IEC61850.
4. http://siemens.siprotec.de/download_neu/applications/IEC61850/IEC61850_message_status.pdf
   Interrogation of the IEC61850 message status
   Why is it not possible to detect a failure with convention wiring via binary input?
   A loss of signal can also occur on protocol based communication links
   Why does IEC61850 detect an interruption of the transmission path?
   How does one obtain the message status?
5. http://siemens.siprotec.de/download_neu/applications/IEC61850/design01/Network%20Sketch%20Design%2001.pdf This link describes the network overview in standard IEC61850 station.
6. http://siemens.siprotec.de/download_neu/applications/IEC61850/design01/Description%20Design%2001.pdf This link explains the limitation on the number of devices to be connected to the network switch, how many rings are possible in a subnet and many other configuration checklist.
   

Concepts to know in Network before you work with IEC-61850 protocol

Concepts to know in Network before you work with IEC-61850 protocol:

1. Different IP address - Class B, Class A, ...
2. Different MAC address -
3. What is multicast mac address?
4. What is RSTP ? Rapid Spanning Tree Protocol.
5. Which protocol is used for Client-Server Communication?
6. What is subnet?How is it decided ?
7. What is multimode FO cable vs Single mode FO cable?
8. Which type of cables are to be used for SIE, SEL and GE devices?
9. XML, HTML, SCL ...
10. Ethernet TCP/IP
11. OSI
12. Network Switches
13. How they perform?
14. Client - Server communication

Will post the brief description later on.

Advantages of using IEC61850 Protocol

Advantages of using IEC61850 Protocol

1. Reduced Hardwiring
2. Improved Performance
3. Improved capability
4. Customized Solutions
5. Flexibility of the various protection/control schemes
6. Improved supervision
7. Trouble shooting much easier
8. Reduced man-power requirement
9. Reduced chances of error
10. Faster completion of project
11. Reduced space requirement
12. Improved functionality
13. Easy to carry out changes/modifications
14. No aging issues

AutoReclose Function in Protection Relays

Auto Reclose Function:

Technically, whenever any transient faults causing the trip of the circuit breaker, mainly for Over head lines occur, most of utilities prefer to reclose the breaker or they try to reclose for number of times, before coming to the conclusion that the fault is permanent.



You must know which kind of faults you need to consider for transient faults. Not all faults are transient. Ph-Gd, O/C or Multi-phase faults generally account for Transient faults. These AR initiation can be other source too. Energized by user-defined precondition to start AR. As per Siemens Relays, Non-directional faults/Directional/Other/via BI is possible. But it is important that fault occurs. Unless relay sees a fault and breaker trips due to that fault, AR sequence will not start.

• AR and Synch Check goes hand in hand. So when you configure any protection, enable 79 (for auto-reclose)and 25(for synch check).


• So, to first know what is AR and then what is synch check to understand AR sequence.


• it is also important to know Power System Data, V, f, VT connection, Vsynch connection, etc.


• Always set the AutoReclose function.


• Use Inbuilt function for checking how auto reclose works by initiating Overcurrent fault.


• Check then how the sequence is initiated.

Source:

1. Siemens Manual for Line Relay 7SA522/

http://siemens.siprotec.de/download_neu/index_e.htm