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  1. GRPatel

    Big blackout. What happened?

    As I could understand from the postings, the episode started with the inadequate transmission capacity. There was a very interesting article in IEEE, Spectrum in July 2001 highlighting the defeciency in transmission system. I reproduce the abstract here under. Energy woes [US National Energy...
  2. GRPatel

    how do you manually calculate the f

    Perhaps, you can calculate fault level of each source and then add up. This could be the simplest to get the idea of order of fault level. I assume that you are interested in steady state fault current.
  3. GRPatel

    Corona forming in 15KV switchgear-WHY?

    I try to understand your problem. To me this appears to be a common problem when you use insulation system of more than one material. When you use more than one solid insulation material, you expect air to make an intermediate layer of insulation. This air, depending on where it is present, gets...
  4. GRPatel

    I understand that by adding a capac

    Short circuit currents have three fold effect. 1. Thermal effect on the lines and components 2. Dynamic forces due to the peak of the current and the frequency and 3. System stability. The capacitors tend to increase the peak of the current at high frequency during the initial period of the...
  5. GRPatel

    Web site Information on Circuit Breaker

    Palafala, The dead tank circuit breakers are now being used to integrate the breakers with other components of the substation. They can be earth switches, disconnectors (isolator), CTs etc. Thay are similar to GIS. You may visit www.abb.com. They have product PASS which can be sen on their website.
  6. GRPatel

    Congrats to electricpete

    Congrates from heart.
  7. GRPatel

    Web site Information on Circuit Breaker

    Carl, Circuit breaker design has two aspects. 1. You can be aprt of the circuit breaker manufacturer and developing a new circuit breaker. In that case you need to know the arcing phenomenon and its interruption, the mechanism design and lot of mechanical as well as dielectric issues. 2. You...
  8. GRPatel

    graphite coating of power cables

    Do you have to extrude or you get some spray or paste to be applied on the tube. I am thinking of this idea for making corona ring for outdoor application. I can, perhaps, bend the tube and apply coat of this semiconducting material. Can some one tell me if such material exists.
  9. GRPatel

    Altitude Derating

    dwil, For the lighter air, you have less number of particles in the air. To expalin in a very simple way, I can you an exmple of a needle to be inserted in a soft material and a hard material. Say foam: it is easier to pierce with lower force. For dense foam, you need more force to pierce. Now...
  10. GRPatel

    ESTIMATION OF UNCERTAINTY OF MEASUREMENT

    Try: ILAC-G17:2002 Introducing the Concept of Uncertainty of Measurement in Testing in Association with the Application of the Standard ISO/IEC 17025 http://www.ilac.org/publication.htm This document describes how the concept of uncertainty of measurement should be introduced taking into...
  11. GRPatel

    Material to slide on Stainless Steel

    How about trying PEEK. It is a substitute of PTFE and better in many ways! You can visit: www.ghardapolymers.com
  12. GRPatel

    Use of "O-Ring" as a spring

    I give you some more inputs. Deformation of rubber spring consists of elastic distortion and creep dependent on stress amplitude and time. The creep under static load can be added a permenant set under dynamic load during first 5x 10^5 stress cycles. After load alleviation and a reflux due to...
  13. GRPatel

    Use of "O-Ring" as a spring

    You can adress your question to: mhalloran@parker.com I presuume you want to use it as spring and not as a damper. You will have to consider temperature and the long time stability, though silicon offers good stability.
  14. GRPatel

    I need to know the utility reports cycloaliphatic resin insulator

    I can share some experiences on stability of dimensions and curing methods. The manufacturers of the resin recommend certain gelation cycle followed by further curing cycle. You can follow the cycle suggested by the manufacturer or you may have to devise your own process to achieve best...
  15. GRPatel

    Definition of Substation

    surya, I have been trying to reach you. You can contact me at patelgunvantray@hotmail.com
  16. GRPatel

    Switchgear High Voltage Test

    If I understand your problem correcly, you have a GIS and you want to test the ground insulation. On one of the conductor you have a breaker which gets energised to the test voltage. The other end of the breaker is earthed and the breaker gap will experience the test voltage. Let us consider...
  17. GRPatel

    Interruption of line charging current

    I did not touch various applications of synchronous switching as we are discussing capacitor switching. You can refer www.abb.com, they have such relays and they outline all possible application. You can even use such relays for reducing short circuit current breaking severity by reducing the...
  18. GRPatel

    Interruption of line charging current

    Now that we are on capacitor current switching, I would like to emphasise that making (closing of CB or Switch) of the current is also important. It creates high frequency inrush current, particularly for the capacitor banks. This high frequency current has tendency to create noise which can...
  19. GRPatel

    Vertical Reach disconnects

    BLadewig, Are you now satisfied? I add further info. here. Pantograph disconnector is one type. The other type is known as verticle break. In this one, the blade moves to 90 degrees verticle (open) from the horizontal (closed) position during opening operation. ABB has, for example, complete...
  20. GRPatel

    Vertical Reach disconnects

    BLadewig, Are you satisfied. I add further infor here. Pantograph disconnector is one type. The other type is known as verticle break. In this one, the blade moves to 90 verticle (open) from the horizontal (closed) position from close to open position. When it is closing it reaches verticle...
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