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  1. jpatricksss

    Plot LV Circuit Breaker Time Current Curve Using Equations

    How to plot the time-current curve from the LV circuit breaker parameters to determine tripping times? What are the standard features of the time current curve and what properties of the CB do you need to know to plot? E.g. I want to plot the time-current curve for In = 100 Amp CB to BS EN...
  2. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    Thank you all for your replies. This is a good forum. I shall enjoy contributing. Conclusions: 1. It is theoretically not possible to have a surface potential which exceeds the GPR. Practically, through modelling inaccuracies, it is. 2. Figure B.8 in IEEE80 shows an error with the EPRI...
  3. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    The image is an extract from IEEE80... Can anybody explain it?
  4. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    Please refer to the attached image from IEEE80.http://files.engineering.com/getfile.aspx?folder=cae34f0c-86ea-4d0b-b783-24c65481c059&file=Surface_Potential_greater_than_GPR.bmp
  5. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    What is the attached image (see original post) from IEEE80 showing me then? Is that not showing surface potential greater than GPR. This occurs for Unequally spaced grid? This may seem like a silly question but I have done some modelling which shows surface potential greater than GPR.
  6. jpatricksss

    3 Phase Voltage Levels

    IEC 60038 Standard Voltages: Three-phase 50 Hz 230 V / 400 V 400 V / 690 V 1000 V Suppliers using 220 V / 380 V or 240 V / 415 V systems were expected by the standard to migrate to the recommended value of 230 V / 400 V by the year 2003. This migration has already been largely completed, as...
  7. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    IEEE 80:2000!
  8. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    IEEE 80:2007
  9. jpatricksss

    Ground Potential Rise > Surface Voltage Potential - possible?

    Hi all, Is it possible to have a surface voltage potential (surface voltage profile) which exceeds the grid potential (GPR)? Refer to Figure B.8 of IEEE (image attached). Is this what it is showing us? Thanks to all. JP
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