Search results for query: *

Dear all, Does anybody know if the CTs used for reactors (330KV) should have a different specification from other CTs and why? Thanks in advance

Dear all, Do you know of any useful information or literature in relation to high voltage tower earthing, concept, design criteria, testing and commissioning etc. Thanks

Dear all, Anyone has any experience with clamp-on ground resistance testers? I am looking into replacing old ground resistance testers which operate on the basis of "Fall of Potential" method with clamp-on testers, which are quicker and more convenient. I appreciate if you could share your...

Dear all, Do you know of any useful information or literature in relation to high voltage substation earthing, concept, design criteria, testing and commissioning etc. Thanks and merry Christmas and Happy New Year.

Hi all, I am investigating power recordings on a site, which does not have considerable sources of producing harmonics. However I see that there are considerable harmonics on the red phase current only which seems strange to me. There are small harmonics on voltage, which is normal and small...

Hi all, I am investigating power recordings on a site, which does not have considerable sources of producing harmonics. However I see that there are considerable harmonics on the red phase current only which seems strange to me. There are small harmonics on voltage, which is normal and small...

Hi all, Do Slip ring Synchronous motors contribute to short circuit level of a power system as do induction motors? Thanks.

Hi all, In establishing the induction motor contribution to a fault level of a system, what criteria can be considered? Are contributions of small LV (415V)motors considered significant to a fault level on an HV switchboard? These small motors normally don't have a considerable inertia and are...

Hi all, What is the X/R ratio of a typical impedance used to connect generator's neutral point to earth? If you know the Impedance (Z) and don't know the X and R, it helps if this ratio is known.

What is the remedy for a switchgear when its fault capacity is exceeded? Let's consider a case where generators are added to a busbar without considering the fault capacity of the board. Is there anything that can be done to rectify the situation? Thanks for your thoughts.

What is the remedy for a switchgear when its fault capacity is exceeded? Let's consider a case where generators are added to a busbar without considering the fault capacity of the board. Is there anything that can be done to rectify the situation? Thanks for your thoughts.

Hi all, Has anyone used HV overhead lines to carry out Substation Earth Impedance testing? If you know of a written procedure for this test, please direct me to it. Thanks

Could anyone assist me in locating the manufacturer/supplier of flexible high voltage telephone type multicore cable. 20 core or 10 Pair with braided screen or foil and drain wire. 5kV core to core insulation 15kv core to screen insulation Bend radius to be best possible, < 10 X OD Temp rating...

What are the benefits (other than controled voltage start-up)and how can a set of staged resistances can be calculated for HV motor starting. Any reading materials? Cheers!

Hi all, In setting an Overcurrent protection curve for a HV motor, how close can you design your O/C curve to the thermal damage curve? Is there any written information that I can read? I normally design my curve below the motor thermal damage curve, but I need to know what the limit is and how...

Hi all, I have a client with some unbalance current problem during start up of their HV motors. They have three Siemens 6.6KV induction motors having a current unbalance @ starting of 15 - 30% for 1-1.5 seconds. They run a 6.6KV HV switchboard with 2 x 5 Mwatt steam turbines as base load and 5...

Hi All, I know that Hi-pot testing on HV paper insulated and screened cables is no longer recommended in the industry, but I still see it on some standards (ex. Australian Standard). What is the case for you who live in Europe or the US. Do you still do this test on HV cables? For XLPE cables...

Hi every one, I am doing a study into the merit of End to End testing of O/H line distance protection schemes using a GPS device to synchronise two test units at two substations, for a utility. I had done these tests three years ago and I know there are some good points in doing them, but I...

Hi all, We have some CDG26 Earth Fault relays ( tap range 0.1 to 0.4A, DMT 3 sec) on our system and one of them has failed to trip on a feeder, as a result an upstream transformer has tripped. We investigated the relay and found out that the relay performs quite satisfactory if tested with...

Hi all, What is the universal metering convention for Active and Reactive Power when it comes to power Export and Import and Feeder and Generator scenario, if any? Your input is appreciated.