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Hi All...thank you for all your responses...

Hi there, Some of the traditional methods for reducing arc-flash is to have to bus differential protection for quicker tripping and at times reducing incident energy on the bus. Now, as far as I know, most of the electrical softwares (EasyPower, ETAP and SKM) allows you to model only...

Hi there, What are the standard formulaes used in desiging an outdoor 44kV current limiting reactor in a substation. Downstream of the reactor is a solidly grounded 44/26kV, 10MVA distribution transformer. Happy if someone could refer me to a section of a book, IEEE or CSA standard? The...

Hi all, How do I calculate the capacitance for a oil-filled transformer and power factor correction capacitor bank. Any reference to texts or IEEE standards will be helpful. Thanks. Sonic 02

Hi, Typically the requirements of the type of relays would be dependent on the Owner. They may have some standards preference for relays of a specific manufacturer. If it is older substation with no source of DC supply, it maybe using electromechanical relays. The protection design needs to...

Hi All, I'm adding four(4) new, 15kV metal-clad switchgear breakers to an existing line-up. I plan to utilize DC power for the tripping, closing, spring-charging and protective relay. Now, my concern is whether the existing battery cells have the adequate capacity (i.e. battery voltage)to...

Hi Sanjay, Refer to Table 53 as well as Rule 12-012 Underground Installations Subrule(2)in CEC 2009. Hope that helps! Regards, Sonic02

Hi Sanjay, The Canadian Code states that for direct buried cables in a trench , you will need a minimum of 1000mm of separation from the top of the conductor to the finished grade level for this voltage class. Now, if you have some form of mechanical protection (i.e. wooden planks) in your...

Hi cranky, Your points noted. Any other thoughts/comments anyone?

Hi All, First question: We have a new 500kVA, 13.8kV/600V dry-type ventilated transformer to be installed in a new electrical room. The dimensions of the electrical room is sufficient so real estate is not a concern here. My main concern would be the most ideal location of the transformer...

I would go with a DC system for charging the breaker spring operating mechanism. A battery bank (eg 125Vdc, 60 cells) may be used to feed a DC panelboard which is being utilized to provide a DC supply for motor spring charging. sonic02

Hi there, There are certain considerations you will need before choosing the right switchgear or disconnect switch for your application. The primary function of the switchgear is to isolate faulty equipment, to reconfigure networks in order to restore power supplies, to divide large network...

Thank you all for the comments.

Hi All, We are planning of installing three(3)- single-phase,25kVA, 13.8kV/600V, pri- Delta and sec- wye-grounded pole-mounted transformer for our system. For protection on the primary-side of the transformer, I was wondering if I should spec out a self-protected transformer in which the surge...

Hi there, Can you run 1kV,teck 90 3C#1 AWG power cable, a 4/0 AWG grounding conductor and Instrumentation Cables (in a 4" rigid PVC conduit) in the same trench as mechanical hot and cold water pipes? Sonic

Hi, I'm in Canada. The ratings (i.e continuous rating (900A) & mom.asymmetrical (40kA))for the 13.8 and 25kv outdoor disconnect switch is the same. I'm under the impression that a 25kV outdoor disconnect switch can be used on an exiting 13.8kV line but would just like to get some...

Hi there, A quick question on disconnect switch. Can we utilize a 25kv outdoor disconnect switch on an existing 13.8kV line ? I know that 13.8kV disconnect switch exists but the client had purchased a 25kv disconnect switch instead. Want some thoughts on that.. Sonic

Hi there, Out client has a arc-resistant 4.16kV Medium Voltage Motor Controller in a seperate electrical room which is located in a larger compressor room. This controller has a plenum at the top to direct any arc-flash to a safe or controlled environment. My question is with regards to the...

Hi rcwilson, It is a 5kV TECK 90 3C-500MCM Non-Shielded cable. This cable has a total diameter of 2.78 inches (including the outer jacket). My concern is the cable bending of that cable in a rigid steel conduit underground (i.e. buried trench).

Hi there, We are planning to install a 5kV TECK 90 Cable buried in a cable trench. One of the client requirements is that any cables buried in a cable trench in a vehicular area needs to be installed in a rigid steel conduit. Now, my question is whether a 5kV TECK 90 cable can be installed in...