Transformer primary side VCB or or Load break switch?

[elecsuni1965]

As per load requirement transfomer has been sized as 1600KVA, 33KV primary and 440Volts seconadry,Dyn11,50Hz. ONAN(oil cooled).Primary tap off from the overhead wooden pole distribution line with load break switch(hand operated) and HRC fuses(25KA rated). My question is this transformer doen't require any Vacuum circuit breaker at primary side?can any one guide me that in which standard it has been detailed about the requirements of primary side protection, either load break switch(manual opertaed switch with HRC fuse links) or breaker?Isn't this transformer require oil , winding, buchholtz relay protection which can be provided with VCB or motor operted load break switch?

 

[davidbeach]

"Required" is something from codes and standards. Where are you; what are the relevant codes and standards? What is required and what is good practice aren't the same thing. Many of the things you list are good practice, and certainly not prohibited by any code I know of, but I've also never run into a "requirement" for more than fuses for transformer protection.

 

[elecsuni1965]

Thanks David ...yes i can understand the difference ...what about the good prcatice?..I am working in Middle east ...following IEC standards(50Hz power supply for this project....for this size oil temperature, winding temperature and Buchholtz relay protection not required?...

 

[oldfieldguy]

1600 kVA is below the size that many people choose to employ any protection above fuses or straight overcurrent protection. I commonly see these here on the US Gulf Coast protected by HV fused disconnects. Where they are fed via circuit breakers, the protection is commonly just overcurrent relaying, possibly including temperature and fault pressure trips.

This is based on observations at dozens of petrochemical plants in this area, but the trend is toward more comprehensive protection systems.

Davidbeach points out that you should look for relevant codes and standards. If these are available, they determine what you must do. In the absence of those standards, then budget, complexity, criticality of loads, etc., all come into play in deciding.

old field guy

 

[elecsuni1965]

Any IEC or IEEE standards?....