How to choose a 1250 transformer busbar?

The specifications you chose are quite acceptable. But in practical applications, it’s better to leave some margin. It is recommended to consider TMY 2*80*8 for reference.

Thank you. I’ve left a 360A margin – is that not enough? 2 (80*8) has 100A more than the 120*10 I chose; if it were you designing it, would you choose 2 (80*8)? I’m a beginner; please give me some advice. Also, for the neutral busbar, can I use a 60*8 one? It was chosen based on half of the current-carrying capacity of my main busbar – is that appropriate? Another question 1: If one of the outlets in a cabinet has a load of 150 KW, I have chosen a circuit breaker with a frame rating of 400A and a rated current of 320A ； Is a 300/5 current transformer a suitable choice for me? The ammeter was also chosen to be 300A – could this be too low? Question 2: For the main circuit breaker on the low-voltage side of the 1250KVA transformer, I have chosen the RDW1C-3200M/3P/2500 model from Renmin Electric (an intelligent universal circuit breaker) with a rated current of 2500A. Is this appropriate? What if we choose a rated current of 2000A? Question 3: When selecting isolators for low-voltage distribution cabinets, is it necessary to choose load isolators? How should an isolating switch be selected for a 600A load? I used to work in automation; I’ve just started working on electrical design now, and there are so many issues. Thank you for your guidance!

1. Choose the 80*8 model with zero emissions. 2. At a load of 150 Kw, the ammeter reads 500 A, and the current transformer is also 500/5A. 3. For the incoming line, the starting current of the total load plus the maximum load must be taken into account; therefore, a 2500A rating is required. Too small is unreliable. 4. For 150Kw, choose a circuit breaker of 320A; for a knife switch, 400-500A is also suitable. It is better to be large rather than small.

The last edit to this post was made by Baghdad on 2012-3-2 at 14:00. Considering the dimensions, spacing, and margin of the transformer’s low-voltage terminals, as well as the convenience of installation, using 1*100*10mm copper strips that meet national standards is sufficient. The busbars are generally short, with sufficient capacity. The most important advice is to measure the width of the low-voltage terminals; it’s best to use copper plates that are 100 mm wide for installation.

This post was last edited by Baghdad on 2012-3-2 22:57. The main feed line does not require the use of isolating switches; drawer-type 2500A circuit breakers are reliable and practical. For lower-level switches, knife switches are used for isolation when the current is below 600A, while drawer-type circuit breakers are preferred for currents above 600A, as they offer reliable and effective protection.

A 600A drawer circuit breaker is quite expensive compared to ordinary circuit breakers, right? Are you referring to the universal type? Should I choose a type B ordinary circuit breaker? Install a 1000A isolating switch at the front.

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Just finished a project: a 1250 transformer, TMY 2*80*8 busbars, with N and PE wires being TMY 80*8. Intelligent universal circuit breakers of 630A and above are referred to as molded case circuit breakers hereafter.

3×2(100×10) + 1(100×8). Refer to the atlas 03D201-4: Layout of 10/0.4kV transformer rooms and installation of common equipment components in substation facilities; on the last page, look at the options regarding the low-voltage side outlets of transformers. Alternatively, consult the Handbook for Industrial and Civil Power Distribution – it’s either in Chapter 2 or Chapter 3, and the information is there as well

As a supplement regarding △-Y, 3×2(100×10) + 1(100×10)