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"Calculation and Selection of Transformer Capacity for Electricity Consumption in Small Districts"

Calculation of transformer capacity selection, in accordance with the conventional method of calculation;

It is the total capacity of the design of residential users in small districts, that is, the sum of the capacity of a household, and because the residential electricity consumption is a single-phase, you need to convert this number into three-phase four-wire power consumption,

So, the relationship between phase current and line current is the root of the problem of 3, that is, the sum of this single-phase power divided by 1.732, transformed into a three-phase four-wire power,

For example, there is now a neighborhood, 200 homes, each household 6-8KW of power consumption, the total of a household is 1400 ÷ 1.732 ≈ 808KW, the number of all the electrical appliances used at the same time, the maximum power, then, actual use This number is the maximum power of all the appliances in the community at the same time, then, the actual use of this situation does not occur, then, there is a call at the same time the rate of electricity consumption, generally choose 70-80%, which is based on the user structure of the neighborhood characteristics, the decision.

But, according to the economic operation of the transformer value of 75%, then, we can offset these two values, according to the power of the transformer capacity, then, the capacity of the transformer is the total power 1400 ÷ 1.732 ≈ 808KW, according to the residents of the situation of the electricity, the power factor is now 0.85-0.9, the apparent power Sp = P÷0.85 = 808/0.85 ≈ 951KVA .

How else can you calculate, first of all, the total 1400 power is divided into three lines of power, that is, single-phase power, 1400 ÷ 3 = 467KW, and then, the single-phase power into three-phase power, 467 × 1.732 ≈ 808KW, and then divided by the power factor of 0.85 is also ≈ 951KVA.

According to the data set of the transformer's standard capacity, it is recommended to choose two transformers, the total capacity of 945KVA, a 630KVA, another 315KVA, in the actual construction process can also be put into use in batches,

If you take into account the future development, you can also choose two 500KVA transformer, or directly choose a 1000KVA.

10KV/0.4KV voltage, 1KVA, 1KVA. KV voltage, 1KVA transformer capacity, how to calculate the rated input and output current;

We know that the transformer power KVA is expressed in the apparent power, the calculation of three-phase alternating current without the need to calculate the power factor, therefore, Sp = √3 × U × I Then, I low = Sp / √3 / 0.4 = 1/0.6928 ≈ 1.4434 That is to say, the rated output current of 1KVA transformer capacity has a rated output current of 1.4434A, with the approximate range chosen depending on the efficiency of the transformer, and the energy consumption ratio. High-voltage 10KV input to the transformer's full load rated current is about; I high = Sp / √3 / 10 = 1 / 17.32 ≈ 0.057737 That is to say, 1KVA capacity of the transformer high-voltage rated input current is 0.05774A.