Calculation Method of Transformer Capacity

In the power system, the total capacity of transformers far exceeds the capacity of generator sets and motors. In the process of transferring electric energy, the transformer consumes part of the effective power and reactive power. Calculating the optimal economic capacity of a transformer reasonably and accurately is one of the necessary means to save energy. What is the capacity unit of the transformer? What is the capacity grade and calculation formula of the transformer?

When we choose a transformer, we will be exposed to two parameters, one is power and the other is capacity. This is also one of the problems that sales staff will have when we consult the transformer manufacturer Shenzhen Kilohertz Technology Co., Ltd. The power of the transformer is expressed in KVA, and the capacity is expressed in KW. When choosing a transformer, we need to tell the sales staff about the actual situation on site so that he can choose a more suitable transformer for us.

Ⅰ. What is a transformer capacity unit?

The capacity of the transformer is responsible for how much power the transformer can drive. For example, a ten kilowatt transformer can drive a load design with a maximum power of ten kilowatts. And this accommodation value represents the capacity of the transformer.

The capacity unit of the power transformer depends on the power. Electrical loads are mostly inductive loads, and the apparent power is equal to the vector sum of active power and reactive power. Therefore, the visual power of the inductive load is greater than the active power. If you choose an active power transformer, the visual power of the inductive load is greater than the capacity of the power transformer, and the load current exceeds the allowable value of the transformer, so the inductive load must be regarded as a power transformer.

Ⅱ. what is the power unit of the transformer:

We all know that electrical appliances have a power unit, and the same is true for transformers. The power unit of the transformer is KVA, which means the total power of the transformer. For example, if the power of the transformer is 10KVA, then the total power of the transformer, including the capacity, is the total maximum power. It is 10KVA. 

Ⅲ. Calculation formula of transformer capacity:

When we are choosing the capacity of the transformer, we should first calculate the maximum power of our actual electrical equipment to make a decision. And this value is to choose the largest value. For example, the starting power of the motor is 10KW, the maximum operating power of the air conditioner is 5KVA, and the maximum total power of the mechanical equipment is 40KW. Add the sum to get:

The maximum starting power of the motor is 10KW+ the maximum operating power of the air conditioner is 5KW+ the maximum total power of mechanical equipment is 40KW=55KW. Then we conclude that the equipment we choose must not be less than 55KW.

However, whether we choose a transformer is not to choose a 55KW transformer. Because the transformer has a certain loss of its own, all electrical equipment has a thermal energy consumption. Generally, the kilohertz is about 80%, so we divide by 55 when we choose. 0.8 is approximately equal to 69KVA. Choose according to the city standard transformer power. Without considering the later expansion to ensure that the equipment can operate easily, we choose an 80KVA transformer. If we need to consider the addition of electrical equipment and capacity expansion in the later period, we can choose a slightly larger equipment.