What are the structural characteristics of the power substation?
The structure of the box-type power substation mainly refers to the arrangement of the three main parts of the box-type station—high-voltage switchgear, transformers and low-voltage power distribution devices.
Generally speaking, the overall layout of the power substation mainly has three forms: assembled, combined and integrated. Assembled type refers to the assembly of high and low voltage complete sets of devices and transformers into metal boxes. Due to the poor integrity of this type of box-type station, large assembly workload, high height, and large floor space, it is rarely used now;
The combined high and low voltage power distribution device does not use the existing complete set of devices, but directly installs the high and low voltage control and protection electrical equipment into the box to make it a whole. Since the overall design is based on the maintenance-free type, there is no need to operate corridors in the box, which reduces the volume of the box-type power substation.
The integrated type is the so-called American box-type transformer. It is based on the transformer, and the fuses and load switches are installed in the transformer box to form an integrated layout. This type of box-type transformer is smaller in volume, and its volume is similar to that of an ordinary oil-immersed transformer of the same capacity, only about 1/3 of the volume of a combined box-type station of the same capacity.
Considering that the assembled type is rarely used, the box-type station can be divided into two categories according to the structure: combined box-type station (European style) and integrated box-type station (American style). Since the IEC standard (IECl330 1st edition 95-11) high-voltage/low-voltage prefabricated substations clearly stipulate the general layout of the box-type station, it is stipulated as a combined layout.
Therefore, the combined type is widely adopted in countries actively adopting IEC standards. As one of the countries actively adopting IEC standards in my country, the box-type power substation used are generally arranged in combination, and the combination type can be divided into two layout types: me type and pin type; integrated box-type station The implementation of the American ANSI standard is widely used in the United States. Box-type stations under different standards are different in terms of wiring methods, types of transformer oil, and transformer materials. For example, in terms of wiring, the American box-type power substation is suitable for the neutral point directly grounded system, but not for the neutral point indirect grounding system, while the European-type station is suitable for both cases.
