Understand the differences between substations, switch stations, substations, distribution rooms, and box transformers in one article!
substation
Definition: Substation, a place where voltage is changed. In order to transport the electricity generated by the power plant to distant places, the voltage must be raised to become high voltage electricity, and then lowered as needed near the user. This voltage raising and lowering work is completed by the substation. The main equipment of a substation is switches and transformers.
Depending on the size, smaller ones are called substations. Substations are larger than substations. Substation: generally a step-down substation with a voltage level below 110KV; Substation: including "step-up" and "step-down" substations of various voltage levels. ）A substation is a power facility in the power system that converts voltage, receives and distributes electrical energy, controls the flow of electricity, and adjusts voltage. It connects the power grid at all levels of voltage through its transformers. Substations are mainly high-voltage substations for medium voltage, or high-voltage substations for one level lower high voltage. Substations occupy a large area, and the land occupation varies according to different voltage levels and capacities. So some people call it a transformer station
Location: From the perspective of power supply economy, the substation should be located close to the load center. From a production perspective, the substation should not hinder production and internal transportation, and the transportation of equipment in the substation itself should also be convenient. From a safety perspective, power distribution stations should avoid flammable and explosive places. The substation should be located on the upwind side of the unit. In enterprises, it is not easy to set up in places where dust and fibers are prone to deposition. Substation should not be located in densely populated areas. The site selection and construction of power distribution stations should also consider requirements for fire extinguishing, corrosion prevention, pollution prevention, waterproofing, rain prevention, snow prevention, earthquake prevention, and prevention of small animals from entering.
Function: A substation is a transitional device that connects power plants to users. Due to the long distance between the power plant and the cities and factories that use electricity, and the low voltage generated by the power plant, the current is very high. If the current is high, it will generate a lot of heat on the transmission line according to Joule's law, which will cause damage to the transmission line. Moreover, converting the current into heat energy is also a loss. Therefore, it is necessary to raise the voltage of the power plant through the substation to 500000 volts, and then transport it over long distances to the cities and factories where we live. Then, the voltage is reduced through local substations and compiled into our daily 220 volt voltage through distribution and other measures.
substation
Definition: A substation is a place where voltage is changed. It is a place in the power system where the voltage and current of electrical energy are transformed, concentrated, and distributed. To ensure the quality of electrical energy and the safety of equipment, voltage adjustment, current control, and protection of transmission and distribution lines and major electrical equipment need to be carried out in the substation. It can be divided into power substations and traction substations (for electric railways and trams) according to their purposes.
Function: The function of a substation is to transfer the electricity generated by a power station, usually with a voltage not exceeding one or two thousand volts. If it is directly transmitted over long distances, the line current will be very high, causing significant energy loss on the line, which is uneconomical, and the transmission power of the line is very low. So it is necessary to use transformers to raise the voltage to tens of thousands or even hundreds of thousands of volts (depending on distance and power) to reduce the line current. In order to connect power lines of different distances and powers into the grid and increase overall safety, multiple substations are needed to match and connect lines of different levels. Similarly, after high-voltage electricity is transmitted to the destination, in order to meet the needs of different users, it needs to be stepped down to several levels such as 10500V, 6300V, 400V (i.e. 380/220V), etc. So in practical applications, so many substations are needed. A general main substation refers to a primary transformer with secondary transformers. The primary transformer is responsible for high-voltage distribution of switches and is not responsible for voltage transmission.
distribution room
Definition: A distribution room, also known as a distribution station, is defined in national standards as a high-voltage distribution device that only functions to open, close, and distribute electrical energy, without a main transformer on the busbar. The voltage level of the distribution room is below 35KV, and there are switches, transformers, capacitors, and related protective measuring devices installed inside. Simply put, building a house and putting transformers, as well as incoming and outgoing cabinets, becomes a distribution room (room). For larger scale buildings, multiple transformers, high voltage cabinets, low voltage cabinets, etc. are used to complete the transformation and distribution of electrical energy in an independent place or an area within the building. The difference between a distribution station and a substation is that the distribution room (distribution station) does not have transformers, while the substation has all transformers. Transformer and distribution stations mainly refer to the transformer and distribution rooms in residential areas or buildings.
The difference between a public distribution room and a dedicated distribution room is that:
1. In terms of permissions, the dedicated distribution room is independently managed by the owner; The public distribution room is managed by the power supply bureau.
2. In terms of load distribution, the load supplied by the dedicated distribution room is the electricity used by public facilities and equipment in the community, such as fire pumps, domestic pumps, fans, elevators, public lighting, and supporting commercial equipment; The load supplied by the public distribution room is exclusively for residential electricity use.
switching station
Definition: Switching station refers to a distribution station that uses switch devices to achieve circuit switching without voltage conversion. It is a power facility that supplies high-voltage power to several surrounding power units, located at the next level of the substation in the power system. Its characteristic is that the voltage on the input and output sides of the power supply is the same. Of course, regional substations also have the function of switching stations. But it should be clarified that the switching station is different from the substation.
Switching stations also refer to power supply and distribution facilities used to receive and distribute electricity, known as switch stations in high-voltage power grids. Switching stations in medium voltage power grids are generally used for receiving and distributing 10kV power. Switching stations generally have two inputs and multiple outputs (usually 4-6 outputs), but according to different requirements, circuit breakers and load switches can be installed for entry and exit. It is a combination of fully Metal Enclosed Switchgear that can operate outdoors at voltage levels below 10KV. The transfer capacity is about 8000KW, providing medium voltage power to the distribution room of the plot or area.
Location: Located near stations, freight yards, electric locomotive depots, hub stations, and other large load areas.
Function: Segmenting the power supply arm to narrow the scope of accidents and improve the reliability and flexibility of power supply; Reduce the complexity of substations; Without changing the voltage level, only expanding the number of feeder circuits is equivalent to a distribution station.
Box type transformer (commonly known as box type transformer)
Definition: Box type substation, also known as prefabricated substation or prefabricated substation.It is a factory prefabricated indoor and outdoor compact distribution equipment consisting of high-voltage switchgear, Distribution Transformers, and low-voltage distribution devices arranged according to a certain wiring scheme. It organically combines the functions of transformer voltage reduction and low-voltage distribution, and is installed in a moisture-proof, rust proof, dust-proof, rodent proof, fireproof, anti-theft, heat-insulating, fully enclosed, and movable steel structure box. It is particularly suitable for urban network construction and renovation, and is a new type of substation that has emerged after civil engineering substations. Generally, high voltage is converted into low voltage, such as converting a 10kV line into a 380V working voltage through a transformer.Box type substations are suitable for mines, factories, oil and gas fields, and wind power stations. They replace the original civil power distribution rooms and substations and become a new type of complete set of transformer and distribution equipment. A box type substation (referred to as a box type substation) generally consists of a high-voltage room, a transformer room, and a low-voltage room. Box type transformer products are relatively simple power distribution devices, and the selection of their transformer parts can be handled according to general principles, with a capacity generally not exceeding 1250kVA. (Temporary transformer: A temporary transformer used for temporary purposes, such as a temporary transformer on a construction site, that will be dismantled in the future and will not be permanently retained for use.)
Location: The first type is mainly used in residential areas and streets in cities during peak electricity consumption periods. When we need to increase the voltage, we need to use our equipment - a box type substation.
The second type is mainly used for temporary power supply, such as on construction sites where we need to renovate electrical equipment in existing buildings. Box type substations are also frequently used during field operations, such as construction sites, docks, airports, and so on.
Function: Box type substations are used in high-rise residential buildings, luxury villas, square parks, residential communities, small and medium-sized factories, mines, oil fields, and temporary construction sites for receiving and distributing electrical energy in the distribution system.
Traction substation
Definition: The function of a traction substation is to convert three-phase 110KV (or 220KV) high-voltage AC power into two single-phase 27.5KV AC power, and then supply power to the overhead contact network (rated voltage of 27.5KV) in both directions of the railway. The overhead contact network on each side of the traction substation is called a power supply arm. The phase of the contact network voltage of the two arms is different, usually isolated by phase separation insulators. The contact network voltage between adjacent substations is generally in phase [BFQ]. During this period, in addition to using phase separation insulators for isolation, partition pavilions are also set up, and bilateral (or unilateral) power supply is implemented through the operation of partition pavilion circuit breakers or isolation switches.
A dedicated substation for electric traction. The traction substation converts the electrical energy sent by the regional power system into electrical energy suitable for electric traction according to the different requirements of current and voltage for electric traction, and then sends it to the overhead contact network installed along the railway line to supply power to electric locomotives, or to the power supply system required for urban transportation such as underground railways to supply power to subway electric vehicles or trams. (There are multiple traction substations along an electrified railway, with a distance of about 40-50 kilometers between adjacent substations. In long electrified railways, in order to segment high-voltage transmission lines to reduce the range of faults, there are usually pillar traction substations every 200-250 kilometers. In addition to fulfilling the functions of general substations, they also distribute the electrical energy sent by the high-voltage power grid to other intermediate substations through their busbars and transmission lines.)
Location: Located between two traction substations to increase the flexibility and reliability of power supply.
Function: Phase separation; Cross regional power supply; Narrowing down the scope of the accident.