Understand the differences and roles of different types of power plants in transmission, transformation, distribution, and utilization!
transformer substation
Introduction:
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. In order to transmit the electricity generated by the power plant to distant places, it is necessary to increase the voltage and convert it into high voltage electricity, and then lower the voltage as needed near the user. This voltage rise and fall work is completed by the substation.
A substation is a process of converting AC-DC-AC in a specific environment. In underwater transmission cables and long-distance transmission, some use high-voltage direct current transmission and transformation forms. Direct current transmission overcomes the capacitance loss of AC transmission and has energy-saving effects.
The substation mainly consists of high-voltage and medium voltage substations, or high-voltage substations with one level lower than high voltage. The substation occupies a large area, which varies according to different voltage levels and capacities. So some people will call it a transformer station. According to the different sizes, the smaller ones are called substations. The substation is larger than the substation.
Function:
A substation is a transitional device that connects the power plant to the user. Due to the long distance from power plants to cities and factories that consume electricity, and the low voltage generated by power plants, the current is very high. If the current is high, according to Joule's law, a large amount of heat will be generated on the transmission line, which can cause damage to the transmission line. Moreover, converting the current into heat energy is also a loss. Therefore, it is necessary to increase the voltage of the power plant through the substation to 500000 volts, and then transmit it over a long distance to the cities and factories where we live. Then, the voltage is reduced through local substations, and through distribution and other measures, it becomes our daily 220 volt voltage.
Location:
From the perspective of power supply economy, the substation should be close to the load center. From a production perspective, the substation should not hinder production and transportation within the factory, and the transportation of the substation's own equipment should also be convenient. From a safety perspective, transformer and distribution stations should avoid flammable and explosive places. The substation should be located on the windward side of the unit. In enterprises, it is not easy to set up in places that are prone to dust and fiber deposition. The substation should not be located in densely populated areas. The site selection and construction of the substation should also take into account the requirements of fire extinguishing, corrosion prevention, pollution prevention, waterproofing, rain prevention, snow prevention, earthquake resistance, and prevention of small animals from entering.
Substation
Introduction:
A substation is a place and 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 are also necessary in the substation. According to their purposes, they can be divided into power substations and traction substations (for electrical railways and trams). The term definition specified in the national standard GB50053-94 "Design Specification for 10kV and Below Substations" is "AC power supply of 10kV and below supplies power to electrical equipment after being transformed by a power transformer". Substations that meet this requirement are referred to as substations.
Function:
The function of a substation is to transfer the electricity generated by a power station, with a voltage generally not exceeding one or two kilovolts. If it is directly transmitted over a long distance, the line current will be very high, resulting in significant energy loss on the line, which is not economical, and the transmission power of the line is very low. So it is necessary to use a transformer to increase 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 with different distances and powers into the power grid and increase overall safety, multiple substations are needed to match and connect lines of different levels. Similarly, after high-voltage electricity is delivered to the destination, in order to meet the needs of different users, it needs to be reduced 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, which is equipped with a secondary transformer. The primary transformer is used for high-voltage distribution and is not responsible for voltage transmission.
Distribution room
Introduction:
A distribution room, also known as a power distribution station, is defined in national standards as "a high-voltage distribution device that only functions to open, close, and distribute electrical energy within the station, 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 measurement devices installed inside.
The difference between a distribution station and a substation is that there are no transformers in the distribution room (substation), while the substation has all transformers.
Location:
Transformer and distribution stations mainly refer to the transformer and distribution rooms in residential areas or buildings. The distribution room is a key part of the building's power supply system, and a dedicated electrician is on duty 24 hours a day.
The difference between a public distribution room and a dedicated distribution room is that:
1. In terms of permissions, the dedicated distribution room is managed independently 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 electricity for 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.
Extended reading: Does the distribution room in the community emit radiation to the human body?
Environmental experts say that scientifically speaking, distribution rooms generate some radiation while generating AC power, but the radiation level is very low and definitely within the national standard range, which may only be slightly higher than that of household appliances such as refrigerators and computers. "Moreover, the power supply facilities in the distribution room are separated by walls, and ordinary brick walls can basically shield radiation, so the radiation in the distribution room has no impact on the human body, and international epidemiological research has never recognized it."
However, environmental experts say that although there is no radiation pollution in the distribution room, the buzzing noise may be a bit noisy. "The noise in the distribution room belongs to low-frequency noise, with strong penetration, but it does not exceed the standard in environmental testing."
Open and close stations
Introduction:
A switching station refers to a distribution station that uses switchgear to open and close circuits without voltage conversion. It is a power facility that supplies high-voltage electricity to several surrounding power consuming units, located at the lower level of a substation in the power system. Its characteristic is that the voltage on the incoming and outgoing 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, and are called switch stations in high-voltage power grids. The switching station in the medium voltage power grid is generally used for the reception and distribution of 10kV power. Switching stations usually have two inputs and multiple outputs (usually 4-6 outputs), but according to different requirements, circuit breakers and load switches can be installed for the inputs and outputs. It is a combination of fully metal enclosed switchgear with a voltage level below 10KV that can operate outdoors. The transfer capacity is about 8000KW, providing medium voltage power to the transformation and distribution rooms 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, reducing the scope of accidents and improving the reliability and flexibility of power supply; Reduce the complexity of substations; Without changing the voltage, only increasing the number of feeder circuits is equivalent to a distribution substation.
Box type transformer (commonly known as box transformer)
Introduction:
Box type substation, also known as prefabricated substation or prefabricated substation. It is a compact factory prefabricated indoor and outdoor 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, dustproof, rodent proof, fireproof, anti-theft, insulated, 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. Usually, high voltage is turned into low voltage, for example, a 10kV line is transformed into a 380V working voltage through a transformer.
A box type substation (abbreviated as a box transformer) generally consists of a high voltage room, a transformer room, and a low voltage room. Box transformer product is a relatively simple transformer and distribution device, and the selection of its transformer part can be handled according to general rules, with a capacity generally not exceeding 1250kVA. Temporary box transformer: A temporary box transformer used for temporary purposes, such as a temporary transformer at a construction site, which will be dismantled in the future and will not be permanently retained for use.
Function:
Box type substations are used in high-rise residential buildings, luxury villas, square parks, residential areas, small and medium-sized factories, mines, oil fields, and temporary construction sites for receiving and distributing electrical energy in the distribution system.
Location:
The first type is mainly used in residential communities and streets in cities during peak electricity usage. 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 the presence of existing buildings. Box type substations are also frequently used in field operations, such as mines, construction sites, docks, airports, and so on.
Traction substation
Introduction:
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 electric traction for current and voltage, and then sends it to the overhead contact network set up along the railway line to supply power to electric locomotives, or to the power supply system required by urban transportation such as subways, to supply power to subway electric vehicles or trams.
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 contact network (rated voltage of 27.5KV) in both the up and down directions of the railway. The contact network on each side of the traction substation is called the power supply arm. The voltage phases of the contact network of these two arms are different, usually separated by phase insulators.
There are multiple traction substations along an electrified railway, with a distance of approximately 40-50 kilometers between adjacent substations. In long electrified railways, in order to segment high-voltage transmission lines and reduce the range of faults, pillar traction substations are generally installed every 200-250 kilometers. In addition to completing the functions of general substations, they also distribute the electrical energy sent from the high-voltage power grid to other intermediate substations through their busbars and transmission lines.
Location:
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 electric traction for current and voltage, and then sends it to the overhead contact network set up along the railway line to supply power to electric locomotives, or to the power supply system required by urban transportation such as subways, to supply power to subway electric vehicles or trams.
Partition pavilion
Introduction:
Set in the middle of two traction substations, it can enable two adjacent contact network power supply sections (up and down of the same power supply arm or two power supply arms of two adjacent substations) to work in parallel or separately. If a short circuit fault occurs in the contact network of a certain section on both sides of the partition hall, the traction substation feeder circuit breaker and the partition pavilion circuit breaker can automatically trip under the action of relay protection, cutting off the contact network of the faulty section, while the contact network of the non faulty section continues to work, thereby reducing the scope of the accident by half.
Function: Phase separation; Cross district power supply; Narrow the scope of the accident.
Location: Located between two traction substations to increase power supply flexibility and reliability.
