The Principle Of Kiosk Substation
Kiosk substation, also called prefabricated substation. It is a high-voltage switchgear, distribution transformer and low-voltage power distribution device. It is a factory prefabricated indoor and outdoor compact power distribution unit that is integrated according to a certain wiring scheme. It organically combines the functions of transformer step-down and low-voltage power distribution, and is installed in a moisture-proof, rust-proof, dust-proof, rat-proof, fire-proof, anti-theft, heat-proof, fully enclosed, movable steel structure box. Especially suitable for urban network construction and reconstruction. It is a brand-new substation emerging after the civil substation. Box-type substations are suitable for mines, factories, enterprises, oil and gas fields and wind power stations. It replaces the original civil power distribution room and power distribution station, and becomes a new complete set of power transformation and distribution equipment.
Kiosk substation (referred to as box-type transformer) is a compact complete set of power distribution equipment that combines high-voltage switchgear distribution transformers, low-voltage switchgear, energy metering devices and reactive power compensation devices in one or several boxes according to a certain wiring scheme. . It is suitable for three-phase AC system with rated voltage of 10/0.4KV for wiring and distributing electrical energy.
Compared with European-style Kiosk substation with the same capacity, the structure of American-type box-type transformers is more reasonable. Since the European-style box-type transformer installs the transformer and the common high-voltage electrical equipment in the same metal shell box, the room temperature of the transformer is very high, which makes it difficult to dissipate heat and affects the output. On the other hand, common high-voltage load switches, fuses and low-voltage switch cabinets are used in the box, so the European-style box is larger in size. The structure of American box transformer and European box transformer is different. From the layout point of view, its low-voltage room, transformer room, and high-voltage room are not herringbone-shaped, but needle-shaped. From a structural point of view, this box-type transformer is divided into two parts: the front part is the high and low voltage operating range, and the operating range includes high and low voltage terminals, load switch operating handle, no-load tap changer, plug-in fuse, oil level gauge, etc. . Place the transformer windings, iron core, high voltage load switch and fuse into the transformer tank of the rear tank and heat sink. The fuel tank and radiator are exposed to the air, and there is no difficulty in dissipating heat. Low-voltage circuit breakers use molded case circuit breakers as main circuit breakers and outgoing circuit breakers. Due to the simplification of the structure, the footprint and volume of this box-type substation are greatly reduced. Due to its small size and only one side door opening, the required floor space is only 1/4 of the European box-type substation, and the volume is only 1/5-1/3 of the European kiosk substation of the same capacity. The high-voltage side of the American box-type transformer is protected by fuses, and the low-voltage side is protected by a plastic case automatic air switch, which is the same as the domestic 10kV distribution transformer. The high-voltage fuse protects the internal fault of the transformer, and the air switch protects the overcurrent, short-circuit and undervoltage faults of the low-voltage side line. Disadvantages of American box transformers. Since the load switch is immersed in oil, the oil is carbonized and decomposed by the arc, and harmful gases such as acetylene are generated, resulting in performance degradation and accidents. There is no obvious break point in sight, and maintenance is inconvenient. Because the American-style low-voltage protection and measurement methods are different from those in China, the American-style kiosk substation itself does not have low-voltage protection and measurement. In order to meet the needs of domestic users, domestic box-type transformers are equipped with low-voltage power distribution cabinets on the low-voltage side. Because the box-type transformer is exposed to direct sunlight for a long time, the heat dissipation of the molded case circuit breaker is affected, so that the circuit breaker cannot break the load and short-circuit current normally, which is easy to cause high-voltage side failure.
