This invention relates to cubicle type substations and especially to combined transformer and prefabricated substations.
Cubicle type substations are widely used in the power transmission and distribution industry and include combined transformer and prefabricated substations. The introduction is as follows:
Combined Transformer
Combined transformer is a term used in China Machinery Industry Standard JB/T 10217-2000 “Combined Transformer.” Since the technology of this product comes from U.S.A., the combined transformer is also called “American Cubicle Transformer.”
In American National Standard ANSI/IEEE C57.12.26, combined transformers are called “three Phases Compartment-Type Pad-Mounted Transformers.” In the above standard, in Chinese patents such as “New type of combined transformer” (Patent No. 00217238.0), and in the product catalogs of American GE company and Shanghai Zhixin Company, the typical structure of a combined transformer is shown as
As the requirement for urban environment beautification progresses people hope to reduce the area occupied by combined transformers. In this regard, the American cubicle type transformer has following disadvantages in structural features:
Prefabricated Substation
In order to meet the requirement which is to arrange power supply cables underground in downtown districts and busy streets in power transmission applications, the prefabricated substation which can transfer HV (1-53 KV) into LV (0.4 KV) is widely used.
Chinese National Standard GB/T17467-1998 “HV/LV Prefabricated Substation” and the International Electrician Committee IEC1330:1995 “HV/LV Prefabricated Substation” stipulate: The prefabricated substation which mainly consists of transformer, HV switch equipment and control equipment, LV switch equipment and control equipment, related internal connection wire (cable, bus bar and others) shall be enclosed with a common casing or a group of casings. The common casing or a group of casings of prefabricated substations is normally divided into three compartments: the HV chamber, the LV chamber and the transformer chamber. In Mr. Hu Zhaoming and Shen Wei's “Cubicle Type Substation” electric power equipment 2000 (1) and William Stemmons “Packaged Power Control Assemblies” Copyright Material IEEE Paper No. PCIC 84-11 technical document and Chinese patent “Prefabricated Substation in Basement” (Patent No. 00205369.1), all the three compartments of prefabricated substations having existing open technology are provided in a planar, parallel and compact layout. Referring to
With the requirement of urban environment beautification, the shortage of existing prefabricated substations has been clearly shown. Large areas have been occupied by substations—since the three compartments are arranged in parallel in a planar manner, the occupied area is the sum total of the three compartments which occupies a large space—this is because the space needed for the whole installation is great. If part of the installation is underground, the waterproof requirement for the HV chamber and the LV chamber will be extremely high and the equipment operation and maintenance will be inconvenient. Meanwhile, the radiation generated from the transformer chamber will produce a high heat output which will be difficult to dissipate with natural ventilation. In addition, the construction cost for an underground pit is high, and if the whole substation is buried underground, an artificial radiation ventilation facility needs to be provided.
An object of the present invention is to provide a cubicle type substation with good radiating effect.
Another object of the present invention is to provide a combined transformer and a prefabricated substation that occupies a small area and is convenient to operation.
The combined transformer includes a transformer chamber, LV chamber, HV chamber and radiator that includes a hollow heat pipe in which a heat transferring medium is filled. One end of the heat pipe is inserted into the transformer chamber, the other end thereof is provided with radiating fins. The LV chamber is set above the transformer chamber while the HV chamber is set at the side of transformer chamber. The transformer chamber and HV chamber are buried underground. The radiating fins are set above the transformer chamber. The traditional liquid radiating fin is located at the side of the transformer chamber.
The prefabricated substation includes a transformer chamber, a transformer installed in the transformer chamber, switch room with LV and HV chamber, and a that has a hollow heat pipe in which a heat transferring medium is filled. One end of the heat pipe is inserted into the transformer, while the other end is provided with radiating fins. The radiating fins are at the outside of the switch room. The switch room is set above the transformer chamber. The HV chamber and the LV chamber each has a door. The transformer chamber is enclosed within ground pit and covered with a cover plate.
In above combined transformer and prefabricated substation, the heat transferring capacity of the heat pipe is great, and the substation has a long service life, a high reliability and occupies a small volume. The radiating effect has been greatly improved. Furthermore, the layout has been changed from the traditional layout so that the transformer chamber, LV chamber and HV chamber are arranged in a parallel and compact way in the same plane. The transformer chamber with large volume, the HV chamber with less operation and radiator at the bottom are set at the lower layer. The LV chamber with frequent operation, maintenance and high waterproof requirement as well as top radiator is set at the upper layer. In application, the lower layer is set underground, and with the upper layer above the ground, the occupied area has been reduced 60-70% compared with the traditionally planar arranged combined transformer. The prefabricated substation having a switch room set above the transformer room can reduce the occupied area 30-40%. In addition, since the switch room for the prefabricated substation is set above the transformer room and above ground, the waterproof and damp-proof function can be realized, meanwhile, the doors for the HV chamber and the LV chamber are easy to be opened, thus, it is convenient for equipment operation and maintenance in the HV chamber and the LV chamber. The transformer room is set underground and natural ventilation and radiation for the transformer can be realized via heat pipe radiator. The oil-immersed transformer has high running reliability and good waterproof performance, hence, 20 years' free of maintenance can be realized.
The following is the further description with two practical examples for the cubical type substation of the present invention. See reference drawings.
Combined Transformer
Referring to
The top radiator 4 is set above the transformer chamber 1 (
The heat pipes 7 consist of steel or copper pipes, the radiating fins 10 are made of steel plates or aluminum plates, and the heat pipes 7 are the radiating fins 10 are welded together. The lower section of the heat pipes 7 can be inserted into the transformer chamber 1 to contact the transformer oil 14 and improve the heat absorption effect for heat pipes 7. The heat pipes 7 can also be welded to a side of transformer chamber 1 so as to reduce the influence to the equipment in transformer chamber 1. The heat pipes 7 transfer the heat in transformer chamber 1 to radiating fins 10 via the medium in heat pipe cavity 11. The radiating fin radiates the heat into the atmosphere above the ground to solve the heat problem since the transformer chamber 1 is buried underground. The bottom radiator 5 is a conventional transformer oil radiator.
The transformer oil 14 is filled up in transformer chamber 1. Not only is the transformer 13 immersed in the oil but also the protective fuse 15, HV load switch 16, and tap switch 17 are immersed in the oil. The transformer oil is fully used to realize insulation.
The socket 24 for protective fuse 15, operating handle 25 for HV load switch 16, and regulating handle 26 for tap switch 17 are set in the LV chamber 2 (
In order to reduce the volume of the upper layer, the socket 24 for protective fuse 15, operating handle 25 for HV load switch 16, and regulating handle 26 for tap switch 17 can also be set in the HV chamber 3 (
The LV outgoing terminal 20 is located in the LV chamber 2. The HV cable socket 27 is located in the HV chamber 3.
An insulation layer 30 is provided between the LV chamber 2 and transformer chamber 1 or radiating fins 10 to prevent the heat in transformer chamber 1 or radiating fins 10 from entering the LV chamber 2.
The bottom radiator 5 is set at the side of the transformer chamber 1 to improve the radiating effect of transformer chamber 1. The heat generated thereof can be transferred into the pit and eliminated out along the periphery of the pit.
A door 8 is provided at a side of the LV chamber 2 so as to open it easily and enter the LV chamber 2 for operation. Under the door 8 is underground cable entry 9, which is used for the LV cable incoming.
In the LV chamber 2 are LV switch 21, oil temperature gauge 22 and oil level meter 23, which are used to control the running status.
As shown in
As shown in
As can be seen from
Referring to
Based on the design principle, the transformer chamber, bottom radiator and HV chamber at lower layer are made of anti-corrosive steel plate with surface anti-corrosive treatment. An air grid inlet is provided on the cover plate of the bottom radiator. The oil-immersed transformer with high reliability can realize waterproof function and 20 years' of free of maintenance. Incoming HV cable adopts all-sealed plug-in/out connector and can be safely operated on hot line under the water. The HV chamber does not need watertight function so that the cost is reduced.
In accordance with the design principles of the present invention, only one of the top radiator and the bottom radiator can be used based on different radiation requirement. If the underground transformer fails, similar to conventional combined transformer, the replacement method for the whole body can be adopted so that a rapid and convenient maintenance can be realized to ensure the power supply.
This invention adopts an upper/lower overlap structure for the transformer chamber, the LV chamber, the HV chamber and the top and bottom radiator, i.e., the half of waterproof transformer chamber, the HV chamber and the bottom radiator which are free of maintenance and operation are buried underground. The LV chamber and the top radiator which have high waterproof requirement and need operation and maintenance are placed above the ground. On the premise of being suitable for running and maintenance, for meeting site installation requirements and not increasing costs, the occupied area by the combined transformer has been reduced in a maximum degree and in a optimum way so as to reach the goal of environment beautification.
Prefabricated Substation
As shown in
During the installation and application, it is only necessary to build a ground pit under the ground and place the lower parts including such as transformer chamber with installed transformer into the pit and allow the upper parts including such as LV chamber to remain above the ground. A cover plate is provided at the ground pit opening. The ground pit cover plate is opened to carry out transformer installation, cable connection and maintenance to some of the equipment. If the transformer in lower parts underground fails, similar to existing substation, maintenance can be quick and convenient and power supply can be ensured.
Number | Date | Country | Kind |
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03108110.X | Mar 2003 | CN | national |
03231909.6 | Jun 2003 | CN | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CN04/00076 | 1/20/2004 | WO | 9/19/2005 |