Compact Prefabricated Substation (American Type)

• Customization: Available
• Task: Adjust
• Structure: Combination
• Model NO.: 24
• Mathematical Model: Linear
• Signal: Continuous
• Function: Automatic Control, Protection, Monitoring, Measurement
• Certification: ISO: 9001, CE
• Condition: Used
• Customized: Customized
• Material: Stainless Steel
• Features: Full Sealed&Insulation, Metalclad Withdrawable
• Application Range: Power Plants
• Transport Package: Standard Export Shipping Package
• Specification: customized
• Trademark: Insulation Electrica
• Origin: China
• HS Code: 3707

Product Description

General Information

This product is a domestically produced American box-type substation developed according to the characteristics of the U.S. box-type substation and combined with the actual domestic situation. As an important power supply unit in cable distribution networks, this product is a complete set of pre-assembled products that integrates high-voltage control, protection, transformation, and distribution equipment. It is widely used in urban and rural distribution networks.

This product places the high-voltage load switch and high-voltage fuse in the transformer oil, and has two structural forms: either in the same box as the transformer body or in separate boxes. The oil tank adopts a fully sealed structure and is equipped with oil temperature gauge, oil level gauge, pressure gauge, pressure release valve, oil drain valve and other components to monitor the operating status of the transformer.

This product is divided into ring network type, terminal type and power supply type. In order to make this product more suitable for the actual requirements of my country's power grid, we have introduced plug-in dry fuses. The blowing of the fuse does not affect the performance of the transformer oil. According to the complexity of the low-voltage feedout requirements, the product is divided into three housing types: standard, enhanced and comprehensive, allowing users and design units to be more flexible and economical when selecting models.

The entire product has the characteristics of small size, easy installation and maintenance, low noise, low loss, anti-theft, strong overload capacity, and full protection. It is suitable for new residential areas, green belts, parks, station hotels, construction sites, airports and other places.

Functions and Features

1. Fully insulated, fully sealed, free of maintenance, and reliable to ensure personal safety.
2. The structure is compact, the volume is only 1/3-1/5 of the European transformer of the same capacity, and the height is low.
3. A box-type structure can be adopted to avoid oil contamination in the transformer tank.
4. The high-voltage side adopts double fuse full-range protection, which greatly reduces costs.
5. It can be used for both ring network and terminal. The cable head can be emergency plugged and unplugged when the load current is 200A.
6. The box body is made of honeycomb double-sandwich composite panel, which has the functions of temperature insulation and heat dissipation.
7. An electronic phase loss protector is installed on the low-voltage side. When abnormal voltage occurs in the system, the main switch can be quickly disconnected.
8. The high-voltage side oil-immersed load switch or SF6 load switch can be upgraded electrically, laying the foundation for realizing distribution network automation.
9. Use oil-immersed S9 or S11 series transformers with better performance.

Use Environmental Conditions

1. The altitude does not exceed 1000m.
2. Ambient temperature: -35C-+40C.
3. Relative humidity: the daily average value is not greater than 95%, and the monthly average value is not greater than 90%.
4. Wind speed: equivalent to 34m/s (not more than 700Pa).
5. Shockproof: horizontal acceleration is not greater than 0.4m/S2, and vertical acceleration is not greater than 0.15m/S2.
6. The inclination of the installation site: no more than 3°.
7. Installation location: A place without fire, explosion hazard, chemically corrosive gas and well-ventilated.
8. When ordering this product beyond the above conditions, you can negotiate with our company.

Technical Parameters

Transformer

The new S9 series transformer body is selected, which has low loss, good overload capacity and strong short-circuit resistance. All fasteners have been anti-loosened. No need to hang the core; you can also choose the S11 series toroidal seamless core transformer with better performance.

Note: According to user requirements, the high voltage tapping range of the transformer can be designed to be ±2×2.5%; b. According to user requirements, the low voltage of the transformer can be designed to be 0.69kV.

Load Break Switch

The load switch is an oil-immersed, three-phase linkage switch, spring operating mechanism; it can be opened and closed with load, and its opening and closing speed has nothing to do with the operating force. The types include two-station, four-station T-type, and four-station V. Models are available for selection.

Fuse

The high-voltage side of the American box transformer is protected by a backup protection fuse and a plug-in fuse in series. The principle is simple, economical and reliable; the backup protection fuse is an oil-immersed high-voltage current-limiting fuse with a large breaking capacity and is only inside the transformer. The built-in double-sensitive fuse of the plug-in fuse operates in case of fault, which can provide dual protection of current and temperature. After the double-sensitive fuse is blown, the fuse core can be easily replaced on site.

Transformer

The new S9 and S11 series three-phase oil-immersed transformers have the advantages of low no-load loss, low temperature rise, low noise, and low height. The no-load loss and load loss of the transformer are lower than those of the original S9 transformer, reaching the current domestic advanced level. The transformer has a fully sealed structure, which effectively isolates atmospheric pollution and insulation degradation caused by moisture. There is a 40-90mm air cushion on the top of the fuel tank, which together with the corrugations of the tank shell can simultaneously dissipate heat and cool down, and effectively reduce the internal pressure.

Substation Principle

In the schematic diagram of the substation, the "I" and "I" lines are ring network feeders, the "ll" branch is the transformer branch, and "V" is the low-voltage output. The substation can be used in both the ring network power supply system and the terminal system, and the conversion is very convenient. The line and "l" branch feeds are switched with the ring network load switch. At the same time, the high-voltage side inlet end of the transformer is equipped with a backup protection fuse and a plug-in fuse to protect the branch from short-circuit faults and overload and over-temperature. Protect. At the same time, high-voltage display devices and lightning arresters can also be installed. The low-voltage end of the transformer is output through the meter and low-voltage circuit breaker.

12kV Prefabricated Substation Schematic Diagram

C:(). Ring network load switch (or terminal load switch).

F1:. Plug-in fuse.

F2:. Backup protection fuse.

T:. Transformer.

Q:. Low voltage circuit breaker.

Substation Structure

It can be seen from the appearance and structural diagram of the 10kV prefabricated substation that the oil tank is divided into upper and lower (or left and right) parts. The upper part is the high-voltage oil tank and the lower part is the transformer oil tank. The two are only electrically connected but not oil-free.

1. Features of sub-box structure: The transformer and high-voltage components such as high-voltage load switches, plug-in fuses and backup current-limiting fuses are placed in sealed oil tanks respectively. The two tanks are arranged horizontally on the left and right sides and are completely separated by partitions. There are Insulated wall bushings are used for wiring between transformers and load switches and can be easily replaced without affecting the use of the other box.
2. Advantages of arranging two boxes left and right:
3. The two boxes do not affect each other.
4. It prevents the upper oil tank from flowing into the bottom oil tank due to the leakage of the partition plate, causing the upper oil tank to be short of oil (lack of oil or no oil will cause the operating load switch to arc, causing danger to equipment and people).
5. Another advantage is that the left and right layout is convenient for maintenance. When the transformer room and load switch room are being inspected, the two boxes do not affect each other, which is convenient and fast (if the transformer is arranged up and down for inspection, the upper oil tank must be completely removed before the oil tank of the transformer can be opened, which is extremely inconvenient for inspection).
6. The sub-box structure solves the problem of transformer oil contamination caused by load switch operation and fuse blowing.

10kV Prefabricated Substation Appearance and Structure Diagram

Instructions

Four-station ring network load switch:

The power piece structure is a "V" shaped structure, see the black part in the picture. "I, II" in the picture are the ring network power supply incoming and outgoing lines, and "T" is the high-voltage incoming line of the transformer connected to the backup fuse and inserted fuse.

The ring network load switch switches the network with load. The four working states of the load switch:

 When in the "1-2-T" position, the "I" and "II" networks are connected, and the transformer has power; (the substation functions as a ring network)

 When in the "I-T" position, the "I" network is connected to the transformer; (substation starting terminal)

 When in the "-T" position, the "" network is connected to the transformer; (from the substation terminal)

 When in the "0" position, the "I, " network and the transformer are disconnected; (all are uncharged)

Use a special operating handle to insert the load switch shaft and rotate it about 130° clockwise or counterclockwise. Each time the load switch is operated, the power piece will rotate one gear.

Switch operation example:

Operation method one: Change the power supply from power supply "I" to power supply "II".

 Insert the special operating handle into the switch shaft;

 Turn the switch clockwise once, then the "V" shaped blade of the switch is in the "I--T" position;

 Turn clockwise again. At this time, the "V" shaped blade is between "-T" and supplies power to the power supply ""; the operation is completed.

Operation method two:

 Insert the special operating handle into the switch shaft;

 Turn the switch counterclockwise once. At this time, the "V" shaped blade of the switch is in the "0" position;

 Turn counterclockwise again. At this time, the "V" shaped blade is between "-T" and supplies power to the power supply ""; the operation is completed.

Both of the above methods can be used to complete the conversion from power supply "I" to power supply "II", but the second method is safer and more reasonable. After the power supply "1" is cut off, it will not be powered again. At the same time, if the power supply ""

If a fault occurs, it will not cause the fault to close. When using method one, dual power supply will occur. When power supply "I" is switched to power supply "II", failure may occur due to different power phases and other reasons.

Two-station terminal load switch:

"I" in the structure diagram is connected to the high-voltage incoming line terminal. When operating, the user inserts the special operating handle into the load switch shaft and rotates it 90 degrees counterclockwise. The load switch turns to the "open" position. The terminal load switch only uses In the terminal power supply mode, the transformer branch is cut off, or the core of the plug-in fuse is replaced. Therefore, the terminal negative load switch only has two positions: opening and closing, and due to its small size and small operating force, it is very convenient to operate. In order to reduce oil pollution in the fuel tank, it is recommended that the user disconnect the low-voltage switch to cut off the low-voltage side load before operating the load switch.

Backup protection fuse:

It is connected in series with the plug-in fuse in the transformer branch (see F1 and F2 in the figure) to form a full-range protection fuse. It only blows when a short-circuit fault occurs inside the substation, so the probability of blowing is very low. It is installed in the oil tank Inside, the fuel tank needs to be opened to update.

Plug-in fuse:

1. Its fuse core has dual sensitivity (temperature and current), that is, it fuses when a fault occurs at the load end (overload or excessive temperature). Plug-in fuses are used in series with backup protection fuses, which can provide full-range protection from small currents (several times IN) to large currents (tens of kiloamps), with a maximum breaking current of 50kA.

1. The reasonable matching of backup fuses and plug-in fuses directly affects the performance of the entire substation. The table below is part of the selection guidelines for fuses in 10kV prefabricated substations and is for reference only. Remember, it is not suitable for use in other types of substations.

*Note:

1. The ratings listed in the table are all fuse ratings. The backup protection fuse only blows when a short-circuit fault occurs inside the substation.
2. The selected transformer is only suitable for Dyn11 connection method.
3. When choosing to insert a fuse, it should be considered that 3-4 times the transformer's full capacity current should melt within 300s, and at the same time, 12 times the transformer's capacity current should not melt in 0.1s.
4. Referring to the relevant IEC standards, the fuse can work in the oil temperature range of -25ºC~+40ºC. When the oil temperature is higher than +40ºC, the rated current of the fuse should be reduced by 1% for every 1ºC
5. The plug-in fuse is a component whose fuse core can be replaced externally. When replacing it, first pull the pull ring of the pressure release valve of the upper fuel tank to balance the pressure inside and outside the fuel tank. In order to ensure the safety of operators and equipment, the plug-in fuse must be plugged and unplugged when there is no load. Therefore, the low-voltage switch must be powered off first to remove all the load on the low-voltage side, and then use the operating handle to turn the handle on the fuse holder. Loosen, then rotate about 90 degrees to eliminate the adhesion between the sealing gasket and the outer wall, and pull out the melt of the fuse 70-80mm diagonally upward, stay for a few seconds, and wait for some oil on the melt to drain away. , and then pull out the melt to prevent oil from dripping on other components outside the tank. Wipe the surface of the melt with a clean cotton cloth before replacing the melt core. When replacing, be sure to pay attention to the parameters marked on the fuse core. Different parameters cannot be substituted. See Appendix 3 for replacement steps. After replacing the fuse core, insert the melt into the fuse holder with force. When turning the handle on the fuse to the locked position, make sure that the stainless steel washer is close to the fuse holder and the handle is buckled on the boss. To ensure that the substation is fully sealed and no moisture enters. Then, close the low-voltage switch again, and the power supply can be restored.
6. Because the substation is a three-phase system, whether it is a backup protection fuse or a plug-in fuse, when one of the phase melts is blown, generally all three phases of the melt must be replaced, unless it is determined that only one phase of the melt has passed fault current.

Elbow type and "T" type cable head:

1. The high-voltage incoming and outgoing lines of the 12kV prefabricated substation use cable incoming and outgoing lines. The high-voltage power supply is led out of the oil tank by an epoxy-cast insulating sleeve. In order to facilitate the manufacturer's testing and user acceptance test, the insulating sleeve itself has the ability to withstand 10kV work. Frequency withstand voltage and lightning impulse withstand voltage capability. Before installing the cable head, you must know whether the user requires the installation of a lightning arrester. If necessary, one set of insulating sleeves at the loop inlet and outlet ends shall be double-pass type, and the other set shall be single-pass type. type.
2. Choose an elbow-shaped or T-shaped cable head that matches the cable cross-section, clean its inner and outer surfaces and the surface of the insulating sleeve with absolute ethanol, apply a little 7501 type vacuum silicone grease on the surface of the sleeve, and follow the instructions in the cable work area Install it according to the special installation specifications, and use the same method to install the special fully sealed zinc oxide arrester on the other end of the double-pass insulating sleeve. Please refer to the accompanying instructions for the installation of the cable head.

Transportation, Installation and Maintenance

Transportation

1. The factory-delivered substation should be filled with 25# (or 45#) transformer oil according to the indication of the oil level gauge in the oil tank. During transportation, loading and unloading, no inversion or flipping, no impact on parts, and no strong vibrations are allowed.
2. Special attention should be paid when lifting and shifting the substation. The lifting hook should be hooked on the hook of the oil tank and lifted slowly to prevent the wire rope from damaging the paint on the surface of the substation, or even causing the center of gravity of the entire substation to shift, tilt, or fall.

Installation

1. When installing the substation on site, attention should be paid to the protection of the paint on the surface of the cabinet. No collisions, cracks, etc. are allowed on the handles of the barometer, oil level gauge, thermometer, plug-in fuse and insulating sleeve components, and the screws should not be loose.
2. Clean the dust and dirt on the outside of the substation, inside the cabinet door, and on the surface of the insulating sleeve.
3. Check whether the nameplate data and product certificate of the substation are consistent with the order form, and check whether documents and spare parts are missing according to the packing list.

Maintenance

The products shipped from the factory have been strictly assembled and adjusted and do not need to be disassembled again during installation to avoid affecting performance. Maintenance is limited to the following situations:

1. Conduct transformer oil sampling and analysis once a year.
2. If the oil level is found to be low, it should be replenished in time. The grade of oil should be the same as the oil in the tank.
3. After the fuse is blown, the cause should be identified. When replacing the fuse core, it should be noted that the specifications and models should be the same as the original specifications.

Experiments before acceptance and operation

1. After unpacking, check whether the documents and attachments are complete.
2. Whether the oil level indicated by the oil level gauge complies with product regulations; whether the tap-changer is in the correct position.
3. Operate the load switch clockwise and counterclockwise four times each. There should be no abnormal phenomena such as "rejection of opening or closing".
4. Measurement of DC resistance on high and low voltage sides.
5. Measurement of transformer ratio.
6. Measurement of insulation resistance and power frequency withstand voltage test (80% of the factory value).

Factory information

1. Shipping list.
2. Product certificate and factory test report.
3. Instruction manual.
4. Relevant electrical drawings.
5. Instructions for main components.
6. Cabinet door keys, operating handles and spare parts specified in the contract.

Ordering instructions

The following information must be provided to our company when calculating goods:

1. Product model and quantity.
2. Transformer model and capacity.
3. Transformer oil (25#, 45#, high ignition point oil).
4. Primary wiring scheme and main component parameters of high and low voltage sides.
5. Cross-section of high-voltage incoming cable.
6. Required spare parts.

American Substation Lifting Diagram

Civil Engineering Drawing of Substation Cable Entrance and Exit Lines

Skills Requirement:

The surface of the concrete platform should be flat, and the combined substation should be fixed on the platform using pressure plates: the form of the grounding bar and cable fixing bracket can be determined according to the actual situation. Cable fixing frames and grounding bars should be embedded in advance. The location of the incoming and outgoing cable holes depends on the specific situation; after the combination transformer is installed, there must be a gap of no less than 1.5m on the front of the switch to facilitate operation. The grounding grid can be made of 12mm galvanized round steel or 40×4 galvanized flat copper. The grounding resistance should meet the requirements of the power department.

American Substation Style Diagram

Special Customization

The above parameters are typical data; if the existing styles do not meet your specific demands, please contact us for a custom design.We have significant personalized customization development and production skills, allowing us to provide tailored solutions to customers all over the world.