American Type Enclosed Substation

● Model meaning of the ZBW-12 type American Type Enclosed substation

● American Type Enclosed substation  structure characteristics

1. American Type Enclosed substation adopts compact structure, small volume, only about 1/3~1.5 of the domestic European box transformer with the same capacity, greatly reducing the floor space.

2. Fully sealed and fully insulated structure, no insulation distance is needed, and personal safety is reliably protected.

3. American Type Enclosed substation using High-voltage wiring for both ring network and terminal, with flexible power supply mode and high reliability.

4. Excellent transformer performance: low loss, low noise and low temperature rise; Strong overload capacity, short circuit resistance and impact resistance.

5. Meet all kinds of low-voltage feed-out requirements, which can be selected according to the scheme or designed by yourself;

6. There are two types of cable heads: 200A elbow plug and 600 A "T" type fixed cable connector, both of which can be equipped with fully insulated zinc oxide arrester. The 200A type cable head can be plugged and unplugged with load and can also play the role of isolating switch.

● Fuse

The high voltage side of American Type Enclosed substation is provided with full range protection by series connection of backup protection fuse and plug-in fuse, which is simple in principle, economical and reliable; The backup protection fuse is an oil-immersed high-voltage current-limiting fuse with large breaking capacity. Only when the transformer fails internally, the plug-in fuse is equipped with a dual-sensitive fuse, which can provide double protection of current and temperature. After the dual-sensitive fuse is blown, the fuse core can be easily replaced on site.

● Structure and operation sequence

1. The layout

For the shape and structure of 10kV ZBW-12 American Type Enclosed substation, see Figure 2 and Figure 3. The oil tank is divided into two parts: the upper part is the high-voltage oil tank and the lower part is the transformer oil tank. The two parts are only electrically connected, but the oil is blocked. The schematic diagram is shown in Figure 1, in which "I" and "I" lines are loop network feeders, "ll" branches are transformer branches, and "V" is low-voltage output. Substation can be used in both ring network power supply system and terminal system, and the conversion is very convenient. The feed of the line and "lⅢ" branch is switched with the load switch of the ring network. At the same time, the incoming terminal of the high-voltage side of the transformer is equipped with backup protection fuses and plug-in fuses to protect the short-circuit fault and overload and overtemperature protection of the branch. At the same time, high-voltage display devices and lightning arresters can also be installed. The low-voltage end of the transformer is output after passing through a meter and a low-voltage circuit breaker.

● Dimensions and Weight of the ZBW-12 American Type Enclosed substation

2. Backup Protection Fuse

It is connected in series with the plug-in fuse in the transformer branch (see R1 and R2 in Figure 2) to form a full-range protection fuse. It only blows when there is a short-circuit fault inside the substation, so the probability of blowing is very low. It is installed in the upper oil tank, and the oil tank needs to be opened if it is to be updated.

3. Plug-in Fuse

◆Its melting core has dual sensitivity (temperature and current), that is, it melts when the load side fails (overload or excessive temperature). Plug-IN fuse and backup protection fuse are used in series, which can protect the whole range from small current (several times in) to large current (several tens of kiloamperes), and the maximum breaking current is 50kA.

◆The reasonable matching of backup fuse and plug-in fuse directly affects the performance of the whole substation. See the following table for a part of the fuse selection guidelines in 10kV American Type Enclosed substation for reference only. NOTE: it is not suitable for other types of substations.