1. Advantages and disadvantages of removable switchgear
At present, most domestic units with strong funds, a large number of switchgears, and high demand for electricity use moveable switchgear. Removable switchgear cabinet body is small and compact, installation area is small, easy to maintain, but the shortcomings are:
(1) Poor current-carrying effect. Due to too many main circuit connectors in the cabinet and movable plug connectors, the cabinet heats up seriously and has poor heat dissipation. However, in most cases, the actual load current is far from the rated current value of the circuit breaker. The current-carrying problem is generally not prominent. However, when the current closure is large, the current-carrying accident is convex, and because the broadcast connector is hidden in the contact box, early accidents are not easy to detect.
(2) The failure rate is relatively high. The use of a removable structure requires high processing accuracy, otherwise the moving contact and the static contact of the circuit breaker are not aligned, resulting in poor contact, severe heat generation, insulation damage, and short-circuit accidents. (Follow WeChat public account: Global Electrical Resources)
2. Advantages of mid-mounted switchgear
In the removable switch cabinet, if the mobile handcart is placed in the middle of the cabinet, it is also called a middle-mounted handcart switch cabinet. For the removable switchgear with a voltage of 12kV, most of the domestic applications have adopted the center-mounted type, and the center-mounted type basically occupies a dominant position.
The 12kV mid-mounted switch cabinet has obvious advantages, that is, a handcart can be installed in the lower part, and the voltage transformer handcart can be placed in the lower space as usual. In this way, the use of the center-mounted type creates favorable conditions for the manufacture of the two-handed car cabinet. Even if the lower part of the cabinet is not equipped with any components, it can also be used as a manhole for maintenance personnel to repair the components in the cable room. In short, a handcart without a main circuit outlet can be installed at the lower part of the ordinary middle-mounted handcart switch cabinet. If two standard handcarts are installed in one cabinet, a special cabinet is required. In addition, when there are many components in the cable room and there are many outgoing loops, the front lower part of the cabinet can be used as a part of the cable room to divert the installation components or cables in the cable room.
For the 40.5kV removable medium voltage cabinet, it does not make much sense to switch to the mid-mounted type, because the circuit breaker trolley is large in size and heavy, and it is placed in the middle of the cabinet to raise the center of gravity of the cabinet and reduce its stability. In addition, the middle part of the circuit breaker handcart cabinet is arranged, and the remaining space in the lower part is already very small.
It does not make much sense. For the 40.5kV switchgear, if the central layout must be adopted, it can only be carried out when the circuit breaker trolley is very small. For example, the vacuum solid color edge circuit breaker is small in size, and it is possible to use the central layout. When using the mid-mounted type, it is necessary to add a handling trolley, even if the circuit breaker trolley is placed in the middle, the lower space saved is limited and cannot be used
Post time: Oct-04-2021