① disconnector should be rated voltage, rated current and the use of environmental conditions to select the appropriate specifications and models, and then short-circuit current dynamic and thermal stability of the check.
② When the isolation switch is selected according to the environmental conditions, Switch-Disconnector the type of indoor, outdoor, ordinary or antifouling can be selected according to the installation location and environmental conditions. Outdoor disconnectors should be able to withstand air pollution and should take into account the temperature changes, rain, fog, ice and other factors; pollution prevention for serious pollution.
③ When the form of isolation switch is selected, Switch-Disconnector it should be determined according to the factors such as the layout characteristics and the requirements of the distribution device.
④ isolation switch according to the structure can be divided into three-column, double-column and v-shaped structure, industrial and mining enterprises 35kV substation outdoor use V-shaped structure.
⑤ isolation switch also with grounding knife and no grounding knife knife, with a grounding knife is generally used for substation into the line. In the choice of isolation switch at the same time must also be selected supporting the manual, electric (or pneumatic) operating mechanism, Switch-Disconnector signal and position indicator and the joint, locking device and other ancillary devices.
⑥ isolation switch should be equipped with grounding switch to ensure that the line or other electrical equipment maintenance of the security. Selection of suitable disconnectors should also take into account the space requirements of the distribution unit and the lead position and form (overhead lines or cables).
⑦ optional isolation switch should have the ability to meet the inductor, the capacitance of small current, should make the voltage transformer, arrester, no load bus, Switch-Disconnector the excitation current does not exceed 2A no-load transformer and capacitor current does not exceed 5A no-load lines, etc. Under normal circumstances can be reliably cut off operation, and in line with the power industry technical management requirements. When the technical performance of the disconnector can not meet the above requirements, it should be made to the manufacturing department, Switch-Disconnector otherwise the corresponding operation shall not be carried out. The disconnector should be able to reliably cut off the bypass current and bus current of the circuit breaker.
① outdoor isolation switch, open-air installation should be installed horizontally, so that with the support of the porcelain insulator can really play a rain effect.
② indoor type of isolation switch, in the vertical installation, the static contact at the top, with a casing can be tilted at an angle to install.
③ Under normal circumstances, the static contact with the power supply, Switch-Disconnector moving contact load, but installed in the power cabinet in the isolation switch using cable into the line, the power supply in the moving side of the contact, commonly known as "pour into the fire "
④ isolation switch on both sides of the bus and cable connection should be strong, covered with copper, aluminum conductor contact, should be used copper and aluminum transition joints.
⑤ disengagement switch dynamic and static contact should be aligned, otherwise there will be a bypass when the phenomenon of closing. After closing the static and dynamic contact contact surface pressure uneven, resulting in poor contact.
⑥ isolation switch operating mechanism, Switch-Disconnector transmission machinery should be high-speed good, so that the closing operation can be normal. But also to meet the three-phase requirements of the same period, that is, when the three-phase dynamic contact at the same time action, different periods of deviation should be less than 3mm.
⑦ in the closing position, the dynamic contact to have enough depth into the cut to ensure that the contact area to meet the requirements, but not allowed to head, requiring dynamic contact from the static contact base 3-5mm pores, or close When the fierce will break the static contact support insulator.