How should electrical Appliance Switches improve insulation levels?
The use of high and low voltage switch in China is very common, with the continuous improvement of technology, this aspect of the product features more and more powerful, but its insulation level is still worthy of reflection, so our country needs to strengthen this aspect, What are the effective measures we should take?
1. In addition to the interphase and the air
The use of air as an insulating medium of the electrical switch, the cabinet phase of the phase between the phase and the ground clearance must comply with the Ministry of Power DL404-91 "indoor AC high voltage electrical switch ordering technical conditions." The rated voltage 10k ` Switch, between the different phase of the conductor and the conductor to the ground between the clearance should be guaranteed to 125mm or more.
2. External insulation creepage distance
According to DL / T539-93 "indoor exchange high pressure switch and components condensation and pollution test technical conditions." Indoor electrical switch insulation by the minimum creepage distance and artificial contamination tolerance is divided into O, 1 and A total of 3. According to the electrical switch operating environment analysis and electrical switch insulation accident situation, the vast majority of Appliance Switches should have a condensing creepage distance. The minimum nominal creepage ratio should be in accordance with Table 6-6.
The technical conditions stipulate the lower limit. When the environment is slightly harsh, some can not be met. In addition, according to operational experience, the epoxy resin insulator surface state of a great impact on hydrophobicity, so the condensation flashover voltage dispersion is very large, that is, creepage than meet the provisions of the electrical switch should also be used as small stars.
3. Interphase insulation baffle
At present in the power grid to run the 6 ^ -1okV electrical switch, cabinet width 630--100mm all kinds of width are.
Car switch, because the distance can not meet the insulation requirements, and the use of the installation of insulated partitions to solve the solution.
The insulation baffle used should be identified by the technical "whole adhesive insulation baffle", its material are: electric heating curing made of epoxy laminated glass cloth board; in recent years, some switch factory using DMC and SMC unsaturated Polyvinylester glass fiber reinforced plastic plate, this material flame retardant to FVO level, arc time up to 180s, after immersion insulation resistance of 10, MS2; and the price is low.
Whether it is to strengthen the interphase and the relative between the air or increase the external insulation creepage or interphase insulation baffle, this is the design of the adjustment method, but the sub-ah and technical improvements are not obvious, so we should from Take measures in this regard.