For high-voltage vacuum circuit breakers that are regularly overhauled, there are the following aspects:
The ones that need to be overhauled per every six months are:
1) Check the appearance of the transmission mechanism of the high-voltage vacuum circuit breaker, clean the dust, and apply grease; tighten the loose fasteners; check the transmission mechanism to ensure the reliable opening and closing of the circuit breaker; clean the circuit breaker, Make it clean to ensure safe operation; apply lubricating grease to make the mechanism flexible and reduce friction and wear.
2) Check whether the iron core of the closing coil is stuck, whether the closing power meets the requirements, and the dead center of the catch (too large a dead center will cause difficulty in opening, and if it is too small, it will easily fall off).
3) Pin condition: Whether the sheet-shaped pin is too thin; whether the column-shaped pin is bent or may fall off.
4) Buffer: Whether the hydraulic buffer is leaking oil, has a small amount of oil or is out of function; whether the spring buffer is working.
5) Whether the tripping core can move freely.
6) Whether there are visible defects in the insulation components. If there are any defects, use a 2500V shake meter to test the insulation to determine whether to replace and make a record.
7) Use a double-arm bridge to measure the DC resistance of the switch after closing (should not be greater than 40Ω), and make a record, if it is greater than Ω, the arc extinguishing chamber should be replaced.
8) Check whether the arc extinguishing chamber is broken, and whether the internal parts are aging.
9) Check the secondary circuit and measure the insulation resistance of the secondary circuit.
The ones that need to be overhauled per year are:
1) Closing time: DC electromagnetic is not more than 0.15s, spring energy storage is not more than 0.15s; the opening time is not more than 0.06s; the synchronism of the three openings is less than or equal to 2ms;
2) The bounce time of closing contact ≤5ms;
3) The average closing speed is 0.55m/s±0.15m/s;
4) Average opening speed (before contact with oil buffer) 1m/s±0.3m/sc
To measure the rated insulation level, generally only measure the lmin power frequency withstand voltage of 42kV, no flashover; unconditionally, the vacuum degree measurement can be omitted, but the power frequency withstand voltage test between phases and fractures must be carried out, and 42kV or higher is required (no power frequency conditions Can be replaced by DC). For vacuum circuit breakers that have been used for 5-10 years, the manufacturer should adjust the contact opening distance, contact stroke, oil buffer buffer stroke, phase center distance, three-phase opening synchronization, closing contact pressure, bounce time, The cumulative allowable wear thickness of the moving and static contacts, etc.
Post time: Sep-15-2021