High or open fuse with fuse protection and isolation of the role of power, it is simple, economical and practical. Distribution lines in rural areas and small and medium sized outdoor transformer is widely used.
In practice, through the high-voltage fuse operations or open constantly sum up, it was found: three-phase load in the first phase breaking, the fracture low voltage (about 1.5UP), arc small; breaking the second phase, the fracture voltage is higher (for the UP = UL), the circuit often occurs after a strong arc, easy to make o-phase short circuit; finally pull the third phase, because the circuit is no longer current, this fool will not produce electricity seems to pull the second phase is to ensure security. In addition, the airflow (wind, wind direction) on the operation of the security implications are obvious. After the arc stretched when the air is likely to cause short circuit between phases.
For safety reasons, open-fuse high-voltage operation down to make the following requirements:
(1) the operator must use the appropriate voltage level, test qualified rods, and wear insulated gloves and anti-lens, to ensure personal safety.
(2) operation is not too much force, so as not to damage the fuses. And the points must be in place together.
(3) In general, power should be asked to pull the load side of low voltage switchgear, high voltage power supply side and then pull down to open fuse. Transmission, the operation sequence and the reverse power. Try to avoid negative Hela or open fuse together because when the larger arc, causing accidents. However, for a capacity of 200kVA and below the distribution transformer, allowing the high side of the fuse points, co-load current.
(4) high-voltage fuse or open phase of the operation sequence:
① power operation should be asked to pull the middle phase, the phase after the pull side. Transmission phase when both sides of the before-and after co-intermediate phase. Pull in power when the first phase of the main reasons for considering a second operation (edge phase) or open fuse when the current is high, at which point the phase has started, the other two fell apart over the open fuse far, to prevent short-circuit arc stretching caused by phase.
② according to the first pull when the wind encountere d intermediate phase, and then pull back the wind phase, the final phase of the order of drawing the wind power. Transmission phase when the first combined wind and then winds back together, and finally co-intermediate phase. This prevents the wind caused by short circuit arc.
(5) try to avoid the rain or when thunder operation.
(6) a sign of failure of the transformer (sound unusual, fuel injection, etc.), not to operate. Application of the transformer power supply line circuit breaker to disconnect.
(7) outside the user can pull or open fuse together small current circuit. For example the following:
① voltage is 10kV, 10km long overhead lines within the no-load pull together.
② voltage of 10kV, and within the capacity of 560kVA transformer no-load pull together.
③ Lahti 10kV load length of cable lines and cable cross-section related. When the cable cross-section of 3 × 35mm2, 3 × 50mm2, 3 × 70mm2, 3 × 95mm2, 3 × 120mm2, 3 × 150mm2, 3 × 185mm2 maximum tension when the combined length of the corresponding are 4.4km, 3.9km, 3.4km, 3.0km, 2.8km, 2.5km, 2.2km.
Therefore, in order to ensure safe operation of equipment and operation and the correctness, we must operate in accordance with the essentials and the related regulations.
Hot Tags: