Buried-Box Substation Tech Principle(1)
A. 6 – 12 kv Lines:
- The single bus section connection.
B. H.V Connection Mode:
1. H.V Side:
Buried-Box Substation .The load switch + current-limiting fuse as main protection of transformer, two groups of insert fuse scope of protection and backup protection fuse series section.Tandem jump three-phase load switch, lack of phase operation does not occur
2. Line Side:
Cable connection using high and new technology of plug type connection, safe and reliable.Load switch DC power electric operation mechanism, since the launch of external AC power condition.
3. The Loop:
Buried-Box Substation ,Configuration testing with current transformer or sensor fault current.
4. H.V Switch:
Buried-Box Substation , SF6 load switch, vacuum circuit breaker, vacuum load switch pneumatic type load switch, vacuum load switch, etc.
5. Power Supply Unit:
a) SMR16-12 ring network cabinet or GT-12 main ring network cabinet, V, C, F.M,may unit are combined according to need.
b) Generally is composed of three intervals, the two ring in and out of the circuit and a transformer intervals.
c) Among them, the load switch: the fault line when the isolation, timely recovery loop continuous power supply;
d) Connected to the fuse in the internal fault protection; Isolation and grounding of fuse and the transformer.
6.The Load Switch Fuse Combination:
a) Protection of transformer, switch gear, load current, alternative circuit breaker, as the protection of transformer switch equipment.
b) To provide close short circuit current capacity, can’t open circuit short circuit current.
c) Used alone away from the power center, and smaller terminal capacity, for reactive power compensation circuit, shunt reactor and motor, etc.
7. Type Current Limiting Fuse:
a). Filled with quartz sand cooling arc around the melt, rely on to achieve effective extinguishing arc, strong cooling in the process of the arc established above the working voltage of the electric arc voltage, strong current limiting capability.
b). After the start of short circuit current rise, hot melt, temperature rise, current up to a point, melting, melt stop electricity flow rise, began to drop along the ab line and in point b current drop to zero, at this time to complete the arc.
c). The entire action process occurs in the porcelain tube seal, in extinguishing arc, turbulence not rushed out of the tube.
d). Of fuse open circuit, the biggest cut-off current and expected current steady-state party, the relationship between root from the current value of the current limiting characteristics can be estimated by the current-limiting fuse protection when fault occurs in the electrical equipment of the mechanical and thermal effect.
e). Structure is simple, cheap and convenient maintenance
Fuse is a major component of fuse body, when the fuse body through the current more than fixed value, the fuse body itself produce joule heat, temperature, make itself reaches melting point, the fuse body to fuse to cut off the overload or short circuit current.
8. H.V Room:
Buried-Box Substation .SF6 load switch or vacuum circuit breaker, fuse, CT/PT lightning arrester. Microcomputer protection device, etc
9. L. V Room:
Buried-Box Substation ,Improved GGD type fixed low-voltage distribution panel, including the main switchgear, metering switchgear, multi loop outlet cabinets, coupling capacitor. Intelligent lighting energy saving device, FEPS power cabinets, intelligent street light control device, etc