with thin styrene. You could also use a piece of PVC pipe for this. The tank’s brackets and sup- ports are also styrene triangles with styrene strips wrapping the perimeter. Using liquid cement
makes these assemblies go to- gether easily. Throughout the project, I applied nut/bolt/wash- er castings of various sizes from Tichy and True Details. Bush- ings (insulators) throughout the substation have little aluminum turnings for their bases and top connectors, which were all pro- duced on a lathe. At this point, I had to think about how the bus conductors were going to be con- nected from one piece of equip- ment to the next, so I left little nubs on the turnings or planned for brass wire to extend beyond the caps to serve as connection points. The primary insulators’ bases are much larger and rep- resent the current transformers found on big transformers and circuit breakers, which are also machined aluminum. The cur-
Circuit Breaker 135 KV Hybrid Circuit Breaker and Earthing Switch. This design was specifically developed for small substations. Combining the breaker and switch in one hous- ing is one reason for its small size. The other is how its arc is quenched when the circuit is broken. This hybrid breaker uses sulfur hexa- fluoride gas to insulate its interior and quench the arc when breaking the circuit. The model’s body is turned aluminum sitting on a soldered brass two-post stand. Again the insulators are plastic auto fasteners.
rent transformers sample the incoming power flow with an in- duction coil and are used for con- trol purposes such as tripping breakers, managing transformer temperatures, and other mea- surement functions. Finding good representation for the large insulators created another challenge. The answer came in the form of auto-body plastic push fasteners. They’re available in all sizes and shapes
at many hardware stores. Another prominent feature and challenge of big transform- ers is the coolant oil tank that sits outside the transformer tank. Known as a Conservator, this vessel acts as a cooling oil surge and storage tank. Lying between the Conservator and the tank is a regulating “Buchholz Control Valve” that throttles oil into and out of the transformer like the thermostat in a car’s cooling sys- tem. There’s a control cabinet attached to the side. Flanking the side opposite the radiators are large lightning arrestors that capture lightning surge currents and shunt them to ground before damaging the transformer itself. The lightning arrestors’ height varies with the operating voltage. Sitting atop the arrestor are coro- na rings. These sci-fi-looking alu- minum rings help prevent arc- over by dissipating the electric field that surrounds high voltage conductors. They were another challenging aspect of the model I
CCVT 135 KV Capacitive Coupled Voltage Trans- formers (CCVT). For a substation to perform its tasks, the power flowing in and out must be con- stantly measured. I mod- eled these mostly out of styrene.
NOVEMBER 2015 63
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100