GB557608A - Improvements in or relating to automatic reclosing circuit breaker systems - Google Patents

Abstract

557,608. Protective cut-out systems. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Aug. 31, 1942, No. 12271. Convention date, Oct. 18. 1941, [Class 38 (v)] A protective system for a polyphase circuit is adapted to open and reclose the breaker on a faulty phase, and, if the breaker opens a second time, open the breakers on all the other phases. Further, if any breaker opens and stays open longer than a given time, all the other breakers are automatically opened. The breakers 2, 4, 6 in the lines 14, 16, 18 have trip coils 20, 22, 24 adapted to be energized by protective relays 32, 34, 36 responsive'to conditions in the associated line. When relay 32, for example, operates, contacts 67, 76 close, the former energizing the trip coil 20 over contacts 74, and the latter energizing over contacts 80 of relay 42 and contacts 84, 87, the coil of a closing relay 38 and the coil 40 of a relay which opens at 94 the energizing circuit of the closing coil 38 until de-energized by the fully-opened breaker at contacts 100. When eventually 38 is energized it closes the circuit of the closing coil 26 at contacts 106, 114 and makes a maintaining circuit for itself at 104. Contacts 114 also make, over contacts 122, the circuit of coil 116 which changes over contact 80 so as to de-energize relay 38 and energize from buses X, Y and over contacts 130 of the reclosed breaker a timing device 52 which, after the given delay, closes contacts 133 and energizes winding 115 of relay 42, so restoring contacts 80 to their original position in readiness for a further automatic reclosure, and also de-energizing relay 52. The original closure of contacts 76 also energized a relay 44 which in turn energized a relay 46 making signalling circuits for a lamp 49 and bell 50, the circuit being reset by manual switch 64. Relay 44 also opens a slowreturn contact 160 so as to afford the circuitbreaker time to reclose. If, therefore, the breaker is immediately tripped open again before relay 52 has completed its operation and while contact 80 is in right-hand position, contact 130 makes over the now-closed contacts 160, a circuit for the relay 54 including the contact 173 of relay 252. Relay 54 closes at contact 168 a circuit for timing relay 58 which includes contact 171 of breaker 4 in upper position and conductors 178, 180, and by means of conductor 184 energizes similar timing relays 169, 170 for breakers 4, 6. The latter relays both make at contacts 194, 204 in their upper positions circuits for their trip coils 22, 24, which are alternative to those made by the relays 34, 36. Contacts 220 of relay 169 also momentarily energize winding 214 of a relay 216 similar to 42, so changing over contact 228, and in like manner contact 230 of relay 231 to prevent a reclosing operation. While any breaker is closed, a contact 234, 236 or 240 in upper position energizes a lamp 62, whereas when all breakers are open, lamp 60 is lit by those contacts in series in lower position. When the breakers are to be manually reclosed, switch 66 is operated to energize relay 252, whereby contacts 256, 265, 267 energize the closing relays 38, 263, 270, respectively. If any breaker opens other than on fault, say breaker 2, relay 58 will be energized over contact 171 of breaker 4 in upper position, leads 174, 176, 178, contact 276 of breaker 2 in lower position and lead 278, and after a delay will close contacts 290 to energize relays 56, 169, 170, which latter effect tripping of breaker 4, 6 in the manner already set out. The latter relays may also be energized by manual switch 294 for tripping all breakers at will. Specification 544,092 is referred to.