DC LOW-VOLTAGE POWER SYSTEM Russian patent published in 2004 - IPC

FIELD: power engineering; auxiliary power supplies for power stations and substations. SUBSTANCE: proposed power system incorporating provision for phase-failure and overvoltage protection has power equipment section disposed in envelope, control section, and measurement section. Power section includes supply mains terminals for connecting knife-blade switch, transformer, circuit breaker, fuses, contactor, and rectifier with series-connected pulse shaper and control-section elements connected to the latter. Measuring instruments and indicators of measurement section as well as output terminals are connected to rectifier output. Connected to knife-blade switch of power equipment section is phase monitoring unit that has series-connected three-phase transformer and three-phase rectifier; connected to the latter is circuit set up of series-connected reactor, variable resistor, and phase-failure relay coil shorted out by polar capacitor. Voltage monitoring unit has serial resonance-tuned circuit connected in parallel with phase monitoring unit choke and set up of resistor, capacitor, and inductance coil shorted out by overvoltage relay coil. Final unit has circuit of series-connected power- section circuit breaker, breaking contact of overvoltage relay, and making contact of phase-failure relay that shorts out variable resistor and phase-failure relay coil. EFFECT: provision for phase- failure and overvoltage protection of system due to introducing phase and voltage monitoring units. 1 cl, 1 dwg