| 摘要 |
A residual current circuit-breaker for two DC traction rectifiers operating at full load having cyclic interruption comprises first and second thyristor traction rectifiers, each of which comprises a three-phase thyristor rectifier bridge connected through a danger switch to three-phase AC supply voltage, negative terminals of both traction rectifiers are connected to a rail-track, positive terminals – to a trolley wire, control electrodes of power thyristors of each of three-phase thyristor rectifier bridges are connected by power thyristors through a control unit to first output of a shaper of control pulses, connected by first input to AC three-phase voltage supply in phase with voltage supply of three-phase thyristor rectifier bridges, a load in the form of electric locomotive motors connected to a contact network through a rejection diode, a measuring pause former, first input of which is connected to second output of a shaper of power thyristor control pulses, an electric power supply which is connected by negative output to positive outputs of the traction rectifier, positive output is connected through a first interlock key and a measuring resistor to negative output of the traction rectifier, a loss current control unit, input of which is connected to output of the first interlock key and input of the measuring resistor of operative current sensor, input of which is connected to output of supply voltage sencor connected to voltage supply, a load current sencor, input of which is connected to positive output of the traction rectifier, output – to second input of the measuring pause former and to first input of a protection unit, second input of which is connected to output of the load current sencor, output of the protection unit is connected to control input of the danger switch. In each traction rectifier following elements are incorporated: first, second, third and fourth optoelectronic isolations, second and third interlock keys, AND logic element , first and second OR logic elements, NOT logic element, input of first optoelectronic isolation of a first traction rectifier is connected to output of second optoelectronic isolation of a second traction rectifier, input of first optoelectronic isolation of the second traction rectifier is connected to output of second optoelectronic isolation of the first traction rectifier, output of first optoelectronic isolation is connected to first input of second OR logic element, input of second optoelectronic isolation is connected to output of third interlock key and second input of second OR logic element, output of which is connected to second input of the shaper of control pulses, input of third interlock key is connected to output of the shaper of control pulses, input of third optoelectronic isolation of the first traction rectifier is connected to output of fourth optoelectronic isolation of the second traction rectifier, input of third optoelectronic isolation of the second traction rectifier is connected to output of fourth optoelectronic isolation of a first traction rectifier, output of third optoelectronic isolation of the first traction rectifier is connected to second input of AND logic element, input of fourth optoelectronic isolation of the first traction rectifier is connected to output of NOT logic element, output of the protection unit is connected to third input of AND logic element, output of which is connected to input of NOT logic element, input of third interlock key and first input of first logic element OR, second input of which is connected to output of the loss current control unit, output – to input of third interlock key, output of second interlock key is connected to input of first interlock key. |
