Arc flash detection apparatus and electrical system including the same

An electrical system comprising:

• a first power bus;
• a second power bus;
• a third power bus;
• a first circuit interrupter electrically connected between the first power bus and the second power bus;
• a second circuit interrupter electrically connected between the second power bus and the third power bus;
• at least one of:
• (a) a shorting apparatus operatively associated with the second power bus, and (b) the first circuit interrupter comprising a trip coil;
• a first current sensor structured to sense a fault current of at least a predetermined magnitude flowing in the second power bus and responsively output a first logical signal;
• a number of light sensors structured to sense an arc flash operatively associated with a number of the second power bus and the third power bus and responsively output a second logical signal;
• a second current sensor structured to sense a fault current of at least a predetermined magnitude flowing in the third power bus and responsively output a third logical signal;
• and
• a circuit structured to delay and invert the third logical signal to provide a fourth logical signal, and to operate the at least one of the shorting apparatus and the trip coil responsive to a logical AND of the first logical signal, the second logical signal and the fourth logical signal.

An arc flash detection apparatus for an electrical system comprising a first power bus, a second power bus, a third power bus, a first circuit interrupter electrically connected between the first power bus and the second power bus, a second circuit interrupter electrically connected between the second power bus and the third power bus, and at least one of:

• (a) a shorting apparatus operatively associated with the second power bus, and (b) the first circuit interrupter comprising a trip coil, the arc flash detection apparatus comprising:
• a current sensor structured to sense a fault current of at least a predetermined magnitude flowing in the second power bus and responsively output a first logical signal;
• a number of light sensors structured to sense an arc flash operatively associated with a number of the second power bus and the third power bus and responsively output a second logical signal;
• and
• a circuit structured to delay and invert the first logical signal to provide a third logical signal, and to operate the at least one of the shorting apparatus and the trip coil responsive to a logical AND of the first logical signal, the second logical signal and the third logical signal.

An arc flash detection apparatus for an electrical system comprising a first power bus, a second power bus, a third power bus, a first circuit interrupter electrically connected between the first power bus and the second power bus, a second circuit interrupter electrically connected between the second power bus and the third power bus, and at least one of:

• (a) a shorting apparatus operatively associated with the second power bus, and (b) the first circuit interrupter comprising a trip coil, the arc flash detection apparatus comprising:
• a first current sensor structured to sense a fault current of at least a predetermined magnitude flowing in the second power bus and responsively output a first logical signal;
• a number of light sensors structured to sense an arc flash operatively associated with a number of the second power bus and the third power bus and responsively output a second logical signal;
• a second current sensor structured to sense a fault current of at least a predetermined magnitude flowing in the third power bus and responsively output a third logical signal;
• and
• a circuit structured to delay and invert the third logical signal to provide a fourth logical signal, and to operate the at least one of the shorting apparatus and the trip coil responsive to a logical AND of the first logical signal, the second logical signal and the fourth logical signal.