Power distribution system and electrical switching apparatus employing a filter trap circuit to provide arc fault trip coordination

An arc fault circuit interrupter comprising:

• a first terminal;
• a second terminal;
• separable contacts electrically connected between said first terminal and said second terminal;
• an operating mechanism structured to open and close said separable contacts;
• an arc fault trip circuit cooperating with said operating mechanism, said arc fault trip circuit being structured to trip open said separable contacts responsive to an arc fault condition;
• an inductor electrically connected in series between said first terminal and said second terminal;
• a first capacitor including a first lead electrically connected between said inductor and said second terminal, and a second lead electrically connected to a ground or neutral conductor;
• and
• a second capacitor including a first lead electrically connected between said first terminal and said inductor, and a second lead electrically connected to said ground or neutral conductor,
• wherein said inductor and said first capacitor are structured to cooperate with a power circuit impedance downstream of said second terminal to form a first filter trap circuit, and
• wherein said inductor and said second capacitor are structured to cooperate with a power circuit impedance upstream of said first terminal to form a second filter trap circuit.

An arc fault circuit interrupter comprising:

• a first terminal;
• a second terminal;
• separable contacts electrically connected between said first terminal and said second terminal;
• an operating mechanism structured to open and close said separable contacts;
• an arc fault trip circuit cooperating with said operating mechanism, said arc fault trip circuit being structured to trip open said separable contacts responsive to an arc fault condition;
• an inductor electrically connected in series between said first terminal and said second terminal;
• a variable capacitance including a first lead electrically connected or electrically connectable between said inductor and said second terminal, and a second lead electrically connected to a ground or neutral conductor;
• and
• a self-adapting circuit structured to vary said variable capacitance,
• wherein said inductor and said variable capacitance are structured to cooperate with a power circuit impedance downstream of said second terminal to form a filter trap circuit having a center frequency, and
• wherein said self-adapting circuit is further structured to change the center frequency of said filter trap circuit, in order to adapt to changes in a power circuit downstream of said second terminal.

A power distribution system comprising:

• a plurality of different zones;
• and
• a plurality of different arc fault circuit interrupters, a number of said plurality of different arc fault circuit interrupters being in each of said different zones,
• wherein each of a plurality of said plurality of different arc fault circuit interrupters comprises:
• a first terminal,
• a second terminal,
• separable contacts electrically connected between said first terminal and said second terminal,
• an operating mechanism structured to open and close said separable contacts,
• an arc fault trip circuit cooperating with said operating mechanism, said arc fault trip circuit being structured to trip open said separable contacts responsive to an arc fault condition,
• an inductor electrically connected in series between said first terminal and said second terminal, and
• a capacitor including a first lead electrically connected between said inductor and said second terminal, and a second lead electrically connected to a ground or neutral conductor,
• wherein said inductor and said capacitor are structured to cooperate with a power circuit impedance downstream of said second terminal to form a filter trap circuit.

A detection apparatus comprising:

• a first terminal;
• a second terminal;
• an arc fault detector circuit structured to detect an arc fault condition;
• an inductor electrically connected in series between said first terminal and said second terminal;
• and
• a capacitor including a first lead electrically connected to said inductor and said second terminal, and a second lead electrically connected to a ground or neutral conductor,
• wherein said inductor and said capacitor are structured to cooperate with a power circuit impedance downstream of said second terminal to form a filter trap circuit.