Lateral fault isolation

A method for isolating a fault in a power distribution network, the network including a power line, a recloser coupled to the power line and a plurality of switching devices coupled to the power line downstream of the recloser, each switching device being capable of detecting fault current in response to the fault and detecting presence of voltage, the method comprising:

• detecting overcurrent in the network from the fault by the recloser and all of the switching devices positioned along a fault path between the recloser and the fault;
• interrupting the overcurrent by opening the recloser;
• detecting loss of voltage and/or absence of current when the recloser opens by the switching devices along the fault path;
• recording a fault count by each switching device that detected overcurrent and then the loss of voltage and/or the absence of current;
• opening each switching device that recorded a predetermined number of fault counts;
• closing the recloser;
• closing a first switching device downstream of the recloser after a predetermined closing time period when the recloser closes;
• closing a next switching device downstream of the first switching device after the predetermined closing time period when the first switching device closes;
• and
• sequentially closing next switching devices along the fault path until a switching device immediately upstream of the fault closes and detects overcurrent from the fault, where that switching device remains open.

A method for isolating a fault in a power distribution network, the network including a power line, a recloser coupled to the power line and a plurality of switching devices coupled to the power line downstream of the recloser, each switching device being capable of detecting fault current in response to the fault and detecting presence of voltage, the method comprising:

• detecting overcurrent in the network from the fault by the recloser and all of the switching devices positioned along a fault path between the recloser and the fault;
• interrupting the overcurrent by opening the recloser;
• detecting loss of voltage and/or absence of current when the recloser opens by the switching devices along the fault path;
• recording a fault count by each switching device that detected overcurrent and then the loss of voltage and/or the absence of current;
• opening each switching device that recorded a predetermined number of fault counts;
• closing the recloser;
• closing a first switching device downstream of the recloser after a predetermined closing time period when the recloser closes;
• closing a next switching device downstream of the first switching device after the predetermined closing time period when the first switching device closes;
• sequentially closing next switching devices along the fault path until a switching device immediately upstream of the fault closes and causes overcurrent on the fault path;
• interrupting the overcurrent again by opening the recloser;
• opening the switching device immediately upstream of the fault;
• and
• again closing the recloser.