Method for identifying a fault event in an electric power distribution grid sector

A non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to:

• acquire, for each electric phase, first data values indicative of a grid current, said first data values being acquired at subsequent sampling instants subdivided in a sequence of time windows;
• process a first portion of said first data values acquired, for each electric phase, at first sampling instants at least partially included in a time window and a second portion of said first data values acquired, for each electric phase, at second sampling instants preceding said first sampling instants and at least partially included in a previous time window preceding said time window to check whether said grid current, at said time window, is subject to an anomalous variation with respect to said previous time window;
• if it is determined that said grid current is not subject to an anomalous variation with respect to said previous time window, repeat said processing said first portion of said first data values for subsequent sampling instants;
• if it is determined that said grid current, starting from an event instant of said time window, is subject to an anomalous variation with respect to said previous time window, process a third portion of one or more of said first data values acquired, for each electric phase, at sampling instants following said event instant to calculate, for each electric phase, second data values indicative of the anomalous variation of said grid current;
• process said second data values calculated for each electric phase to check whether the anomalous variation of said grid current is due to a characteristic transitional operating period of an electric load of a grid sector of a main grid;
• process said second data values calculated for each electric phase to calculate third data values indicative of the anomalous variation of said grid current;
• for each electric load, select second reference data values indicative of a predicted current absorbed by said electric load during a characteristic transitional operating period of said electric load;
• for each electric load, process said third data values and said second reference data values to calculate an error value indicative of a difference between the anomalous variation of said grid current and the predicted current absorbed by said electric load during said characteristic transitional operating period;
• select a minimum error value among the error values calculated for said electric loads;
• compare said minimum error value with a second threshold value;
• repeat the previous steps for a second number of sampling instants following said event instant;
• and
• check whether said minimum error value exceeds said second threshold value for said second number of sampling instants.

A computerized device for operating a switching device comprising:

• a processor;
• and
• a memory device including instructions configured to be executable by the processor effective to:
• acquire, for each electric phase, first data values indicative of a grid current, said first data values being acquired at subsequent sampling instants subdivided in a sequence of time windows;
• process a first portion of said first data values acquired, for each electric phase, at first sampling instants at least partially included in a time window and a second portion of said first data values acquired, for each electric phase, at second sampling instants preceding said first sampling instants and at least partially included in a previous time window preceding said time window to check whether said grid current, at said time window, is subject to an anomalous variation with respect to said previous time window;
• if it is determined that said grid current is not subject to an anomalous variation with respect to said previous time window, repeat said processing said first portion of said first data values for subsequent sampling instants;
• if it is determined that said grid current, starting from an event instant of said time window, is subject to an anomalous variation with respect to said previous time window, process a third portion of one or more of said first data values acquired, for each electric phase, at sampling instants following said event instant to calculate, for each electric phase, second data values indicative of the anomalous variation of said grid current;
• process said second data values calculated for each electric phase to check whether the anomalous variation of said grid current is due to a characteristic transitional operating period of an electric load of a grid sector of a main grid;
• process said second data values calculated for each electric phase to calculate third data values indicative of the anomalous variation of said grid current;
• for each electric load, select second reference data values indicative of a predicted current absorbed by said electric load during a characteristic transitional operating period of said electric load;
• for each electric load, process said third data values and said second reference data values to calculate an error value indicative of a difference between the anomalous variation of said grid current and the predicted current absorbed by said electric load during said characteristic transitional operating period;
• select a minimum error value among the error values calculated for said electric loads;
• compare said minimum error value with a second threshold value;
• repeat the previous steps for a second number of sampling instants following said event instant;
• and
• check whether said minimum error value exceeds said second threshold value for said second number of sampling instants.

An electronic protection system comprising:

• a switching device;
• a processor;
• and
• a memory device including instructions configured to be executable by the processor effective to:
• acquire, for each electric phase, first data values indicative of a grid current, said first data values being acquired at subsequent sampling instants subdivided in a sequence of time windows;
• process a first portion of said first data values acquired, for each electric phase, at first sampling instants at least partially included in a time window and a second portion of said first data values acquired, for each electric phase, at second sampling instants preceding said first sampling instants and at least partially included in a previous time window preceding said time window to check whether said grid current, at said time window, is subject to an anomalous variation with respect to said previous time window;
• if it is determined that said grid current is not subject to an anomalous variation with respect to said previous time window, repeat said processing said first portion of said first data values for subsequent sampling instants;
• if it is determined that said grid current, starting from an event instant of said time window, is subject to an anomalous variation with respect to said previous time window, process a third portion of one or more of said first data values acquired, for each electric phase, at sampling instants following said event instant to calculate, for each electric phase, second data values indicative of the anomalous variation of said grid current;
• process said second data values calculated for each electric phase to check whether the anomalous variation of said grid current is due to a characteristic transitional operating period of an electric load of a grid sector of a main grid;
• process said second data values calculated for each electric phase to calculate third data values indicative of the anomalous variation of said grid current;
• for each electric load, select second reference data values indicative of a predicted current absorbed by said electric load during a characteristic transitional operating period of said electric load;
• for each electric load, process said third data values and said second reference data values to calculate an error value indicative of a difference between the anomalous variation of said grid current and the predicted current absorbed by said electric load during said characteristic transitional operating period;
• select a minimum error value among the error values calculated for said electric loads;
• compare said minimum error value with a second threshold value;
• repeat the previous steps for a second number of sampling instants following said event instant;
• and
• check whether said minimum error value exceeds said second threshold value for said second number of sampling instants.