Abstract: A protection relay is disclosed that generates a trip signal to operate a circuit breaker in case of a fault condition. A first module provides measurement and analysis of power parameters of the power line connecting the power equipment that is being protected, the protection being provided by generating a first trip signal for operating a circuit breaker connected in the power line. One or more second modules can boost performance of the protection relay by measurement and analysis of power parameters-to generate a second trip signal for operating a circuit breaker connected in the power line. The first trip signal and the second trip signal are logically combined to generate a trip signal that operates the circuit breaker.

Abstract: An interface is disclosed for a self powered protection relay that uses mechanical switches for its configuration. The protection relay can include a base relay for measurement of line current and for generation of a trip signal, and a Human Machine Interface (HMI) unit for specifying, by a user, a base setting of an operating parameter of the protection relay. The base relay can be self-powered from the line and the HMI unit can include an auxiliary power supply. The protection relay is configured with mechanical switches provided in the protection relay. The HMI unit in the protection relay is designed to detect and alert the user of the relay of any change in the base setting carried out with one or more mechanical switches provided in the relay in powered and unpowered conditions of the base relay.

Abstract: A method of determining a fault direction parameter of a fault on an AC transmission line of a power distribution system relative to a measurement location of the transmission line. The method includes measuring a time-dependent AC current of the transmission line at the measurement location to obtain time-domain current data indicative of the measured current, obtaining a time of the fault on the transmission line, identifying first and second times by identifying a periodically re-occurring feature of the current data, such that the fault time is between the first and second times, extracting, from the current data, an offset indicative parameter indicative of a time offset of the current at the fault time and between the first and second times, calculating an offset direction parameter by comparing the offset indicative parameter to a non-offset indicative parameter, and establishing the fault direction parameter based on the offset direction parameter.

Abstract: A protection feature is disclosed for a self powered protection relay having, for example, sensitive earth fault protection. Protection can be achieved in tandem with optimal power on trip time and with integrated logic for inrush discrimination. The self supplied protection relay can include a current processing module to measure and evaluate line current to generate a trip signal, and to suppress inrush current to block earth fault detection during an inrush condition and thereby increase sensitivity of fault detection.

Abstract: A method of determining a fault parameter of a fault on an AC transmission line 10 of a power distribution system 1 relative to a measurement location 12 of the transmission line 10 comprising: measuring a time-dependent current of the transmission line 10 at the measurement location 12; transmitting a current signal indicative of the measured current to a decision logic section 36, the current signal comprising a plurality of pre-fault current values and a plurality of post-fault current values; determining, by the decision logic section 36, a plurality of phase difference values indicative of respective phase differences between respective pre-fault current values and respective post-fault current values; accumulating the plurality of phase difference values into an accumulated phase difference parameter; obtaining the fault parameter by comparing the accumulated phase difference parameter to a threshold value; and outputting the determined fault parameter.

Abstract: A protection relay is disclosed that generates a trip signal to operate a circuit breaker in case of a fault condition. A first module provides measurement and analysis of power parameters of the power line connecting the power equipment that is being protected, the protection being provided by generating a first trip signal for operating a circuit breaker connected in the power line. One or more second modules can boost performance of the protection relay by measurement and analysis of power parameters-to generate a second trip signal for operating a circuit breaker connected in the power line. The first trip signal and the second trip signal are logically combined to generate a trip signal that operates the circuit breaker.

Abstract: A protection feature is disclosed for a self powered protection relay having, for example, sensitive earth fault protection. Protection can be achieved in tandem with optimal power on trip time and with integrated logic for inrush discrimination. The self supplied protection relay can include a current processing module to measure and evaluate line current to generate a trip signal, and to suppress inrush current to block earth fault detection during an inrush condition and thereby increase sensitivity of fault detection.