Abstract: A system, method, and apparatus for power transmission fault zone detection. Each phase of a three-phase current in the power system is monitored, a modal component is determined from the three-phase current, high frequency transients in the modal component are extracted using wavelet packet transformation, and a travelling wave front is detected in the modal component indicating the fault. A wave sign is determined and the signs of two travelling waves are logically combined to determine whether or not the fault is within a protected zone.

Abstract: A method and algorithm are disclosed that can be used to determine if an electrical fault exists within a protection zone defined as in the area between specific current transformers. (CTs). Currents from CTs are brought into a microprocessor (or other device) that converts the analog currents into digital quantities. The current quantities are summed both vectorially and arithmetically by the microprocessor. The mathematical derivative of the vector and the arithmetic sums are compared in order to determine if an electrical fault exists within the protection zone. An electrical trip signal is generated by the microprocessor if the fault is deemed to be in the protection zone.

Abstract: A method and device for detecting damaging sub-harmonic frequencies in a power system, and recording data or initiating protective action. A microprocessor based sub-harmonic protection relay (S-PRO) monitors system voltages and currents from voltage and current transformers on the power system that may be present in the 5 Hz to 25 Hz frequency window. The user of S-PRO has full programming control to select bandwidths of frequencies or specific frequency components of the collected system voltages and currents. S-PRO can be user programmed to either detect the sub-harmonic power quantities and record them for future use in simulations or to initiate protective action. Protective action may include initiating output contact closure on the device to shut down equipment or to initiate corrective actions to prevent damage.

Abstract: A method of electrical fault determination using the phase angle information of all the currents entering and leaving a protection zone, to determine whether a fault, if any, is internal or external to the protection zone.

Abstract: In a line protection unit for monitoring fault conditions of an electrical power line and actuating breakers to disconnect the line from a power supply bus, the supply bus is in the ring bus arrangement including a first bus and an auxiliary bus so that each power line includes first and second breakers. The three phase current in the line is monitored at both the breakers and summed in the unit to allow calculation of the fault conditions based upon the total current in the line. In the event of a fault condition, both breakers are tripped. In the event of breaker failure so that current continues to flow, this is detected in the unit and all the first breakers tripped to prevent the faulty breaker from allowing current to flow to the faulty line.

Abstract: In a line protection unit for monitoring fault conditions of an electrical power line and actuating breakers to disconnect the line from a power supply bus, the supply bus is in the ring bus arrangement including a first bus and an auxiliary bus so that each power line includes fist and second breakers. The three phase current in the line is monitored at both the breakers and summed in the unit to allow calculation of the fault conditions based upon the total current in the line. In the event of a fault condition, both breakers are tripped. In the event of breaker failure so that current continues to flow, this is detected in the unit and all the first breakers tripped to prevent the faulty breaker from allowing current to flow to the faulty line.

Abstract: In a three phase bus protection unit for monitoring fault conditions of an electrical power bus and actuating breakers to disconnect the associated power supply and feeder lines from the bus, there is provided for each line a current sensor responsive to the three phase currents passing through the respective breaker and the unit includes a plurality of current input terminals and a voltage input terminal for receiving the voltage output of a voltage sensor on the bus. A processor element in the unit generates digital data indicative of the instantaneous values of the voltage and of the currents and effects pre-determined algorithmic calculations on the digital values of the voltage and the currents to determine a presence of a fault condition in the current through any one of the breakers. In addition a processor element acts to sum the digital values of the currents to determine that sum of currents flowing into the bus and the sum of currents flowing.

Abstract: A monitoring system for an electrical power transmission network or grid provides a recording network that can capture data on the response of the electrical power system over a wide geographical area to de-stabilizing electrical events. The captured data is obtained from multiple recording locations provided by individual recording units storing data on voltage and current on respective power transmission lines of the network. When an event is detected by one of the units, the central station interrogates the other units to obtain data based upon the same time as determined by a GPS clock at each unit and is thus automatically time-synchronized so that an overall coordinated snapshot of the power system dynamics is achieved. The wide-area capture is achieved through standard non-dedicated Internet, Intranet, and/or switched telephone network communication links.