Described herein are methods and systems for detecting electrical discharges that precede electrical fires in electrical wiring. One or more sensor devices coupled to a circuit detect one or more signal waveforms generated by electrical activity on the circuit. The sensor devices identify one or more transient signals within the one or more signal waveforms, and generate one or more transient characteristics based upon the identified transient signals. A server communicably coupled to the sensor devices receives the one or more transient characteristics. The server analyzes the one or more transient characteristics to identify one or more electrical discharge indications. The server generates one or more alert signals when one or more electrical discharge indications are identified.

Aspects of the subject disclosure may include, for example, a waveguide system for determining an event associated with a mode of transmitting or receiving electromagnetic waves on a surface of a transmission medium, identifying according to the event an updated mode for transmitting or receiving adjusted electromagnetic waves on the surface of a transmission medium, and transmitting or receiving the adjusted electromagnetic waves based on the updated mode. Other embodiments are disclosed.

Disclosed herein is a system for time aligning electric power system measurements at an intelligent electronic device (IED) using samples and sample time offset from merging units. The merging units do not require access to a common time signal. The IED does not require storage of a communication latency with the merging units. The sample time offset corresponds to a latency between obtaining the sample and receipt of the sample at the IED. The IED aligns samples from various merging units using sample time offset values communicated from the merging units to the IED. The IED performs monitoring and protection functions using the time aligned samples.

The present invention related to the field of power system protection and control, presents a voltage travelling wave differential protection method considering the influence of frequency-dependent parameters, which provides more accurate and rapid fault identification. The technical scheme of the present invention is as follows: a calculation method of voltage travelling-wave differential protection for VSC-HVDC transmission lines, taking the influence of the frequency-dependent parameters into consideration, the steps are as follows: calculating a characteristic impedance and propagation coefficient of the frequency-dependent transmission line in time domain, collecting voltage and current signals at the both ends of the transmission line and then calculating the forward and backward voltage travelling wave, respectively, comparing a differential value of voltage travelling wave with a preset threshold value to determine whether the internal fault occurs. The present invention is mainly applied in the field of power system protection and control.

Systems and methods may mitigate risk of fire caused by an electric power system. In one embodiment, a system may include an intelligent electronic device (IED). The IED includes a communication subsystem to receive a signal from a sensor related to a condition of the electric conductor. A processing subsystem in communication with the communication subsystem may operate in at least two modes comprising a high security mode and a fire prevention mode. In the fire prevention mode, the IED may interrupt a flow of electric current based on the signal from the at least one sensor associated with the electric conductor. In the high security mode, the system may interrupt a flow of electric current based on the signal from the at least one sensor associated with the electric conductor and based on a second condition relating to the electric conductor.

The invention relates to protection from faults in a power transmission system having two or more transmission lines. Travelling waves are detected from a signal obtained with a measurement equipment associated with a bus of the power transmission system. Arrival times of a first peak of a first travelling wave, a second travelling wave and a third travelling wave, are detected from the signal. A value for line length is calculated from the arrival times and propagation velocity of the travelling wave in the corresponding transmission line. The calculated value is compared with an actual length of the corresponding transmission line, for determining if the fault is an internal fault or an external fault. According to the fault being one of the internal fault and the external fault, a signal for controlling a switching device associated with the corresponding transmission line is generated.

A method can be used to determine a fault location in a power transmission line that connects a first terminal with a second terminal. Parameters associated with travelling waves are detected from measurements carried out at the first and second terminals. The parameters include arrival times of first and second peaks of the travelling waves at the first and second terminals respectively, and rise times of the first peaks of corresponding travelling waves. A first half, a second half, or a mid-point of the power transmission line is identified as having a fault based on the parameters. The fault location can be estimated based on the arrival times of the first and second peaks of the travelling waves detected from measurements carried out at the first and second terminals, a velocity of propagation of the travelling wave in the power transmission line, and/or a length of the power transmission line.

There is disclosed a method for identifying one or more faulted conductors in a power transmission system having at least two power-transmitting conductors and a method for determining fault location. Both methods include steps of monitoring current signals which are representative of currents in the conductors at a generally common location within the power transmission system; filtering the current signals; determining a maximum rate of change of each filtered current signal within a predetermined time interval after the fault event has commenced; and calculating a ratio of a pair of the maximum rates of change of the filtered current signals. For fault classification, the ratio is compared against a discrimination factor to identify the one or more faulted conductors. For fault location, the calculated ratio is compared against the calibration data to determine the distance from the connection terminal of the faulted conductor to the fault location.

In a line to line fault detection and protection system, a source end power supply supplies power to a remote load over a transmission line and monitors the dynamic behavior of a transmission line power characteristic. If that dynamic behavior is outside a constraint that is actively imposed on the transmission line dynamic behavior by a load end power conditioning system, a possible line to line fault is recognized. The preferred power characteristic is current and the preferred constraint is a maximum rate of change of current drawn from the transmission line by the load end power conditioning system.

A material medium, such as an optical fiber or electrical cable, is used to carry services. The material medium is monitored with at least one diagnostic sensor. The diagnostic sensor may measure the operational health of the material medium, or may measure local environmental conditions around the material medium.