Comparison of impedance based fault location methods for power distribution systems

A smart grid for improving the management of a power utility grid is provided. The smart grid as presently disclosed includes using sensors in various portions of the power utility grid, using communications and computing technology, such as additional bus structures, to upgrade an electric power grid so that it can operate more efficiently and reliably and support additional services to consumers. The smart grid may include distributed intelligence in the power utility grid (separate from the control center intelligence) including devices that generate data in different sections of the grid, analyze the generated data, and automatically modify the operation of a section of the power grid.

Method and system for managing a power grid

A system, device, and method of providing information for a power distribution system is provided. In one embodiment, a method of using a device that receives power from the low voltage power of the power distribution system and experiences a power loss during a local power outage may perform the processes of monitoring a voltage of the low voltage power line, detecting a voltage reduction below a threshold voltage for a predetermined time period, storing information of the voltage reduction in a non-volatile memory prior to the power outage, and transmitting a notification to a remote computer system prior to the outage. The monitoring may comprise making a plurality of measurements of the voltage during a time interval and averaging the plurality of voltage measurements. In addition, the method may include transmitting an alert message upon power up after the outage to indicate a power restoration local to the device.

Method and apparatus for communicating power distribution event and location

High impedance fault detection: A review

The present invention is directed to an electrical wiring inspection system. The system includes an electrical measurement apparatus having at least one load center connector configured to couple the electrical measurement apparatus to a load center, at least one branch circuit connective device configured to couple the electrical measurement apparatus to a portion of a branch circuit, and at least one electrical measurement circuit disposed between the at least one load center connector and the at least one branch circuit connective device. The at least one electrical measurement circuit is configured to perform a series of electrical test procedures to obtain a plurality of electrical parameters. A portable computing device (PCD) includes processing circuitry, a user interface coupled to the processing circuitry, and at least one communications interface configured to couple the portable computing device to the electrical measurement apparatus. The processing circuitry is configured to direct the at least one electrical measurement circuit via the at least one communications interface to perform the series of electrical test procedures in response to an input from the user interface.

Automated electrical wiring inspection system

Electric power systems will always be exposed to the failure of their components. When a fault occurs on a line, it is crucial for the fault location to be identified as accurately as possible, allowing the damage caused by the fault to be repaired quickly before the line is put back into service. Fault Location on Power Lines enables readers to pinpoint the location of a fault on power lines following a disturbance. If a fault location cannot be identified quickly and this causes prolonged line outage during a period of peak load, severe economic losses may occur and reliability of service may be questioned. The growth in size and complexity of power systems has increased the impact of failure to locate a fault and therefore heightened the importance of fault location research studies, attracting widespread attention among researchers in recent years. Fault location cannot be truly understood, applied, set, tested and analysed without a deep and detailed knowledge of the interiors of fault locators. Consequently, the nine chapters are organised according to the design of different locators. The authors do not simply refer the reader to manufacturers documentation, but instead have compiled detailed information to allow for in-depth comparison. Fault Location on Power Lines describes basic algorithms used in fault locators, focusing on fault location on overhead transmission lines, but also covering fault location in distribution networks. An application of artificial intelligence in this field is also presented, to help the reader to understand all aspects of fault location on overhead lines, including both the design and application standpoints. Professional engineers, researchers, and postgraduate and undergraduate students will find Fault Location on Power Lines a valuable resource, which enables them to reproduce complete algorithms of digital fault locators in their basic forms.

Fault Location on Power Networks

A method for locating a fault in a two-terminal power transmission or distribution line comprises the steps of receiving measurements of the three phase currents from both terminals, receiving measurements of the three phase voltages from one line terminal, receiving parameters of the line and receiving the fault type. Based on this information the distance to fault from the one terminal where the phase voltages were measured is determined and output. Since only the phase voltages of one line terminal are needed, the functionality of a device, in particular a current 15 differential relay, can be expanded to determine the distance to fault in an off-line mode.

Method and device for fault location in a two-terminal transmission or distribution power line

The present invention relates to a method for location of a fault which has occurred on one of a plurality of lines in a power distribution network where the location is performed with the said of measured values of the common supply voltage of the said plurality of lines and the currents of the said plurality of lines after the occurrence of a fault; calculating the equivalent positive-sequence impedance Z~ and zero--sequence impedance Z~ of the network in a pre-fault steady state for all M nodes based on knowledge of the configuration and topology of the network, and obtaining, via a superordinate protection system, which of said plurality of lines has become faulty and which type of fault has occurred. The invention is characterised by calculating the equivalent impedance Z ek using fault loop calculation depending on the fault type as (see formula I) where (see formula II), (see formula III) and: V ph - voltage at the faulty phase, Z 1 f - positive-sequence fault-loop impedance obtained from measurements, I p, I pN - adequately: fault- loop and residual currents obtained from measurements, and checking if Im(Z ek)>= 0, k = 1,2,..M wherein, upon being fulfilled, the distance to fault is chosen.

Method and device of fault location for distribution networks

A method to locate a fault from one end of a section of a power line (A-B). Measurements of current, voltage and angles between the phases are made at a first A end of a said power line section. Upon detection of a fault condition between said first end and a second end of said power line, distance to the fault is found by calculating symmetrical components of currents for said current and voltage measure at said first end, then calculating a distance d from said first end 2 to the fault F the distance d to the fault using a quadratic equation.A value for source impedance at the first and/or second end used in the method may be a representative value or a measured value. The invention may be applied to a single line or parallel lines. In other aspects of the invention a fault locator device for carrying out the method and a computer program for carrying out the method are described.

Fault location using measurements of current and voltage from one end of a line

A method and an adaptive distance protection relay for compensating for a remote line end infeed effect during determination of a distance (d) to a resistive fault on a three- phase power transmission line are presented. It is assumed that a fault current (IF) flows through the fault resistance (RF). A fault loop impedance (Zrelay) is first calculated by a known algorithm from phase voltages (Vph1, Vph2, Vph3) and phase currents (Iph1, Iph2, Iph3). Then a shift of the fault loop impedance (ΔZ) is determined from the fault loop impedance (Zrelay), the impedance of the transmission line for the positive current sequence (Z1L) and the phase angle (ϒ) of a complex fault current distribution factor (kF), where the fault current distribution factor (kF) is the ratio of the fault loop current (Irelay) to the fault current (IF). Finally, the distance to fault (d) is calculated by subtracting the impedance shift (ΔZ) from the fault loop impedance (Zrelay) and dividing the result by the impedance of the transmission line for the positive current sequence (Z1L).

Murari Saha

Papers

Fault Location on Power Networks

Method and device for fault location in a two-terminal transmission or distribution power line

Method and device of fault location for distribution networks

Fault location using measurements of current and voltage from one end of a line

Method and adaptive distance protection relay for power transmission lines