Abb Research Ltd.

Abb Schweiz Ag

Hitachi Energy Switzerland Ag

Abb Power Grids Switzerland Ag

Abb Ab

Abb Technology Ag

Hitachi Energy Ltd

Jianping Wang

Kai Liu

YouYi Li

Reynaldo Nuqui

Zoran Gajic

Youyi Li

Jiuping Pan

Mustafa Ibrahim

Bertil Berggren

Kerstin Linden

Juiping Pan

Amit Purohit

Zhao Wang

Bernhard Deck

Tord Bengtsson

Pedro Rodriguez

Obbalareddi Demudu Naidu

Bin Su

Sachin Srivastava

Od Naidu

Antonis Marinopoulos

Ying Yang

Kailash Srivastava

Vinay Kariwala

Gabriel Olguin

Arkadiusz Burek

Lei Jing

Zhanpeng Shi

Qianjin Liu

Aken-Kai Liu

Naidu Obbalareddi Demudu

Zoran Gaijc

Mikael G&ouml;ransson

Mikael Goransson

Jianzhong Fan

Liwei Wang

Fabian Hohn

Hussain Albinali

There is provided mechanisms for differential protection of a transmission line () of a transmission system (). A method comprises obtaining a restraining current and a differential current from the transmission line (S). The method comprises determining a compensation current for the differential current (S). The method comprises providing the differential current as compensated for by the compensation current and the restraining current to a differential protection arrangement for making a trip decision (S). The method comprises detecting an internal fault for the transmission system (S). The method comprises, as a result thereof, providing the differential current without being compensated for by the compensation current and the restraining current to the differential protection arrangement for making the trip decision (S).

Differential protection of a transmission line

A method of determining a fault in a protected zone of a power line comprises obtaining measurements at a measurement point at one end of the power line, processing the measurements in a number of parallel processing branches comprising at least two parallel processing branches, wherein the processing in each branch comprises filtering the measurements in a corresponding low pass filter for obtaining a corresponding set of filtered measurements, wherein the cut-off frequencies of the low pass filters in these parallel processing branches differ from each other, performing reach calculations on the filtered measurements for obtaining corresponding reach point quantities, and comparing the reach point quantities with corresponding thresholds. Finally, it is determined that there is a fault within the protected zone if any threshold is crossed.

Determining of a power line fault

A method, system and apparatus of fault detection in line protection for a power transmission system. A voltage (u) at a measurement point on an electrical line is obtained. The measurement point is a point at which a protection device for the line protection is installed. A current (i) at the measurement point is further obtained and a differential value of the current is determined. Then, a voltage (u) at a setting point on the electrical line is determined from the voltage (u) at the measurement point, the current (i) at the measurement point and the differential value of the current (i) according to a time domain lumped parameter model for the electrical line. The voltage change between the determined voltage at the setting point during the fault period and a voltage at the setting point determined during a pre-fault period can be further determined. The fault detection can be performed based on the determined voltage change and a fault threshold. It can ensure voltage determination accuracy and detection reliability with a low sampling rate. Moreover, the solution can work right after the fault inception, almost no waiting time is required, and thus it may achieve a super-fast line protection.

Method, system and apparatus for fault detection in line protection for power transmission system

A method for detecting fault in a power transmission line of a power transmission system and protection system using the same. The method includes: obtaining a system parameter of the power transmission system, adjusting protection reachability of a fault detecting element based on the obtained system parameter such that the adjusted protection reachability of the fault detecting element is applicable to a predetermined protection range, identifying whether there is an internal fault occurring on the transmission line using the adjusted fault detecting element, and generating a fault detection decision signal indicating the identified fault. If the predetermined protection range is desirable for the fault detecting element, its protection reachability may be adjusted in consideration of the influence imposed by the SIR such that the reach point of the adjusted fault detecting element can be extended to approach the end of the predetermined protection range. Consequently, the influence on its accuracy by various SIR values can be taken into account and accordingly the fault detecting solution can remove substantial errors as a result thereof.

Method for detecting fault in power transmission line and protection system using the same

An arrangement and method for zero sequence differential protection of a transmission line of a power system are disclosed. A zero sequence differential protection unit is configured to detect an internal fault of the transmission line using current measurements of each phase A, B, C of the transmission line. The zero sequence differential protection unit is configured to initiate a trip when an internal fault is detected. A phase selection unit is configured to determine whether or not any of the phases A, B, C of the transmission line is faulty using a comparison of differential values of the current measurements for each phase. The phase selection unit is configured to, based on the initiation of the trip, determine which of the phases A, B, C is faulty and to finalize the trip for any faulty phase.

Zero sequence current based line differential protection solution

A method can be used for fault detection of a transmission. The method includes obtaining instantaneous measurements of local voltages and local currents of the transmission line, obtaining filtered measurements of the local voltages and local currents by subjecting the measurements of the local voltages and local currents to low pass filtering, obtaining a compensated voltage calculated by subjecting the filtered measurements to a differential equation based algorithm, and performing fault detection by forming a ratio between the compensated voltage and the a reference voltage. An internal fault is determined when the ratio is below a threshold and an external fault is determined when ratio is larger than above the threshold.

Time domain distance protection based on polarity comparison for power transmission lines

A method can be used for phase selection using multi-terminal measurements of a transmission line of a power system. The method includes obtaining, using measurements from a plurality of terminals of the transmission line, delta differential current values &#x394;I(t), &#x394;I(t), &#x394;I(t), at time t, between pre-fault differential current measurements and post-fault differential current measurements from all three phases (A, B, C) of the transmission line. The method also includes determining at least one of the phases to be faulty when the absolute value of the corresponding delta differential current value is larger than k times the minimum of all the absolute values I&#x394;I(t)|, |&#x394;I(t)|, |&#x394;I(t)| of the delta differential current values, where k&#x3e;1 is a scale factor.

High sensitive phase selection method

A mechanism for travelling wave pilot protection of a transmission line and method for receiving indications of a travelling wave from two terminals of a transmission line, wherein two terminals are time synchronized. The method includes making a trip decision based on the indications using a short trip window. An arrangement is configured to perform the disclosed method.

Travelling wave pilot protection of a transmission line based on time synchronization

A method for detecting fault direction of a transmission line of an AC power system and a control system using the same. The method includes sampling current values and voltage values at one end of the transmission line for a series of time points; computing instantaneous voltage values at compensated point on the transmission line from the current value samples and the voltage value samples based on a time domain lumped parameter differential equation for the transmission line for the series of time points; recording the current value samples and the computed instantaneous voltage values at the compensated point; computing at least one voltage fault component each using the recorded computed instantaneous voltage values for at least the at least two of the series of time points; identifying the fault direction in consideration of the at least one computed voltage fault component and the at least one computed current fault component; and generating a fault direction signal indicating the identified fault direction. Where a fault directional element is designed using the voltage fault components at the compensated point, it will work well for the AC power system with strong power source.

Method and control system for fault direction detection

A method and system is provided for locating a fault in a mixed power transmission line. The method is implemented by an Intelligent Electronic Device (IED) of the mixed line. The IED detects a travelling wave from one or more signals received from one or more measurement equipment. Thereafter, the IED identifies a line section with the fault, and generates two or more estimates for the location of the fault based on a time difference between arrival of two peaks of the travelling wave, a velocity of propagation of the travelling wave in the line section identified with the fault, and a length of one or more line sections. The IED determines the location of the fault based on a comparison of each estimate with a threshold, wherein the threshold is estimated based on the one or more signals, equivalent source impedance of each source and total line impedance.

Method and system for locating a fault in a mixed power transmission line

A method, control system and protective relay are provided for detecting faulted phases of transmission lines in an AC power system. The method includes sampling electric signals at one end of the transmission lines at a series of time points; computing instantaneous voltage values of electric signals at compensated points on the transmission lines from the values of the sampled electric signals based on a time domain lumped parameter differential equation for the transmission lines for the series of time points; recording the computed instantaneous voltage values of the electric signals; computing fault component or sudden-change of the instantaneous voltage values of the electrical signals; detecting the faulted phases or fault types by comparing the calculated fault component of the instantaneous voltage values at the preset compensated points; and generating signals indicating the faulted phases of fault types.

Method and control system for faulted phase detection

There is provided mechanisms for travelling wave protection of a transmission line. A method includes performing high-pass filtering of a current and/or voltage measurement of a transmission line so as to detect fault-caused high-frequency components of the current and/or voltage measurement. The method includes providing a result of the high-pass filtering as input to a trip decision maker performing travelling wave detection.

Travelling wave protection of a transmission line based on high-pass filtering

An objective of the application is to provide a method for detecting a disturbance in a power system within a digital substation and an apparatus using the same. The method includes: sensing electrical parameters at an end of a transmission line; sampling the sensed electrical parameters; extracting traveling-wave information from high frequency component of the samples using a signal processing method; and if the extracted traveling-wave information indicating occurrence of the disturbance, transmitting the extracted traveling-wave information to an intelligent electronic device of the digital substation from a merging unit or non-conventional instrument transformer of the digital substation. As compared with the amount of the sample data of the sensed electrical parameters, the amount of the data representing the extracted traveling-wave information is reduced. Thus the extracted traveling-wave information can be transmitted via a data link with a relatively narrow bandwidth, such as the process bus under standard IEC 61850.

Method and apparatus for detection of power system disturbance within a digital substation

A method is provided for protection in a mixed power transmission line by controlling a switching device connected thereto through an Intelligent Electronic Device (IED). The mixed line has two or more sections with at least one overhead section (A) and at least one underground section (B), wherein every two consecutive sections are connected at a junction (C). The method is implemented by the IED (), which receives a signal from a measurement equipment. The IED detects a travelling wave from the signal, and determines a first peak of the travelling wave and at least one a peak width, a rise time and a discharge time of the first peak. The IED identifies the section with the fault based on a comparison of at least one of the peak width, the rise time and the discharge time with a corresponding threshold value of each junction, and controls the switching device based on the comparison.

Method for protection in a mixed power transmission line

There is provided mechanisms for detecting a fault of a transmission line () in a power system () comprising at least one of an extreme weak system () and an extreme strong system (). A method comprises obtaining travelling wave polarities from two terminals () of the transmission line during occurrence of the fault, the travelling wave polarities being defined by two current polarities and two voltage polarities. The method comprises determining the obtained travelling wave polarities to be detectable and the obtained travelling wave polarities to be non-detectable. The method comprises detecting the fault to be internal based on the detectable travelling wave polarities and the non-detectable travelling wave polarities. There is also provided an arrangement configured to perform such a method.

Fault detection of a transmission line

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Västerås, Sweden

Jianping Wang